The effects of marine environmental factors-temperature （T）, dissolved oxygen （DO）, salinity （S） and pH--on the oxidation-reduction potential （ORP） of natural seawater were studied in laboratory. The results s...The effects of marine environmental factors-temperature （T）, dissolved oxygen （DO）, salinity （S） and pH--on the oxidation-reduction potential （ORP） of natural seawater were studied in laboratory. The results show an indistinct relationship between these four factors and the ORE but they did impact the ORP. Common mathematical methods were not applicable for describing the relationship. Therefore, a grey relational analysis （GRA） method was developed. The degrees of correlation were calculated according to GILA and the values of T, pH, DO and S were 0.744, 0.710, 0.692 and 0.690, respectively. From these values, the relations of these factors to the ORP could be described and evaluated, and those of T and pH were relatively major. In general, ORP is influenced by the synergic effect of T, DO, pH and S, with no single factor having an outstanding role.展开更多
Membrane fouling remains the primary economic barrier to the widespread implementation of membrane bioreactors (MBRs), despite the fact that they lead to the production of high-quality effluent. Operational conditions...Membrane fouling remains the primary economic barrier to the widespread implementation of membrane bioreactors (MBRs), despite the fact that they lead to the production of high-quality effluent. Operational conditions are critical factors influencing membrane fouling. This study aimed to investigate the simultaneous impacts of temperature and hydraulic retention time (HRT) variations on membrane fouling. Experiments were conducted at three different temperatures (18°C, 25°C, and 32°C) and HRTs (6 h, 9 h, and 15 h). The results demonstrated that increases in both temperature and HRT contributed to a reduction in membrane fouling. Additionally, a positive interaction between temperature and HRT was observed in the linear slope variation of membrane permeation, with temperature variations exerting a greater influence on membrane fouling than HRT variations. Fouling factor analysis revealed that increases in temperature and HRT led to decreased concentrations of soluble microbial products (SMP) and extracellular polymeric substances (EPS), particularly carbohydrates, in the activated sludge. Analyses of the cake layer of the membrane indicated that increasing temperature and HRT reduced EPS levels, particularly polysaccharides and proteins;altered primary protein structure;and increased the mean particle size distribution. Ultimately, these changes led to reductions in both reversible and irreversible hydraulic resistances. This study highlights the importance of optimizing operational parameters such as temperature and HRT to enhance membrane performance and treatment efficiency in MBR systems while mitigating fouling.展开更多
To identify the root causes of heavy metal contamination in soils as well as prevent and control such contamination from its sources,this study explored the accumulation patterns and ecological risks of heavy metals l...To identify the root causes of heavy metal contamination in soils as well as prevent and control such contamination from its sources,this study explored the accumulation patterns and ecological risks of heavy metals like Cd and Pb in solid waste in mining areas and across the water body,sediment,soil and agricultural product ecosystem surrounding the mining areas.Focusing on the residual solid waste samples in lead-zinc deposits in a certain area of Guizhou Province,along with samples of topsoils,irrigation water,river sediments,and crops from surrounding areas.This study analyzed the distributions of eight heavy metals,i.e.,Cd,As,Cr,Hg,Pb,Zn,Cu,and Ni,in the samples through field surveys and sample tests.Furthermore,this study assessed the contamination levels and ecological risks of heavy metals in soils,sediments,and agricultural products using methods such as the single-factor index,Nemerow composite index,and potential ecological risk assessment.The results indicate that heavy metals in the solid waste samples all exhibited concentrations exceeding their risk screening values,with 60%greater than their risk intervention values.The soils and sediments demonstrate slight and moderate comprehensive ecological risks of heavy metals.The single-factor potential ecological risks of heavy metals in both the soil and sediment samples decreased in the order of Hg,Cd,Pb,As,Cu,Zn,Cr,and Ni,suggesting the same sources of heavy metals in the soils and sediments.Most of the agricultural product samples exhibited over-limit concentrations of heavy metals dominated by Cd,Pb,Ni,and Cr,excluding Hg and As.The agricultural product assessment using the Nemerow composite index reveals that 35%of the agricultural product samples reached the heavy metal contamination level,implying that the agricultural products from farmland around the solid waste dumps have been contaminated with heavy metals.The eight heavy metals in the soil,sediment,and agricultural product samples manifested high coefficients of variation(CVs),indicating pronounced spatial variability.This suggests that their concentrations in soils,sediments,and agricultural products are significantly influenced by human mining activities.Additionally,the agricultural products exhibit strong transport and accumulation capacities for Cd,Cu,and Zn.展开更多
Expanded polystyrene (EPS) is a common type of microplastics (MPs) often found in coastal areas especially aquaculture areas.It is considered as an important site for microbial colonization and biofilm formation,as we...Expanded polystyrene (EPS) is a common type of microplastics (MPs) often found in coastal areas especially aquaculture areas.It is considered as an important site for microbial colonization and biofilm formation,as well as a carrier of pollutants like heavy metals.However,the dynamic changes of bacterial communities attached to EPS and their interaction with heavy metals are still poorly unknown.In this study,a one-year field exposure experiment was conducted at an aquaculture farm near Donghai Island,in Leizhou Bay,Zhanjiang,Guangdong,in South China Sea.The bacterial communities attached to EPS MPs were examined by 16S r DNA high-throughput sequencing,and the relationships between bacterial biofilms and heavy metals were explored.The results show that there were notable seasonal variations in the bacterial diversity of EPS MPs.Species biodiversity was the highest in summer and the lowest in winter.The greatest number of bacterial species and lowest level of uniformity were observed in the spring.The bacterial community structure changed with exposure time,and the most significant difference in the 12-month group (P<0.05) was found.The dominant bacterial species attached to EPS MPs were mainly Proteobackteria and Firmicutes at the phylum level,and Pseudomonas and Exiguobacterium were dominant at the genus level.Furthermore,EPS MPs acted as transport carriers for potential pathogenic bacteria.High correlations were found between bacterial species and the total concentration of heavy metals on EPS MPs,as well as their speciation fractions.Different chemical speciation of heavy metals migrated and altered over seasons within biofilms,which would further exacerbate the ecological risks.展开更多
From a quantum chemistry standpoint,the impact of the structural properties of the compounds on activated carbon’s adsorption ability was specifically investigated.The compounds whose adsorption behavior followed the...From a quantum chemistry standpoint,the impact of the structural properties of the compounds on activated carbon’s adsorption ability was specifically investigated.The compounds whose adsorption behavior followed the Langmuir isotherm model were selected as the research objects.An optimal quantitative structure-activity relationship(QSAR)model was built by using the multiple linear regression(MLR)method,with the saturation adsorption capacity Q_(m) from the Langmuir adsorption isotherm as the response variable and the structural parameters of 50 organic compounds as independent variables.The results show that the optimal model exhibits good stability,reliability and robustness,with a regression coefficient R^(2)of 0.88,an adjusted regression coefficient R_(adj)^(2) of 0.87,an internal validation coefficient q^(2) of 0.81,and an external validation coefficient Q_(ext)^(2) of 0.68.The variables included in the optimal model indicate that the polarity of the molecule,the molecular potential energy,and the stability and bonding strength of the organic compound are the main factors affecting the adsorption on activated carbon.The results provide key information for predicting the adsorption capacity of organic compounds on activated carbon and offer a theoretical reference for adsorption treatment in water environments.展开更多
Carbon dioxide(CO_(2))is the primary greenhouse gas contributing to anthropogenic climate change which is associated with human activities.The majority of CO_(2) emissions are results of the burning of fossil fuels fo...Carbon dioxide(CO_(2))is the primary greenhouse gas contributing to anthropogenic climate change which is associated with human activities.The majority of CO_(2) emissions are results of the burning of fossil fuels for energy,as well as industrial processes such as steel and cement production.Carbon capture,utilization,and storage(CCUS)is a sustainable technology promising in terms of reducing CO_(2) emissions that would otherwise contribute to climate change.From this perspective,the discussion on carbon capture focuses on chemical absorption technology,primarily due to its commercialization potential.The CO_(2) absorptive capacity and absorption rate of various chemical solvents have been summarized.The carbon utilization focuses on electrochemical conversion routes converting CO_(2) into potentially valuable chemicals which have received particular attention in recent years.The Faradaic conversion efficiencies for various CO_(2) reduction products are used to describe efficiency improvements.For carbon storage,successful deployment relies on a better understanding of fluid mechanics,geomechanics,and reactive transport,which are discussed in details.展开更多
The increasing amount of cyanided tailings produced as a by-product has gained significant attention in recent years because of the rapid development of the gold industry and extensive exploitation of gold mineral res...The increasing amount of cyanided tailings produced as a by-product has gained significant attention in recent years because of the rapid development of the gold industry and extensive exploitation of gold mineral resources. The effective use of these secondary resources is becoming an important and urgent problem for all environmental protection staff. Manganese-catalyzed ozonation for the pre-oxidation of cyanided tailings was studied and the effects of Mn2＋dosage, initial sulfuric acid concentration, ozone volume flow, temperature and agitation speed on pretreatment were examined. The optimum reaction conditions were observed to be： ore pulp density 2.5%, agitation speed 700 r/min,temperature 60°C, Mn2＋dosage 40 g/L, ozone volume flow 80 L/hr, initial sulfuric acid concentration 1 mol/L, and reaction time 6 hr. Under these conditions, the leaching rate of Fe and weight loss could reach 94.85% and 48.89% respectively. The leaching process of cyanided tailings by Mn2＋/O3 was analyzed, and it was found that the leaching of pyrite depends on synergetic oxidation by high-valent manganese and O3, in which the former played an important part.展开更多
Approximately 7000 m^3 of aged refuse （AR） with a placement of over eight years was excavated from Shanghai Refuse Landfill, the largest landfill in China, and used for the construction of a two-stage bioreactor （A...Approximately 7000 m^3 of aged refuse （AR） with a placement of over eight years was excavated from Shanghai Refuse Landfill, the largest landfill in China, and used for the construction of a two-stage bioreactor （AR biofilter） media for the biological treatment of 100 m3 of refuse landfill leachate. It was found that over 64% of COD, 96.9%-99.8% of NH4^＋-N, and 95.8%-99.8% of BOD5 could be removed by the AR biofilter, when the leachate with initial COD, BOD5, and NH4^＋-N concentrations were 986-4128 mg/L, 264--959 mg/L,m and 538-1583 mg/L, respectively. The corresponding concentrations in the effluent were reduced to below 30（000 mg/L, 2-12 mg/L, and 10-20 mg/L, respectively. The effluent was clear and pale yellow with suspended solid below 150 mg/L and color below 150 Pt/Co degree. Meanwhile, the total nitrogen removal was only 49%-63%, indicating a relative poor denitrification capacity of AR biofilter. The effluent pH was neutral and the population of Escherichia coli was less than 10^-1 CFU/mL. Hence, it was considered that the demonstration project can work well for the effective treatment of leachate.展开更多
To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collec...To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collection plates were determined firstly. Then the model parameters for the resistance of perforated and collection plates, obtained by small-scale flow simulation, were validated by medium-scale experiments. Through the comparison of the resistance and velocity distribution between simulation results and experimental data, the simplified model is proved to present the resistance characteristics of perforated and collection plates accurately. Numerical results show that after optimization, both the flow rate and the pressure drop in the upper room of electric field regions are basically equivalent to those of the lower room, and the velocity distribution in flue inlet of WESP becomes more uniform. Through the application in practice, the effectiveness and reliability of the optimization scheme are proved, which can provide valuable reference for further optimization of WESP.展开更多
The occurrence of antibiotics in the environment has recently raised serious concerns regarding their potential threat to human health and aquatic ecosystem. A new magnetic nanocomposite, Fe304@C （Fe304 coated with c...The occurrence of antibiotics in the environment has recently raised serious concerns regarding their potential threat to human health and aquatic ecosystem. A new magnetic nanocomposite, Fe304@C （Fe304 coated with carbon）, was synthesized, characterized, and then applied to remove five commonly-used sulfonamides （SAs） from water. Due to its combinational merits of the outer functionalized carbon shell and the inner magnetite core, Fe3O4@C exhibited a high adsorption affinity for selected SAs and a fast magnetic separability. The adsorption kinetics of SAs on Fe304 @ C could be expressed by the pseudo second-order model. The adsorption isotherms were fitted well with the Dual-mode model, revealing that the adsorption process consisted of an initial partitioning stage and a subsequent hole-filling stage. Solution pH exerted a strong impact on the adsorption process with the maximum removal efficiencies （74% to 96%） obtained at pH 4.8 for all selected SAs. Electrostatic force and hydrogen bonding were two major driving forces for adsorption, and electron-donor-acceptor interactions may also make a certain contribution. Because the synthesized Fe304@C showed comprehensive advantages of high adsorptivity, fast magnetic separability, and prominent reusability, it has potential applications in water treatment.展开更多
Shape controlled structure of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce（NO3）3·6H2O. The resulting products were characterized by X-ray powder diffr...Shape controlled structure of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce（NO3）3·6H2O. The resulting products were characterized by X-ray powder diffraction （XRD）, electron microscopy （SEM） and other techniques. On the basis of the experimental results, CeVO4 nanoparticles exhibited the crystal tetragonal structure and the pH value of solu-tion had an important effect on the crystal structure and morphology of CeVO4 nanoparticles. Furthermore, the tribological properties of CeVO4 nanoparticles as additives in liquid paraffin were evaluated on a four-ball tester. The results indicated that the wear resistance was im-proved by the additive CeVO4 nanoparticles which exhibited very good antiwear and friction reduction performance in wear.展开更多
A hydrophobic hypercrosslinked polymeric resin LC-1 was prepared and characterized. The properties of LC-1 resin were compared with those of a commercial hypercrosstinked polymer NDA-201 resin. In addition, the dynami...A hydrophobic hypercrosslinked polymeric resin LC-1 was prepared and characterized. The properties of LC-1 resin were compared with those of a commercial hypercrosstinked polymer NDA-201 resin. In addition, the dynamic adsorption of trichloroethylene （TCE） onto LC-1 under dry and humid conditions at 303 K was investigated, the result shows that LC-1 possesses high hydrophobic property and can remove TCE from gas stream without effect of high humidity efficiently.展开更多
Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leaching of the ore. Sulfuric acid solution with a flo...Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leaching of the ore. Sulfuric acid solution with a flow rate of 3.12 L·m-2·h-1 and pH 1.5 passed through each column continuously for 90 d. In the first and the second column, bioleaching was performed without agglomeration of the ore and on the agglomerated ore, respectively. 28wt% of the copper was extracted in the first column after 40 d, while this figure was 38wt% in the second column. After 90 d, however, the overall extractions were almost the same for both of them. Bioleaching with mesophilic bacteria was performed in the third column without agglomeration of the ore and in the fourth column on the agglomerated ore. After 40 d, copper extractions in the third and the fourth columns were 62wt% and 70wt%, respectively. Copper extractions were 75wt% for both the columns after 90 d. For the last column, bioleaching was performed with moderate thermophilic bacteria and agglomerated ore. Copper extractions were 80wt% and 85wt% after 40 and 90 d, respectively. It was concluded that crushing and agglomeration of the ore using bacteria could enhance the copper extraction considerably.展开更多
The oxidation of As（Ⅲ） with potassium permanganate was studied under conditions including pH, initial As（Ⅲ） concentration and dosage of Mn（Ⅶ）. The results have shown that potassium permanganate was an effecti...The oxidation of As（Ⅲ） with potassium permanganate was studied under conditions including pH, initial As（Ⅲ） concentration and dosage of Mn（Ⅶ）. The results have shown that potassium permanganate was an effective agent for oxidation of As（Ⅲ） in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As（Ⅲ） by Mn（Ⅲ）. Although theoretical redox analyses suggest that Mn（Ⅶ） should have better performance in oxidization of As（Ⅲ） within lower pH ranges, the experimental results show that the oxidation efficiencies of As（Ⅲ） under basic and acidic conditions were similar, which may be due to the adsorption of As（Ⅲ） on the Mn（OH）2 and MnO2 resulting from the oxidation of As（Ⅲ）.展开更多
The Yaojialing deposit is the first large-scale Zn-Au-Cu polymetallic skarn deposit located in the Shatanjiao ore field of the Tongling area in the Middle-Lower Yangtze belt.It has distinct metallogenic characteristic...The Yaojialing deposit is the first large-scale Zn-Au-Cu polymetallic skarn deposit located in the Shatanjiao ore field of the Tongling area in the Middle-Lower Yangtze belt.It has distinct metallogenic characteristics and is clearly different from the known skarn Cu-Au deposits in the Tongling area and the Middle-Lower Yangtze belt.Previous studies of the Yaojialing deposit have included rock geochemistry,alteration and mineralization characteristics,as well as metallogenesis and metallogenic models.However,there are still numerous problems concerning the coexistence of multiple elements,metallogenetic specialization of the magma and the metallogenic model.In this study,using the latest production exploration work on the deposit,we investigated the Yaojialing deposit including its geological characteristics,petrography,LA-ICP MS zircon U-Pb dating and whole rock geochemistry.Two kinds of magmatic rocks have been distinguished for the first time in the deposit,amongst which the granodiorite porphyry exposed on the surface of the mining area,which is the host rock of the veined lead-zinc ore body,is the wall-rock intrusion;and the deep concealed quartz monzonite porphyry is the causative intrusion,the distribution of orebodies and wall-rock alteration characteristics showing regular zoning around the quartz monzonite porphyry.The^(206)Pb/^(238)U weighted average age of the granodiorite porphyry is 140.2±1.0 Ma(MSWD=0.85,n=13)by LA-ICP MS zircon U-Pb dating,while the quartz monzonite porphyry is 138.9±1.2 Ma(MSWD=0.60,n=16),which is consistent with petrographic evidence.The geochemical characteristics show that the quartz monzonite porphyry is a high-K calc-alkaline series peraluminous rock.The trace element characteristics show that the quartz monzonite porphyry is enriched in LILE such as K,Rb,Sr,Ba and LREE,yet depleted in HFSE such as Nb,Ta,P and Ti.The Yaojialing deposit shows the mineralization characteristics of proximal skarn and distal skarn,having the common characteristics of'multi-storey'and'Trinity'metallogenic models.展开更多
The implementation of ultra-low emission(ULE)limits(SO_(2):35 mg/m3,NOx:50 mg/m3,PM:10 mg/m3)promoted the development of flue gas treatment technologies in China.Pollutant control technology development for Chinese co...The implementation of ultra-low emission(ULE)limits(SO_(2):35 mg/m3,NOx:50 mg/m3,PM:10 mg/m3)promoted the development of flue gas treatment technologies in China.Pollutant control technology development for Chinese coal-fired power plants was summarized and an analysis of the applicability and cost of pollutant control technologies was conducted.Detailed data were collected from 30 ultra-low emission coal-fired units across China.Based on a cost analysis model,the average unit power generation incremental costs were 0.0144and 0.0095 CNY/(kW·hr)for SO_(2)and NOx control technologies,respectively.The unit power generation incremental cost of twin spray tower technology was 7.2%higher than that of dual-loop spray tower technology.The effect of key parameters on operating cost was analyzed.The unit power generation incremental cost increased because of increments in the electricity price for SO_(2)control technology and the price of the reductant in NOx control technology.With high sulfur content or NOx concentration,the unit power generation incremental cost caused by pollutant control increased,whereas the unit pollutant abatement cost decreased.However,the annual operating hours or load increased,thereby leading to a decline in unit power generation incremental cost and unit pollutant abatement cost.展开更多
The performance of the immobilized lysozyme and the native lysozyme on enhancing the excess sludge dewaterability was investigated.The results indicated that the specific resistance to filtration(SRF)decreased by 62.8...The performance of the immobilized lysozyme and the native lysozyme on enhancing the excess sludge dewaterability was investigated.The results indicated that the specific resistance to filtration(SRF)decreased by 62.8%for native lysozyme and 53.6%for immobilized lysozyme at the enzyme dosage of 9 mg/g(dry sludge).Correlation analysis was carried out to explore the role of different extracellular polymeric substance(EPS)fractions on excess sludge dewaterability.The results illustrated that the SRF negatively correlated with protein,polysaccharide from soluble EPS(S-EPS)and loosely bound EPS(LB-EPS)and positively correlated with that from tightly bound EPS(TB-EPS).Three-dimensional excitation emission matrix(3D-EEM)fluorescence analysis combined with the scanning electron microscope(SEM)images,revealed that sludge floc structure and microbial cells were destroyed by enzymatic treatment,and that the enzymatic hydrolysis could help to improve the transformation of hydrophilic groups from TB-EPS and the performance of the excess sludge dewatering process.The assessment of hydrolysis using the immobilized enzyme provided a new insight for the safe disposal of the sludge.展开更多
The pollution of antibiotics commonly existed throughout the entire aquaculture process,but the residues of antibiotics at different aquaculture stages have rarely been studied.This study investigated the occurrence,d...The pollution of antibiotics commonly existed throughout the entire aquaculture process,but the residues of antibiotics at different aquaculture stages have rarely been studied.This study investigated the occurrence,distribution and risk assessment of antibiotics at different aquaculture stages (the non-aquaculture stage,the early aquaculture stage,the middle aquaculture stage,and the late aquaculture stage) in two typical marine aquaculture areas(Mahegang River and Dingzi Bay) surrounding the Yellow Sea.Fluoroquinolones and tetracyclines were commonly used antibiotics in the aquaculture of these areas with high detection frequencies (17%to 83%).Compared among four aquaculture stages,the highest concentration of antibiotics (9032.08 ng/L) in aquaculture ponds was detected at the late aquaculture stage.And the antibiotic pollution level of natural water was directly related to the aquaculture stages.Similarly,at the aquaculture stages,the detection frequency of antibiotics in sediments was higher than that at the non-aquaculture stage.Based on the correlation analysis,the concentration of main antibiotics in water showed a positive correlation with total nitrogen (p<0.05) and chlorophyll a (p<0.01),while it showed a negative correlation with salinity (p<0.01) in coastal water of the Dingzi Bay.According to the risk assessment,with the development of aquaculture stages,the selection pressure of fluoroquinolones and tetracyclines on resistant bacteria had increased.And the ecological risks caused by sulfonamides and tetracyclines to aquatic organisms had also increased markedly.Overall,this study may provide a reference for formulating regulatory policies regarding antibiotic use at different aquaculture stages.展开更多
To prepare tungsten/rubber composites with good gamma-ray shielding performances and fine mechanical properties,a composite surface modifier is employed to make surface modification of the tungsten powders.
Chitosan–metal complexes have been widely studied in wastewater treatment, but there are still various factors in complex preparation which are collectively responsible for improving the adsorption capacity need to b...Chitosan–metal complexes have been widely studied in wastewater treatment, but there are still various factors in complex preparation which are collectively responsible for improving the adsorption capacity need to be further studied. Thus, this study investigates the factors affecting the adsorption ability of chitosan–metal complex adsorbents, including various kinds of metal centers, different metal salts and crosslinking degree. The results show that the chitosan–Fe（ Ⅲ） complex prepared by sulfate salts exhibited the best adsorption efficiency（100%） for various dyes in very short time duration（10 min）, and its maximum adsorption capacity achieved 349.22 mg/g. The anion of the metal salt which was used in preparation played an important role to enhance the adsorption ability of chitosan–metal complex. SO4^（2-） ions not only had the effect of crosslinking through electrostatic interaction with amine group of chitosan polymer, but also could facilitate the chelation of metal ions with chitosan polymer during the synthesis process.Additionally, the p H sensitivity and the sensitivity of ionic environment for chitosan–metal complex were analyzed. We hope that these factors affecting the adsorption of the chitosan–metal complex can help not only in optimizing its use but also in designing new chitosan–metal based complexes.展开更多
基金Supporte by the Knowledge Innovation Project of the Chinese Academy of Sciences (No KZCX2-YW-210)National Key Technology Research and Development Program (No2007BAB27B04)the High Technology Research and Development Program of China (No 2001AA635080)
文摘The effects of marine environmental factors-temperature （T）, dissolved oxygen （DO）, salinity （S） and pH--on the oxidation-reduction potential （ORP） of natural seawater were studied in laboratory. The results show an indistinct relationship between these four factors and the ORE but they did impact the ORP. Common mathematical methods were not applicable for describing the relationship. Therefore, a grey relational analysis （GRA） method was developed. The degrees of correlation were calculated according to GILA and the values of T, pH, DO and S were 0.744, 0.710, 0.692 and 0.690, respectively. From these values, the relations of these factors to the ORP could be described and evaluated, and those of T and pH were relatively major. In general, ORP is influenced by the synergic effect of T, DO, pH and S, with no single factor having an outstanding role.
文摘Membrane fouling remains the primary economic barrier to the widespread implementation of membrane bioreactors (MBRs), despite the fact that they lead to the production of high-quality effluent. Operational conditions are critical factors influencing membrane fouling. This study aimed to investigate the simultaneous impacts of temperature and hydraulic retention time (HRT) variations on membrane fouling. Experiments were conducted at three different temperatures (18°C, 25°C, and 32°C) and HRTs (6 h, 9 h, and 15 h). The results demonstrated that increases in both temperature and HRT contributed to a reduction in membrane fouling. Additionally, a positive interaction between temperature and HRT was observed in the linear slope variation of membrane permeation, with temperature variations exerting a greater influence on membrane fouling than HRT variations. Fouling factor analysis revealed that increases in temperature and HRT led to decreased concentrations of soluble microbial products (SMP) and extracellular polymeric substances (EPS), particularly carbohydrates, in the activated sludge. Analyses of the cake layer of the membrane indicated that increasing temperature and HRT reduced EPS levels, particularly polysaccharides and proteins;altered primary protein structure;and increased the mean particle size distribution. Ultimately, these changes led to reductions in both reversible and irreversible hydraulic resistances. This study highlights the importance of optimizing operational parameters such as temperature and HRT to enhance membrane performance and treatment efficiency in MBR systems while mitigating fouling.
文摘To identify the root causes of heavy metal contamination in soils as well as prevent and control such contamination from its sources,this study explored the accumulation patterns and ecological risks of heavy metals like Cd and Pb in solid waste in mining areas and across the water body,sediment,soil and agricultural product ecosystem surrounding the mining areas.Focusing on the residual solid waste samples in lead-zinc deposits in a certain area of Guizhou Province,along with samples of topsoils,irrigation water,river sediments,and crops from surrounding areas.This study analyzed the distributions of eight heavy metals,i.e.,Cd,As,Cr,Hg,Pb,Zn,Cu,and Ni,in the samples through field surveys and sample tests.Furthermore,this study assessed the contamination levels and ecological risks of heavy metals in soils,sediments,and agricultural products using methods such as the single-factor index,Nemerow composite index,and potential ecological risk assessment.The results indicate that heavy metals in the solid waste samples all exhibited concentrations exceeding their risk screening values,with 60%greater than their risk intervention values.The soils and sediments demonstrate slight and moderate comprehensive ecological risks of heavy metals.The single-factor potential ecological risks of heavy metals in both the soil and sediment samples decreased in the order of Hg,Cd,Pb,As,Cu,Zn,Cr,and Ni,suggesting the same sources of heavy metals in the soils and sediments.Most of the agricultural product samples exhibited over-limit concentrations of heavy metals dominated by Cd,Pb,Ni,and Cr,excluding Hg and As.The agricultural product assessment using the Nemerow composite index reveals that 35%of the agricultural product samples reached the heavy metal contamination level,implying that the agricultural products from farmland around the solid waste dumps have been contaminated with heavy metals.The eight heavy metals in the soil,sediment,and agricultural product samples manifested high coefficients of variation(CVs),indicating pronounced spatial variability.This suggests that their concentrations in soils,sediments,and agricultural products are significantly influenced by human mining activities.Additionally,the agricultural products exhibit strong transport and accumulation capacities for Cd,Cu,and Zn.
基金Supported by the Hainan Province Science and Technology Special Fund (No.ZDYF2022SHFZ317)the Guangdong Province Key Laboratory of Applied Marine Biology (No.2023B1212060047)the Program for Scientific Research Start-up Funds of Guangdong Ocean University (No.060302332301)。
文摘Expanded polystyrene (EPS) is a common type of microplastics (MPs) often found in coastal areas especially aquaculture areas.It is considered as an important site for microbial colonization and biofilm formation,as well as a carrier of pollutants like heavy metals.However,the dynamic changes of bacterial communities attached to EPS and their interaction with heavy metals are still poorly unknown.In this study,a one-year field exposure experiment was conducted at an aquaculture farm near Donghai Island,in Leizhou Bay,Zhanjiang,Guangdong,in South China Sea.The bacterial communities attached to EPS MPs were examined by 16S r DNA high-throughput sequencing,and the relationships between bacterial biofilms and heavy metals were explored.The results show that there were notable seasonal variations in the bacterial diversity of EPS MPs.Species biodiversity was the highest in summer and the lowest in winter.The greatest number of bacterial species and lowest level of uniformity were observed in the spring.The bacterial community structure changed with exposure time,and the most significant difference in the 12-month group (P<0.05) was found.The dominant bacterial species attached to EPS MPs were mainly Proteobackteria and Firmicutes at the phylum level,and Pseudomonas and Exiguobacterium were dominant at the genus level.Furthermore,EPS MPs acted as transport carriers for potential pathogenic bacteria.High correlations were found between bacterial species and the total concentration of heavy metals on EPS MPs,as well as their speciation fractions.Different chemical speciation of heavy metals migrated and altered over seasons within biofilms,which would further exacerbate the ecological risks.
基金National Natural Science Foundation of China(No.21876025)National Key R&D Program of China(No.2023YFC3207204)Shanghai Municipal Education Commission Artificial Intelligence-Enabled Scientific Research Plan,China(No.SMEC-AI-DHUZ-07)。
文摘From a quantum chemistry standpoint,the impact of the structural properties of the compounds on activated carbon’s adsorption ability was specifically investigated.The compounds whose adsorption behavior followed the Langmuir isotherm model were selected as the research objects.An optimal quantitative structure-activity relationship(QSAR)model was built by using the multiple linear regression(MLR)method,with the saturation adsorption capacity Q_(m) from the Langmuir adsorption isotherm as the response variable and the structural parameters of 50 organic compounds as independent variables.The results show that the optimal model exhibits good stability,reliability and robustness,with a regression coefficient R^(2)of 0.88,an adjusted regression coefficient R_(adj)^(2) of 0.87,an internal validation coefficient q^(2) of 0.81,and an external validation coefficient Q_(ext)^(2) of 0.68.The variables included in the optimal model indicate that the polarity of the molecule,the molecular potential energy,and the stability and bonding strength of the organic compound are the main factors affecting the adsorption on activated carbon.The results provide key information for predicting the adsorption capacity of organic compounds on activated carbon and offer a theoretical reference for adsorption treatment in water environments.
基金the National Natural Science Foun-dation of China(51836006).
文摘Carbon dioxide(CO_(2))is the primary greenhouse gas contributing to anthropogenic climate change which is associated with human activities.The majority of CO_(2) emissions are results of the burning of fossil fuels for energy,as well as industrial processes such as steel and cement production.Carbon capture,utilization,and storage(CCUS)is a sustainable technology promising in terms of reducing CO_(2) emissions that would otherwise contribute to climate change.From this perspective,the discussion on carbon capture focuses on chemical absorption technology,primarily due to its commercialization potential.The CO_(2) absorptive capacity and absorption rate of various chemical solvents have been summarized.The carbon utilization focuses on electrochemical conversion routes converting CO_(2) into potentially valuable chemicals which have received particular attention in recent years.The Faradaic conversion efficiencies for various CO_(2) reduction products are used to describe efficiency improvements.For carbon storage,successful deployment relies on a better understanding of fluid mechanics,geomechanics,and reactive transport,which are discussed in details.
基金supported by the Innovation Foundation of Donghua University for Doctoral Candidates (No. BC201132)the Shanghai Leading Academic Discipline Project (No. B604)
文摘The increasing amount of cyanided tailings produced as a by-product has gained significant attention in recent years because of the rapid development of the gold industry and extensive exploitation of gold mineral resources. The effective use of these secondary resources is becoming an important and urgent problem for all environmental protection staff. Manganese-catalyzed ozonation for the pre-oxidation of cyanided tailings was studied and the effects of Mn2＋dosage, initial sulfuric acid concentration, ozone volume flow, temperature and agitation speed on pretreatment were examined. The optimum reaction conditions were observed to be： ore pulp density 2.5%, agitation speed 700 r/min,temperature 60°C, Mn2＋dosage 40 g/L, ozone volume flow 80 L/hr, initial sulfuric acid concentration 1 mol/L, and reaction time 6 hr. Under these conditions, the leaching rate of Fe and weight loss could reach 94.85% and 48.89% respectively. The leaching process of cyanided tailings by Mn2＋/O3 was analyzed, and it was found that the leaching of pyrite depends on synergetic oxidation by high-valent manganese and O3, in which the former played an important part.
文摘Approximately 7000 m^3 of aged refuse （AR） with a placement of over eight years was excavated from Shanghai Refuse Landfill, the largest landfill in China, and used for the construction of a two-stage bioreactor （AR biofilter） media for the biological treatment of 100 m3 of refuse landfill leachate. It was found that over 64% of COD, 96.9%-99.8% of NH4^＋-N, and 95.8%-99.8% of BOD5 could be removed by the AR biofilter, when the leachate with initial COD, BOD5, and NH4^＋-N concentrations were 986-4128 mg/L, 264--959 mg/L,m and 538-1583 mg/L, respectively. The corresponding concentrations in the effluent were reduced to below 30（000 mg/L, 2-12 mg/L, and 10-20 mg/L, respectively. The effluent was clear and pale yellow with suspended solid below 150 mg/L and color below 150 Pt/Co degree. Meanwhile, the total nitrogen removal was only 49%-63%, indicating a relative poor denitrification capacity of AR biofilter. The effluent pH was neutral and the population of Escherichia coli was less than 10^-1 CFU/mL. Hence, it was considered that the demonstration project can work well for the effective treatment of leachate.
文摘To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collection plates were determined firstly. Then the model parameters for the resistance of perforated and collection plates, obtained by small-scale flow simulation, were validated by medium-scale experiments. Through the comparison of the resistance and velocity distribution between simulation results and experimental data, the simplified model is proved to present the resistance characteristics of perforated and collection plates accurately. Numerical results show that after optimization, both the flow rate and the pressure drop in the upper room of electric field regions are basically equivalent to those of the lower room, and the velocity distribution in flue inlet of WESP becomes more uniform. Through the application in practice, the effectiveness and reliability of the optimization scheme are proved, which can provide valuable reference for further optimization of WESP.
基金supported by the National Natural Science Foundation of China(No.51221892)the Ministry of Science and Technology of China(No.2012AA062606,2012BAJ25B04)the People Programme(Marie CurieActions) of the European Union’s Seventh Programme FP7/2007-2013 under a REA grant(No.318926)
文摘The occurrence of antibiotics in the environment has recently raised serious concerns regarding their potential threat to human health and aquatic ecosystem. A new magnetic nanocomposite, Fe304@C （Fe304 coated with carbon）, was synthesized, characterized, and then applied to remove five commonly-used sulfonamides （SAs） from water. Due to its combinational merits of the outer functionalized carbon shell and the inner magnetite core, Fe3O4@C exhibited a high adsorption affinity for selected SAs and a fast magnetic separability. The adsorption kinetics of SAs on Fe304 @ C could be expressed by the pseudo second-order model. The adsorption isotherms were fitted well with the Dual-mode model, revealing that the adsorption process consisted of an initial partitioning stage and a subsequent hole-filling stage. Solution pH exerted a strong impact on the adsorption process with the maximum removal efficiencies （74% to 96%） obtained at pH 4.8 for all selected SAs. Electrostatic force and hydrogen bonding were two major driving forces for adsorption, and electron-donor-acceptor interactions may also make a certain contribution. Because the synthesized Fe304@C showed comprehensive advantages of high adsorptivity, fast magnetic separability, and prominent reusability, it has potential applications in water treatment.
基金supported by the State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences (0804)
文摘Shape controlled structure of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce（NO3）3·6H2O. The resulting products were characterized by X-ray powder diffraction （XRD）, electron microscopy （SEM） and other techniques. On the basis of the experimental results, CeVO4 nanoparticles exhibited the crystal tetragonal structure and the pH value of solu-tion had an important effect on the crystal structure and morphology of CeVO4 nanoparticles. Furthermore, the tribological properties of CeVO4 nanoparticles as additives in liquid paraffin were evaluated on a four-ball tester. The results indicated that the wear resistance was im-proved by the additive CeVO4 nanoparticles which exhibited very good antiwear and friction reduction performance in wear.
基金Department of Environmental Protection of Jiangsu Province for financial support(No.2007029).
文摘A hydrophobic hypercrosslinked polymeric resin LC-1 was prepared and characterized. The properties of LC-1 resin were compared with those of a commercial hypercrosstinked polymer NDA-201 resin. In addition, the dynamic adsorption of trichloroethylene （TCE） onto LC-1 under dry and humid conditions at 303 K was investigated, the result shows that LC-1 possesses high hydrophobic property and can remove TCE from gas stream without effect of high humidity efficiently.
文摘Bioleaching was examined for copper extraction from a low grade ore using mesophilic and moderate thermophilic bacteria. Five equal size columns were used for the leaching of the ore. Sulfuric acid solution with a flow rate of 3.12 L·m-2·h-1 and pH 1.5 passed through each column continuously for 90 d. In the first and the second column, bioleaching was performed without agglomeration of the ore and on the agglomerated ore, respectively. 28wt% of the copper was extracted in the first column after 40 d, while this figure was 38wt% in the second column. After 90 d, however, the overall extractions were almost the same for both of them. Bioleaching with mesophilic bacteria was performed in the third column without agglomeration of the ore and in the fourth column on the agglomerated ore. After 40 d, copper extractions in the third and the fourth columns were 62wt% and 70wt%, respectively. Copper extractions were 75wt% for both the columns after 90 d. For the last column, bioleaching was performed with moderate thermophilic bacteria and agglomerated ore. Copper extractions were 80wt% and 85wt% after 40 and 90 d, respectively. It was concluded that crushing and agglomeration of the ore using bacteria could enhance the copper extraction considerably.
文摘The oxidation of As（Ⅲ） with potassium permanganate was studied under conditions including pH, initial As（Ⅲ） concentration and dosage of Mn（Ⅶ）. The results have shown that potassium permanganate was an effective agent for oxidation of As（Ⅲ） in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As（Ⅲ） by Mn（Ⅲ）. Although theoretical redox analyses suggest that Mn（Ⅶ） should have better performance in oxidization of As（Ⅲ） within lower pH ranges, the experimental results show that the oxidation efficiencies of As（Ⅲ） under basic and acidic conditions were similar, which may be due to the adsorption of As（Ⅲ） on the Mn（OH）2 and MnO2 resulting from the oxidation of As（Ⅲ）.
基金supported by the 812 Geological Teamthe Tongling Nonferrous Metals Group Holdings Co.,Ltd+1 种基金financially supported by the National Key Research and Development Program of China(2016YFC0600206)the Major Research Program of the National Natural Science Foundation of China(91962218)。
文摘The Yaojialing deposit is the first large-scale Zn-Au-Cu polymetallic skarn deposit located in the Shatanjiao ore field of the Tongling area in the Middle-Lower Yangtze belt.It has distinct metallogenic characteristics and is clearly different from the known skarn Cu-Au deposits in the Tongling area and the Middle-Lower Yangtze belt.Previous studies of the Yaojialing deposit have included rock geochemistry,alteration and mineralization characteristics,as well as metallogenesis and metallogenic models.However,there are still numerous problems concerning the coexistence of multiple elements,metallogenetic specialization of the magma and the metallogenic model.In this study,using the latest production exploration work on the deposit,we investigated the Yaojialing deposit including its geological characteristics,petrography,LA-ICP MS zircon U-Pb dating and whole rock geochemistry.Two kinds of magmatic rocks have been distinguished for the first time in the deposit,amongst which the granodiorite porphyry exposed on the surface of the mining area,which is the host rock of the veined lead-zinc ore body,is the wall-rock intrusion;and the deep concealed quartz monzonite porphyry is the causative intrusion,the distribution of orebodies and wall-rock alteration characteristics showing regular zoning around the quartz monzonite porphyry.The^(206)Pb/^(238)U weighted average age of the granodiorite porphyry is 140.2±1.0 Ma(MSWD=0.85,n=13)by LA-ICP MS zircon U-Pb dating,while the quartz monzonite porphyry is 138.9±1.2 Ma(MSWD=0.60,n=16),which is consistent with petrographic evidence.The geochemical characteristics show that the quartz monzonite porphyry is a high-K calc-alkaline series peraluminous rock.The trace element characteristics show that the quartz monzonite porphyry is enriched in LILE such as K,Rb,Sr,Ba and LREE,yet depleted in HFSE such as Nb,Ta,P and Ti.The Yaojialing deposit shows the mineralization characteristics of proximal skarn and distal skarn,having the common characteristics of'multi-storey'and'Trinity'metallogenic models.
基金supported by the National Key Research and Development Program of China(No.2019YFC0214803)Zhejiang Provincial Natural Science Foundation of China(No.LQ21D050002).
文摘The implementation of ultra-low emission(ULE)limits(SO_(2):35 mg/m3,NOx:50 mg/m3,PM:10 mg/m3)promoted the development of flue gas treatment technologies in China.Pollutant control technology development for Chinese coal-fired power plants was summarized and an analysis of the applicability and cost of pollutant control technologies was conducted.Detailed data were collected from 30 ultra-low emission coal-fired units across China.Based on a cost analysis model,the average unit power generation incremental costs were 0.0144and 0.0095 CNY/(kW·hr)for SO_(2)and NOx control technologies,respectively.The unit power generation incremental cost of twin spray tower technology was 7.2%higher than that of dual-loop spray tower technology.The effect of key parameters on operating cost was analyzed.The unit power generation incremental cost increased because of increments in the electricity price for SO_(2)control technology and the price of the reductant in NOx control technology.With high sulfur content or NOx concentration,the unit power generation incremental cost caused by pollutant control increased,whereas the unit pollutant abatement cost decreased.However,the annual operating hours or load increased,thereby leading to a decline in unit power generation incremental cost and unit pollutant abatement cost.
基金“Textile Light”Application Basic Research in China(No.J201503)National Natural Science Foundation of China(No.U1660107)Graduate Innovation Fund of Donghua University,China(No.16D311304)
文摘The performance of the immobilized lysozyme and the native lysozyme on enhancing the excess sludge dewaterability was investigated.The results indicated that the specific resistance to filtration(SRF)decreased by 62.8%for native lysozyme and 53.6%for immobilized lysozyme at the enzyme dosage of 9 mg/g(dry sludge).Correlation analysis was carried out to explore the role of different extracellular polymeric substance(EPS)fractions on excess sludge dewaterability.The results illustrated that the SRF negatively correlated with protein,polysaccharide from soluble EPS(S-EPS)and loosely bound EPS(LB-EPS)and positively correlated with that from tightly bound EPS(TB-EPS).Three-dimensional excitation emission matrix(3D-EEM)fluorescence analysis combined with the scanning electron microscope(SEM)images,revealed that sludge floc structure and microbial cells were destroyed by enzymatic treatment,and that the enzymatic hydrolysis could help to improve the transformation of hydrophilic groups from TB-EPS and the performance of the excess sludge dewatering process.The assessment of hydrolysis using the immobilized enzyme provided a new insight for the safe disposal of the sludge.
基金supported by the National Natural Science Foundation of China (Nos.51709157 and U20A20146)the Youth Interdisciplinary Science and Innovative Research Groups of Shandong University (No.2020QNQT014)。
文摘The pollution of antibiotics commonly existed throughout the entire aquaculture process,but the residues of antibiotics at different aquaculture stages have rarely been studied.This study investigated the occurrence,distribution and risk assessment of antibiotics at different aquaculture stages (the non-aquaculture stage,the early aquaculture stage,the middle aquaculture stage,and the late aquaculture stage) in two typical marine aquaculture areas(Mahegang River and Dingzi Bay) surrounding the Yellow Sea.Fluoroquinolones and tetracyclines were commonly used antibiotics in the aquaculture of these areas with high detection frequencies (17%to 83%).Compared among four aquaculture stages,the highest concentration of antibiotics (9032.08 ng/L) in aquaculture ponds was detected at the late aquaculture stage.And the antibiotic pollution level of natural water was directly related to the aquaculture stages.Similarly,at the aquaculture stages,the detection frequency of antibiotics in sediments was higher than that at the non-aquaculture stage.Based on the correlation analysis,the concentration of main antibiotics in water showed a positive correlation with total nitrogen (p<0.05) and chlorophyll a (p<0.01),while it showed a negative correlation with salinity (p<0.01) in coastal water of the Dingzi Bay.According to the risk assessment,with the development of aquaculture stages,the selection pressure of fluoroquinolones and tetracyclines on resistant bacteria had increased.And the ecological risks caused by sulfonamides and tetracyclines to aquatic organisms had also increased markedly.Overall,this study may provide a reference for formulating regulatory policies regarding antibiotic use at different aquaculture stages.
基金financially supported by the National Natural Science Foundation of China (No. 52078247)Qing Lan Project of Yangzhou University (Dr. LJL)
文摘To prepare tungsten/rubber composites with good gamma-ray shielding performances and fine mechanical properties,a composite surface modifier is employed to make surface modification of the tungsten powders.
基金supported by the National Natural Science Foundation of China (No. 21407021)the Shanghai Yang-Fan Program of Science and Technology Commission of Shanghai (No. 14YF1405000)+1 种基金the National Key Research and Development Program of China (No. 2016YFC0400501)the Fundamental Research Funds for the Central Universities and DHU Distinguished Young Professor Program
文摘Chitosan–metal complexes have been widely studied in wastewater treatment, but there are still various factors in complex preparation which are collectively responsible for improving the adsorption capacity need to be further studied. Thus, this study investigates the factors affecting the adsorption ability of chitosan–metal complex adsorbents, including various kinds of metal centers, different metal salts and crosslinking degree. The results show that the chitosan–Fe（ Ⅲ） complex prepared by sulfate salts exhibited the best adsorption efficiency（100%） for various dyes in very short time duration（10 min）, and its maximum adsorption capacity achieved 349.22 mg/g. The anion of the metal salt which was used in preparation played an important role to enhance the adsorption ability of chitosan–metal complex. SO4^（2-） ions not only had the effect of crosslinking through electrostatic interaction with amine group of chitosan polymer, but also could facilitate the chelation of metal ions with chitosan polymer during the synthesis process.Additionally, the p H sensitivity and the sensitivity of ionic environment for chitosan–metal complex were analyzed. We hope that these factors affecting the adsorption of the chitosan–metal complex can help not only in optimizing its use but also in designing new chitosan–metal based complexes.
