Fe_(3)O_(4)magnetic xerogel composites were prepared by polycondensation of resorcinol(R)-formaldehyde reaction via a sol-gel process in an aqueous solution through varying the molar ratio of Fe_(3)O_(4)nanoparticles(...Fe_(3)O_(4)magnetic xerogel composites were prepared by polycondensation of resorcinol(R)-formaldehyde reaction via a sol-gel process in an aqueous solution through varying the molar ratio of Fe_(3)O_(4)nanoparticles(MNPs),catalyst(C),and water(W)content.MNPs were obtained by co-precipitation(MC),oxidation of iron salts(MO),or solvothermal synthesis(MS).Both MNPs and magnetic xerogels were examined regarding the performance of arsenic and fluoride removal in a batch system.The MC-based MNPs had higher adsorption capacities for both fluoride(202.9 mg/g)and arsenic(3.2 mg/g)than other MNPs in optimum conditions.The X-ray diffraction,Fourier transform infrared spectroscopy,and energy-dispersive X-ray spectroscopy confirmed that Fe was composed into the polymeric matrix of magnetic xerogels that contained 0.59%-4.42%of Fe with a molar ratio of MNPs(M)to R between 0.01 and 0.10.With low R/C and optimum M/R ratios,an increase in the surface area of magnetic xerogels affected the fluoride and arsenic adsorption capacities.The magnetic xerogel composites with the MC-based MNPs prepared at a fixed R/C ratio(100)and at different R/W(0.05-0.06)and M/R(0.07-0.10)ratios had a high arsenic removal efficiency of 100%at an As(V)concentration of 0.1 mg/L and pH of 3.0.The maximum adsorption capacities of magnetic xerogels were approximately five times higher than those of the xerogels without MNP composites.Therefore,Fe_(3)O_(4)nanoparticles enhanced the adsorption of arsenate and fluoride.The variations of alkaline catalyst and water content significantly affected the resulting properties of textural and surface chemistry of magnetic xerogel composites.展开更多
In this study,a microbial consortium isolated from an activated sludge tank of a conventional wastewater treatment plant was immobilized using sodium alginate(SA)as a support material for contaminant biodegradation in...In this study,a microbial consortium isolated from an activated sludge tank of a conventional wastewater treatment plant was immobilized using sodium alginate(SA)as a support material for contaminant biodegradation in wastewater.A volume of 500 mL of activated sludge was immobilized in the SA beads(with a mass concentration of 25 g/L).The resulting SA beads were characterized,introduced into a fluidized bed reactor,fed with 1000 mL of the sample,and characterized again after the treatment process.The SA-immobilized microorganisms were tested first for degradation of organic matter(expressed as chemical oxygen demand)and total phosphorous in domestic wastewater,achieving removal efficiencies of 71%and 93%,respectively,after 12 h.Subsequently,the SA-immobilized microorganisms were tested for degradation of a basic blue 9(BB9)textile dye in a condition that simulated textile wastewater.The efficiency of the BB9 degradation was found to be as high as 99.5%after 2 h.According to these results,SA-immobilized microorganisms were found to be an environmentally friendly and cost-effective alternative for treatment of municipal and industrial wastewater effluents.展开更多
基金supported by the Mexican Institute of Water Technology(Grant No.DP2101.1)the Catedras-CONACyT Program of the National Council of Science and Technology(Project No.159).
文摘Fe_(3)O_(4)magnetic xerogel composites were prepared by polycondensation of resorcinol(R)-formaldehyde reaction via a sol-gel process in an aqueous solution through varying the molar ratio of Fe_(3)O_(4)nanoparticles(MNPs),catalyst(C),and water(W)content.MNPs were obtained by co-precipitation(MC),oxidation of iron salts(MO),or solvothermal synthesis(MS).Both MNPs and magnetic xerogels were examined regarding the performance of arsenic and fluoride removal in a batch system.The MC-based MNPs had higher adsorption capacities for both fluoride(202.9 mg/g)and arsenic(3.2 mg/g)than other MNPs in optimum conditions.The X-ray diffraction,Fourier transform infrared spectroscopy,and energy-dispersive X-ray spectroscopy confirmed that Fe was composed into the polymeric matrix of magnetic xerogels that contained 0.59%-4.42%of Fe with a molar ratio of MNPs(M)to R between 0.01 and 0.10.With low R/C and optimum M/R ratios,an increase in the surface area of magnetic xerogels affected the fluoride and arsenic adsorption capacities.The magnetic xerogel composites with the MC-based MNPs prepared at a fixed R/C ratio(100)and at different R/W(0.05-0.06)and M/R(0.07-0.10)ratios had a high arsenic removal efficiency of 100%at an As(V)concentration of 0.1 mg/L and pH of 3.0.The maximum adsorption capacities of magnetic xerogels were approximately five times higher than those of the xerogels without MNP composites.Therefore,Fe_(3)O_(4)nanoparticles enhanced the adsorption of arsenate and fluoride.The variations of alkaline catalyst and water content significantly affected the resulting properties of textural and surface chemistry of magnetic xerogel composites.
文摘In this study,a microbial consortium isolated from an activated sludge tank of a conventional wastewater treatment plant was immobilized using sodium alginate(SA)as a support material for contaminant biodegradation in wastewater.A volume of 500 mL of activated sludge was immobilized in the SA beads(with a mass concentration of 25 g/L).The resulting SA beads were characterized,introduced into a fluidized bed reactor,fed with 1000 mL of the sample,and characterized again after the treatment process.The SA-immobilized microorganisms were tested first for degradation of organic matter(expressed as chemical oxygen demand)and total phosphorous in domestic wastewater,achieving removal efficiencies of 71%and 93%,respectively,after 12 h.Subsequently,the SA-immobilized microorganisms were tested for degradation of a basic blue 9(BB9)textile dye in a condition that simulated textile wastewater.The efficiency of the BB9 degradation was found to be as high as 99.5%after 2 h.According to these results,SA-immobilized microorganisms were found to be an environmentally friendly and cost-effective alternative for treatment of municipal and industrial wastewater effluents.
