Mineral fulvic acid(MFA)was used as an eco-friendly pyrite depressant to recover chalcopyrite by flotation with the use of the butyl xanthate as a collector.Flotation experiments showed that MFA produced a stronger in...Mineral fulvic acid(MFA)was used as an eco-friendly pyrite depressant to recover chalcopyrite by flotation with the use of the butyl xanthate as a collector.Flotation experiments showed that MFA produced a stronger inhibition effect on pyrite than on chalcopyrite.The separation of chalcopyrite from pyrite was realized by introducing 150 mg/L MFA at a pulp pH of approximately 8.0.The copper grade,copper recovery,and separation efficiency were 28.03%,84.79%,and 71.66%,respectively.Surface adsorption tests,zeta potential determinations,and localized electrochemical impedance spectroscopy tests showed that more MFA adsorbed on pyrite than on chalcopyrite,which weakened the subsequent interactions between pyrite and the collector.Atomic force microscope imaging further confirmed the adsorption of MFA on pyrite,and X-ray photoelectron spectroscopy results indicated that hydrophilic Fe-based species on the pyrite surfaces increased after exposure of pyrite to MFA,thereby decreasing the floatability of pyrite.展开更多
In this study,synthetic wastewater containing 110μg/L arsenate(As(V)),0-20 mg/L fulvic acid(FA),and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+.The mechanisms of FA and phosphate effects on As(V)removal by fer...In this study,synthetic wastewater containing 110μg/L arsenate(As(V)),0-20 mg/L fulvic acid(FA),and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+.The mechanisms of FA and phosphate effects on As(V)removal by ferric chloride were determined using 0.22-10μm pore-size filtration,Zetasizer analysis,and in situ flow through cell ATR-FTIR.The results showed that up to 20mg/L FA had almost no effect on the solubility of ferric hydroxide precipitates and adsorption of As(V)by the precipitates.When FA concentration increased from 0 to 20 mg/L,the adsorption of FA led to higher negative zeta potential of the precipitates and the strong electrostatic repulsion between the precipitates decreased the particle size of ferric hydroxide flocs fromlarger than 10μmto smaller than 1μm.In the presence of 5-20 mg/L FA,46%-63%As(V)was adsorbed onto the flocs with particle size in the range of 0.45-1μm.On the other hand,phosphate did not affect the size of ferric hydroxide flocs and significantly increased the dissolved As(V)concentration because it competed with As(V)for adsorption sites on ferric hydroxide precipitates.The addition of 5mg/L cationic organic flocculant significantly reduced the effect of FA on As(V)removal,but did not reduce the effect of phosphate on As(V)removal.The findings of this study will help develop effective arsenic treatment techniques and predict the mobility of arsenic in the environment.展开更多
Increasing soil phosphorus(P)availability and plant P uptake are potential approaches to alleviate low P stress in plants and mitigate P resource shortages.Application of fulvic acid(FA)in soil is observed to increase...Increasing soil phosphorus(P)availability and plant P uptake are potential approaches to alleviate low P stress in plants and mitigate P resource shortages.Application of fulvic acid(FA)in soil is observed to increase plant growth and P uptake.However,the biological mechanisms underlying these effects remain largely unknown.In this study,based on a three-year field experiment,multi-omics analyses were performed to reveal the effects of FA on rice growth and P uptake,the expression of P transporter genes,root exudates,and rhizosphere bacterial communities in a P-deficient soil.The results showed that FA application significantly promoted rice growth and P absorption under P deficiency,in association with the upregulation of P transporter genes expression and increased rhizosphere P mobilization.FA increased the transformation of non-labile to labile P in the rhizosphere by increasing the secretion of Pdissolving exudates and changing a rhizosphere bacterial community with high P-mobilization capacity,and the variations in the rhizosphere bacterial community were coupled with those of the root exudates,especially glutamylproline,tryptophanamide,5-chloro-2′-deoxyuridine,L-menthyl(R,S)-3-hydroxybutyrate,and 2,7-diamino-7-iminoheptanoic acid.These findings reveal the multiple positive effects of FA on rice P uptake and indicate the potential utilization of FA in increasing P utilization in rice production.展开更多
This study employed multispectral techniques to evaluate fulvic acid(FA)compositional characteristic and elucidate its biodegradation mechanisms during partial nitritation(PN)process.Results showed that FA removal eff...This study employed multispectral techniques to evaluate fulvic acid(FA)compositional characteristic and elucidate its biodegradation mechanisms during partial nitritation(PN)process.Results showed that FA removal efficiency(FRE)decreased from 90.22 to 23.11%when FA concentrations in the reactor were increased from 0 to 162.30 mg/L,and that molecular size,degree of aromatization and humification of the effluent FA macromolecules all increased after treatment.Microbial population analysis indicated that the proliferation of the Comamonas,OLB12 and Thauera exhibit high FA utilization capacity in lower concentrations(<50.59 mg/L),promoting the degradation and removal of macromolecular FA.In addition,the sustained increase in external FA may decrease the abundance of above functional microorganisms,resulting in a rapid drop in FRE.Furthermore,from the genetic perspective,the elevated FA levels restricted carbohydrate(ko00620,ko00010 and ko00020)and nitrogen(HAO,AMO,NIR and NOR)metabolism-related pathways,thereby impeding FA removal and total nitrogen loss associated with N_(2)O emissions.展开更多
Using the Widdel medium with extracted microcystin(MC)as the sole carbon and nitrogen sources,the MC-degrading bacteria community S_6 was enriched from the sediment of Litopenaeus vannamei pond,and a novel MC-degradin...Using the Widdel medium with extracted microcystin(MC)as the sole carbon and nitrogen sources,the MC-degrading bacteria community S_6 was enriched from the sediment of Litopenaeus vannamei pond,and a novel MC-degrading bacteria strain was isolated from S_6.According to 16S rDNA gene sequence and biochemical characteristics,the isolated strain was identified and named Nitratireductor aquimarinus D_(1).Fulvic acid(FA),as a widely existing photosensitizer involved in MC photodegradation,coexists with MC-degrading bacteria in natural water.The synergistic effects of N.aquimarinus D_(1) and FA on MC degradation were evaluated via comparing the degradation rate of MC induced by N.aquimarinus D_(1) and FA alone and in combination under natural light conditions.Compared with the control group,the supplementation of N.aquimarinus D_(1) and FA alone or in combination could significantly increase the degradation rate of MC(P<0.05).In the first 36 h,the degradation effect of FA on MC was better than that of N.aquimarinus D_(1),but the degradation effect was opposite at 48 h.N.aquimarinus D_(1) and FA did not show synergistic effect on MC degradation until 48 h.In the application of N.aquimarinus and FA to degrade MC in aquaculture pond,there might be a time-lag effect in the synergistic degradation.展开更多
ObjectiveThis study aimed to investigate the effect of fulvic acid on the growth and yield components of direct seeding rice （Nanjing 44）. MethodThe rice seeds were soaked in 0 （water as a control）, 1, 2, 4 and 6 ...ObjectiveThis study aimed to investigate the effect of fulvic acid on the growth and yield components of direct seeding rice （Nanjing 44）. MethodThe rice seeds were soaked in 0 （water as a control）, 1, 2, 4 and 6 g/L fulvic acid （FA） before sowed. Then, the rice morphological indices, leaf chlorophyll content, photosynthesis parameters, root activity and chlorophyll fluorescence parameters were measured in the following field studies. ResultCompared with the control, the leaf area index, chlorophyll content, net photosynthetic rate, stomatal conductance and dry matter weight and some fluorescence parameters such as the maximum photochemical efficiency of photosystem II （PSII） （Fv/Fm）, excitation energy capture efficiency of opened PSII reaction center （Fv’/Fm’） and efficiency of the open reaction centre （ΦPS II） increased by different levels at both jointing stage and heading stage of direct seeding rice, whose seeds were soaked by FA with different concentrations. High FA concentration （4-6 g/L） significantly increased the cultivated rice leaf area index, chlorophyll content, net photosynthetic rate, stomatal conductance, transpiration rate and dry matter weight by 10.32% -22.88% , 5.88% -13.11% , 12.16% -26.84% , 11.43% -88.46% , 10.63% -21.63% , 18.49% -19.68% , respectively, thereby improving the physiological function and light energy transform efficiency of rice at the growth stage. With FA concentration increasing, the yield, effective panicles, grain number per panicle and seed setting rate were increased significantly compared with the control by 17.52%-18.71%, 3.46%-3.85%, 6.30%- 6.51% and 7.82%-8.69% respectively. ConclusionSoaking rice seed with FA could be considered as an effective way to improve the rice competitiveness at early growth stage.展开更多
[Objective] The aim was to evaluate the feasibility of biotechnology fulvic acid produced by microbial community LCM9 by the use of corn straws as substrate and its application effect.[Method]Microbial community was o...[Objective] The aim was to evaluate the feasibility of biotechnology fulvic acid produced by microbial community LCM9 by the use of corn straws as substrate and its application effect.[Method]Microbial community was obtained from the nature samples,and corn straws were used as fermentation substrate.The yield of biotechnology fulvic acid and its application effect was evaluated.[Result]The yield of biotechnology fulvic acid was up to 15.7% when the water content was 75.0% and fermented after 7 d using corn straws as the only source of nutrition.After 500 mg/kg of biotechnology fulvic acid was added for 5 d,the root length and bud length could be increased by 59.1% and 97.1%,respectively.[Conclusion]A higher yield of biotechnology fulvic acid could be obtained by the method in this experiment and the product could enhance the growth of wheat seedlings.展开更多
[Objective] This study aimed to investigate the effects of soaking cultivated rice seeds with fulvic acid （FA） on physiological and ecological properties of weedy rice in the direct seeding cultivated rice field. [M...[Objective] This study aimed to investigate the effects of soaking cultivated rice seeds with fulvic acid （FA） on physiological and ecological properties of weedy rice in the direct seeding cultivated rice field. [Method] Weedy rice JS-Y1 and culti-vated rice Nanjing 44 were used as experimental materials for field plot trials to an-alyze the effects of soaking cultivated rice seeds with 0 （water as control）, 4, 6, 8 g/L FA on til ering dynamics, plant height, chlorophyl content, photosynthetic perfor-mance, gas exchange parameters and yield components of weedy rice at different growth stages. [Result] Among the 4 plants/m2 weedy rice plots, with the increase of FA concentration, til er number, plant height, chlorophyl content, net photosynthetic rate （Pn）, stomatal conductance （Gs） and transpiration rate （Tr） of weedy rice were reduced. Under the 4-6 g/L FA concentration, til er numbers of weedy rice at differ-ent growth stages were reduced by 13.84%-35.71% compared with control at the same density and the most significant reduction was on the 22nd d after weedy rice germination; chlorophyl contents of weedy rice at the jointing stage were significant-ly reduced by 7.90%-8.88%. Furthermore, in the plots with 4 g/L FA, weedy rice plant heights at the heading stage and grain fil ing stage were significantly reduced by 6.37%-9.10%; Pn, Gs and Tr of weedy rice at the jointing stage and grain fil ing stage were significantly reduced by 10.19%-16.05%, 12.57%-23.33% and 10.28%-19.76%, respectively; 1 000-grain weight, effective panicle number per plant and panicles weight per plant of weedy rice at the maturity stage were significantly re-duced by 3.19%, 21.21% and 27.27%, correspondingly. [Conclusion] In 4 plants/m2 weedy rice plots, because soaking cultivated rice seeds with 4 g/L FA could regu-late the growth and development of cultivated rice, the soaking with FA could change the ecological relationship between cultivated rice and weedy rice, affect weedy rice physiological and ecological properties and al eviate the competitive inhi-bition of weedy rice on cultivated rice.展开更多
[Objective] This study was to investigate the effects of fulvic acid on agronomic traits and yield of autumn potato. [Method] The effects of fulvic acid on growth period, plant morphology, tuber, net photosynthetic ra...[Objective] This study was to investigate the effects of fulvic acid on agronomic traits and yield of autumn potato. [Method] The effects of fulvic acid on growth period, plant morphology, tuber, net photosynthetic rate, chlorophyll content, leaf area index （LAI） and yield of autumn potato were investigated. [Result] The application of fulvic acid prolonged the growth period and increased the plant height, stem diameter, leaf chlorophyll content, LAI, net photosynthetic rate, tuber number per plant, tuber weight per plant and marketable tuber rate of autumn potato, thus increasing the yield. Applying fulvic acid prolonged the growth period of autumn potato by 1-3 d and significantly increased the plant height, net photosynthetic rate, tuber weight per plant and yield of autumn potato （P〈0.05, P〈0.01）. When the application amount of compound fertilizer was reduced by half, applying fulvic acid almost showed the same seedling emergence stage, mature stage, growth period and net photosynthetic rate with applying full amount of compound fertilizer. In particular, no significant difference was found in the yield of autumn potato between fullamount and half-amount compound fertilizer treatment groups in the premise of solid- liquid fulvic acid combined application. [Conclusion] In the premise of unchanged yield, applying fulvic acid can reduce the application of chemical fertilizers and reduce the non-point source pollution of chemical fertilizers.展开更多
This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species...This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species investigated in the experiments included inorganic mononuclear, organic mononuclear, mononuclear, polymer, soluble, and suspended forms. It was found that the effects of fulvic acid and humic acid on aluminum speciation depended mainly on their molecular weight. Fulvic acid with molecular weight less than 5000 Dalton had little influence on aluminum speciation; while fulvic acid with molecular weight larger than 5000 Dalton and humic acid would increase the concentration of soluble aluminum significantly even at concentration below 0.5 mg/L （calculated as TOC）. Aluminum species, in the present of fulvic acid with molecular weight larger than 5000 Dalton and humic acid, were more stable than that in the present of fluvic acid with molecular mass less than 5000 Dalton, and varied little with reaction time. Within pH range 6.5-7.5, soluble aluminum increased notably in water with organic matter. As the concentration of residual chlorine increased, the effects of fulvic acid and humic acid became weak. The reactions between humic acid, fulvic acid with large molecular weight, and aluminum were considered to be a multi-dentate coordination process. With the consideration of aluminum bioavailability, reducing the concentration of fulvic acid and humic acid and keeping the pH value among 6.5-7.5 were recommended during drinking water treatment.展开更多
A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natur...A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natural water bodies,and its influence mechanism was proposed.A TiO_2 nanotube arrays(TNAs) material is served as the photoanode.Methanol,ethanediol,and glycerol were chosen as the representative of LMHCs in this study.The adsorption performance of organics on the surface of TNAs was investigated by using the instantaneous photocurrent value.The adsorption constants of FA,methanol,ethanediol,and glycerol were 43.44,19.32,7.00,and 1.30,respectively,which indicates that FA has the strongest adsorption property.The degradation performance of these organics and their mixture were observed in a thin-layer reactor.It shows that FA could hardly achieve exhausted mineralization alone,while LMHCs could be easily oxidized completely in the same condition.The degradation degree of FA,which is added LMHCs,improves significantly and the best promotion effect is achieved by glycerol.The promotion effect of LMHCs in the degradation of FA could be contributed to the formation of a tremendous amount of hydroxyl radicals in the NPEC process.The hydroxyl radicals could facilitate the complete degradation of both FA and its intermediate products.Among the chosen LMHCs,glycerol molecule which has three hydroxyls could generate the most hydroxyl radicals and contribute the best effective promotion.This work provides a new way to promote the NPEC degradation of FA and a direction to remove humus from polluted water.展开更多
The long-term impact of fulvic acid(FA)on partial nitritation(PN)systemwas initially examined in this study.The obtained results revealed that the FA lower than 50 mg/L had negligible effect on the nitrite accumulatio...The long-term impact of fulvic acid(FA)on partial nitritation(PN)systemwas initially examined in this study.The obtained results revealed that the FA lower than 50 mg/L had negligible effect on the nitrite accumulation rate(NAR nearly 100%)and ammonium removal rate(ARR 56.85%),while FA over 50 mg/L decreased ARR from 56.85%to 0.7%.Sludge characteristics analysis found that appropriate FA(<50 mg/L)exposure promoted the settling performance and granulation of PN sludge by removing Bacteroidetes and accumulating Chloroflexi.The analysis of metagenomics suggested that the presence of limited FA(0-50 mg/L)stimulated the generation of NADH,which favors the denitrification and nitrite reduction.The negative impact of FA on the PN system could be divided into two stages.Initially,limited FA(50-120 mg/L)was decomposed by Anaerolineae to stimulate the growth and propagation of heterotrophic bacteria(Thauera).Increasing heterotrophs competed with AOB(Nitrosomonas)for dissolved oxygen,causing AOB to be eliminated and ARR to declined.Subsequently,when FA dosage was over 120 mg/L,Anaerolineae were inhibited and heterotrophic bacteria reduced,resulting in the abundance of AOB recovered.Nevertheless,the ammonium transformation pathway was suppressed because genes amoABC and hao were obviously reduced,leading to the deterioration of reactor performance.Overall,these results provide theoretical guidance for the practical application of PN for the treatment of FA-containing sewage.展开更多
A surfactant modified zeolite（ SMZ）, i. e. , a zeolite modified by using hexadecyl trimethyl ammonium bromide （HDTMA） was used to remove fulvic acids（FA） from aqueous solution. The effects of the relevant parame...A surfactant modified zeolite（ SMZ）, i. e. , a zeolite modified by using hexadecyl trimethyl ammonium bromide （HDTMA） was used to remove fulvic acids（FA） from aqueous solution. The effects of the relevant parameters, such as the loading level of HDTMA, the contact time, the initial FA concentration, the pH, and the types of the metal carious and organics were examined. The results show that SMZ with an HDTMA loading-level of 120% of the external cation exchange capacity（ECEC） of zeolite exhibits the best performance. Although the removal of fulvic acids by SMZ occurs rapidly within the first 30 min of the contact time, a contact time of at least 4 h is required to attain the adsorption equilibrium. The removal capacity of FA by SMZ decreases with the increase of the initial FA concentration. The pH has an effect on the FA removal efficiency because it can influence the characteristics of the FA molecules. The removal of FA is considerably enhanced by Ca^2＋ or Mg^2＋ ions and is adversely affected by phenol or pentachlorophenol（PCP）. Under the optimum conditions, 98% of FA could be removed by SMZ. Furthermore, the desorption of FA and the regeneration of SMZ were studied. The results show that a 30% ethanol solution is sufficient for the regeneration of SMZ.展开更多
The degradation of fulvic acid（FA） by nanoparticle TiO2 in a submerged membrane photocatalysis（SMPC） reactor was studied. In this reactor, photocatalytic oxidation and membrane separation co-occured. The continuou...The degradation of fulvic acid（FA） by nanoparticle TiO2 in a submerged membrane photocatalysis（SMPC） reactor was studied. In this reactor, photocatalytic oxidation and membrane separation co-occured. The continuous air supplier provided O2 for the photocatalytical reaction and mixed the solution through an airflow controller. The particle TiO2 could automatically settle due to gravity without particle agglomeration so it could be easily separated by microfiltration（MF） membrane. It was efficient to maintain high flux of membranes. The effects of operational parameters on the photocatalytic oxidation rate of FA were investigated. Results indicated that photocatalyst at 0.5 g/L and airflow at 0.06 m^3/h were the optimum condition for the removal of fulvic acid, the removal efficiency was higher in acid media than that in alkaline media. The effects of different filtration duration on permeate flux rate of MF with P25 powder and with nanoparticle TiO2 were compared. Experimental results indicated that the permeate flux rate of MF was improved and the membrane fouling phenomenon was reduced with the addition of nanoparticle TiO2 catalyst compared with conventional P25 powder. Therefore, this submerged membrane photocatalysis reactor can faciliate potential application of photocatalytic oxidation process in drinking water treatment.展开更多
Fulvic acids extracted from a typical rice-production region near Taihu Lake of China were fractionated into three fractions including F4.8, F7.0 and F11.0 （eluted by pH 4.8 buffer, pH 7.0 buffer and pH 11.0 buffer, ...Fulvic acids extracted from a typical rice-production region near Taihu Lake of China were fractionated into three fractions including F4.8, F7.0 and F11.0 （eluted by pH 4.8 buffer, pH 7.0 buffer and pH 11.0 buffer, respectively）. Sorption of fulvic acid （FA） fractions onto kaolinite was studied by batch adsorption experiments, and characterizations of kaolinite before and after adsorption were investigated using scanning electron microscopy （SEM）. Adsorption isotherms of kaolinite for three FA fractions fit well with the Langrnuir adsorption model. The adsorption density of the three fractions was positively correlated with the ratio of the amount of the alkyl carbon to that of carboxyl and carbonyl carbon in FA fractions and followed an order of F11.0 〉 F7.0 〉 F4.8. Hydrophobic interaction was one of the control mechanisms for the sorption of FA fraction onto kaolinite. SEM images confirmed that compared to blank kaolinite samples, kaolinite samples coated by a FA fraction displayed an opener and more dispersed conformation resulting from the disruption of the floc structure in complex. Dispersion of kaolinite after adsorption was due to the repulsion between negatively charged FA-coated particles, which is closely related to the amount of FA fractions absorbed on kaolinite.展开更多
Humus is often used as an organic modifier to reduce the bioaccumulation of heavy metals in plants, but the effects of different humus components from different sources on the fate of mercury(Hg) in paddy fields are s...Humus is often used as an organic modifier to reduce the bioaccumulation of heavy metals in plants, but the effects of different humus components from different sources on the fate of mercury(Hg) in paddy fields are still unclear. Here, fulvic acid(FA) and humic acid(HA) extracted from composted straw(CS), composted cow dung(CCD), peat soil(PM) and lignite coal(LC) were used to understand their effects on the methylation and bioaccumulation of Hg in paddy soil by pot experiments. Amendments of both FA and HA largely increased the abundance of Hg-methylating microbes and low-molecular-weight organic matters(e.g, cysteine) in paddy soil. They were also found to change the aromaticity, molecular size and Chromophoric DOM concentration of DOM, and resulted in heterogeneous effects on migration and transformation of Hg. All the FA-amended treatments increased the mobility and methylation of Hg in soil and its absorption in roots. Nevertheless, FA from different sources have heterogeneous effects on transport of Hg between rice tissues. FA-CCD and FA-PM promoted the translocation of Me Hg from roots to rice grains by 32.95% and 41.12%, while FA-CS and FA-LC significantly inhibited the translocation of inorganic Hg(IHg) by 52.65% and 66.06% and of Me Hg by 46.65% and 36.23%, respectively. In contrast, all HA-amended treatments reduced the mobility of soil Hg, but promoted Hg methylation in soil. Among which, HA-CCD and HA-PM promoted the translocation of Me Hg in rice tissues by 88.95% and 64.10%, while its accumulation in rice grains by 28.43% and 28.69%, respectively. In general, the application of some FA and HA as organic modifiers to reduce Hg bioaccumulation in rice is not feasible.展开更多
Knowledge of different effects of various organic materials on soil humic substance is important for both environmental safety and sustainable agriculture.A pot experiment was conducted at Jilin Agricultural Universit...Knowledge of different effects of various organic materials on soil humic substance is important for both environmental safety and sustainable agriculture.A pot experiment was conducted at Jilin Agricultural University,Jilin Province in northeast China to discover the influence of herb residue,animal excrement,woody residue,animal remnant on fulvic acid（FA） composition and structure using differential thermal analysis-thermogravimetric（DTA-TG）,fourier transform infrared spectroscopy（FTIR） and elemental analysis.DTA-TG showed the range of peak temperature in the first exothermic reaction increased following the trend： CK〉herb residue〉animal excrement〉woody residue=animal remnant,and the most weight loss was observed in animal excrement.Moreover,the second exothermic reaction of CK-and animal excrement-FA was presented as double peaks,the order of weight loss in that area was animal remnant〉CK〉woody residue〉animal excrement〉herb residue.According to FTIR,herb residue displayed higher adsorption intensity at 2 950,1 420,1 240 and 1 030 cm-1,animal excrement was in reverse.At the same time,herb residue-and animal excrement-FA had an absorption peak at 1 720 cm-1,while other organic materials didn＇t have this peak.As elemental analysis showed,FA isolated from various treatments was significantly distinct.It was clearly shown from our results that FA composition and structure in amended soils may be affected in different ways and at various extents on dependence of the nature and origin of amendment.展开更多
The formation constants of Co￣(2+), Ni￣(2+), Cu￣(2+) and Zn￣(2+) complexes with humic acid (HA) and fulvicacid (FA) in red soil were determined by the potentiometric titration method. The constants as a functionof...The formation constants of Co￣(2+), Ni￣(2+), Cu￣(2+) and Zn￣(2+) complexes with humic acid (HA) and fulvicacid (FA) in red soil were determined by the potentiometric titration method. The constants as a functionof composition of the complexation solutions were obtained by two graphical approaches respectively Theformation constants decreased with increasing concentration of metal in the solution. The results provideunambiguous evidence for the heterogeneity of the function groups of humic substances. The formationconstants of FA were much smaller than those of HA, and the formation constants of Cu￣(2+) were muchgreater than those of Co￣(2+) , Ni￣(2+) and Zn￣(2+) . The potentiometric titration method for determining formationconstants are also discussed in the article.展开更多
The acid-base buffer characteristics of fulvic acid (FA) and barium fulvate (BaFA)were analyzed. Each share of the sample or model agents (phthalic acid and salicylic acid)were separately mixed into a series of shares...The acid-base buffer characteristics of fulvic acid (FA) and barium fulvate (BaFA)were analyzed. Each share of the sample or model agents (phthalic acid and salicylic acid)were separately mixed into a series of shares of dilute solutions of HCI or NaOH with a series of concentration. The original pH values of the solutions were arranged from 2 to 13.Final balanced pH of each share was measured. The pH changes show that FA and BaFApossess buffer ability, whereas the model agents do not. The tendency of balanced pHvalues was 5.4 for FA and 7.4 for BaFA, whereas the original pH was 4.0-8.5; balancedpH changed little. At room temperature, the maximum buffer capacities were as follows:18.11 mmol hydroxyl per gram FA, 11.25 mmol hydroxyl per gram BaFA, 1.19 mmol protonper gram FA, and 1.45 mmol proton per gram BaFA. Mathematics analysis shows thatlogarithm of buffer capacities of FA and BaFA is linearly dependent on original pH. Compared with BaFA and model agents, it is concluded that FA buffer capacity against hydroxylrelies not only on its acidic groups, BaFA buffer capacity against hydroxyl does not rely onits acidic groups, and FA buffer capacity against proton is not related with its carboxyl andphenolic hydroxyl group. The pH values of FA-water solutions with different concentrationsfrom 1 to 10 grams per liter were measured. Their pH values were slightly affected by itsconcentration. Thus, FA possesses a much stronger buffer ability against water dilutionthan common buffer agent. All the pH values of FA water solutions were very nearby 5.4,just the same as the balanced pH tendency for adding FA.展开更多
[Objective]The paper was to clarify the application of biochemical fulvic acid potassium on the survival rate and growth of various trees transplanted in the process of landscaping.[Method]Two experimental treatments(...[Objective]The paper was to clarify the application of biochemical fulvic acid potassium on the survival rate and growth of various trees transplanted in the process of landscaping.[Method]Two experimental treatments(i.e.decomposed organic fertilizer+biochemical fulvic acid potassium water soluble fertilizer,decomposed organic fertilizer+compound fertilizer)were designed to determine the changes in physical and chemical properties before and after soil treatment,and the survival rate,plant height and ground diameter of four different cultivated plants within one year,and the effects of applying biochemical fulvic acid potassium on cultivated plants were investigated.[Result]The soil organic matter,total nitrogen,alkali-hydrolyzable nitrogen,soil available phosphorus,soil available potassium and p H value in the soil treated with decomposed organic fertilizer+biochemical fulvic acid potassium soluble fertilizer,and decomposed organic fertilizer+compound fertilizer increased significantly,and the soil bulk density decreased obviously.The survival rates,plant heights and ground diameters of four different cultivated plants were significantly improved after application of decomposed organic fertilizer+biochemical fulvic acid potassium water soluble fertilizer,and decomposed organic fer-tilizer+compound fertilizer(P<0.05).[Conclusion]The application of biochemical fulvic acid potassium on cultivated plants effectively improved soil fertility,increased the utilization of nitrogen,phosphorus and potassium,improved the growth of plants,and promoted the growth of landscaping plants after transplantation.展开更多
基金supported by Fundamental Research Projects of Yunnan Province,China(Nos.202101BE070001-009,202301AU070189).
文摘Mineral fulvic acid(MFA)was used as an eco-friendly pyrite depressant to recover chalcopyrite by flotation with the use of the butyl xanthate as a collector.Flotation experiments showed that MFA produced a stronger inhibition effect on pyrite than on chalcopyrite.The separation of chalcopyrite from pyrite was realized by introducing 150 mg/L MFA at a pulp pH of approximately 8.0.The copper grade,copper recovery,and separation efficiency were 28.03%,84.79%,and 71.66%,respectively.Surface adsorption tests,zeta potential determinations,and localized electrochemical impedance spectroscopy tests showed that more MFA adsorbed on pyrite than on chalcopyrite,which weakened the subsequent interactions between pyrite and the collector.Atomic force microscope imaging further confirmed the adsorption of MFA on pyrite,and X-ray photoelectron spectroscopy results indicated that hydrophilic Fe-based species on the pyrite surfaces increased after exposure of pyrite to MFA,thereby decreasing the floatability of pyrite.
基金financially supported by the New Jersey Department of Environmental ProtectionUS EPA。
文摘In this study,synthetic wastewater containing 110μg/L arsenate(As(V)),0-20 mg/L fulvic acid(FA),and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+.The mechanisms of FA and phosphate effects on As(V)removal by ferric chloride were determined using 0.22-10μm pore-size filtration,Zetasizer analysis,and in situ flow through cell ATR-FTIR.The results showed that up to 20mg/L FA had almost no effect on the solubility of ferric hydroxide precipitates and adsorption of As(V)by the precipitates.When FA concentration increased from 0 to 20 mg/L,the adsorption of FA led to higher negative zeta potential of the precipitates and the strong electrostatic repulsion between the precipitates decreased the particle size of ferric hydroxide flocs fromlarger than 10μmto smaller than 1μm.In the presence of 5-20 mg/L FA,46%-63%As(V)was adsorbed onto the flocs with particle size in the range of 0.45-1μm.On the other hand,phosphate did not affect the size of ferric hydroxide flocs and significantly increased the dissolved As(V)concentration because it competed with As(V)for adsorption sites on ferric hydroxide precipitates.The addition of 5mg/L cationic organic flocculant significantly reduced the effect of FA on As(V)removal,but did not reduce the effect of phosphate on As(V)removal.The findings of this study will help develop effective arsenic treatment techniques and predict the mobility of arsenic in the environment.
基金supported by the Higher Education Scientific Research Project of the Anhui Province(Natural Sciences)(2023AH051039)Anhui Provincial Natural Resources Science and Technology Project(2023-K-4)+1 种基金the National Key Research&Development Program of China(2023YFD1902300)Anhui Provincial Natural Science Foundation(2108085QC123).
文摘Increasing soil phosphorus(P)availability and plant P uptake are potential approaches to alleviate low P stress in plants and mitigate P resource shortages.Application of fulvic acid(FA)in soil is observed to increase plant growth and P uptake.However,the biological mechanisms underlying these effects remain largely unknown.In this study,based on a three-year field experiment,multi-omics analyses were performed to reveal the effects of FA on rice growth and P uptake,the expression of P transporter genes,root exudates,and rhizosphere bacterial communities in a P-deficient soil.The results showed that FA application significantly promoted rice growth and P absorption under P deficiency,in association with the upregulation of P transporter genes expression and increased rhizosphere P mobilization.FA increased the transformation of non-labile to labile P in the rhizosphere by increasing the secretion of Pdissolving exudates and changing a rhizosphere bacterial community with high P-mobilization capacity,and the variations in the rhizosphere bacterial community were coupled with those of the root exudates,especially glutamylproline,tryptophanamide,5-chloro-2′-deoxyuridine,L-menthyl(R,S)-3-hydroxybutyrate,and 2,7-diamino-7-iminoheptanoic acid.These findings reveal the multiple positive effects of FA on rice P uptake and indicate the potential utilization of FA in increasing P utilization in rice production.
基金supported by the Key Research and Development Project of Shandong (Nos.2021CXGC011202,2020CXGC011404,and 2022CXGC021002)the National Natural Science Foundation of China (No.22276006)。
文摘This study employed multispectral techniques to evaluate fulvic acid(FA)compositional characteristic and elucidate its biodegradation mechanisms during partial nitritation(PN)process.Results showed that FA removal efficiency(FRE)decreased from 90.22 to 23.11%when FA concentrations in the reactor were increased from 0 to 162.30 mg/L,and that molecular size,degree of aromatization and humification of the effluent FA macromolecules all increased after treatment.Microbial population analysis indicated that the proliferation of the Comamonas,OLB12 and Thauera exhibit high FA utilization capacity in lower concentrations(<50.59 mg/L),promoting the degradation and removal of macromolecular FA.In addition,the sustained increase in external FA may decrease the abundance of above functional microorganisms,resulting in a rapid drop in FRE.Furthermore,from the genetic perspective,the elevated FA levels restricted carbohydrate(ko00620,ko00010 and ko00020)and nitrogen(HAO,AMO,NIR and NOR)metabolism-related pathways,thereby impeding FA removal and total nitrogen loss associated with N_(2)O emissions.
基金Supported by the National Natural Science Foundation of China(Nos.32172978,31772857)the Natural Science Foundation of Tianjin(No.22JCYBJC00430)+2 种基金the Tianjin Science and Technology Planning Project(No.22ZYCGSN00050)the Fundamental Research Funds of Tianjin Universities(Nos.2020ZD06,2021KJ110)the Gansu Science and Technology Project(Nos.21CX6NP223,2023ZZ1NC006)。
文摘Using the Widdel medium with extracted microcystin(MC)as the sole carbon and nitrogen sources,the MC-degrading bacteria community S_6 was enriched from the sediment of Litopenaeus vannamei pond,and a novel MC-degrading bacteria strain was isolated from S_6.According to 16S rDNA gene sequence and biochemical characteristics,the isolated strain was identified and named Nitratireductor aquimarinus D_(1).Fulvic acid(FA),as a widely existing photosensitizer involved in MC photodegradation,coexists with MC-degrading bacteria in natural water.The synergistic effects of N.aquimarinus D_(1) and FA on MC degradation were evaluated via comparing the degradation rate of MC induced by N.aquimarinus D_(1) and FA alone and in combination under natural light conditions.Compared with the control group,the supplementation of N.aquimarinus D_(1) and FA alone or in combination could significantly increase the degradation rate of MC(P<0.05).In the first 36 h,the degradation effect of FA on MC was better than that of N.aquimarinus D_(1),but the degradation effect was opposite at 48 h.N.aquimarinus D_(1) and FA did not show synergistic effect on MC degradation until 48 h.In the application of N.aquimarinus and FA to degrade MC in aquaculture pond,there might be a time-lag effect in the synergistic degradation.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201303022)National Key Technology Research and Development Program during the 12th Five-Year Plan Period(2012BAD19B02)~~
文摘ObjectiveThis study aimed to investigate the effect of fulvic acid on the growth and yield components of direct seeding rice （Nanjing 44）. MethodThe rice seeds were soaked in 0 （water as a control）, 1, 2, 4 and 6 g/L fulvic acid （FA） before sowed. Then, the rice morphological indices, leaf chlorophyll content, photosynthesis parameters, root activity and chlorophyll fluorescence parameters were measured in the following field studies. ResultCompared with the control, the leaf area index, chlorophyll content, net photosynthetic rate, stomatal conductance and dry matter weight and some fluorescence parameters such as the maximum photochemical efficiency of photosystem II （PSII） （Fv/Fm）, excitation energy capture efficiency of opened PSII reaction center （Fv’/Fm’） and efficiency of the open reaction centre （ΦPS II） increased by different levels at both jointing stage and heading stage of direct seeding rice, whose seeds were soaked by FA with different concentrations. High FA concentration （4-6 g/L） significantly increased the cultivated rice leaf area index, chlorophyll content, net photosynthetic rate, stomatal conductance, transpiration rate and dry matter weight by 10.32% -22.88% , 5.88% -13.11% , 12.16% -26.84% , 11.43% -88.46% , 10.63% -21.63% , 18.49% -19.68% , respectively, thereby improving the physiological function and light energy transform efficiency of rice at the growth stage. With FA concentration increasing, the yield, effective panicles, grain number per panicle and seed setting rate were increased significantly compared with the control by 17.52%-18.71%, 3.46%-3.85%, 6.30%- 6.51% and 7.82%-8.69% respectively. ConclusionSoaking rice seed with FA could be considered as an effective way to improve the rice competitiveness at early growth stage.
基金Supported by Doctor Research Fund of Liaocheng University~~
文摘[Objective] The aim was to evaluate the feasibility of biotechnology fulvic acid produced by microbial community LCM9 by the use of corn straws as substrate and its application effect.[Method]Microbial community was obtained from the nature samples,and corn straws were used as fermentation substrate.The yield of biotechnology fulvic acid and its application effect was evaluated.[Result]The yield of biotechnology fulvic acid was up to 15.7% when the water content was 75.0% and fermented after 7 d using corn straws as the only source of nutrition.After 500 mg/kg of biotechnology fulvic acid was added for 5 d,the root length and bud length could be increased by 59.1% and 97.1%,respectively.[Conclusion]A higher yield of biotechnology fulvic acid could be obtained by the method in this experiment and the product could enhance the growth of wheat seedlings.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201303022)National "Twelfth Five-year" Plan for Science & Technology Support Development Program of China(2012BAD19B02)Key Programs for Science and Technology Development of Anhui Province(1301032001)~~
文摘[Objective] This study aimed to investigate the effects of soaking cultivated rice seeds with fulvic acid （FA） on physiological and ecological properties of weedy rice in the direct seeding cultivated rice field. [Method] Weedy rice JS-Y1 and culti-vated rice Nanjing 44 were used as experimental materials for field plot trials to an-alyze the effects of soaking cultivated rice seeds with 0 （water as control）, 4, 6, 8 g/L FA on til ering dynamics, plant height, chlorophyl content, photosynthetic perfor-mance, gas exchange parameters and yield components of weedy rice at different growth stages. [Result] Among the 4 plants/m2 weedy rice plots, with the increase of FA concentration, til er number, plant height, chlorophyl content, net photosynthetic rate （Pn）, stomatal conductance （Gs） and transpiration rate （Tr） of weedy rice were reduced. Under the 4-6 g/L FA concentration, til er numbers of weedy rice at differ-ent growth stages were reduced by 13.84%-35.71% compared with control at the same density and the most significant reduction was on the 22nd d after weedy rice germination; chlorophyl contents of weedy rice at the jointing stage were significant-ly reduced by 7.90%-8.88%. Furthermore, in the plots with 4 g/L FA, weedy rice plant heights at the heading stage and grain fil ing stage were significantly reduced by 6.37%-9.10%; Pn, Gs and Tr of weedy rice at the jointing stage and grain fil ing stage were significantly reduced by 10.19%-16.05%, 12.57%-23.33% and 10.28%-19.76%, respectively; 1 000-grain weight, effective panicle number per plant and panicles weight per plant of weedy rice at the maturity stage were significantly re-duced by 3.19%, 21.21% and 27.27%, correspondingly. [Conclusion] In 4 plants/m2 weedy rice plots, because soaking cultivated rice seeds with 4 g/L FA could regu-late the growth and development of cultivated rice, the soaking with FA could change the ecological relationship between cultivated rice and weedy rice, affect weedy rice physiological and ecological properties and al eviate the competitive inhi-bition of weedy rice on cultivated rice.
基金Supported by Program for Potato Innovative Research Team in Sichuan ProvinceScience and Technology Support Program of Nanchong City~~
文摘[Objective] This study was to investigate the effects of fulvic acid on agronomic traits and yield of autumn potato. [Method] The effects of fulvic acid on growth period, plant morphology, tuber, net photosynthetic rate, chlorophyll content, leaf area index （LAI） and yield of autumn potato were investigated. [Result] The application of fulvic acid prolonged the growth period and increased the plant height, stem diameter, leaf chlorophyll content, LAI, net photosynthetic rate, tuber number per plant, tuber weight per plant and marketable tuber rate of autumn potato, thus increasing the yield. Applying fulvic acid prolonged the growth period of autumn potato by 1-3 d and significantly increased the plant height, net photosynthetic rate, tuber weight per plant and yield of autumn potato （P〈0.05, P〈0.01）. When the application amount of compound fertilizer was reduced by half, applying fulvic acid almost showed the same seedling emergence stage, mature stage, growth period and net photosynthetic rate with applying full amount of compound fertilizer. In particular, no significant difference was found in the yield of autumn potato between fullamount and half-amount compound fertilizer treatment groups in the premise of solid- liquid fulvic acid combined application. [Conclusion] In the premise of unchanged yield, applying fulvic acid can reduce the application of chemical fertilizers and reduce the non-point source pollution of chemical fertilizers.
基金supported by the National Natural Science Foundation of China (No.50838005)the Changjiang Scholars and Innovative Research Team in University(No.IRT0853)the American Aluminum Foundation
文摘This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species investigated in the experiments included inorganic mononuclear, organic mononuclear, mononuclear, polymer, soluble, and suspended forms. It was found that the effects of fulvic acid and humic acid on aluminum speciation depended mainly on their molecular weight. Fulvic acid with molecular weight less than 5000 Dalton had little influence on aluminum speciation; while fulvic acid with molecular weight larger than 5000 Dalton and humic acid would increase the concentration of soluble aluminum significantly even at concentration below 0.5 mg/L （calculated as TOC）. Aluminum species, in the present of fulvic acid with molecular weight larger than 5000 Dalton and humic acid, were more stable than that in the present of fluvic acid with molecular mass less than 5000 Dalton, and varied little with reaction time. Within pH range 6.5-7.5, soluble aluminum increased notably in water with organic matter. As the concentration of residual chlorine increased, the effects of fulvic acid and humic acid became weak. The reactions between humic acid, fulvic acid with large molecular weight, and aluminum were considered to be a multi-dentate coordination process. With the consideration of aluminum bioavailability, reducing the concentration of fulvic acid and humic acid and keeping the pH value among 6.5-7.5 were recommended during drinking water treatment.
基金the National High Technology Research and Development Program of China(Grant No.2009AA063003)the National Nature Science Foundation of China(Grant No.20677039) for financial support
文摘A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natural water bodies,and its influence mechanism was proposed.A TiO_2 nanotube arrays(TNAs) material is served as the photoanode.Methanol,ethanediol,and glycerol were chosen as the representative of LMHCs in this study.The adsorption performance of organics on the surface of TNAs was investigated by using the instantaneous photocurrent value.The adsorption constants of FA,methanol,ethanediol,and glycerol were 43.44,19.32,7.00,and 1.30,respectively,which indicates that FA has the strongest adsorption property.The degradation performance of these organics and their mixture were observed in a thin-layer reactor.It shows that FA could hardly achieve exhausted mineralization alone,while LMHCs could be easily oxidized completely in the same condition.The degradation degree of FA,which is added LMHCs,improves significantly and the best promotion effect is achieved by glycerol.The promotion effect of LMHCs in the degradation of FA could be contributed to the formation of a tremendous amount of hydroxyl radicals in the NPEC process.The hydroxyl radicals could facilitate the complete degradation of both FA and its intermediate products.Among the chosen LMHCs,glycerol molecule which has three hydroxyls could generate the most hydroxyl radicals and contribute the best effective promotion.This work provides a new way to promote the NPEC degradation of FA and a direction to remove humus from polluted water.
基金supported by the Key Research&Developmental Program of Shandong Province(Nos.2021CXGC011202,2020CXGC011404)the Beijing Natural Science Foundation(No.8192004)the Beijing Major Science and Technology Projects(No.Z181100005318001)
文摘The long-term impact of fulvic acid(FA)on partial nitritation(PN)systemwas initially examined in this study.The obtained results revealed that the FA lower than 50 mg/L had negligible effect on the nitrite accumulation rate(NAR nearly 100%)and ammonium removal rate(ARR 56.85%),while FA over 50 mg/L decreased ARR from 56.85%to 0.7%.Sludge characteristics analysis found that appropriate FA(<50 mg/L)exposure promoted the settling performance and granulation of PN sludge by removing Bacteroidetes and accumulating Chloroflexi.The analysis of metagenomics suggested that the presence of limited FA(0-50 mg/L)stimulated the generation of NADH,which favors the denitrification and nitrite reduction.The negative impact of FA on the PN system could be divided into two stages.Initially,limited FA(50-120 mg/L)was decomposed by Anaerolineae to stimulate the growth and propagation of heterotrophic bacteria(Thauera).Increasing heterotrophs competed with AOB(Nitrosomonas)for dissolved oxygen,causing AOB to be eliminated and ARR to declined.Subsequently,when FA dosage was over 120 mg/L,Anaerolineae were inhibited and heterotrophic bacteria reduced,resulting in the abundance of AOB recovered.Nevertheless,the ammonium transformation pathway was suppressed because genes amoABC and hao were obviously reduced,leading to the deterioration of reactor performance.Overall,these results provide theoretical guidance for the practical application of PN for the treatment of FA-containing sewage.
基金Supported by the National High-tech and Development of Program of China(No. 2003AA601060).
文摘A surfactant modified zeolite（ SMZ）, i. e. , a zeolite modified by using hexadecyl trimethyl ammonium bromide （HDTMA） was used to remove fulvic acids（FA） from aqueous solution. The effects of the relevant parameters, such as the loading level of HDTMA, the contact time, the initial FA concentration, the pH, and the types of the metal carious and organics were examined. The results show that SMZ with an HDTMA loading-level of 120% of the external cation exchange capacity（ECEC） of zeolite exhibits the best performance. Although the removal of fulvic acids by SMZ occurs rapidly within the first 30 min of the contact time, a contact time of at least 4 h is required to attain the adsorption equilibrium. The removal capacity of FA by SMZ decreases with the increase of the initial FA concentration. The pH has an effect on the FA removal efficiency because it can influence the characteristics of the FA molecules. The removal of FA is considerably enhanced by Ca^2＋ or Mg^2＋ ions and is adversely affected by phenol or pentachlorophenol（PCP）. Under the optimum conditions, 98% of FA could be removed by SMZ. Furthermore, the desorption of FA and the regeneration of SMZ were studied. The results show that a 30% ethanol solution is sufficient for the regeneration of SMZ.
文摘The degradation of fulvic acid（FA） by nanoparticle TiO2 in a submerged membrane photocatalysis（SMPC） reactor was studied. In this reactor, photocatalytic oxidation and membrane separation co-occured. The continuous air supplier provided O2 for the photocatalytical reaction and mixed the solution through an airflow controller. The particle TiO2 could automatically settle due to gravity without particle agglomeration so it could be easily separated by microfiltration（MF） membrane. It was efficient to maintain high flux of membranes. The effects of operational parameters on the photocatalytic oxidation rate of FA were investigated. Results indicated that photocatalyst at 0.5 g/L and airflow at 0.06 m^3/h were the optimum condition for the removal of fulvic acid, the removal efficiency was higher in acid media than that in alkaline media. The effects of different filtration duration on permeate flux rate of MF with P25 powder and with nanoparticle TiO2 were compared. Experimental results indicated that the permeate flux rate of MF was improved and the membrane fouling phenomenon was reduced with the addition of nanoparticle TiO2 catalyst compared with conventional P25 powder. Therefore, this submerged membrane photocatalysis reactor can faciliate potential application of photocatalytic oxidation process in drinking water treatment.
文摘Fulvic acids extracted from a typical rice-production region near Taihu Lake of China were fractionated into three fractions including F4.8, F7.0 and F11.0 （eluted by pH 4.8 buffer, pH 7.0 buffer and pH 11.0 buffer, respectively）. Sorption of fulvic acid （FA） fractions onto kaolinite was studied by batch adsorption experiments, and characterizations of kaolinite before and after adsorption were investigated using scanning electron microscopy （SEM）. Adsorption isotherms of kaolinite for three FA fractions fit well with the Langrnuir adsorption model. The adsorption density of the three fractions was positively correlated with the ratio of the amount of the alkyl carbon to that of carboxyl and carbonyl carbon in FA fractions and followed an order of F11.0 〉 F7.0 〉 F4.8. Hydrophobic interaction was one of the control mechanisms for the sorption of FA fraction onto kaolinite. SEM images confirmed that compared to blank kaolinite samples, kaolinite samples coated by a FA fraction displayed an opener and more dispersed conformation resulting from the disruption of the floc structure in complex. Dispersion of kaolinite after adsorption was due to the repulsion between negatively charged FA-coated particles, which is closely related to the amount of FA fractions absorbed on kaolinite.
基金supported by Science and Technology Project of Guizhou Province (Nos. QKHZC[2020]4Y031QKHJC[2020]1Y187 )+2 种基金the Natural Science Foundation of China (Nos. 4176301742007305 )the Program Foundation of Institute for Scientific Research of Karst Area of NSFC-GZGOV (No. U1612442 )。
文摘Humus is often used as an organic modifier to reduce the bioaccumulation of heavy metals in plants, but the effects of different humus components from different sources on the fate of mercury(Hg) in paddy fields are still unclear. Here, fulvic acid(FA) and humic acid(HA) extracted from composted straw(CS), composted cow dung(CCD), peat soil(PM) and lignite coal(LC) were used to understand their effects on the methylation and bioaccumulation of Hg in paddy soil by pot experiments. Amendments of both FA and HA largely increased the abundance of Hg-methylating microbes and low-molecular-weight organic matters(e.g, cysteine) in paddy soil. They were also found to change the aromaticity, molecular size and Chromophoric DOM concentration of DOM, and resulted in heterogeneous effects on migration and transformation of Hg. All the FA-amended treatments increased the mobility and methylation of Hg in soil and its absorption in roots. Nevertheless, FA from different sources have heterogeneous effects on transport of Hg between rice tissues. FA-CCD and FA-PM promoted the translocation of Me Hg from roots to rice grains by 32.95% and 41.12%, while FA-CS and FA-LC significantly inhibited the translocation of inorganic Hg(IHg) by 52.65% and 66.06% and of Me Hg by 46.65% and 36.23%, respectively. In contrast, all HA-amended treatments reduced the mobility of soil Hg, but promoted Hg methylation in soil. Among which, HA-CCD and HA-PM promoted the translocation of Me Hg in rice tissues by 88.95% and 64.10%, while its accumulation in rice grains by 28.43% and 28.69%, respectively. In general, the application of some FA and HA as organic modifiers to reduce Hg bioaccumulation in rice is not feasible.
基金funded by the National Key Technology R&D Program of China (2012BAD14B05, 2013BAC09B01)the Major Achievement Transfer Project of Jilin Province, China (20130309005NY)
文摘Knowledge of different effects of various organic materials on soil humic substance is important for both environmental safety and sustainable agriculture.A pot experiment was conducted at Jilin Agricultural University,Jilin Province in northeast China to discover the influence of herb residue,animal excrement,woody residue,animal remnant on fulvic acid（FA） composition and structure using differential thermal analysis-thermogravimetric（DTA-TG）,fourier transform infrared spectroscopy（FTIR） and elemental analysis.DTA-TG showed the range of peak temperature in the first exothermic reaction increased following the trend： CK〉herb residue〉animal excrement〉woody residue=animal remnant,and the most weight loss was observed in animal excrement.Moreover,the second exothermic reaction of CK-and animal excrement-FA was presented as double peaks,the order of weight loss in that area was animal remnant〉CK〉woody residue〉animal excrement〉herb residue.According to FTIR,herb residue displayed higher adsorption intensity at 2 950,1 420,1 240 and 1 030 cm-1,animal excrement was in reverse.At the same time,herb residue-and animal excrement-FA had an absorption peak at 1 720 cm-1,while other organic materials didn＇t have this peak.As elemental analysis showed,FA isolated from various treatments was significantly distinct.It was clearly shown from our results that FA composition and structure in amended soils may be affected in different ways and at various extents on dependence of the nature and origin of amendment.
文摘The formation constants of Co￣(2+), Ni￣(2+), Cu￣(2+) and Zn￣(2+) complexes with humic acid (HA) and fulvicacid (FA) in red soil were determined by the potentiometric titration method. The constants as a functionof composition of the complexation solutions were obtained by two graphical approaches respectively Theformation constants decreased with increasing concentration of metal in the solution. The results provideunambiguous evidence for the heterogeneity of the function groups of humic substances. The formationconstants of FA were much smaller than those of HA, and the formation constants of Cu￣(2+) were muchgreater than those of Co￣(2+) , Ni￣(2+) and Zn￣(2+) . The potentiometric titration method for determining formationconstants are also discussed in the article.
文摘The acid-base buffer characteristics of fulvic acid (FA) and barium fulvate (BaFA)were analyzed. Each share of the sample or model agents (phthalic acid and salicylic acid)were separately mixed into a series of shares of dilute solutions of HCI or NaOH with a series of concentration. The original pH values of the solutions were arranged from 2 to 13.Final balanced pH of each share was measured. The pH changes show that FA and BaFApossess buffer ability, whereas the model agents do not. The tendency of balanced pHvalues was 5.4 for FA and 7.4 for BaFA, whereas the original pH was 4.0-8.5; balancedpH changed little. At room temperature, the maximum buffer capacities were as follows:18.11 mmol hydroxyl per gram FA, 11.25 mmol hydroxyl per gram BaFA, 1.19 mmol protonper gram FA, and 1.45 mmol proton per gram BaFA. Mathematics analysis shows thatlogarithm of buffer capacities of FA and BaFA is linearly dependent on original pH. Compared with BaFA and model agents, it is concluded that FA buffer capacity against hydroxylrelies not only on its acidic groups, BaFA buffer capacity against hydroxyl does not rely onits acidic groups, and FA buffer capacity against proton is not related with its carboxyl andphenolic hydroxyl group. The pH values of FA-water solutions with different concentrationsfrom 1 to 10 grams per liter were measured. Their pH values were slightly affected by itsconcentration. Thus, FA possesses a much stronger buffer ability against water dilutionthan common buffer agent. All the pH values of FA water solutions were very nearby 5.4,just the same as the balanced pH tendency for adding FA.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201503119-03-02)。
文摘[Objective]The paper was to clarify the application of biochemical fulvic acid potassium on the survival rate and growth of various trees transplanted in the process of landscaping.[Method]Two experimental treatments(i.e.decomposed organic fertilizer+biochemical fulvic acid potassium water soluble fertilizer,decomposed organic fertilizer+compound fertilizer)were designed to determine the changes in physical and chemical properties before and after soil treatment,and the survival rate,plant height and ground diameter of four different cultivated plants within one year,and the effects of applying biochemical fulvic acid potassium on cultivated plants were investigated.[Result]The soil organic matter,total nitrogen,alkali-hydrolyzable nitrogen,soil available phosphorus,soil available potassium and p H value in the soil treated with decomposed organic fertilizer+biochemical fulvic acid potassium soluble fertilizer,and decomposed organic fertilizer+compound fertilizer increased significantly,and the soil bulk density decreased obviously.The survival rates,plant heights and ground diameters of four different cultivated plants were significantly improved after application of decomposed organic fertilizer+biochemical fulvic acid potassium water soluble fertilizer,and decomposed organic fer-tilizer+compound fertilizer(P<0.05).[Conclusion]The application of biochemical fulvic acid potassium on cultivated plants effectively improved soil fertility,increased the utilization of nitrogen,phosphorus and potassium,improved the growth of plants,and promoted the growth of landscaping plants after transplantation.
