Based on the increasingly serious formaldehyde pollution, effective degradation of formaldehyde has become a practical problem that humans urgently need to solve. Among many treatment methods, activated carbon has the advantages of large specific surface area, high adsorption efficiency, and uniform pore size distribution. As a kind of clean photocatalytic material for formaldehyde degradation, titanium dioxide supported by activated carbon has become a research hotspot to develop adsorption-catalytic materials for formaldehyde degradation. In this paper, the research progress of activated carbon and its modification, the photocatalytic principle and modification of titanium dioxide, and TiO2/AC materials are reviewed. The results show that the pore size distribution gradient and acidic oxygen-containing functional groups of activated carbon play key roles in the formaldehyde adsorption process. TiO2 doped with metal ions and nonmetal ions can significantly improve the photocatalytic activity. The TiO2/AC material can greatly improve the photocatalytic rate and achieve the technical goal of efficient and clean degradation for formaldehyde.
{"title":"Research Progress of Adsorption and Photocatalysis of Formaldehyde on TiO2/AC","authors":"Xinwei Zhu, Denghui Wang, S. Hui","doi":"10.1155/2021/8790974","DOIUrl":"https://doi.org/10.1155/2021/8790974","url":null,"abstract":"Based on the increasingly serious formaldehyde pollution, effective degradation of formaldehyde has become a practical problem that humans urgently need to solve. Among many treatment methods, activated carbon has the advantages of large specific surface area, high adsorption efficiency, and uniform pore size distribution. As a kind of clean photocatalytic material for formaldehyde degradation, titanium dioxide supported by activated carbon has become a research hotspot to develop adsorption-catalytic materials for formaldehyde degradation. In this paper, the research progress of activated carbon and its modification, the photocatalytic principle and modification of titanium dioxide, and TiO2/AC materials are reviewed. The results show that the pore size distribution gradient and acidic oxygen-containing functional groups of activated carbon play key roles in the formaldehyde adsorption process. TiO2 doped with metal ions and nonmetal ions can significantly improve the photocatalytic activity. The TiO2/AC material can greatly improve the photocatalytic rate and achieve the technical goal of efficient and clean degradation for formaldehyde.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43732144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A composite material of sodium dodecyl benzene sulfonate- (SDBS-) modified maifanite and anhydride-modified Fe@SiO2@PEI (PEI) was used as an adsorbent for the removal of hexavalent chromium (Cr(VI)) and bivalent cadmium (Cd(II)) from groundwater by using column experiments and simulated PRB test. In this study, the optimum proportion of SDBS-modified maifanite and anhydride-modified Fe@SiO2@PEI was 5 : 1. In the column experiments, it was found that the penetration time increased with the increase of the initial concentrations (30, 60, and 90 mg/L) and the decrease of the flow rates (5.45, 10.9, and 16.35 mL/min) at an influent pH of 6.5 ± 0.3 . It was also obtained that the removal rates of Cr(VI) and Cd(ІІ) reached 99.93% and 99.79% at an initial Cr(VI) and Cd(ІІ) concentration of 30 mg/L with the flow rate of 10.9 mL/min, respectively, at 6 h. Furthermore, excellent removal effectiveness of Cr(VI) and Cd(ІІ) (85.94% and 83.45%, respectively) was still achieved in simulated PRB test at a flow rate of 5.45 mL/min with the heavy metal solution concentration of 5.0 ± 0.5 mg/L (Cr(VI) and Cd(II) concentration were, respectively, 5.0 ± 0 . 5 mg/L); and the adsorbent had not completely failed by the end of the trial. Yoon-Nelson model was successfully applied to predict the breakthrough curves for the assessment of composite material heavy metal removal performance and was in good agreement with the experimental data of the heavy metal removal efficiency. The strong removal ability of the adsorbent could be attributed to the fact that maifanite with a large diameter can provide support and increase the permeability coefficient and porosity and that zero-valent iron (ZVI) can convert Cr(VI) to Cr(III) and improve the adsorption capacity of maifanite. The obtained results suggested that the novel PRB fillers have great significance for preventing and controlling Cr(VI)/Cd(ІІ)-contaminated groundwater.
{"title":"Remediation of Cr(VI)/Cd(ІІ)-Contaminated Groundwater with Simulated Permeable Reaction Barriers Filled with Composite of Sodium Dodecyl Benzene Sulfonate-Modified Maifanite and Anhydride-Modified Fe@SiO2@Polyethyleneimine: Environmental Factors and Effectiveness","authors":"Jingqing Gao, Yalin Zhai, Zhenzheng Huang, Peng Ren, Jianlei Gao, Zhijun Chen, Shunling Li","doi":"10.1155/2021/4998706","DOIUrl":"https://doi.org/10.1155/2021/4998706","url":null,"abstract":"A composite material of sodium dodecyl benzene sulfonate- (SDBS-) modified maifanite and anhydride-modified Fe@SiO2@PEI (PEI) was used as an adsorbent for the removal of hexavalent chromium (Cr(VI)) and bivalent cadmium (Cd(II)) from groundwater by using column experiments and simulated PRB test. In this study, the optimum proportion of SDBS-modified maifanite and anhydride-modified Fe@SiO2@PEI was 5 : 1. In the column experiments, it was found that the penetration time increased with the increase of the initial concentrations (30, 60, and 90 mg/L) and the decrease of the flow rates (5.45, 10.9, and 16.35 mL/min) at an influent pH of \u0000 \u0000 6.5\u0000 ±\u0000 0.3\u0000 \u0000 . It was also obtained that the removal rates of Cr(VI) and Cd(ІІ) reached 99.93% and 99.79% at an initial Cr(VI) and Cd(ІІ) concentration of 30 mg/L with the flow rate of 10.9 mL/min, respectively, at 6 h. Furthermore, excellent removal effectiveness of Cr(VI) and Cd(ІІ) (85.94% and 83.45%, respectively) was still achieved in simulated PRB test at a flow rate of 5.45 mL/min with the heavy metal solution concentration of \u0000 \u0000 5.0\u0000 ±\u0000 0.5\u0000 \u0000 mg/L (Cr(VI) and Cd(II) concentration were, respectively, \u0000 \u0000 5.0\u0000 ±\u0000 0\u0000 .\u0000 \u0000 5 mg/L); and the adsorbent had not completely failed by the end of the trial. Yoon-Nelson model was successfully applied to predict the breakthrough curves for the assessment of composite material heavy metal removal performance and was in good agreement with the experimental data of the heavy metal removal efficiency. The strong removal ability of the adsorbent could be attributed to the fact that maifanite with a large diameter can provide support and increase the permeability coefficient and porosity and that zero-valent iron (ZVI) can convert Cr(VI) to Cr(III) and improve the adsorption capacity of maifanite. The obtained results suggested that the novel PRB fillers have great significance for preventing and controlling Cr(VI)/Cd(ІІ)-contaminated groundwater.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":"1 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64758993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The distribution characteristics of typical heavy metals (HMs) and Pb isotopic compositions in profile soils from different areas were investigated in Baiyin district, northwest China. The soil samples from the ore district and the sewage irrigation area showed an obvious enrichment of HMs in different depths, and the difference in the longitudinal migration depth of Pb, Cu, Zn, and Cd was insignificant, which might be due to the migration behavior of HMs mainly controlled by carbonate in alkaline soil. With the sewage irrigation activities, the content of soil organic matter was no longer the main controlling factor for the migration behavior of HMs. In ore district and sewage irrigation area, the HMs contents of nonresidual fractions in topsoil were much higher than that in the corresponding deep soil, which indicated that HMs activities in topsoil were significantly high. The Pb isotopic compositions of profile soils indicated that the long-term mining and smelting activities remained the main source of vertical enrichment of HMs in Baiyin district. Moreover, the Pb isotope ratios 206Pb/207Pb of nonresidual fractions (1.1359-1.1916) were all lower than that in the corresponding residual fractions (1.1641-1.2010), showing the characteristics that HMs input from anthropogenic source were in different degrees. The Pb isotopic compositions of residual fractions in the topsoil of ore district and sewage irrigation area (1.1641 and 1.1703) were between the two end-members composed of background soil and local mineral samples, which suggested that some anthropogenic HMs might enter into the residual components in the soil that was greatly affected by the input of HMs.
{"title":"Distribution Characteristics of Heavy Metals and Pb Isotope in Profile Soils from a Mining and Smelting Area in Northwestern China","authors":"Bihong He, Weixue Xie, Yuhui Wang, Wentao Zhang, Xueyun Ma, Jianjun Liang, Ping Li, Q. Fan","doi":"10.1155/2021/5913182","DOIUrl":"https://doi.org/10.1155/2021/5913182","url":null,"abstract":"The distribution characteristics of typical heavy metals (HMs) and Pb isotopic compositions in profile soils from different areas were investigated in Baiyin district, northwest China. The soil samples from the ore district and the sewage irrigation area showed an obvious enrichment of HMs in different depths, and the difference in the longitudinal migration depth of Pb, Cu, Zn, and Cd was insignificant, which might be due to the migration behavior of HMs mainly controlled by carbonate in alkaline soil. With the sewage irrigation activities, the content of soil organic matter was no longer the main controlling factor for the migration behavior of HMs. In ore district and sewage irrigation area, the HMs contents of nonresidual fractions in topsoil were much higher than that in the corresponding deep soil, which indicated that HMs activities in topsoil were significantly high. The Pb isotopic compositions of profile soils indicated that the long-term mining and smelting activities remained the main source of vertical enrichment of HMs in Baiyin district. Moreover, the Pb isotope ratios 206Pb/207Pb of nonresidual fractions (1.1359-1.1916) were all lower than that in the corresponding residual fractions (1.1641-1.2010), showing the characteristics that HMs input from anthropogenic source were in different degrees. The Pb isotopic compositions of residual fractions in the topsoil of ore district and sewage irrigation area (1.1641 and 1.1703) were between the two end-members composed of background soil and local mineral samples, which suggested that some anthropogenic HMs might enter into the residual components in the soil that was greatly affected by the input of HMs.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45324642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qi Jing, Shuo Qiao, Wenyu Xiao, Le Tong, Zhongyu Ren
In this study, nano zero-valent iron-reduced graphene oxide (NZVI-rGO) composites were synthesized to remove 2,4-dichlorophenol (2,4-DCP) as an efficient adsorbent. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicated that NZVI particles were successfully loaded and dispersed uniformly on rGO nanosheets. Fourier transform infrared spectroscopy (FTIR) analysis showed that the interaction between NZVI-rGO and 2,4-DCP promoted the adsorption process. A three-level, four-factor Box-Behnken design (BBD) of the response surface methodology (RSM) was used to optimize the influencing factors including NZVI-rGO dosage, 2,4-DCP initial concentration, reaction time and initial pH. A statistically significant, well-fitting quadratic regression model was successfully constructed to predict 2,4-DCP removal rate. The high F value (15.95), very low P value (<0.0001), nonsignificant lack of fit, and appropriate coefficient of determination ( R 2 = 0.941 ) demonstrate a good correlation between the experimental and predicted values of the proposed model. The analyses of variance reveal that NZVI-rGO dosage and reaction time have a positive effect on 2,4-DCP removal, whereas the increase of contaminant concentration and initial pH inhibit the removal, whereas the effect of contaminant concentration and initial pH is in reverse, where the change of NZVI-rGO dosage has the greatest effect. The optimum condition is1.215 g/L of NZVI-rGO dosage, 20.856 mg/L of 2,4-DCP concentration, 4.115 of pH, and 8.157 min of reaction time. It is verified by parallel experiments under the optimum condition, achieving the removal efficiency of100%.
{"title":"Efficient Removal of 2,4-DCP by Nano Zero-Valent Iron-Reduced Graphene Oxide: Statistical Modeling and Process Optimization Using RSM-BBD Approach","authors":"Qi Jing, Shuo Qiao, Wenyu Xiao, Le Tong, Zhongyu Ren","doi":"10.1155/2021/7130581","DOIUrl":"https://doi.org/10.1155/2021/7130581","url":null,"abstract":"In this study, nano zero-valent iron-reduced graphene oxide (NZVI-rGO) composites were synthesized to remove 2,4-dichlorophenol (2,4-DCP) as an efficient adsorbent. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicated that NZVI particles were successfully loaded and dispersed uniformly on rGO nanosheets. Fourier transform infrared spectroscopy (FTIR) analysis showed that the interaction between NZVI-rGO and 2,4-DCP promoted the adsorption process. A three-level, four-factor Box-Behnken design (BBD) of the response surface methodology (RSM) was used to optimize the influencing factors including NZVI-rGO dosage, 2,4-DCP initial concentration, reaction time and initial pH. A statistically significant, well-fitting quadratic regression model was successfully constructed to predict 2,4-DCP removal rate. The high \u0000 \u0000 F\u0000 \u0000 value (15.95), very low \u0000 \u0000 P\u0000 \u0000 value (<0.0001), nonsignificant lack of fit, and appropriate coefficient of determination (\u0000 \u0000 \u0000 \u0000 R\u0000 \u0000 \u0000 2\u0000 \u0000 \u0000 =\u0000 0.941\u0000 \u0000 ) demonstrate a good correlation between the experimental and predicted values of the proposed model. The analyses of variance reveal that NZVI-rGO dosage and reaction time have a positive effect on 2,4-DCP removal, whereas the increase of contaminant concentration and initial pH inhibit the removal, whereas the effect of contaminant concentration and initial pH is in reverse, where the change of NZVI-rGO dosage has the greatest effect. The optimum condition is1.215 g/L of NZVI-rGO dosage, 20.856 mg/L of 2,4-DCP concentration, 4.115 of pH, and 8.157 min of reaction time. It is verified by parallel experiments under the optimum condition, achieving the removal efficiency of100%.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41539373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Do, Minh Nguyet Ha, T. Nguyen, H. Ha, T. Nguyen
In this article, ZnO-Ag nanohybrids were chemically synthesized in the aqueous medium by reducing silver nitrate with sodium borohydride NaBH4. These nanohybrids were then homogeneously dispersed into the diacrylate urethane/1,6-hexanediol diacrylate resin system at a content of 2 wt%. The structural morphology, mechanical resistances, and crosslinking of the as-prepared nanocomposite coating (nanocoating) were evaluated. The antimicrobial characteristic was tested by keeping track of the lag-log growth phase of E. coli bacteria in the coating existence among cell cultures. The obtained data indicated that the nanohybrids added into the UV curing diacrylate urethane matrices had significantly increased the abrasion resistance, relative hardness, and conversion of the acrylate groups of the nanocoating. In addition, the antibacterial test revealed that the nanocoating had good antibacterial property against E. coli, whereas for the pure coating (without ZnO-Ag nanoparticles), there was no antibacterial activity observed.
{"title":"Crosslinking, Mechanical Properties, and Antimicrobial Activity of Photocurable Diacrylate Urethane/ZnO-Ag Nanocomposite Coating","authors":"T. Do, Minh Nguyet Ha, T. Nguyen, H. Ha, T. Nguyen","doi":"10.1155/2021/7387160","DOIUrl":"https://doi.org/10.1155/2021/7387160","url":null,"abstract":"In this article, ZnO-Ag nanohybrids were chemically synthesized in the aqueous medium by reducing silver nitrate with sodium borohydride NaBH4. These nanohybrids were then homogeneously dispersed into the diacrylate urethane/1,6-hexanediol diacrylate resin system at a content of 2 wt%. The structural morphology, mechanical resistances, and crosslinking of the as-prepared nanocomposite coating (nanocoating) were evaluated. The antimicrobial characteristic was tested by keeping track of the lag-log growth phase of E. coli bacteria in the coating existence among cell cultures. The obtained data indicated that the nanohybrids added into the UV curing diacrylate urethane matrices had significantly increased the abrasion resistance, relative hardness, and conversion of the acrylate groups of the nanocoating. In addition, the antibacterial test revealed that the nanocoating had good antibacterial property against E. coli, whereas for the pure coating (without ZnO-Ag nanoparticles), there was no antibacterial activity observed.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46363478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nitrogen and phosphorus are commonly recognized as causing eutrophication in aquatic systems, and their transport in subsurface environments has also aroused great public attention. This research presented four natural clay minerals (NCMs) evaluated for their effectiveness of NH4+ and PO43- adsorption from wastewater. All the NCMs were fully characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), BET analysis, and adsorption kinetics and isotherms to better understand the adsorption mechanism-property relationship. The results show that the adsorption efficiency of the four NCMs for phosphate was better than that for ammonia nitrogen. The removal rate of phosphate was higher than 65%, generally in the range of 80%-90%, while the removal rate of ammonia nitrogen was less than 50%. The adsorption kinetic behavior followed the pseudo-second-order kinetic model. The ammonia nitrogen adsorption isotherm was in good agreement with the Freundlich isotherm equilibrium model, and the phosphate adsorption isotherm matched the Langmuir model. Among all the NCMs studied, bentonite (7.13 mg/g) and kaolinite (5.37 mg/g) showed higher adsorption capacities for ammonia nitrogen, while zeolite (0.21 mg/g) and attapulgite (0.17 mg/g) showed higher adsorption capacities for phosphate. This study provides crucial baseline knowledge for the adsorption of nitrogen and phosphate by different kinds of NCMs.
{"title":"Experimental Study of the Adsorption of Nitrogen and Phosphorus by Natural Clay Minerals","authors":"T. Fan, Miao Wang, Xingming Wang, Yingxiang Chen, Shun Wang, Hongbin Zhan, Xiaoyang Chen, Akang Lu, Shijiao Zha","doi":"10.1155/2021/4158151","DOIUrl":"https://doi.org/10.1155/2021/4158151","url":null,"abstract":"Nitrogen and phosphorus are commonly recognized as causing eutrophication in aquatic systems, and their transport in subsurface environments has also aroused great public attention. This research presented four natural clay minerals (NCMs) evaluated for their effectiveness of NH4+ and PO43- adsorption from wastewater. All the NCMs were fully characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), BET analysis, and adsorption kinetics and isotherms to better understand the adsorption mechanism-property relationship. The results show that the adsorption efficiency of the four NCMs for phosphate was better than that for ammonia nitrogen. The removal rate of phosphate was higher than 65%, generally in the range of 80%-90%, while the removal rate of ammonia nitrogen was less than 50%. The adsorption kinetic behavior followed the pseudo-second-order kinetic model. The ammonia nitrogen adsorption isotherm was in good agreement with the Freundlich isotherm equilibrium model, and the phosphate adsorption isotherm matched the Langmuir model. Among all the NCMs studied, bentonite (7.13 mg/g) and kaolinite (5.37 mg/g) showed higher adsorption capacities for ammonia nitrogen, while zeolite (0.21 mg/g) and attapulgite (0.17 mg/g) showed higher adsorption capacities for phosphate. This study provides crucial baseline knowledge for the adsorption of nitrogen and phosphate by different kinds of NCMs.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49374562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lu Peng, Qiming Mao, Lin-Ying Cao, Hailong Sun, Xiande Xie, S. Luo
The eco-restoration was a very effective measure to solve the problem of environmental pollution caused by the exposed mine surface in the stone coal mine site. In this study, the dominant plant, Indigofera amblyantha Craib, was well adapted to the eco-restoration in stone coal mining area. The changes of nutrient elements, pH, heavy metals in substrate material, the biological concentration/transfer factor, and the distribution and diversity of bacteria and fungi in rhizosphere soil were investigated. The results show that the plant communities help slow down the loss of nutrient elements and the increase of the concentrations of heavy metals in the eco-restoration process. The Indigofera amblyantha Craib had the advantaged ability to enrich and transfer Cd, Cu, Mn, and its diversity index of microbial communities in rhizosphere soils was higher than that of other quadrats. These excellent properties found in this work help reveal the insight into the adaptability of Indigofera amblyantha Craib in the eco-restoration of stone coal mines. It is valuable to evaluate Indigofera amblyantha Craib for eco-restoration engineering of stone coal mine and extend the application in heavy metal contaminated sites.
{"title":"Insight into the Adaptability of Dominant Plant Indigofera amblyantha Craib for Ecological Restoration of Rock Slopes in Stone Coal Mine","authors":"Lu Peng, Qiming Mao, Lin-Ying Cao, Hailong Sun, Xiande Xie, S. Luo","doi":"10.1155/2021/3827991","DOIUrl":"https://doi.org/10.1155/2021/3827991","url":null,"abstract":"The eco-restoration was a very effective measure to solve the problem of environmental pollution caused by the exposed mine surface in the stone coal mine site. In this study, the dominant plant, Indigofera amblyantha Craib, was well adapted to the eco-restoration in stone coal mining area. The changes of nutrient elements, pH, heavy metals in substrate material, the biological concentration/transfer factor, and the distribution and diversity of bacteria and fungi in rhizosphere soil were investigated. The results show that the plant communities help slow down the loss of nutrient elements and the increase of the concentrations of heavy metals in the eco-restoration process. The Indigofera amblyantha Craib had the advantaged ability to enrich and transfer Cd, Cu, Mn, and its diversity index of microbial communities in rhizosphere soils was higher than that of other quadrats. These excellent properties found in this work help reveal the insight into the adaptability of Indigofera amblyantha Craib in the eco-restoration of stone coal mines. It is valuable to evaluate Indigofera amblyantha Craib for eco-restoration engineering of stone coal mine and extend the application in heavy metal contaminated sites.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44621936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, polypyrrole-modified red mud (PRM) was prepared for the efficient removal of anionic dyes (methyl orange and Congo red) from aqueous solutions. The phytotoxicity (bean sprouts) of the dye solution before and after dye removal was investigated. Adsorption kinetics confirmed that the adsorption of methyl orange (MO) and Congo red (CR) on PRM was controlled by chemical reactions between the functional groups of polypyrrole and dyes. From Langmuir isotherm fitting, we found the theoretical adsorption capacities of MO and CR on PRM were 194.1 and 314.9 mg/g, respectively. The adsorption progress of MO and CR on PRM was found to be spontaneous and endothermic. The column studies demonstrated that, under dynamic flow, the PRM can efficiently remove MO and CR from aqueous solution, with adsorption capacities of 31.08 and 55.04 mg/g, respectively. In the toxicity test, the phytotoxicity of the column effluents (after dye removal) was significantly lowered compared to the initial dye influents. After the removal of MO and CR, the average root length of bean sprouts was increased from 3.30 cm to 5.18 cm and from 3.01 cm to 7.00 cm, respectively. These findings highlighted the efficient removal of dyes by PRM from aqueous solution, demonstrating the possible application of PRM for the removal of dye from dye-contaminated wastewaters.
{"title":"Anionic Dye Removal by Polypyrrole-Modified Red Mud and Its Application to a Lab-Scale Column: Adsorption Performance and Phytotoxicity Assessment","authors":"Feng Zhang, Yue Yin, Chunlei Qiao, Yabin Luan, Mengyan Guo, Yihua Xiao, Changqing Liu","doi":"10.1155/2021/7694783","DOIUrl":"https://doi.org/10.1155/2021/7694783","url":null,"abstract":"In this study, polypyrrole-modified red mud (PRM) was prepared for the efficient removal of anionic dyes (methyl orange and Congo red) from aqueous solutions. The phytotoxicity (bean sprouts) of the dye solution before and after dye removal was investigated. Adsorption kinetics confirmed that the adsorption of methyl orange (MO) and Congo red (CR) on PRM was controlled by chemical reactions between the functional groups of polypyrrole and dyes. From Langmuir isotherm fitting, we found the theoretical adsorption capacities of MO and CR on PRM were 194.1 and 314.9 mg/g, respectively. The adsorption progress of MO and CR on PRM was found to be spontaneous and endothermic. The column studies demonstrated that, under dynamic flow, the PRM can efficiently remove MO and CR from aqueous solution, with adsorption capacities of 31.08 and 55.04 mg/g, respectively. In the toxicity test, the phytotoxicity of the column effluents (after dye removal) was significantly lowered compared to the initial dye influents. After the removal of MO and CR, the average root length of bean sprouts was increased from 3.30 cm to 5.18 cm and from 3.01 cm to 7.00 cm, respectively. These findings highlighted the efficient removal of dyes by PRM from aqueous solution, demonstrating the possible application of PRM for the removal of dye from dye-contaminated wastewaters.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45822306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kashir Ali, Muhammad Usama Javaid, Zaman Ali, Muhammad Junaid Zaghum
Wastewater has a high concentration of dyes and heavy metals, which are the two most significant contaminants. Due to their high toxicity and vulnerability, they possess a potential threat to human health as well as the ecosystem. There are many ways to eliminate these pollutants from water but adsorption has attained much interest because of its low cost, easy application, and no secondary pollutants. Biomass is considered an ecological burden and a reason for the reduction in the earth’s carrying capacity. These materials may be used as cost-effective adsorbents to remove dyes and heavy metals from wastewater. This paper highlights recent advances made in dye and heavy metal adsorption in the last 10 years. The prime focus of this review paper is on the direct application of these biomasses without any chemical or physical alteration. The removal efficiencies and adsorption capabilities of different biomass-derived adsorbents for the removal of dyes and heavy metals from wastewater are summarised in this study. Additionally, the adsorption mechanisms underlying the removal of dyes and heavy metals using biomass-derived adsorbents have been discussed, with a focus on two kinetic models: pseudofirst-order and pseudosecond-order. Furthermore, the Langmuir and Freundlich isotherms were utilised to verify the experimental findings and to quantify the amount and degree of adsorption favorability. Based on what has been covered in the literature, the conclusion has been drawn. The future research needs are proposed in the area of biomass-derived adsorbent development, their modification for improved efficiencies, and application on large-scale wastewater treatment plants.
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Metal (Fe) and nonmetal (P) were used to modify TiO2, and then, several functional groups such as P-O, P=O, Fe-O, and -OH were introduced on its surface to enhance the adsorption capacity for Cd(II), which could reach 121 mg/g. According to the experimental analysis of adsorption performance, chemical adsorption dominates the adsorption process, and the adsorption capacity increases with increasing temperature within a certain range. The results of competitive adsorption experiments showed that both Pb(II) and Cu(II) affect the adsorption of Cd(II) and that the adsorption order of P-Fe-TiO2 for heavy metal ions is Pb II > Cd II > Cu II . We further investigated the adsorption mechanism of P-Fe-TiO2 for Cd(II) and the reasons for the difference in competitive adsorption and used DFT calculations to confirm the experimental results. In the analysis of binding energy and frontier molecular orbitals (FMOs), we confirmed that charge transfer occurred during the adsorption process, so chemical reactions occurred. The binding energy of P-Fe-TiO2 and Pb(II) is the largest. The results of the competitive adsorption experiment also confirmed that the adsorbent has the greatest effect on Pb. Mulliken analysis was used to identify the best binding site on the adsorbent. The results of electrostatic potential, total potential, and differential charge analysis further prove the conclusions described above.
利用金属(Fe)和非金属(P)对TiO2进行修饰，在其表面引入P-O、P=O、Fe-O和-OH等官能团，提高了TiO2对Cd(II)的吸附能力，吸附量可达121 mg/g。根据吸附性能的实验分析，化学吸附在吸附过程中占主导地位，吸附量在一定范围内随温度的升高而增大。竞争吸附实验结果表明，Pb(II)和Cu(II)对Cd(II)的吸附均有影响，P-Fe-TiO2对重金属离子的吸附顺序为Pb II > Cd II > Cu II。我们进一步研究了P-Fe-TiO2对Cd(II)的吸附机理和竞争吸附差异的原因，并利用DFT计算对实验结果进行了验证。在结合能和前沿分子轨道(FMOs)的分析中，我们证实了吸附过程中发生了电荷转移，因此发生了化学反应。P-Fe-TiO2与Pb(II)的结合能最大。竞争吸附实验结果也证实了吸附剂对铅的吸附效果最大。用Mulliken分析法确定吸附剂上的最佳结合位点。静电势、总势和差电荷分析的结果进一步证明了上述结论。
{"title":"Electron-Scale Insights into the Single and Coadsorption Cd(II) Behaviors of a Metal-Nonmetal-Modified Titanium Dioxide","authors":"Jingjing Ren, Liuchun Zheng, Feixiong Yang, Hua-Zhi Yu, Tao Zhang, Qianya Zhou, Hao Zeng, Lijuan Zhang, Peipei Meng","doi":"10.1155/2021/4556493","DOIUrl":"https://doi.org/10.1155/2021/4556493","url":null,"abstract":"Metal (Fe) and nonmetal (P) were used to modify TiO2, and then, several functional groups such as P-O, P=O, Fe-O, and -OH were introduced on its surface to enhance the adsorption capacity for Cd(II), which could reach 121 mg/g. According to the experimental analysis of adsorption performance, chemical adsorption dominates the adsorption process, and the adsorption capacity increases with increasing temperature within a certain range. The results of competitive adsorption experiments showed that both Pb(II) and Cu(II) affect the adsorption of Cd(II) and that the adsorption order of P-Fe-TiO2 for heavy metal ions is \u0000 \u0000 Pb\u0000 \u0000 \u0000 II\u0000 \u0000 \u0000 >\u0000 Cd\u0000 \u0000 \u0000 II\u0000 \u0000 \u0000 >\u0000 Cu\u0000 \u0000 \u0000 II\u0000 \u0000 \u0000 \u0000 . We further investigated the adsorption mechanism of P-Fe-TiO2 for Cd(II) and the reasons for the difference in competitive adsorption and used DFT calculations to confirm the experimental results. In the analysis of binding energy and frontier molecular orbitals (FMOs), we confirmed that charge transfer occurred during the adsorption process, so chemical reactions occurred. The binding energy of P-Fe-TiO2 and Pb(II) is the largest. The results of the competitive adsorption experiment also confirmed that the adsorbent has the greatest effect on Pb. Mulliken analysis was used to identify the best binding site on the adsorbent. The results of electrostatic potential, total potential, and differential charge analysis further prove the conclusions described above.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42269772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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