H. Reynel-Ávila, K. I. Camacho-Aguilar, A. Bonilla-Petriciolet, D. Mendoza-Castillo, H. A. González-Ponce, R. Trejo-Valencia
This review covers the preparation, characterization, and application of magnetic adsorbents obtained from carbon-based sources and their application in the adsorption of both inorganic and organic pollutants from water. Different preparation routes to obtain magnetic adsorbents from activated carbon, biochar, hydrochar, graphene, carbon dots, carbon nanotubes, and carbon nanocages, including the magnetic phase incorporated on the solid surface, are described and discussed. The performance of these adsorbents is analyzed for the removal of fluoride, arsenic, heavy metals, dyes, pesticides, pharmaceuticals, and other emerging and relevant water pollutants. Properties of these adsorbents and the corresponding adsorption mechanisms have been included in this review. Overall, this type of magnetic adsorbents offers an alternative for facing the operational problems associated to adsorption process in water treatment. However, some gaps have been identified in the proper physicochemical characterization of these adsorbents, the development of green and low-cost preparation methods for their industrial production and commercialization, the regeneration and final disposal of spent adsorbents, and their application in the multicomponent adsorption of water pollutants.
{"title":"Engineered Magnetic Carbon-Based Adsorbents for the Removal of Water Priority Pollutants: An Overview","authors":"H. Reynel-Ávila, K. I. Camacho-Aguilar, A. Bonilla-Petriciolet, D. Mendoza-Castillo, H. A. González-Ponce, R. Trejo-Valencia","doi":"10.1155/2021/9917444","DOIUrl":"https://doi.org/10.1155/2021/9917444","url":null,"abstract":"This review covers the preparation, characterization, and application of magnetic adsorbents obtained from carbon-based sources and their application in the adsorption of both inorganic and organic pollutants from water. Different preparation routes to obtain magnetic adsorbents from activated carbon, biochar, hydrochar, graphene, carbon dots, carbon nanotubes, and carbon nanocages, including the magnetic phase incorporated on the solid surface, are described and discussed. The performance of these adsorbents is analyzed for the removal of fluoride, arsenic, heavy metals, dyes, pesticides, pharmaceuticals, and other emerging and relevant water pollutants. Properties of these adsorbents and the corresponding adsorption mechanisms have been included in this review. Overall, this type of magnetic adsorbents offers an alternative for facing the operational problems associated to adsorption process in water treatment. However, some gaps have been identified in the proper physicochemical characterization of these adsorbents, the development of green and low-cost preparation methods for their industrial production and commercialization, the regeneration and final disposal of spent adsorbents, and their application in the multicomponent adsorption of water pollutants.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41734279","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}
G. Yan, P. Wang, Yuqian Li, Zhangjie Qin, Shuai Lan, Yupeng Yan, Qin Zhang, Xiaodi Cheng
The material, δ-MnO2, has exhibited superior performance on the removal of methylene blue (MB), but the process is significantly impacted by pH, and the impacting mechanism is still unclear. In this study, the effects of pH on the removal mechanism of MB using synthesized δ-MnO2 were investigated by distinguishing the adsorption and oxidation of MB by δ-MnO2 during the removal process in the dark. The results show that the total removal efficiency of MB by δ-MnO2 decreased significantly with an increase in the pH. MB could be removed by δ-MnO2 via an adsorption mechanism and oxidation mechanism, and the proportion of adsorptive removal and oxidative removal was different under different pH conditions. With an increase in the initial pH from 2.00 to 8.05, the redox potential of δ-MnO2 decreased, and its oxidation ability for the removal of MB also gradually decreased. In contrast, the surface negative charges of δ-MnO2 increased with an increase in the pH, and the adsorption ability towards positively charged MB also gradually increased. This indicates that the effects of pH on the removal of MB by δ-MnO2 are primarily dominated by its influence on the oxidation ability of δ-MnO2. In addition, it is further proved that the pH value has a significant effect on the oxidation and adsorption of MB on δ-MnO2. Moreover, the significant effects of pH on the oxidation of MB by δ-MnO2 are further demonstrated by observing the changes in Mn2+ and the UV-Vis spectra of intermediate products during the reaction, as well as the changes in the FTIR and XPS characterizations of δ-MnO2 after the reaction.
{"title":"Adsorption-Oxidation Mechanism of δ-MnO2 to Remove Methylene Blue","authors":"G. Yan, P. Wang, Yuqian Li, Zhangjie Qin, Shuai Lan, Yupeng Yan, Qin Zhang, Xiaodi Cheng","doi":"10.1155/2021/3069392","DOIUrl":"https://doi.org/10.1155/2021/3069392","url":null,"abstract":"The material, δ-MnO2, has exhibited superior performance on the removal of methylene blue (MB), but the process is significantly impacted by pH, and the impacting mechanism is still unclear. In this study, the effects of pH on the removal mechanism of MB using synthesized δ-MnO2 were investigated by distinguishing the adsorption and oxidation of MB by δ-MnO2 during the removal process in the dark. The results show that the total removal efficiency of MB by δ-MnO2 decreased significantly with an increase in the pH. MB could be removed by δ-MnO2 via an adsorption mechanism and oxidation mechanism, and the proportion of adsorptive removal and oxidative removal was different under different pH conditions. With an increase in the initial pH from 2.00 to 8.05, the redox potential of δ-MnO2 decreased, and its oxidation ability for the removal of MB also gradually decreased. In contrast, the surface negative charges of δ-MnO2 increased with an increase in the pH, and the adsorption ability towards positively charged MB also gradually increased. This indicates that the effects of pH on the removal of MB by δ-MnO2 are primarily dominated by its influence on the oxidation ability of δ-MnO2. In addition, it is further proved that the pH value has a significant effect on the oxidation and adsorption of MB on δ-MnO2. Moreover, the significant effects of pH on the oxidation of MB by δ-MnO2 are further demonstrated by observing the changes in Mn2+ and the UV-Vis spectra of intermediate products during the reaction, as well as the changes in the FTIR and XPS characterizations of δ-MnO2 after the reaction.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47132397","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}
Soil leucine aminopeptidase (LAP) is a hydrolytic enzyme involved in the acquisition of nitrogen by microorganisms. In contaminated soils, LAP activity is affected not only by the type and concentration of heavy metals but also by the form of enzyme. Here, we investigated the degree and mechanism of cadmium (Cd) inhibition of soil LAP and purified LAP. We also examined the effect of montmorillonite and kaolinite on LAP and LAP contaminated with Cd. The results showed that Cd inhibition of LAP activity increased with increasing Cd concentration and that Cd exerted noncompetitive inhibition of LAP. The addition of clay minerals decreases LAP activity and the maximum reaction rate ( V max ), regardless of the presence of Cd. Montmorillonite decreases the affinity of LAP to the substrate ( K m ), while kaolinite increases the affinity of LAP to the substrate. The clay mineral-immobilized LAP showed an increase in resistance to Cd contamination compared with the free LAP. The results obtained in this study may aid in understanding the toxic effects of heavy metals on soil enzymes.
{"title":"Clay Minerals Change the Toxic Effect of Cadmium on the Activities of Leucine Aminopeptidase","authors":"Shunyu Huang, Jingji Li, Ji-peng Wang","doi":"10.1155/2021/1024085","DOIUrl":"https://doi.org/10.1155/2021/1024085","url":null,"abstract":"Soil leucine aminopeptidase (LAP) is a hydrolytic enzyme involved in the acquisition of nitrogen by microorganisms. In contaminated soils, LAP activity is affected not only by the type and concentration of heavy metals but also by the form of enzyme. Here, we investigated the degree and mechanism of cadmium (Cd) inhibition of soil LAP and purified LAP. We also examined the effect of montmorillonite and kaolinite on LAP and LAP contaminated with Cd. The results showed that Cd inhibition of LAP activity increased with increasing Cd concentration and that Cd exerted noncompetitive inhibition of LAP. The addition of clay minerals decreases LAP activity and the maximum reaction rate (\u0000 \u0000 \u0000 \u0000 V\u0000 \u0000 \u0000 max\u0000 \u0000 \u0000 \u0000 ), regardless of the presence of Cd. Montmorillonite decreases the affinity of LAP to the substrate (\u0000 \u0000 \u0000 \u0000 K\u0000 \u0000 \u0000 m\u0000 \u0000 \u0000 \u0000 ), while kaolinite increases the affinity of LAP to the substrate. The clay mineral-immobilized LAP showed an increase in resistance to Cd contamination compared with the free LAP. The results obtained in this study may aid in understanding the toxic effects of heavy metals on soil enzymes.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44826243","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 exposed slopes formed by stone mining had caused serious problems of environmental pollution. The ecological restoration was a very effective measure to solve it. In this study, the Indigofera amblyantha Craib was the dominant species in the ecorestoration during the first two years of ecological restoration, which was based on analyzing the importance value (IV) and diversity indexes of plant species. Meanwhile, the ecorestoration process helps slow down the increase of the concentrations of some heavy metals in the substrate material; however, the changing trends of these metals were not uniform. The root and leaf were the main parts of heavy metal distribution, respectively, corresponding to Pb, Cr, As, Sb, and Ni in root and Cu, Mn, and V in leaf. It confirmed that Indigofera amblyantha Craib had an advantage ability to enrich and transfer Cd, Cu, and Mn obtained from their biological concentration factor (BCF) and biological transfer factor (BTF). The Sb, Cd, and V were the main factors affecting the IV by the redundancy analysis. These fine characters of Indigofera amblyantha Craib help explain it well adapted to the ecorestoration of stone coal mines. The current results are valuable to evaluate and extend the application in ecorestoration engineering of mining areas and other heavy metal-contaminated sites.
{"title":"The Absorption and Distribution of Heavy Metals of Dominant Plant for Ecological Restoration of Stone Coal Mine","authors":"Lu Peng, Shuang Luo, Li-zhi Xiong, Hailong Sun","doi":"10.1155/2021/4694528","DOIUrl":"https://doi.org/10.1155/2021/4694528","url":null,"abstract":"The exposed slopes formed by stone mining had caused serious problems of environmental pollution. The ecological restoration was a very effective measure to solve it. In this study, the Indigofera amblyantha Craib was the dominant species in the ecorestoration during the first two years of ecological restoration, which was based on analyzing the importance value (IV) and diversity indexes of plant species. Meanwhile, the ecorestoration process helps slow down the increase of the concentrations of some heavy metals in the substrate material; however, the changing trends of these metals were not uniform. The root and leaf were the main parts of heavy metal distribution, respectively, corresponding to Pb, Cr, As, Sb, and Ni in root and Cu, Mn, and V in leaf. It confirmed that Indigofera amblyantha Craib had an advantage ability to enrich and transfer Cd, Cu, and Mn obtained from their biological concentration factor (BCF) and biological transfer factor (BTF). The Sb, Cd, and V were the main factors affecting the IV by the redundancy analysis. These fine characters of Indigofera amblyantha Craib help explain it well adapted to the ecorestoration of stone coal mines. The current results are valuable to evaluate and extend the application in ecorestoration engineering of mining areas and other heavy metal-contaminated sites.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":"2021 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43609872","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}
This investigation suggests the implementation of ZSM-5 activated carbon composite as a prolific adsorbent for the continuous elimination of Pb2+ ions from water. Continuous adsorption experiments were performed by varying three parameters such as process flow rate (2-6 mL min-1), bed height (2-6 cm), and initial concentration (250–750 mg L-1). The highest loading capacity of the fixed-bed 213.3 mg L-1 was achieved with optimal values of 2 mL min-1 of flow rate, bed height of 6 cm, and initial concentration of 750 mg L-1, respectively. The breakthrough curves and saturation points were found to appear quickly for increasing flow rates and initial concentration and vice versa for bed depth. The lower flow rates with higher bed depths have exhibited optimal performances of the fixed-bed column. The mechanism of adsorption of Pb2+ ions was found to be ion exchange with Na+ ions from ZMS-5 and pore adsorption onto activated carbon. The breakthrough curves were verified with three well-known mathematical models such as the Adams-Bohart, Thomas, and Yoon-Nelson models. The later models showed the best fit to the column data over the Adams-Bohart model that can be utilized to understand the binding of Pb2+ ions onto the composite. Regeneration of ZSM-5/activated carbon was achieved successfully with 0.1 M HCl within 60 min of contact time. The outcomes conclude that ZSM-5 activated carbon composite is a prolific material for the continuous removal of water loaded with Pb2+ ions.
该研究表明，ZSM-5活性炭复合材料是一种高效的吸附剂，可连续去除水中的Pb2+离子。通过改变工艺流速（2-6）等三个参数进行连续吸附实验 mL min-1），床高（2-6 cm）和初始浓度（250–750 毫克 L-1）。固定床的最高装载能力213.3 毫克 L-1的最佳值为2 mL 流速的min-1，床高6 cm，初始浓度为750 毫克 L-1。发现穿透曲线和饱和点随着流速和初始浓度的增加而迅速出现，反之亦然。较低的流速和较高的床层深度显示出固定床柱的最佳性能。Pb2+离子的吸附机理是与ZMS-5中的Na+离子进行离子交换，并在活性炭上进行孔吸附。突破曲线用三个著名的数学模型进行了验证，如Adams-Bohart、Thomas和Yoon-Nelson模型。与Adams-Bohart模型相比，后来的模型显示出与柱数据的最佳拟合，该模型可用于理解Pb2+离子与复合材料的结合。ZSM-5/活性炭在0.1 60内的M HCl 最小接触时间。结果表明，ZSM-5活性炭复合材料是一种用于连续去除负载Pb2+离子的水的多产材料。
{"title":"Removal of Pb2+ Ions by ZSM-5/AC Composite in a Fixed-Bed Bench Scale System","authors":"R. Lakshmipathy, G. L. Balaji, I. R. Rico","doi":"10.1155/2021/2013259","DOIUrl":"https://doi.org/10.1155/2021/2013259","url":null,"abstract":"This investigation suggests the implementation of ZSM-5 activated carbon composite as a prolific adsorbent for the continuous elimination of Pb2+ ions from water. Continuous adsorption experiments were performed by varying three parameters such as process flow rate (2-6 mL min-1), bed height (2-6 cm), and initial concentration (250–750 mg L-1). The highest loading capacity of the fixed-bed 213.3 mg L-1 was achieved with optimal values of 2 mL min-1 of flow rate, bed height of 6 cm, and initial concentration of 750 mg L-1, respectively. The breakthrough curves and saturation points were found to appear quickly for increasing flow rates and initial concentration and vice versa for bed depth. The lower flow rates with higher bed depths have exhibited optimal performances of the fixed-bed column. The mechanism of adsorption of Pb2+ ions was found to be ion exchange with Na+ ions from ZMS-5 and pore adsorption onto activated carbon. The breakthrough curves were verified with three well-known mathematical models such as the Adams-Bohart, Thomas, and Yoon-Nelson models. The later models showed the best fit to the column data over the Adams-Bohart model that can be utilized to understand the binding of Pb2+ ions onto the composite. Regeneration of ZSM-5/activated carbon was achieved successfully with 0.1 M HCl within 60 min of contact time. The outcomes conclude that ZSM-5 activated carbon composite is a prolific material for the continuous removal of water loaded with Pb2+ ions.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41745563","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. Fan, Jie Zhao, Yingxiang Chen, Miao Wang, Xingming Wang, Shun Wang, Xiaoyang Chen, Akang Lu, Shijiao Zha
Plastic particles with a diameter of 5 mm or less are called microplastics. Microplastics are one of the primary sources of pollution in the environment. It has been proven that microplastics are also carriers of heavy metals, but there are few studies on their adsorption mechanism. In this study, the adsorption of Pb, Cu, Cd, and Zn by polypropylene (PP) microplastics was analyzed and discussed. The morphology of PP was observed by scanning electron microscopy (SEM), the surface elemental composition of PP was determined by X-ray photoelectron spectroscopy (XPS), and the functional groups of PP were analyzed by Fourier transform infrared spectroscopy (FTIR). The results showed that the adsorption behavior of microplastics to different heavy metals could be balanced in 32 hours. Kinetics experiments showed that the adsorption process could be fitted well by a two-stage dynamic model, and the adsorption of Pb and Cu by PP is greater than that of Cd and Zn. The Freundlich model has the best fitting effect on Pb for the adsorption isothermal results. The Langmuir model showed that the process is favorable for adsorption. The adsorption of mixed heavy metals by microplastics showed that when the concentration of the mixed adsorption mass was low, the presence of a coexistence system promoted the adsorption of Zn and Cu by microplastics. With an increasing concentration, the adsorption of 4 heavy metals by microplastics is inhibited.
{"title":"Coexistence and Adsorption Properties of Heavy Metals by Polypropylene Microplastics","authors":"T. Fan, Jie Zhao, Yingxiang Chen, Miao Wang, Xingming Wang, Shun Wang, Xiaoyang Chen, Akang Lu, Shijiao Zha","doi":"10.1155/2021/4938749","DOIUrl":"https://doi.org/10.1155/2021/4938749","url":null,"abstract":"Plastic particles with a diameter of 5 mm or less are called microplastics. Microplastics are one of the primary sources of pollution in the environment. It has been proven that microplastics are also carriers of heavy metals, but there are few studies on their adsorption mechanism. In this study, the adsorption of Pb, Cu, Cd, and Zn by polypropylene (PP) microplastics was analyzed and discussed. The morphology of PP was observed by scanning electron microscopy (SEM), the surface elemental composition of PP was determined by X-ray photoelectron spectroscopy (XPS), and the functional groups of PP were analyzed by Fourier transform infrared spectroscopy (FTIR). The results showed that the adsorption behavior of microplastics to different heavy metals could be balanced in 32 hours. Kinetics experiments showed that the adsorption process could be fitted well by a two-stage dynamic model, and the adsorption of Pb and Cu by PP is greater than that of Cd and Zn. The Freundlich model has the best fitting effect on Pb for the adsorption isothermal results. The Langmuir model showed that the process is favorable for adsorption. The adsorption of mixed heavy metals by microplastics showed that when the concentration of the mixed adsorption mass was low, the presence of a coexistence system promoted the adsorption of Zn and Cu by microplastics. With an increasing concentration, the adsorption of 4 heavy metals by microplastics is inhibited.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43092921","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 performance of a clay mineral geomembrane used in the context of a geological barrier for industrial and radioactive waste confinement must pass through the understanding of its hydrous response as well as the limits of the cation exchange process which are closely related to the solid/liquid ratio constraint. The Na-rich montmorillonite is used, as starting material, to evaluate the link between the applied external constraint (variable solid/liquid ratio) and the structural response of the material. The geochemical constraint is realized at the laboratory scale, and the possible effects are investigated in the cases of Ba2+ and Ni2+ heavy metal cations. The structural analysis is achieved using the XRD profile modeling approach to quantify the interlayer space (IS) deformation. The quantitative XRD analysis, which consists of the comparison of experimental 001 reflections with the calculated ones deduced from structural models, allowed us to determine the optimal structural parameters describing IS configuration along the c ∗ axis. The obtained result showed an interstratified hydration character, for both studied exchangeable cations, regardless of the solid/liquid ratio being described probably by a partial cation exchange process. The theoretical mixed layer structure (MLS) suggests the coexistence of more one cristallite species saturated by more than one exchangeable cations, indicating a partial saturation of all exchangeable sites. The optimum structural parameter values, from the theoretical model, allowed us to follow the evolution of several intrinsic properties versus the applied constraint strength. The variable solid/liquid ratio effect on the material porosity is examined by the BET-specific surface area and BJH pore size distribution (PSD) analyses. The adsorption measurement outcomes confirm XRD results concerning mainly the link between several intrinsic clay properties and the constraint strength.
{"title":"How the Solid/Liquid Ratio Affects the Cation Exchange Process and Porosity in the Case of Dioctahedral Smectite: Structural Analysis?","authors":"C. Mejri, W. Oueslati, A. B. H. Amara","doi":"10.1155/2021/9732092","DOIUrl":"https://doi.org/10.1155/2021/9732092","url":null,"abstract":"The performance of a clay mineral geomembrane used in the context of a geological barrier for industrial and radioactive waste confinement must pass through the understanding of its hydrous response as well as the limits of the cation exchange process which are closely related to the solid/liquid ratio constraint. The Na-rich montmorillonite is used, as starting material, to evaluate the link between the applied external constraint (variable solid/liquid ratio) and the structural response of the material. The geochemical constraint is realized at the laboratory scale, and the possible effects are investigated in the cases of Ba2+ and Ni2+ heavy metal cations. The structural analysis is achieved using the XRD profile modeling approach to quantify the interlayer space (IS) deformation. The quantitative XRD analysis, which consists of the comparison of experimental 001 reflections with the calculated ones deduced from structural models, allowed us to determine the optimal structural parameters describing IS configuration along the \u0000 \u0000 c\u0000 ∗\u0000 \u0000 axis. The obtained result showed an interstratified hydration character, for both studied exchangeable cations, regardless of the solid/liquid ratio being described probably by a partial cation exchange process. The theoretical mixed layer structure (MLS) suggests the coexistence of more one cristallite species saturated by more than one exchangeable cations, indicating a partial saturation of all exchangeable sites. The optimum structural parameter values, from the theoretical model, allowed us to follow the evolution of several intrinsic properties versus the applied constraint strength. The variable solid/liquid ratio effect on the material porosity is examined by the BET-specific surface area and BJH pore size distribution (PSD) analyses. The adsorption measurement outcomes confirm XRD results concerning mainly the link between several intrinsic clay properties and the constraint strength.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44635266","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, a simple chemical modification was applied to a sustainable and abundantly available resource, kangkong root (KR), to remove methyl violet 2B (MV) dye. The chemically modified adsorbent (NaOH-KR) was obtained using NaOH solution treatment. Batch adsorption experiments were carried out to investigate the effects of pH, ionic strength, contact time, adsorbent dosage, and initial dye concentration. A regeneration experiment was also carried out to assess the potential of reusability. The adsorption process was modelled using various kinetics and isotherm models, whereby the best-fitting models were evaluated by using the coefficient of determination ( R 2 ) and error functions. The Sips ( R 2 = 0.9714 , χ2 =0.16) and pseudo-second-order ( R 2 = 0.9996 , χ 2 = 0.007 ) models were identified to best represent the adsorption process. The Sips model predicted a maximum adsorption capacity at 551.5 mg g-1 for NaOH-KR, which is 55% improvement in performance when compared to nonmodified KR. Lastly, the regeneration experiment showed that NaOH-KR was able to maintain reasonable dye removal even after five consecutive cycles of regenerating and reusing.
{"title":"Effective and Simple NaOH-Modification Method to Remove Methyl Violet Dye via Ipomoea aquatica Roots","authors":"YieChen Lu, M. R. R. Kooh, L. Lim, N. Priyantha","doi":"10.1155/2021/5932222","DOIUrl":"https://doi.org/10.1155/2021/5932222","url":null,"abstract":"In this study, a simple chemical modification was applied to a sustainable and abundantly available resource, kangkong root (KR), to remove methyl violet 2B (MV) dye. The chemically modified adsorbent (NaOH-KR) was obtained using NaOH solution treatment. Batch adsorption experiments were carried out to investigate the effects of pH, ionic strength, contact time, adsorbent dosage, and initial dye concentration. A regeneration experiment was also carried out to assess the potential of reusability. The adsorption process was modelled using various kinetics and isotherm models, whereby the best-fitting models were evaluated by using the coefficient of determination (\u0000 \u0000 \u0000 \u0000 R\u0000 \u0000 \u0000 2\u0000 \u0000 \u0000 \u0000 ) and error functions. The Sips (\u0000 \u0000 \u0000 \u0000 R\u0000 \u0000 \u0000 2\u0000 \u0000 \u0000 =\u0000 0.9714\u0000 \u0000 , χ2 =0.16) and pseudo-second-order (\u0000 \u0000 \u0000 \u0000 R\u0000 \u0000 \u0000 2\u0000 \u0000 \u0000 =\u0000 0.9996\u0000 \u0000 , \u0000 \u0000 \u0000 \u0000 χ\u0000 \u0000 \u0000 2\u0000 \u0000 \u0000 =\u0000 0.007\u0000 \u0000 ) models were identified to best represent the adsorption process. The Sips model predicted a maximum adsorption capacity at 551.5 mg g-1 for NaOH-KR, which is 55% improvement in performance when compared to nonmodified KR. Lastly, the regeneration experiment showed that NaOH-KR was able to maintain reasonable dye removal even after five consecutive cycles of regenerating and reusing.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44485990","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 comparison to other conventional methods like adsorption and reverse osmosis (RO), capacitive deionization (CDI) has only been investigated extensively for the removal of inorganic pollutants from water, demonstrating limited practicality. Herein, the study investigated the use of CDI for the removal of paraquat (PQ) herbicide from water by using commercial activated carbon (AC) electrodes. The CDI performance was examined as a function of the initial PQ concentration, applied voltage, flowrate, treatment time, and cycle stability testing in the batch mode approach. The applied voltage had a beneficial effect on the removal efficiency, whereas the removal efficiency of PQ declined as the initial PQ concentration increased. However, the electrosorption capacity gradually increased with the increase of initial feed solutions’ concentration. The maximum removal efficiency and electrosorption capacity achieved at 5 mg/L and 20 mg/L PQ initial concentrations, an applied voltage of 1.2 V, and 5 mL/min flowrate were 100% and 0.33 mg/g and 52.5% and 0.7 mg/g, respectively. Washing the electrodes with distilled water achieved sequential desorption of PQ, and the process produces a waste stream that can be disposed of or treated further. Therefore, the CDI method is considered a promising and efficient method for removing organic pollutants from water including pesticides.
{"title":"Capacitive Deionization for the Removal of Paraquat Herbicide from Aqueous Solution","authors":"T. Alfredy, Joyce Elisadiki, Y. Jande","doi":"10.1155/2021/9601012","DOIUrl":"https://doi.org/10.1155/2021/9601012","url":null,"abstract":"In comparison to other conventional methods like adsorption and reverse osmosis (RO), capacitive deionization (CDI) has only been investigated extensively for the removal of inorganic pollutants from water, demonstrating limited practicality. Herein, the study investigated the use of CDI for the removal of paraquat (PQ) herbicide from water by using commercial activated carbon (AC) electrodes. The CDI performance was examined as a function of the initial PQ concentration, applied voltage, flowrate, treatment time, and cycle stability testing in the batch mode approach. The applied voltage had a beneficial effect on the removal efficiency, whereas the removal efficiency of PQ declined as the initial PQ concentration increased. However, the electrosorption capacity gradually increased with the increase of initial feed solutions’ concentration. The maximum removal efficiency and electrosorption capacity achieved at 5 mg/L and 20 mg/L PQ initial concentrations, an applied voltage of 1.2 V, and 5 mL/min flowrate were 100% and 0.33 mg/g and 52.5% and 0.7 mg/g, respectively. Washing the electrodes with distilled water achieved sequential desorption of PQ, and the process produces a waste stream that can be disposed of or treated further. Therefore, the CDI method is considered a promising and efficient method for removing organic pollutants from water including pesticides.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44429946","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}
Buhani, Suharso, Nurul Miftahza, D. Permatasari, Sumadi
In this research, biomass modification of Nannochloropsis sp. with surfactant cetyltrimethylammonium bromide (CTAB) through a cation exchange reaction to produce adsorbent Nannochloropsis sp.-cetyltrimethylammonium bromide (AlgN-CTAB) has been carried out. Biomass modification of Nannochloropsis sp. by CTAB has been successfully carried out through confirmation from the analysis data produced by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDX). AlgN-CTAB adsorbent has been tested for its adsorption ability against anionic dye of methyl orange (MO) in solution by way of a sequence of experiments by the batch method. The optimum conditions for MO removal from the solution occurred at an adsorbent quantity of 0.1 g, pH of 5, and an interaction time of 60 min. MO adsorption kinetic data by AlgN and AlgN-CTAB tended to take the kinetic model of pseudo-second-order (PSO) with PSO rate constant ( k 2 ) values of 0.56 and 2.17 g mg-1 min-1, serially. The MO adsorption isotherm pattern by AlgN tends to take the Freundlich adsorption isotherm, whereas in AlgN-CTAB it follows the Langmuir and Dubinin-Radushkevich adsorption isotherms. The results of the adsorption-desorption of MO by AlgN-CTAB with 4 repetition cycles resulted in % removal of MO > 80 % . The AlgN-CTAB adsorbent can be used repeatedly and is very effective in absorbing MO in water.
本研究以表面活性剂十六烷基三甲基溴化铵（CTAB）为原料，通过阳离子交换反应对Nannochloropsis sp.进行了生物量改性，制备了吸附剂Nannochlopsis sp.-十六烷基三三甲铵（AlgN-CTAB）。通过傅立叶变换红外光谱（FTIR）、扫描电子显微镜和能量色散X射线光谱（SEM-EDX）的分析数据证实，CTAB成功地对Nannochloropsis sp.进行了生物量改性。采用分批法对AlgN-CTAB吸附剂对溶液中甲基橙（MO）阴离子染料的吸附性能进行了测试。从溶液中去除MO的最佳条件是吸附剂量为0.1 g、 pH为5，相互作用时间为60 AlgN和AlgN-CTAB的最小MO吸附动力学数据倾向于采用伪二阶（PSO）动力学模型，PSO速率常数（k2）分别为0.56和2.17 g mg-1 min-1，连续。AlgN对MO的吸附等温线倾向于Freundlich吸附等温线，而在AlgN-CTAB中则遵循Langmuir和Dubinin-Radushkevich吸附等温线。AlgN-CTAB对MO的吸附-解吸4个重复循环的结果表明，MO的去除率>80%。AlgN-CTAB吸附剂可以重复使用，对水中MO的吸收非常有效。
{"title":"Improved Adsorption Capacity of Nannochloropsis sp. through Modification with Cetyltrimethylammonium Bromide on the Removal of Methyl Orange in Solution","authors":"Buhani, Suharso, Nurul Miftahza, D. Permatasari, Sumadi","doi":"10.1155/2021/1641074","DOIUrl":"https://doi.org/10.1155/2021/1641074","url":null,"abstract":"In this research, biomass modification of Nannochloropsis sp. with surfactant cetyltrimethylammonium bromide (CTAB) through a cation exchange reaction to produce adsorbent Nannochloropsis sp.-cetyltrimethylammonium bromide (AlgN-CTAB) has been carried out. Biomass modification of Nannochloropsis sp. by CTAB has been successfully carried out through confirmation from the analysis data produced by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDX). AlgN-CTAB adsorbent has been tested for its adsorption ability against anionic dye of methyl orange (MO) in solution by way of a sequence of experiments by the batch method. The optimum conditions for MO removal from the solution occurred at an adsorbent quantity of 0.1 g, pH of 5, and an interaction time of 60 min. MO adsorption kinetic data by AlgN and AlgN-CTAB tended to take the kinetic model of pseudo-second-order (PSO) with PSO rate constant (\u0000 \u0000 \u0000 \u0000 k\u0000 \u0000 \u0000 2\u0000 \u0000 \u0000 \u0000 ) values of 0.56 and 2.17 g mg-1 min-1, serially. The MO adsorption isotherm pattern by AlgN tends to take the Freundlich adsorption isotherm, whereas in AlgN-CTAB it follows the Langmuir and Dubinin-Radushkevich adsorption isotherms. The results of the adsorption-desorption of MO by AlgN-CTAB with 4 repetition cycles resulted in % removal of \u0000 \u0000 MO\u0000 >\u0000 80\u0000 %\u0000 \u0000 . The AlgN-CTAB adsorbent can be used repeatedly and is very effective in absorbing MO in water.","PeriodicalId":7315,"journal":{"name":"Adsorption Science & Technology","volume":" ","pages":""},"PeriodicalIF":2.9,"publicationDate":"2021-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49589107","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：