Wastewater contamination by heavy metals and synthetic dyes presents a significant environmental challenge,necessitating effective and sustainable separation techniques.This review article provides a detailed examinat...Wastewater contamination by heavy metals and synthetic dyes presents a significant environmental challenge,necessitating effective and sustainable separation techniques.This review article provides a detailed examination of magnesium oxide(MgO)nanoparticles as an innovative nanoadsorbent for wastewater treatment,with a specific focus on heavy metal and dye removal.The review comprehensively explores various aspects of MgO nanoparticles,including their structural characteristics and synthesis techniques.The article delves into the morphology and crystallographic arrangement of MgO nanoparticles,offering insights into their structural attributes.Given the complexity of adsorption processes,the review identifies and analyzes parameters influencing the adsorption efficiency of MgO nanoparticles,such as temperature,pH,contact time,initial concentration,and co-existing ions.The interplay between these parameters and the adsorption capability of MgO nanoparticles emphasizes the importance of optimizing operational conditions.Furthermore,the review assesses various synthesis methods for MgO nanoparticles,including sol-gel,hydrothermal,precipitation,green synthesis,solvothermal,and template-assisted techniques.It discusses the advantages,limitations,and resulting nanoparticle characteristics of each method,enabling readers to grasp the implications of synthesis processes on adsorption efficiency.This comprehensive review consolidates current insights into the effectiveness of MgO nanoparticles as a potent nanoadsorbent for removing heavy metals and dyes from wastewater covering a wide spectrum of aspects related to MgO nanoparticles.Moreover,there is a need to investigate the use of MgO in the treatment of actual wastewater or river water,in order to leverage its cost-effectiveness and high efficiency for practical water treatment applications in real-time.展开更多
A new type of dissolved air released flotation column is developed to treat wastewater containing Cr(Ⅵ) based on advantages of both dissolved air floatation and column floatation. By using a column with a diameter ...A new type of dissolved air released flotation column is developed to treat wastewater containing Cr(Ⅵ) based on advantages of both dissolved air floatation and column floatation. By using a column with a diameter of 50 mm and a specially made dissolved air releaser, micro-bubbles inside the column can be formed. N2H4H2O was used as reductant, AlCl3 as flocculant, C12H25SO3Na(SDS) as surfactant in the experiment. The effects of pH of wastewater, pressure of dissolved air, ratio of return water, and concentration of flocculant and surfactant on the removal efficiency are studied. The results show that the efficiency of dissolved air released flotation column is much higher than that of other approaches after the operation parameters are optimized, with the reduction ratio of Cr(Ⅵ ) in wastewater reaching 98%. So this technique can be widely used in wastewater treatment展开更多
One of the main environmental pollutants is heavy metals. Due to extensive usage in industry, these metals enter biological cycle rapidly and contaminated water and soil resources rapidly. In this work, lead, copper, ...One of the main environmental pollutants is heavy metals. Due to extensive usage in industry, these metals enter biological cycle rapidly and contaminated water and soil resources rapidly. In this work, lead, copper, zinc and chromium of Bandar Abbas wastewater are examined. For this research, nine stations were set for measurement in urban level in Bandar Abbas and sampling of aforesaid metals was performed in fall and winter 2006 in these stations. After extraction and preparation operations using APDC-MIBK, samples were measured using flame atomic absorption system. According to results, concentrate of studied metals was lower than allowable standard value set by Iran environmental protection organization for agricultural purposes and sewage to ground level waters. In addition, efficiency of Bandar Abbas wastewater treatment plant to remove these metals is 40% - 70% from which highest removal is for zinc as much as 71.1% and lowest level is for copper as much as 40.5%. However, copper level was higher than allowable level for agricultural purposes in spring and summer (0.21 mg/L and 0.23 mg/L, respectively) and lower in fall and winter (0.103 mg/L and 0.098 mg/L, respectively). Furthermore, changes in concentration of metals in these stations in various seasons were measured and analyzed using one-way variance analysis and simultaneous effects of time and place on measured variables were analyzed using two-way variance analysis.展开更多
Heavy metal pollution from industrial wastewater is a worldwide environmental issue. Biosorption of heavy metals by using biosorbents derived from various types of biomass has been shown to be effective for the uptake...Heavy metal pollution from industrial wastewater is a worldwide environmental issue. Biosorption of heavy metals by using biosorbents derived from various types of biomass has been shown to be effective for the uptake of heavy metal ions. In this study, biosorbents derived from the biomass of a group of marine macroalgae were used for the removal and recovery of heavy metal ions from aqueous solutions. Results indicated that the biosorbents have high uptake capacities and affinities for a number of heavy metal ions. The uptake capacities of the biosorbents were in the range of 1.0 to 1.5mmol·g-1 for divalent heavy metal ions. The kinetics of the uptake process was fast and the process can be used in both batch and fixed-bed operations. It appears that the biosorption process by using biosorbents from marine macroalgae can be an efficient and cost effective technology for the treatment of heavy metal containing wastewater.展开更多
The Fava Beans were used in this work as low cost adsorbent material for removal of Pb(II), Cd(II) and Zn(II) ions from aqueous solutions. The samples were prepared without farther treatment and sorted according to th...The Fava Beans were used in this work as low cost adsorbent material for removal of Pb(II), Cd(II) and Zn(II) ions from aqueous solutions. The samples were prepared without farther treatment and sorted according to the particles diameter by standard sieves 250 - 500 μm. Batch adsorption experiments were carried out to study the adsorption process, several parameters such as Initial pH of adsorbent, effect of contact time, effect of adsorbent amount and effect of metal concentration were conducted in these experiments. The effects of any one of those previously mentioned parameters on the adsorption capacity were studied while the other parameters were kept constant. It was found that the obtained maximum adsorption capacities of Fave beans for the removal of selected heavy metals were very high. This provide us to use Fava beans as a low coast adsorbent material to clean up the water in the environment from toxic heavy metals such as Pb(II), Cd(II) and Zn(II) ions.展开更多
Dewatered municipal sludge samples were collected from five municipal wastewater treatment plants (WWTPs) and one industrial WWTP in Guangzhou, China. A number of agricultural parameters and total metal concentratio...Dewatered municipal sludge samples were collected from five municipal wastewater treatment plants (WWTPs) and one industrial WWTP in Guangzhou, China. A number of agricultural parameters and total metal concentrations in the sludge were determined. Metal speciation was also studied. The results showed that sewage sludge had high organic carbon, and was rich in such nutrients as N and P. The concentrations of Mn, Zn, and Cu were the highest, followed by Ni, Pb, and Cr, Cd had the lowest concentration. In addition, the concentrations of the aforementioned heavy metals in the sludge samples were higher than those recorded in the background data for crop soils. With the exception of Cu and Cd from site S1, and Ni from sites S1, $2, and $5, all other metal concentrations conformed to permissible levels prescribed by the national application standard of acid soil in China (GB 18918--2002). The results of the BCR sequential extraction showed that the concentrations of Mn and Zn were predominant in acid-soluble/exchangeable and reducible fractions. Cu was principally distributed in oxidizable and residual fractions, whereas Cr was present in oxidizable and residual fractions, Pb was found in the state of residual fractions, and the distribution of Ni and Cd did not show significant characteristics.展开更多
Activated sludge was immobilized into Ca-alginate beads via entrapment, and biosorption of three heavy metal ions, copper(Ⅱ), zinc(Ⅱ), and chromimum(Ⅱ), from aqueous solution in the concentration range of 10\_100 m...Activated sludge was immobilized into Ca-alginate beads via entrapment, and biosorption of three heavy metal ions, copper(Ⅱ), zinc(Ⅱ), and chromimum(Ⅱ), from aqueous solution in the concentration range of 10\_100 mg/L was studied by using both entrapped activated sludge and inactivated free biomass at pH≤5. A biphasic metal adsorption pattern was observed in all immobilized biomass experiments. The biosorption of metal ions by the biosorbents increased with the initial concentration increased in the medium. The adsorption rate of immobilized pre-treated activated sludge(PAS) was much lower than that of free PAS due to the increase in mass transfer resistance resulting from the polymeric matrix. Biosorption equilibrium of beads was established in about 20 h and the adsorbed heavy metal ions did not change further with time. No significant effect of temperature was observed in the test for free biomass while immobilized PAS appeared to be strong temperature dependent in the test range of 10 and 40℃. Besides, the content of activated sludge in the calcium alginate bead has an influence on the uptake of heavy metals. The sorption equilibrium was well modeled by Langmuir isotherm, implying monomolecular adsorption mechanism. Carboxyl group in cell wall played an important role in surface adsorption of heavy metal ions on PAS.展开更多
A laboratory scale algal column reactor packed with 75 ml alginate algal beads was used to treat 30 mg/L Cu and Ni with a HRT of 30 minutes. At the end of loading 4L metal solution, over 97% of Cu and 91% of Ni were r...A laboratory scale algal column reactor packed with 75 ml alginate algal beads was used to treat 30 mg/L Cu and Ni with a HRT of 30 minutes. At the end of loading 4L metal solution, over 97% of Cu and 91% of Ni were removed from the wastewater with a final residual of 1.76 mg/L Cu and 8.8 mg/L Ni. Up flow was preferred to down flow in maintaining a constant flow rate and hence HRT. Amount of metal recovered during regeneration depended on concentration and nature of regenerant used. Dilute acid was a better regenerant than calcium in terms of metal recovered (90%) and volume needed for regeneration. The consistency in the metal removal performance by the algal column over 10 metal treatment and regeneration cycles suggested that the algal beads can treat Cu or Ni bearing wastewater over 400 times its own volume.展开更多
The removal efficiencies of heavy metals(As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants(WWTPs) and compared with those in four main activated sludge processes. S...The removal efficiencies of heavy metals(As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants(WWTPs) and compared with those in four main activated sludge processes. Significant differences of heavy metal removal efficiencies were observed among four activated sludge processes. The removal efficiency for As(75.5%) in the oxidation ditch(OD) process is significantly higher than that in the conventional activated sludge(CAS) process(38.6%) or sequencing batch reactor(SBR) process(51.4%). The mean removal efficiencies for Cu and Ni in the OD process are 90.5% and 46.7%, respectively, while low mean removal efficiencies are observed for Cu(69.9%) and Ni(16.5%), respectively, in the SBR process. The removal efficiencies for Cu and Ni in the OD process are significantly higher than those in the anaerobic-anoxic-oxic(A2-O) process. These results highlight the differences of removal efficiencies for heavy metals in different processes and should be considered when selecting a wastewater treatment process.展开更多
Polyacrylamide-urea-sulfanilamide(PUS) was prepared as a novel heavy metal ions chelator and successfully used to simultaneously remove heavy metals from wastewater effluents.The effects of reaction parameters(sodi...Polyacrylamide-urea-sulfanilamide(PUS) was prepared as a novel heavy metal ions chelator and successfully used to simultaneously remove heavy metals from wastewater effluents.The effects of reaction parameters(sodium hydroxide,material ratio,temprature and contact time) were monitored to specify the best synthesis conditions.PUS was chemically characterized by means of infrared spectroscopy(FTIR) and ultraviolet-visible(UV-Vis).The simultaneous chelation performance of PUS towards selected heavy metals ions,Ni2+,Cu2+,Pb2+,Zn2+,Cd2+ was discussed,showing that Ni2+,Cu2+,Pb2+,Zn2+ could be better chelated.It is indicated that the synthesized PUS is a potential remediation material when used for the treatment of wastewater containing metal ions.展开更多
Many different techniques may be used to remove industrial pollutants from wastewater. Adsorption using activated carbon has been reported to be an effective method. This work proposes the use of a vegetable residue(b...Many different techniques may be used to remove industrial pollutants from wastewater. Adsorption using activated carbon has been reported to be an effective method. This work proposes the use of a vegetable residue(black sapote seeds) as a raw material for its synthesis. These carbons were chemically activated using phosphoric acid and carbonized at 673 and 873 K. Adsorption isotherms were constructed for the textile dyes on the carbons, and this data was treated using Langmuir’s equation to quantitatively describe the adsorption process. The synthesized carbons were characterized using FTIR, EA, SEM, Nitrogen adsorption(specific surface areas of 879 and 652 m2·g-1), and their points of zero charge(2.1 and 2.3). It was possible to adsorb both heavy metals and textile dyes present in aqueous solutions and wastewaters using these activated carbons. Heavy metals were adsorbed almost completely by both carbons. Cationic dyes where adsorbed(58–59.8 mg·g-1) in greater amounts compared to anionic dyes(10–58.8 mg·g-1). The amount of anionic dyes adsorbed increased almost 30% by changing the pH of the solutions. One of the carbons was thermally regenerated on three occasions without losing its adsorption capacity and it was proved in a flow system.展开更多
基金the support of the Khalifa University internal funding CIRA-2021-071(8474000416),Khalifa University,UAEthe financial support from the Science batch of 1976-1980 of the University of Peradeniya,Sri Lanka。
文摘Wastewater contamination by heavy metals and synthetic dyes presents a significant environmental challenge,necessitating effective and sustainable separation techniques.This review article provides a detailed examination of magnesium oxide(MgO)nanoparticles as an innovative nanoadsorbent for wastewater treatment,with a specific focus on heavy metal and dye removal.The review comprehensively explores various aspects of MgO nanoparticles,including their structural characteristics and synthesis techniques.The article delves into the morphology and crystallographic arrangement of MgO nanoparticles,offering insights into their structural attributes.Given the complexity of adsorption processes,the review identifies and analyzes parameters influencing the adsorption efficiency of MgO nanoparticles,such as temperature,pH,contact time,initial concentration,and co-existing ions.The interplay between these parameters and the adsorption capability of MgO nanoparticles emphasizes the importance of optimizing operational conditions.Furthermore,the review assesses various synthesis methods for MgO nanoparticles,including sol-gel,hydrothermal,precipitation,green synthesis,solvothermal,and template-assisted techniques.It discusses the advantages,limitations,and resulting nanoparticle characteristics of each method,enabling readers to grasp the implications of synthesis processes on adsorption efficiency.This comprehensive review consolidates current insights into the effectiveness of MgO nanoparticles as a potent nanoadsorbent for removing heavy metals and dyes from wastewater covering a wide spectrum of aspects related to MgO nanoparticles.Moreover,there is a need to investigate the use of MgO in the treatment of actual wastewater or river water,in order to leverage its cost-effectiveness and high efficiency for practical water treatment applications in real-time.
基金Projects 50425414 supported by National Fund for Distinguished Young Scholars and B200403 by Science and Technology Fund of China University ofMining &Technology
文摘A new type of dissolved air released flotation column is developed to treat wastewater containing Cr(Ⅵ) based on advantages of both dissolved air floatation and column floatation. By using a column with a diameter of 50 mm and a specially made dissolved air releaser, micro-bubbles inside the column can be formed. N2H4H2O was used as reductant, AlCl3 as flocculant, C12H25SO3Na(SDS) as surfactant in the experiment. The effects of pH of wastewater, pressure of dissolved air, ratio of return water, and concentration of flocculant and surfactant on the removal efficiency are studied. The results show that the efficiency of dissolved air released flotation column is much higher than that of other approaches after the operation parameters are optimized, with the reduction ratio of Cr(Ⅵ ) in wastewater reaching 98%. So this technique can be widely used in wastewater treatment
文摘One of the main environmental pollutants is heavy metals. Due to extensive usage in industry, these metals enter biological cycle rapidly and contaminated water and soil resources rapidly. In this work, lead, copper, zinc and chromium of Bandar Abbas wastewater are examined. For this research, nine stations were set for measurement in urban level in Bandar Abbas and sampling of aforesaid metals was performed in fall and winter 2006 in these stations. After extraction and preparation operations using APDC-MIBK, samples were measured using flame atomic absorption system. According to results, concentrate of studied metals was lower than allowable standard value set by Iran environmental protection organization for agricultural purposes and sewage to ground level waters. In addition, efficiency of Bandar Abbas wastewater treatment plant to remove these metals is 40% - 70% from which highest removal is for zinc as much as 71.1% and lowest level is for copper as much as 40.5%. However, copper level was higher than allowable level for agricultural purposes in spring and summer (0.21 mg/L and 0.23 mg/L, respectively) and lower in fall and winter (0.103 mg/L and 0.098 mg/L, respectively). Furthermore, changes in concentration of metals in these stations in various seasons were measured and analyzed using one-way variance analysis and simultaneous effects of time and place on measured variables were analyzed using two-way variance analysis.
基金Supported in part by the Australian Research Council (Small Grant Scheme) and a Royal Thai Government Scholarship.
文摘Heavy metal pollution from industrial wastewater is a worldwide environmental issue. Biosorption of heavy metals by using biosorbents derived from various types of biomass has been shown to be effective for the uptake of heavy metal ions. In this study, biosorbents derived from the biomass of a group of marine macroalgae were used for the removal and recovery of heavy metal ions from aqueous solutions. Results indicated that the biosorbents have high uptake capacities and affinities for a number of heavy metal ions. The uptake capacities of the biosorbents were in the range of 1.0 to 1.5mmol·g-1 for divalent heavy metal ions. The kinetics of the uptake process was fast and the process can be used in both batch and fixed-bed operations. It appears that the biosorption process by using biosorbents from marine macroalgae can be an efficient and cost effective technology for the treatment of heavy metal containing wastewater.
文摘The Fava Beans were used in this work as low cost adsorbent material for removal of Pb(II), Cd(II) and Zn(II) ions from aqueous solutions. The samples were prepared without farther treatment and sorted according to the particles diameter by standard sieves 250 - 500 μm. Batch adsorption experiments were carried out to study the adsorption process, several parameters such as Initial pH of adsorbent, effect of contact time, effect of adsorbent amount and effect of metal concentration were conducted in these experiments. The effects of any one of those previously mentioned parameters on the adsorption capacity were studied while the other parameters were kept constant. It was found that the obtained maximum adsorption capacities of Fave beans for the removal of selected heavy metals were very high. This provide us to use Fava beans as a low coast adsorbent material to clean up the water in the environment from toxic heavy metals such as Pb(II), Cd(II) and Zn(II) ions.
基金Project(51308132) supported by the National Natural Science Foundation of ChinaProject(2012B050300023) supported by the Scientific and Technological Planning Project of Guangdong Province,China+1 种基金Project(LYM11059) supported by the Foundation for Distinguished Young Talents in Higher Education of Guangdong,ChinaProjects(2011B090400161,2011B090400144) supported by the Cooperation Foundation for Industry,University and Research Institute,Guangdong Province and Ministry of Education of China
文摘Dewatered municipal sludge samples were collected from five municipal wastewater treatment plants (WWTPs) and one industrial WWTP in Guangzhou, China. A number of agricultural parameters and total metal concentrations in the sludge were determined. Metal speciation was also studied. The results showed that sewage sludge had high organic carbon, and was rich in such nutrients as N and P. The concentrations of Mn, Zn, and Cu were the highest, followed by Ni, Pb, and Cr, Cd had the lowest concentration. In addition, the concentrations of the aforementioned heavy metals in the sludge samples were higher than those recorded in the background data for crop soils. With the exception of Cu and Cd from site S1, and Ni from sites S1, $2, and $5, all other metal concentrations conformed to permissible levels prescribed by the national application standard of acid soil in China (GB 18918--2002). The results of the BCR sequential extraction showed that the concentrations of Mn and Zn were predominant in acid-soluble/exchangeable and reducible fractions. Cu was principally distributed in oxidizable and residual fractions, whereas Cr was present in oxidizable and residual fractions, Pb was found in the state of residual fractions, and the distribution of Ni and Cd did not show significant characteristics.
文摘Activated sludge was immobilized into Ca-alginate beads via entrapment, and biosorption of three heavy metal ions, copper(Ⅱ), zinc(Ⅱ), and chromimum(Ⅱ), from aqueous solution in the concentration range of 10\_100 mg/L was studied by using both entrapped activated sludge and inactivated free biomass at pH≤5. A biphasic metal adsorption pattern was observed in all immobilized biomass experiments. The biosorption of metal ions by the biosorbents increased with the initial concentration increased in the medium. The adsorption rate of immobilized pre-treated activated sludge(PAS) was much lower than that of free PAS due to the increase in mass transfer resistance resulting from the polymeric matrix. Biosorption equilibrium of beads was established in about 20 h and the adsorbed heavy metal ions did not change further with time. No significant effect of temperature was observed in the test for free biomass while immobilized PAS appeared to be strong temperature dependent in the test range of 10 and 40℃. Besides, the content of activated sludge in the calcium alginate bead has an influence on the uptake of heavy metals. The sorption equilibrium was well modeled by Langmuir isotherm, implying monomolecular adsorption mechanism. Carboxyl group in cell wall played an important role in surface adsorption of heavy metal ions on PAS.
文摘A laboratory scale algal column reactor packed with 75 ml alginate algal beads was used to treat 30 mg/L Cu and Ni with a HRT of 30 minutes. At the end of loading 4L metal solution, over 97% of Cu and 91% of Ni were removed from the wastewater with a final residual of 1.76 mg/L Cu and 8.8 mg/L Ni. Up flow was preferred to down flow in maintaining a constant flow rate and hence HRT. Amount of metal recovered during regeneration depended on concentration and nature of regenerant used. Dilute acid was a better regenerant than calcium in terms of metal recovered (90%) and volume needed for regeneration. The consistency in the metal removal performance by the algal column over 10 metal treatment and regeneration cycles suggested that the algal beads can treat Cu or Ni bearing wastewater over 400 times its own volume.
基金Project(2012AA06A202)supported by Hi-tech Research and Development Project of China
文摘The removal efficiencies of heavy metals(As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants(WWTPs) and compared with those in four main activated sludge processes. Significant differences of heavy metal removal efficiencies were observed among four activated sludge processes. The removal efficiency for As(75.5%) in the oxidation ditch(OD) process is significantly higher than that in the conventional activated sludge(CAS) process(38.6%) or sequencing batch reactor(SBR) process(51.4%). The mean removal efficiencies for Cu and Ni in the OD process are 90.5% and 46.7%, respectively, while low mean removal efficiencies are observed for Cu(69.9%) and Ni(16.5%), respectively, in the SBR process. The removal efficiencies for Cu and Ni in the OD process are significantly higher than those in the anaerobic-anoxic-oxic(A2-O) process. These results highlight the differences of removal efficiencies for heavy metals in different processes and should be considered when selecting a wastewater treatment process.
基金Funded by the Cooperative Project of Yulin City,Shaanxi Province,201
文摘Polyacrylamide-urea-sulfanilamide(PUS) was prepared as a novel heavy metal ions chelator and successfully used to simultaneously remove heavy metals from wastewater effluents.The effects of reaction parameters(sodium hydroxide,material ratio,temprature and contact time) were monitored to specify the best synthesis conditions.PUS was chemically characterized by means of infrared spectroscopy(FTIR) and ultraviolet-visible(UV-Vis).The simultaneous chelation performance of PUS towards selected heavy metals ions,Ni2+,Cu2+,Pb2+,Zn2+,Cd2+ was discussed,showing that Ni2+,Cu2+,Pb2+,Zn2+ could be better chelated.It is indicated that the synthesized PUS is a potential remediation material when used for the treatment of wastewater containing metal ions.
基金VIEP-BUAP,Mexico for their financial support during the development of the project PECA-ING-17-GCONACYT,Mexico for scholarship number 596493.
文摘Many different techniques may be used to remove industrial pollutants from wastewater. Adsorption using activated carbon has been reported to be an effective method. This work proposes the use of a vegetable residue(black sapote seeds) as a raw material for its synthesis. These carbons were chemically activated using phosphoric acid and carbonized at 673 and 873 K. Adsorption isotherms were constructed for the textile dyes on the carbons, and this data was treated using Langmuir’s equation to quantitatively describe the adsorption process. The synthesized carbons were characterized using FTIR, EA, SEM, Nitrogen adsorption(specific surface areas of 879 and 652 m2·g-1), and their points of zero charge(2.1 and 2.3). It was possible to adsorb both heavy metals and textile dyes present in aqueous solutions and wastewaters using these activated carbons. Heavy metals were adsorbed almost completely by both carbons. Cationic dyes where adsorbed(58–59.8 mg·g-1) in greater amounts compared to anionic dyes(10–58.8 mg·g-1). The amount of anionic dyes adsorbed increased almost 30% by changing the pH of the solutions. One of the carbons was thermally regenerated on three occasions without losing its adsorption capacity and it was proved in a flow system.