Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge ...Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge the gap between supply and demand.In this concern,a new material called Si-6G PAMAMPPAAM dendrimers modified silica gel terminated with phenylphosphonic acid-amide moieties was developed and its ability to adsorb Nd(Ⅲ)and Er(Ⅲ)from the phosphoric acid solution was investigated.K inetics and isotherm of the uptake process were investigated to explo re the so rption characte ristics.The attained results show that both metal ions exhibit the same adsorption performance,and the uptake process is depicted as a chemisorption,monolayer,uniform,and homogeneous process.The equilibrium state is achieved within 120 min,and the maximum uptake capacity is 16.7 mg Nd(Ⅲ)/g,and 14.0 mg Er(Ⅲ)/g.Sorption thermodynamics is an endothermic,spontaneous,and feasible uptake process.Nitric acid(1.0 mol/L)is found to be efficient for adsorbing about 94.3%and 92.5%of neodymium(Ⅲ)and erbium(Ⅲ)respectively,and the prepared Si-6G PAMAM-PPAAM demonstrates excellent stability over five consecutive sorption/desorption cycles.Preliminary tests on commercial phosphoric acid demonstrate that Si-6G PAMAM-PPAAM retains its effective REEs uptake from a complex comm ercial phosph oric acid solution.展开更多
Helium sorption cooler technology is a key means to realize highly reliable low-vibration very lowtemperature environments,which have important applications in fields such as quantum computing and space exploration.Th...Helium sorption cooler technology is a key means to realize highly reliable low-vibration very lowtemperature environments,which have important applications in fields such as quantum computing and space exploration.The laboratory designed a superfluid suppression small hole and a multi-ribbed condenser,developed a reliable-performance helium sorption cooler(HSC),and conducted experimental studies.Experimental results show that the prototype can achieve the lowest cooling temperature of 873 mK without load by filling 6MPa helium at room temperature.The low-temperature hold time is 26 h,and the temperature fluctuation is within 0.8 mK.The cooling power of the helium sorption cooler is 1 mW@0.98 K@3.5 h.Experimental results indicate that when the charging pressure is reduced to 4MPa,theminimum temperature decreases to 836mK,and the hold time shortens to 16 h.When the pre-cooling temperature increases from 3.9 to 4.9 K,the hold time is reduced to 3 h.展开更多
Co-contamination of chlorinated hydrocarbons and arsenic is frequently observed in the chemically contaminated sites and their surroundings in China.However,the interaction between these complex contaminants in soil r...Co-contamination of chlorinated hydrocarbons and arsenic is frequently observed in the chemically contaminated sites and their surroundings in China.However,the interaction between these complex contaminants in soil remains is unclear.This study collected ten background soils with varying properties from various regions throughout China,and investigated the sorption and desorption process of trichloroethylene(TCE)in the exogenous arsenate(As(V))contaminated soils.The results of the batch experiments demonstrated that TCE was rapidly adsorbed by soil organic matter(SOM).Both SOM and minerals contributed to the slow sorption equilibrium process.The sorption isotherms were linear,while the desorption isotherms were non-linear.In Heilongjiang(HLJ)soil,As(V)contamination increased the TCE sorption contribution of black carbon and decreased the contribution of minerals.During the aging process of As(V)in soils,SOM was replaced by AsO_4~(3-),which formed complexes with soil Fe/Al oxides,resulting in a significant increase in hydroxyl groups and hydrophilicity of the soil surface.This hindered the hydrophobic sorption of TCE.Additionally,As(V)contamination affected soil geotechnical properties,and the Ascations precipitation could block the sorption micropores.The collective results of these processes caused a reduction in the sorption of TCE on the majority of As(V)-contaminated soils(702-5854 mg/kg)in comparison to background soils(1194-6374 mg/kg).The systematic investigation of sorption-desorption behaviors of TCE in As(V)-contaminated soils will provide a scientific basis for the calculation of soil environmental capacity of heavy metalorganic combined contamination in the future.展开更多
This work investigates a combined cooling,heating,and power(CCHP)generation system utilizing waste energy.A cascade-CCHP system is developed,consisting of a 23.65-kWe organic Rankine cycle(ORC),a 4.00-kW adsorption ch...This work investigates a combined cooling,heating,and power(CCHP)generation system utilizing waste energy.A cascade-CCHP system is developed,consisting of a 23.65-kWe organic Rankine cycle(ORC),a 4.00-kW adsorption chiller,a 4.11-kW absorption chiller,a 15.99-kW drying room,and an incinerator of 150 kg/h.A net energy production of 36.08 kWh is achieved from a CCHP energy efficiency of 9.98%.The levelized cost for producing a total energy output of 2,020,592 kWh over a lifespan of 20 years is approximately 0.106 USD/kWh.The life cycle assessment(LCA)yields a single score of approximately 0.000151 Pt,mainly attributed to raw materials used in the construction process of 87.16%.In addition,the combustion ash is processed into concrete blocks measuring 39 cm×19 cm×7 cm,in accordance with the Industrial Product Standard(TIS)58-2533,with a water absorption value below 5%and a compressive strength exceeding 25 kg/cm2.The CCHP system demonstrates a novel method of waste-to-energy(WtE),and the construction material from waste combustion ash can also support a new concept of waste-to-zero(WtZ).展开更多
The effect of using 2%and 10%sodium hydroxide solution as surface treatment of rape straw on its water vapor adsorption properties is analyzed in the relative humidity(RH)range of 0%to 98%.Scanning electron microscopy...The effect of using 2%and 10%sodium hydroxide solution as surface treatment of rape straw on its water vapor adsorption properties is analyzed in the relative humidity(RH)range of 0%to 98%.Scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),and Fourier-transform infrared spectroscopy(FTIR)are used to investigate the morphological,chemical and structural changes of the treated straw surface.The mineral particles formed on the surface after the treatment are analyzed using X-ray diffraction(XRD).The application of sodium hydroxide solution results in the disruption of the straw surface.As the concentration of sodium hydroxide increases,the disruption of the straw surface increases,and the ability of the straw to adsorb water vapor also increases over the entire RH range.In addition to the surface disruption and chemical changes caused by the alkaline treatment,the differences in the equilibrium moisture content of treated and untreated rape straw can also be attributed to the formation of minerals on the straw surface,namely calcite for the 2%sodium hydroxide solution,and gaylussite and thermonatrite for the 10%solution.展开更多
Spinal cord injury presents a significant challenge in regenerative medicine due to the complex and deli-cate nature of neural tissue repair.This study aims to design a conductive hydrogel embedded with magnetic MgFe_...Spinal cord injury presents a significant challenge in regenerative medicine due to the complex and deli-cate nature of neural tissue repair.This study aims to design a conductive hydrogel embedded with magnetic MgFe_(2)O_(4) nanoparticles to establish a bioelectrically active and spatially stable microenvironment that promotes spinal cord regeneration through computational analysis(BIOVIA Materials Studio).Hydrogels,known for their biocompatibility and extracellular matrix-mimicking properties,support essential cellular behaviors such as adhesion,proliferation,and migration.The integration of MgFe_(2)O_(4) nanoparticles imparts both electrical conductivity and magnetic responsiveness,enabling controlled transmission of electrical signals that are crucial for guiding cellular processes like differentiation and directed migration.Furthermore,the hydrogel acts as a delivery medium,facilitating the adsorption of MgFe_(2)O_(4) nanoparticles onto spinal tissue through strong Van der Waals and intramolecular interactions.The computational simulations revealed a robust adsorption profile,with a binding distance of 20.180Åand a cumulative adsorption energy of 2740.42 kcal/mol,indicating stable nanoparticle-tissue interactions.Pressure-dependent sorption analysis further demonstrated that reduced pressure conditions enhance adsorption strength,promoting tighter material-tissue integration.The adverse Van der Waals energy and increased intramolecular energy observed under these conditions underscore the importance of optimized adsorption settings for functional tissue interface formation.Altogether,the conductive hydrogel-MgFe_(2)O_(4) composite system offers a promising therapeutic platform by combining structural support,electrical stimulation,and magnetic guidance,thereby enhancing cell-material interactions and fostering an environment conducive to spinal cord tissue repair.展开更多
Connate water strongly restricts shale gas enrichment and production,and most artificially injected water is confined in shale pore networks owing to low water recovery during hydraulic fracturing,which leads to a mor...Connate water strongly restricts shale gas enrichment and production,and most artificially injected water is confined in shale pore networks owing to low water recovery during hydraulic fracturing,which leads to a more complex pore water distribution.However,previous studies have focused on the water vapor sorption of gas shales rather than liquid pore water.This study clarifies the occurrence and distribution of pore water and the controlling factors by conducting thermogravimetry(TGA)under liquid water saturation and water vapor sorption experiments on four gas shales from the Wufeng Formation in South China.Nuclear magnetic resonance(NMR)T_(2)and T_(1)-T_(2)technologies were used to monitor the dynamic changes and states of moisture,and the microscopic pore structures during water vapor sorption were detected using low-temperature nitrogen adsorption-desorption.The results indicate that TGA is adequate for determining the adsorbed,bound,and movable water contents.These four gas shales are characterized by high adsorbed and movable water contents,and some bound water.The adsorbed water primarily occurs in tiny pores(<100 nm),controlled by organic matter,followed by clay mine rals.The movable water,typically associated with quartz,primarily exists in pores of>100 nm,particularly macropores of>1000 nm.The bound water predominantly correlates with pores ranging from 10 to 2000 nm in clay minerals.The water vapor sorption process of the gas shale is well clarified.Water molecules primarily adsorb on the clay mineral's hydrophilic surface,followed by oxygen functional groups in the organic matter.Therefore,clay mine rals control water vapor sorption at low relative humidity(RH<0.75),whereas organic matter primarily affects vapor sorption at high RH.The TGA of liquid wate r-saturated gas shales can clarify the water distributions in full-scale pore networks,whereas the water vapor sorption method primarily discloses the moisture in small nanopores(<100 nm)but ignores most bound and movable water.This paper provides insight into liquid water distribution and occurre nce states within shale pore netwo rks,contributing to a better understanding of gas-wate r-rock interaction systems in-situ and hydraulic fracturing shale gas formations.展开更多
By means of the synthetic approach of non－polar or weak polar oil－sorbed polymers，the gel sorption resin（GSR） and the multiporous sorption resin（MSR） were prepared．The structure of the resins，sorption power...By means of the synthetic approach of non－polar or weak polar oil－sorbed polymers，the gel sorption resin（GSR） and the multiporous sorption resin（MSR） were prepared．The structure of the resins，sorption power，sorption speed，desorption，and sorption of organic compounds from sewage，exhaust gas and soil were discussed．Moreover，the resins were used to decrease LOD and BOD5 values of water waste from sewage factory．Theyare a klndof potential materials for environmental control．展开更多
Systematic study on sorption behavior of o-nitrophenol on marine sediments was conducted. Isotherms of sorption of o-nitrophenol on marine sediments could be described by Freundlich model; and the isotherm of sorption...Systematic study on sorption behavior of o-nitrophenol on marine sediments was conducted. Isotherms of sorption of o-nitrophenol on marine sediments could be described by Freundlich model; and the isotherm of sorption of o-nitrophenol on HCl-treated sediment could be described by Langmuir model. The sorption behavior was affected by various factors including organic carbon content, aqueous solution salinity, temperature, and acidity. The sorption amount of o-nitrophenol increased when salinity and acidity of the aqueous solution increase, but decreased with increasing temperature. Organic carbon content in sediments had apparent effect on the behavior except for HCl-treated sediments.展开更多
Sorption characteristics of both an organic pollutant (phenol) and a heavy metal (cadmium ion) on the clay layer of a Lou soil (Eum-orthic Anthrosol in Chinese Soil Taxonomy) along with the sorption mechanism were inv...Sorption characteristics of both an organic pollutant (phenol) and a heavy metal (cadmium ion) on the clay layer of a Lou soil (Eum-orthic Anthrosol in Chinese Soil Taxonomy) along with the sorption mechanism were investigated using three soil treatments: modification with a cationic surfactant cetyltrimethylammonium bromide added at an amount equivalent to 50% and 100% of the soil CEC (50%CB and 100%CB), modification with an amphoteric surface-modifying agent dodecyldimethylbetaine (commercially known as BS-12) added at an amount equivalent to 50% and 100% of the soil CEC (50% BS and 100%BS), and an unmodified control (CK). Results showed that the BS soil treatments increased sorption of both the heavy metal Cd2+ and the organic pollutant phenol. The equilibrium sorption amount of Cd2+ decreased in the order: 50%BS > 100%BS > CK > 50%CB > 100%CB, with the BS soil treatments being about 1.3 to 1.8 times higher and the CB soil treatments about 23% to 41% lower than CK. Both the single-site and two-site Langmuir models could be applied to describe the sorption of Cd2+ in each soil treatment. The equilibrium sorption amount of phenol on the soil samples decreased in the order: 100%CB > 50%CB > 100%BS > 50%BS > CK, with the CB soil treatments being 41.0 to 79.6 times higher and the BS soil treatments 4.0 to 8.3 times higher than CK. The Freundlich equation could also be used to describe the sorption characteristics of phenol. In the BS soil treatments, both an organophobic long carbon chain and hydrophilic charged groups resulted in a relatively strong sorption ability for both heavy metals and organic pollutants. In addition, the sorption ratio K, the ratio of phenol sorption amount of the modified soil to that of CK, increased initially and decreased later with the amount of phenol added, and the critical sorption ratio KC, the peak value of the sorption ratio curve plotted against the added phenol concentration, was a good index for evaluating the sorption ability of phenol in the soil.展开更多
Knowledge of phosphorus （P） behavior in long-term fertilized soils is essential for programming fertilization practices and for sustaining environmental quality. The long-term （1984-1997） effects of various fertil...Knowledge of phosphorus （P） behavior in long-term fertilized soils is essential for programming fertilization practices and for sustaining environmental quality. The long-term （1984-1997） effects of various fertilization treatments on P changes and sorption isotherms as well as the relationship of soil properties to P sorption and P forms were evaluated in an Ustic Isohumisol, a calcareous soil, on the Loess Plateau, China. Compared to 1984, after 13 years of crop production, total soil P in the no-P treatments （control and N treatment） decreased by 5%-7%, but in the phosphorus fertilizer alone （P）, nitrogen and phosphorus fertilizers in combination （NP）, manure alone （M）, and nitrogen and phosphorus fertilizers and manure in combination （NPM） treatments, it increased by 22%, 19%, 28%, and 58%, respectively. Residual fertilizer P was found mainly in NH4Ac-soluble P （Cas-P）, followed by NaHCO3-soluble P （NaHCO3-P）, and NH4F-soluble P （Al-P）. Phosphorus sorption in the soils with different fertilization practices fit the Langmuir equations. Phosphorus sorption capacity in the no-P treatments increased, whereas it decreased in the P-included treatments （P, NP, and NPM treatments）. Phosphorus sorption maximum （Qm） was significantly and negatively correlated to inorganic P including NaHCO3-P, Cas-P, NaOH-Na2CO3-soluble P （Fe-P）, and Al-P （P ≤ 0.01）. Moreover, long-term fertilization increased soil organic carbon in the NP, M, and NPM treatments and decreased pH in the NP and NPM treatments. Thus, the ability of the soil to release sorbed P to the environment increased under long-term P fertilization.展开更多
Norfloxacin sorption and the factors （soil organic matter （SOM）, pH, and exogenous copper （Cu） influencing the sorption were investigated in a black soil （soil B）, a fluvo-aquic soil （soil F）, and a red soil ...Norfloxacin sorption and the factors （soil organic matter （SOM）, pH, and exogenous copper （Cu） influencing the sorption were investigated in a black soil （soil B）, a fluvo-aquic soil （soil F）, and a red soil （soil R）. With increasing norfloxacin concentrations, sorption amount of norfloxacin increased in both the bulk soils and their SOM-removed soils, but the sorption capacity of SOM-removed soils was higher than that of their corresponding bulk soils, indicating that the process of norfloxacin sorption in soil was influenced by the soil properties including SOM. The sorption data in all bulk soils and SOM-removed soils were fitted to Freundlich and Langmuir models. The correlation coefficients suggested that the experimental data fitted better to Freundlich equation than to Langmuir equation. Furthermore, the data from soil F and SOM-removed F could not be described by Langmuir equation. The norfloxacin sorption amount decreased in soil B and soil F, whereas it increased in soil R as solution pH increased. The maximum KD and Koc were achieved in soil R when the equilibrium solution pH was 6. The norfloxacin sorption was also influenced by the exogenous Cu^2＋, which depended on the soil types and Cu^2＋ concentrations. With increasing Cu^2＋ concentrations in solution, generally, sorption amount, KD and Koc for norfloxacin in soils increased and were up to a peak at 100 mg/L Cu^2＋, and then the sorption amount decreased regardless of norfloxacin levels.展开更多
Biochar derived from partial combustion of vegetation is ubiquitous and potentially effective in sequestration of environmental contaminants. Biochars were prepared by burning of red gum （Eucalyptus spp.） woodchips ...Biochar derived from partial combustion of vegetation is ubiquitous and potentially effective in sequestration of environmental contaminants. Biochars were prepared by burning of red gum （Eucalyptus spp.） woodchips at 450 and 850℃ （labeled as BC450 and BC850）. These two biochars were found to possess markedly different properties in terms of surface area and porosity. Short-term equilibration tests （24 hr） were conducted to assess the sorption-desorption behavior of pyrimethanil in the soil amended with various amounts of biochar of each type, with a special focus on the desorption behavior of the sorbed pesticide through four times successive desorption by dilution. Sorption coefficient and isotherm nonlinearity of the amended soils progressively increased with the content of biochar in the soil. Biochar BC850 with higher surface area and microporosity showed a stronger effect on the reversibility of sorption pesticide. The soils amended with 5% BC450 and 1% BC850 had nearly the same sorption capacity for pyrimethanil; however, their desorption processes were very different with 13.65% and 1.49% of the sorbed pesticide being released, respectively. This study suggested that biochar in soil could be an important factor for immobilization of a pesticide and thus affecting its environment fate in soil.展开更多
Adsorption experiments were carried out to investigate the sorption behaviors of naphthalene and phenanthrene in six different soils and to determine the effects of temperature, linear alkylbenzene sulfonate （LAS） a...Adsorption experiments were carried out to investigate the sorption behaviors of naphthalene and phenanthrene in six different soils and to determine the effects of temperature, linear alkylbenzene sulfonate （LAS） and cetylrimethyl ammonium bromide （CTAB） on sorption. The results show that for a given sorbent phenanthrene exhibited greater nonlinear and stronger sorption than naphthalene. There was a strong negative correlation for the Koc values with organic carbon content （foc）. The increase of temperature was not favorable to sorption. Sorption decreased along with the increasing aqueous LAS concentration from 0 to 1000 mg/L. At low CTAB concentration （〈 100 mg/L）, the adsorption increased as CTAB hemimicelles formed on the soil surface. At high concentration, CTAB decreased the adsorption by occupying active hydrophobic adsorption sites and solubilization of naphthalene and phenanthrene.展开更多
A comparative study based on MgH2 ball-milled with altered Ni particle sizes under different conditions was conducted to reveal the effect of close contact between hydrides and metal catalysts on their hydrogen sorpti...A comparative study based on MgH2 ball-milled with altered Ni particle sizes under different conditions was conducted to reveal the effect of close contact between hydrides and metal catalysts on their hydrogen sorption properties.It is found that the Mg+nano-Ni(5 at%)composites not only exhibit a substantial decreased onset desorption temperature by approximately 180℃ but also dramatically enhance the absorption kinetics by sixteen times in comparison with those of pure MgH_(2).This remarkable kinetics enhancement can be explained by the superior catalytic effect of Ni present in composites that highly depends on its particle size and its close contact with MgH2.展开更多
The pores in shales are mainly of nanometer-scale, and their pore size distribution is very important for the preservation and exploitation of shale gas. This study focused on the organic-rich Lower Silurian black sha...The pores in shales are mainly of nanometer-scale, and their pore size distribution is very important for the preservation and exploitation of shale gas. This study focused on the organic-rich Lower Silurian black shale from four wells in the Upper Yangtze Platform, and their TOC, mineralogical composition and pore characterization were investigated. Low pressure N2 and CO2 adsorption were conducted at 77.35 K and 273.15 K, respectively, and the pore structures were characterized by modified Brunauer-Emmett-Teller （BET）, Dubinin-Radushkevich （DR）, t-plot, Barrett- Joyner-Halenda （BJH） and density functional theory （DFT） methods and then the relationship between pore structure and shale gas sorption capacity was discussed. The results indicate that （1） The Lower Silurian shale has high TOC content of 0.92%~96%, high quartz content of 30.6%-69.5%, and high clays content of 24.1%-51.2%. The total specific surface area varies from 7.56 m^2/g to 25.86 m^2/g. Both the total specific surface area and quartz content are positively associated with the TOC content. （2） Shale samples with higher TOC content have more micropores, which results in more complex nanopore structure. Micropore volumes/surface areas and non-micropore surface areas all increase with the increasing TOC content. （3） A combination of N2 and CO2 adsorption provides the most suitable detection range （~0.3-60 nm） and has high reliability and accuracy for nanopore structure characterization. （4） The TOC content is the key factor to control the gas sorption capacity of the Lower Silurian shale in the Upper Yangtze Platform.展开更多
A batch equilibrium techniques was used to examine the effect of dissolved organic matter （DOM） extracted from both non-treated sludge （NTS） and heat-expanded sludge （HES） on the sorption and desorption of chlor...A batch equilibrium techniques was used to examine the effect of dissolved organic matter （DOM） extracted from both non-treated sludge （NTS） and heat-expanded sludge （HES） on the sorption and desorption of chlorotoluron （3-（3-chloro-p-tolyl）-1,1-dimethylurea） in two types of soils, a yellow fluvo-aquic and a red soil from China. Without DOM,sorption of chlorotoluron was significantly greater （P 〈 0.05） in the red soil than in the yellow fluvo-aquic soil. However,with DOM the effect was dependent on the soil type and nature of DOM. Chlorotoluron sorption was lower in the yellow fluvo-aquic soil than in the red soil, suggesting that with the same DOM levels the yellow fluvo-aquic soil had a lower sorption capacity for this herbicide. Application of DOM from both NTS and HES led to a general decrease in sorption to the soils and an increase in desorption from the soils. Desorption of chlorotoluron also significantly increased （P 〈 0.05） with an increase in the DOM concentration. Additionally, for sorption and desorption, at each DOM treatment level the NTS treatments were significantly lower （P 〈 0.05） than the HES treatments. This implied that non-treated sludge had a greater effect on the sorption and desorption of chlorotoluron than heat-expanded sludge.展开更多
The effects of freeze-thaw cycles on sorption/desorption of dissolved organic carbon （DOC） in two wetland soils and one reclaimed wetland soil were investigated. DOC concentrations added were 0-600 mg/L. Laboratory ...The effects of freeze-thaw cycles on sorption/desorption of dissolved organic carbon （DOC） in two wetland soils and one reclaimed wetland soil were investigated. DOC concentrations added were 0-600 mg/L. Laboratory incubations of sorption/desorption of DOC had been carried out at -15℃ for 10 h, and then at ＋5℃ for 13 h. Soil samples were refrozen and thawed subsequently for 5 cycles. Initial Mass model was used to describe sorption behavior of DOC. The results indicate that freeze-thaw cycles can significantly increase the sorption capacity of DOC and reduce the desorption capacity of DOC in the three soils. The freeze-thaw effects on desorpfion of DOC in soils increase with the increasing freeze-thaw cycles. The conversion of natural wetlands to soybean farmland can decrease the sorption capacity and increase the desorption capacity of DOC in soils. Global warming and reclamation may increase DOC release, and subsequently increase the loss of carbon and the emission of greenhouse gas.展开更多
Sorption of U(VI) onto TiO_2 as functions of pH, ionic strength, contact time, soil humic acid(SHA), solid-to-liquid ratio and temperature was studied under ambient conditions using batch and spectroscopic approaches....Sorption of U(VI) onto TiO_2 as functions of pH, ionic strength, contact time, soil humic acid(SHA), solid-to-liquid ratio and temperature was studied under ambient conditions using batch and spectroscopic approaches. The sorption of U(VI) on TiO_2 was significantly dependent on pH and ionic strength. The presence of SHA slightly enhanced the sorption of U(VI) on TiO_2 below pH 4.0, while it inhibited U(VI) sorption in the higher pH range. U(VI)sorption on TiO_2 was favored at high temperatures, and the sorption process was estimated to be endothermic and spontaneous. Reduction of U(VI) to lower valent species was confirmed by X-ray photo-electron spectroscopy analysis. It is very interesting to find that U(VI) sorption on TiO_2 was promoted in solutions with higher back-ground electrolyte concentrations. In the presence of U(VI), higher back-ground electrolyte made more TiO_2 particles aggregate through(001) facets, leading more(101) facets to be exposed. Therefore, the reduction of U(VI) was enhanced by the exposed(101) facets and more U(VI) removal was observed.展开更多
The adsorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR) for Er(Ⅲ) were investigated. The optima adsorption condition of DAAR for Er(Ⅲ) is pH 6.20 in HAc NaAc medium. The sta...The adsorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR) for Er(Ⅲ) were investigated. The optima adsorption condition of DAAR for Er(Ⅲ) is pH 6.20 in HAc NaAc medium. The statically saturated adsorption capacity is 189 mg·g -1 resin at 298 K. The Er (Ⅲ) adsorbed on DAAR can be eluted reaching 100% by 2 mol·L -1 HCl used as eluant. The resin can be regenerated and reused without apparent decreasing of adsorption capacity. The apparent adsorption rate constant is k 298 =1.94×10 -5 s -1 . The apparent activation energy is 24.7 kJ·mol -1 . The adsorption behavior of DAAR for Er(Ⅲ) obeys the Freundlich isotherm. The thermodynamic adsorption parameters, enthalpy change Δ H of DAAR for Er(Ⅲ) is 24.1 kJ·mol -1 . The molar coordination ratio of the functional group of DAAR to Er (Ⅲ) is 3∶1. The adsorption mechanism of DAAR for Er (Ⅲ) was examined by using chemical method and IR spectrometry. The coordination compound is formed between oxygen atoms in the functional group of DAAR and Er(Ⅲ).展开更多
文摘Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge the gap between supply and demand.In this concern,a new material called Si-6G PAMAMPPAAM dendrimers modified silica gel terminated with phenylphosphonic acid-amide moieties was developed and its ability to adsorb Nd(Ⅲ)and Er(Ⅲ)from the phosphoric acid solution was investigated.K inetics and isotherm of the uptake process were investigated to explo re the so rption characte ristics.The attained results show that both metal ions exhibit the same adsorption performance,and the uptake process is depicted as a chemisorption,monolayer,uniform,and homogeneous process.The equilibrium state is achieved within 120 min,and the maximum uptake capacity is 16.7 mg Nd(Ⅲ)/g,and 14.0 mg Er(Ⅲ)/g.Sorption thermodynamics is an endothermic,spontaneous,and feasible uptake process.Nitric acid(1.0 mol/L)is found to be efficient for adsorbing about 94.3%and 92.5%of neodymium(Ⅲ)and erbium(Ⅲ)respectively,and the prepared Si-6G PAMAM-PPAAM demonstrates excellent stability over five consecutive sorption/desorption cycles.Preliminary tests on commercial phosphoric acid demonstrate that Si-6G PAMAM-PPAAM retains its effective REEs uptake from a complex comm ercial phosph oric acid solution.
基金supported by the Hundred Talents Programof the Chinese Academy of Sciences,the Pre-Research Project JZX7Y20220414101801the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB35000000)the National Natural Science Foundation Projects(No.51806231).
文摘Helium sorption cooler technology is a key means to realize highly reliable low-vibration very lowtemperature environments,which have important applications in fields such as quantum computing and space exploration.The laboratory designed a superfluid suppression small hole and a multi-ribbed condenser,developed a reliable-performance helium sorption cooler(HSC),and conducted experimental studies.Experimental results show that the prototype can achieve the lowest cooling temperature of 873 mK without load by filling 6MPa helium at room temperature.The low-temperature hold time is 26 h,and the temperature fluctuation is within 0.8 mK.The cooling power of the helium sorption cooler is 1 mW@0.98 K@3.5 h.Experimental results indicate that when the charging pressure is reduced to 4MPa,theminimum temperature decreases to 836mK,and the hold time shortens to 16 h.When the pre-cooling temperature increases from 3.9 to 4.9 K,the hold time is reduced to 3 h.
基金supported by the National Key R&D Program(Nos.2021YFC1809101 and 2022YFC3701404)the Fundamental Research Funds for the Central Universities(No.2022300301)。
文摘Co-contamination of chlorinated hydrocarbons and arsenic is frequently observed in the chemically contaminated sites and their surroundings in China.However,the interaction between these complex contaminants in soil remains is unclear.This study collected ten background soils with varying properties from various regions throughout China,and investigated the sorption and desorption process of trichloroethylene(TCE)in the exogenous arsenate(As(V))contaminated soils.The results of the batch experiments demonstrated that TCE was rapidly adsorbed by soil organic matter(SOM).Both SOM and minerals contributed to the slow sorption equilibrium process.The sorption isotherms were linear,while the desorption isotherms were non-linear.In Heilongjiang(HLJ)soil,As(V)contamination increased the TCE sorption contribution of black carbon and decreased the contribution of minerals.During the aging process of As(V)in soils,SOM was replaced by AsO_4~(3-),which formed complexes with soil Fe/Al oxides,resulting in a significant increase in hydroxyl groups and hydrophilicity of the soil surface.This hindered the hydrophobic sorption of TCE.Additionally,As(V)contamination affected soil geotechnical properties,and the Ascations precipitation could block the sorption micropores.The collective results of these processes caused a reduction in the sorption of TCE on the majority of As(V)-contaminated soils(702-5854 mg/kg)in comparison to background soils(1194-6374 mg/kg).The systematic investigation of sorption-desorption behaviors of TCE in As(V)-contaminated soils will provide a scientific basis for the calculation of soil environmental capacity of heavy metalorganic combined contamination in the future.
基金National Research Council of Thailand(NRCT)and the School of Renewable Energy and Maejo University for the project to produce and develop graduates in renewable energy for ASEAN countries for graduate students(2021).
文摘This work investigates a combined cooling,heating,and power(CCHP)generation system utilizing waste energy.A cascade-CCHP system is developed,consisting of a 23.65-kWe organic Rankine cycle(ORC),a 4.00-kW adsorption chiller,a 4.11-kW absorption chiller,a 15.99-kW drying room,and an incinerator of 150 kg/h.A net energy production of 36.08 kWh is achieved from a CCHP energy efficiency of 9.98%.The levelized cost for producing a total energy output of 2,020,592 kWh over a lifespan of 20 years is approximately 0.106 USD/kWh.The life cycle assessment(LCA)yields a single score of approximately 0.000151 Pt,mainly attributed to raw materials used in the construction process of 87.16%.In addition,the combustion ash is processed into concrete blocks measuring 39 cm×19 cm×7 cm,in accordance with the Industrial Product Standard(TIS)58-2533,with a water absorption value below 5%and a compressive strength exceeding 25 kg/cm2.The CCHP system demonstrates a novel method of waste-to-energy(WtE),and the construction material from waste combustion ash can also support a new concept of waste-to-zero(WtZ).
基金supported by the Czech Science Foundation,under project No.20-12166S.
文摘The effect of using 2%and 10%sodium hydroxide solution as surface treatment of rape straw on its water vapor adsorption properties is analyzed in the relative humidity(RH)range of 0%to 98%.Scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),and Fourier-transform infrared spectroscopy(FTIR)are used to investigate the morphological,chemical and structural changes of the treated straw surface.The mineral particles formed on the surface after the treatment are analyzed using X-ray diffraction(XRD).The application of sodium hydroxide solution results in the disruption of the straw surface.As the concentration of sodium hydroxide increases,the disruption of the straw surface increases,and the ability of the straw to adsorb water vapor also increases over the entire RH range.In addition to the surface disruption and chemical changes caused by the alkaline treatment,the differences in the equilibrium moisture content of treated and untreated rape straw can also be attributed to the formation of minerals on the straw surface,namely calcite for the 2%sodium hydroxide solution,and gaylussite and thermonatrite for the 10%solution.
基金the“Young Talent Research Grant”:(600-RMC/YTR/5/3(004/2022)Universiti Teknologi Mara(UiTM)for providing the financial support.
文摘Spinal cord injury presents a significant challenge in regenerative medicine due to the complex and deli-cate nature of neural tissue repair.This study aims to design a conductive hydrogel embedded with magnetic MgFe_(2)O_(4) nanoparticles to establish a bioelectrically active and spatially stable microenvironment that promotes spinal cord regeneration through computational analysis(BIOVIA Materials Studio).Hydrogels,known for their biocompatibility and extracellular matrix-mimicking properties,support essential cellular behaviors such as adhesion,proliferation,and migration.The integration of MgFe_(2)O_(4) nanoparticles imparts both electrical conductivity and magnetic responsiveness,enabling controlled transmission of electrical signals that are crucial for guiding cellular processes like differentiation and directed migration.Furthermore,the hydrogel acts as a delivery medium,facilitating the adsorption of MgFe_(2)O_(4) nanoparticles onto spinal tissue through strong Van der Waals and intramolecular interactions.The computational simulations revealed a robust adsorption profile,with a binding distance of 20.180Åand a cumulative adsorption energy of 2740.42 kcal/mol,indicating stable nanoparticle-tissue interactions.Pressure-dependent sorption analysis further demonstrated that reduced pressure conditions enhance adsorption strength,promoting tighter material-tissue integration.The adverse Van der Waals energy and increased intramolecular energy observed under these conditions underscore the importance of optimized adsorption settings for functional tissue interface formation.Altogether,the conductive hydrogel-MgFe_(2)O_(4) composite system offers a promising therapeutic platform by combining structural support,electrical stimulation,and magnetic guidance,thereby enhancing cell-material interactions and fostering an environment conducive to spinal cord tissue repair.
基金This study was financially supported by the National Natural Science Foundation of China(42302160)the PhD Scientific Research and Innovation Foundation of the Education Department of Hainan Province Joint Project of Sanya Yazhou Bay Science and Technology City(HSPHDSRF-2024-07-001)Educational Reform of Hainan Higher Education Institutions(Hnjg2024-276)。
文摘Connate water strongly restricts shale gas enrichment and production,and most artificially injected water is confined in shale pore networks owing to low water recovery during hydraulic fracturing,which leads to a more complex pore water distribution.However,previous studies have focused on the water vapor sorption of gas shales rather than liquid pore water.This study clarifies the occurrence and distribution of pore water and the controlling factors by conducting thermogravimetry(TGA)under liquid water saturation and water vapor sorption experiments on four gas shales from the Wufeng Formation in South China.Nuclear magnetic resonance(NMR)T_(2)and T_(1)-T_(2)technologies were used to monitor the dynamic changes and states of moisture,and the microscopic pore structures during water vapor sorption were detected using low-temperature nitrogen adsorption-desorption.The results indicate that TGA is adequate for determining the adsorbed,bound,and movable water contents.These four gas shales are characterized by high adsorbed and movable water contents,and some bound water.The adsorbed water primarily occurs in tiny pores(<100 nm),controlled by organic matter,followed by clay mine rals.The movable water,typically associated with quartz,primarily exists in pores of>100 nm,particularly macropores of>1000 nm.The bound water predominantly correlates with pores ranging from 10 to 2000 nm in clay minerals.The water vapor sorption process of the gas shale is well clarified.Water molecules primarily adsorb on the clay mineral's hydrophilic surface,followed by oxygen functional groups in the organic matter.Therefore,clay mine rals control water vapor sorption at low relative humidity(RH<0.75),whereas organic matter primarily affects vapor sorption at high RH.The TGA of liquid wate r-saturated gas shales can clarify the water distributions in full-scale pore networks,whereas the water vapor sorption method primarily discloses the moisture in small nanopores(<100 nm)but ignores most bound and movable water.This paper provides insight into liquid water distribution and occurre nce states within shale pore netwo rks,contributing to a better understanding of gas-wate r-rock interaction systems in-situ and hydraulic fracturing shale gas formations.
文摘By means of the synthetic approach of non－polar or weak polar oil－sorbed polymers，the gel sorption resin（GSR） and the multiporous sorption resin（MSR） were prepared．The structure of the resins，sorption power，sorption speed，desorption，and sorption of organic compounds from sewage，exhaust gas and soil were discussed．Moreover，the resins were used to decrease LOD and BOD5 values of water waste from sewage factory．Theyare a klndof potential materials for environmental control．
文摘Systematic study on sorption behavior of o-nitrophenol on marine sediments was conducted. Isotherms of sorption of o-nitrophenol on marine sediments could be described by Freundlich model; and the isotherm of sorption of o-nitrophenol on HCl-treated sediment could be described by Langmuir model. The sorption behavior was affected by various factors including organic carbon content, aqueous solution salinity, temperature, and acidity. The sorption amount of o-nitrophenol increased when salinity and acidity of the aqueous solution increase, but decreased with increasing temperature. Organic carbon content in sediments had apparent effect on the behavior except for HCl-treated sediments.
基金Project supported by the National Natural Science Foundation of China (No. 40301021).
文摘Sorption characteristics of both an organic pollutant (phenol) and a heavy metal (cadmium ion) on the clay layer of a Lou soil (Eum-orthic Anthrosol in Chinese Soil Taxonomy) along with the sorption mechanism were investigated using three soil treatments: modification with a cationic surfactant cetyltrimethylammonium bromide added at an amount equivalent to 50% and 100% of the soil CEC (50%CB and 100%CB), modification with an amphoteric surface-modifying agent dodecyldimethylbetaine (commercially known as BS-12) added at an amount equivalent to 50% and 100% of the soil CEC (50% BS and 100%BS), and an unmodified control (CK). Results showed that the BS soil treatments increased sorption of both the heavy metal Cd2+ and the organic pollutant phenol. The equilibrium sorption amount of Cd2+ decreased in the order: 50%BS > 100%BS > CK > 50%CB > 100%CB, with the BS soil treatments being about 1.3 to 1.8 times higher and the CB soil treatments about 23% to 41% lower than CK. Both the single-site and two-site Langmuir models could be applied to describe the sorption of Cd2+ in each soil treatment. The equilibrium sorption amount of phenol on the soil samples decreased in the order: 100%CB > 50%CB > 100%BS > 50%BS > CK, with the CB soil treatments being 41.0 to 79.6 times higher and the BS soil treatments 4.0 to 8.3 times higher than CK. The Freundlich equation could also be used to describe the sorption characteristics of phenol. In the BS soil treatments, both an organophobic long carbon chain and hydrophilic charged groups resulted in a relatively strong sorption ability for both heavy metals and organic pollutants. In addition, the sorption ratio K, the ratio of phenol sorption amount of the modified soil to that of CK, increased initially and decreased later with the amount of phenol added, and the critical sorption ratio KC, the peak value of the sorption ratio curve plotted against the added phenol concentration, was a good index for evaluating the sorption ability of phenol in the soil.
基金the National Basic Research Program of China(No.2005CB121102)the Knowledge Innovation Program of the Chinese Academy of Sciences(No.KZCX2-YW-424-2)the West Star Foundation of the Chinese Academy of Sciences
文摘Knowledge of phosphorus （P） behavior in long-term fertilized soils is essential for programming fertilization practices and for sustaining environmental quality. The long-term （1984-1997） effects of various fertilization treatments on P changes and sorption isotherms as well as the relationship of soil properties to P sorption and P forms were evaluated in an Ustic Isohumisol, a calcareous soil, on the Loess Plateau, China. Compared to 1984, after 13 years of crop production, total soil P in the no-P treatments （control and N treatment） decreased by 5%-7%, but in the phosphorus fertilizer alone （P）, nitrogen and phosphorus fertilizers in combination （NP）, manure alone （M）, and nitrogen and phosphorus fertilizers and manure in combination （NPM） treatments, it increased by 22%, 19%, 28%, and 58%, respectively. Residual fertilizer P was found mainly in NH4Ac-soluble P （Cas-P）, followed by NaHCO3-soluble P （NaHCO3-P）, and NH4F-soluble P （Al-P）. Phosphorus sorption in the soils with different fertilization practices fit the Langmuir equations. Phosphorus sorption capacity in the no-P treatments increased, whereas it decreased in the P-included treatments （P, NP, and NPM treatments）. Phosphorus sorption maximum （Qm） was significantly and negatively correlated to inorganic P including NaHCO3-P, Cas-P, NaOH-Na2CO3-soluble P （Fe-P）, and Al-P （P ≤ 0.01）. Moreover, long-term fertilization increased soil organic carbon in the NP, M, and NPM treatments and decreased pH in the NP and NPM treatments. Thus, the ability of the soil to release sorbed P to the environment increased under long-term P fertilization.
基金supported by the National Key Basic Research Support Foundation of China (No.2005CB121105), the Ministry of Science and Technology of China (No. 2006BAD05B05)the International Foundation for Science (No. C/4076).
文摘Norfloxacin sorption and the factors （soil organic matter （SOM）, pH, and exogenous copper （Cu） influencing the sorption were investigated in a black soil （soil B）, a fluvo-aquic soil （soil F）, and a red soil （soil R）. With increasing norfloxacin concentrations, sorption amount of norfloxacin increased in both the bulk soils and their SOM-removed soils, but the sorption capacity of SOM-removed soils was higher than that of their corresponding bulk soils, indicating that the process of norfloxacin sorption in soil was influenced by the soil properties including SOM. The sorption data in all bulk soils and SOM-removed soils were fitted to Freundlich and Langmuir models. The correlation coefficients suggested that the experimental data fitted better to Freundlich equation than to Langmuir equation. Furthermore, the data from soil F and SOM-removed F could not be described by Langmuir equation. The norfloxacin sorption amount decreased in soil B and soil F, whereas it increased in soil R as solution pH increased. The maximum KD and Koc were achieved in soil R when the equilibrium solution pH was 6. The norfloxacin sorption was also influenced by the exogenous Cu^2＋, which depended on the soil types and Cu^2＋ concentrations. With increasing Cu^2＋ concentrations in solution, generally, sorption amount, KD and Koc for norfloxacin in soils increased and were up to a peak at 100 mg/L Cu^2＋, and then the sorption amount decreased regardless of norfloxacin levels.
文摘Biochar derived from partial combustion of vegetation is ubiquitous and potentially effective in sequestration of environmental contaminants. Biochars were prepared by burning of red gum （Eucalyptus spp.） woodchips at 450 and 850℃ （labeled as BC450 and BC850）. These two biochars were found to possess markedly different properties in terms of surface area and porosity. Short-term equilibration tests （24 hr） were conducted to assess the sorption-desorption behavior of pyrimethanil in the soil amended with various amounts of biochar of each type, with a special focus on the desorption behavior of the sorbed pesticide through four times successive desorption by dilution. Sorption coefficient and isotherm nonlinearity of the amended soils progressively increased with the content of biochar in the soil. Biochar BC850 with higher surface area and microporosity showed a stronger effect on the reversibility of sorption pesticide. The soils amended with 5% BC450 and 1% BC850 had nearly the same sorption capacity for pyrimethanil; however, their desorption processes were very different with 13.65% and 1.49% of the sorbed pesticide being released, respectively. This study suggested that biochar in soil could be an important factor for immobilization of a pesticide and thus affecting its environment fate in soil.
基金supported by the National NaturalScience Foundation of China (No. 40372109)the National Basic Research Program (973) of China (No.2004CB418502).
文摘Adsorption experiments were carried out to investigate the sorption behaviors of naphthalene and phenanthrene in six different soils and to determine the effects of temperature, linear alkylbenzene sulfonate （LAS） and cetylrimethyl ammonium bromide （CTAB） on sorption. The results show that for a given sorbent phenanthrene exhibited greater nonlinear and stronger sorption than naphthalene. There was a strong negative correlation for the Koc values with organic carbon content （foc）. The increase of temperature was not favorable to sorption. Sorption decreased along with the increasing aqueous LAS concentration from 0 to 1000 mg/L. At low CTAB concentration （〈 100 mg/L）, the adsorption increased as CTAB hemimicelles formed on the soil surface. At high concentration, CTAB decreased the adsorption by occupying active hydrophobic adsorption sites and solubilization of naphthalene and phenanthrene.
基金financially supported by the National Natural Science Foundation of China(Nos.51671001 and 51701004)the Natural Science Foundation of Anhui Province(No.1708085ME99)。
文摘A comparative study based on MgH2 ball-milled with altered Ni particle sizes under different conditions was conducted to reveal the effect of close contact between hydrides and metal catalysts on their hydrogen sorption properties.It is found that the Mg+nano-Ni(5 at%)composites not only exhibit a substantial decreased onset desorption temperature by approximately 180℃ but also dramatically enhance the absorption kinetics by sixteen times in comparison with those of pure MgH_(2).This remarkable kinetics enhancement can be explained by the superior catalytic effect of Ni present in composites that highly depends on its particle size and its close contact with MgH2.
基金the financial support of the National Science and Technology Major Project(No.2016ZX05034-001)National Natural Science Foundation of China(No.41472112)
文摘The pores in shales are mainly of nanometer-scale, and their pore size distribution is very important for the preservation and exploitation of shale gas. This study focused on the organic-rich Lower Silurian black shale from four wells in the Upper Yangtze Platform, and their TOC, mineralogical composition and pore characterization were investigated. Low pressure N2 and CO2 adsorption were conducted at 77.35 K and 273.15 K, respectively, and the pore structures were characterized by modified Brunauer-Emmett-Teller （BET）, Dubinin-Radushkevich （DR）, t-plot, Barrett- Joyner-Halenda （BJH） and density functional theory （DFT） methods and then the relationship between pore structure and shale gas sorption capacity was discussed. The results indicate that （1） The Lower Silurian shale has high TOC content of 0.92%~96%, high quartz content of 30.6%-69.5%, and high clays content of 24.1%-51.2%. The total specific surface area varies from 7.56 m^2/g to 25.86 m^2/g. Both the total specific surface area and quartz content are positively associated with the TOC content. （2） Shale samples with higher TOC content have more micropores, which results in more complex nanopore structure. Micropore volumes/surface areas and non-micropore surface areas all increase with the increasing TOC content. （3） A combination of N2 and CO2 adsorption provides the most suitable detection range （~0.3-60 nm） and has high reliability and accuracy for nanopore structure characterization. （4） The TOC content is the key factor to control the gas sorption capacity of the Lower Silurian shale in the Upper Yangtze Platform.
基金Project supported by the National Natural Science Foundation of China (No. 30170537).
文摘A batch equilibrium techniques was used to examine the effect of dissolved organic matter （DOM） extracted from both non-treated sludge （NTS） and heat-expanded sludge （HES） on the sorption and desorption of chlorotoluron （3-（3-chloro-p-tolyl）-1,1-dimethylurea） in two types of soils, a yellow fluvo-aquic and a red soil from China. Without DOM,sorption of chlorotoluron was significantly greater （P 〈 0.05） in the red soil than in the yellow fluvo-aquic soil. However,with DOM the effect was dependent on the soil type and nature of DOM. Chlorotoluron sorption was lower in the yellow fluvo-aquic soil than in the red soil, suggesting that with the same DOM levels the yellow fluvo-aquic soil had a lower sorption capacity for this herbicide. Application of DOM from both NTS and HES led to a general decrease in sorption to the soils and an increase in desorption from the soils. Desorption of chlorotoluron also significantly increased （P 〈 0.05） with an increase in the DOM concentration. Additionally, for sorption and desorption, at each DOM treatment level the NTS treatments were significantly lower （P 〈 0.05） than the HES treatments. This implied that non-treated sludge had a greater effect on the sorption and desorption of chlorotoluron than heat-expanded sludge.
基金Under the auspices of Knowledge Innovation Programs of Chinese Academy of Sciences (No. KZCX2-YW-309)National Natural Science Foundation of China (No. 40871089, 40830535)
文摘The effects of freeze-thaw cycles on sorption/desorption of dissolved organic carbon （DOC） in two wetland soils and one reclaimed wetland soil were investigated. DOC concentrations added were 0-600 mg/L. Laboratory incubations of sorption/desorption of DOC had been carried out at -15℃ for 10 h, and then at ＋5℃ for 13 h. Soil samples were refrozen and thawed subsequently for 5 cycles. Initial Mass model was used to describe sorption behavior of DOC. The results indicate that freeze-thaw cycles can significantly increase the sorption capacity of DOC and reduce the desorption capacity of DOC in the three soils. The freeze-thaw effects on desorpfion of DOC in soils increase with the increasing freeze-thaw cycles. The conversion of natural wetlands to soybean farmland can decrease the sorption capacity and increase the desorption capacity of DOC in soils. Global warming and reclamation may increase DOC release, and subsequently increase the loss of carbon and the emission of greenhouse gas.
基金supported by the Natural National Science Foundation of China (Nos.21601169,41573128,21601179 and 21647009)the Natural National Science Foundation of Gansu Province (No.17JR5RA309)+2 种基金the Key Laboratory Project of Gansu Province (No.1309RTSA041)CAS "Light of West China" Programthe "100-Talent" Program from the Chinese Academy of Sciences in Lanzhou Center for Oil and Gas Resources,Institute of Geology and Geophysics,CAS
文摘Sorption of U(VI) onto TiO_2 as functions of pH, ionic strength, contact time, soil humic acid(SHA), solid-to-liquid ratio and temperature was studied under ambient conditions using batch and spectroscopic approaches. The sorption of U(VI) on TiO_2 was significantly dependent on pH and ionic strength. The presence of SHA slightly enhanced the sorption of U(VI) on TiO_2 below pH 4.0, while it inhibited U(VI) sorption in the higher pH range. U(VI)sorption on TiO_2 was favored at high temperatures, and the sorption process was estimated to be endothermic and spontaneous. Reduction of U(VI) to lower valent species was confirmed by X-ray photo-electron spectroscopy analysis. It is very interesting to find that U(VI) sorption on TiO_2 was promoted in solutions with higher back-ground electrolyte concentrations. In the presence of U(VI), higher back-ground electrolyte made more TiO_2 particles aggregate through(001) facets, leading more(101) facets to be exposed. Therefore, the reduction of U(VI) was enhanced by the exposed(101) facets and more U(VI) removal was observed.
文摘The adsorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR) for Er(Ⅲ) were investigated. The optima adsorption condition of DAAR for Er(Ⅲ) is pH 6.20 in HAc NaAc medium. The statically saturated adsorption capacity is 189 mg·g -1 resin at 298 K. The Er (Ⅲ) adsorbed on DAAR can be eluted reaching 100% by 2 mol·L -1 HCl used as eluant. The resin can be regenerated and reused without apparent decreasing of adsorption capacity. The apparent adsorption rate constant is k 298 =1.94×10 -5 s -1 . The apparent activation energy is 24.7 kJ·mol -1 . The adsorption behavior of DAAR for Er(Ⅲ) obeys the Freundlich isotherm. The thermodynamic adsorption parameters, enthalpy change Δ H of DAAR for Er(Ⅲ) is 24.1 kJ·mol -1 . The molar coordination ratio of the functional group of DAAR to Er (Ⅲ) is 3∶1. The adsorption mechanism of DAAR for Er (Ⅲ) was examined by using chemical method and IR spectrometry. The coordination compound is formed between oxygen atoms in the functional group of DAAR and Er(Ⅲ).
