Mixed bacteria were enriched from heavy metals mine soil for cadmium(Cd(Ⅱ))-containing wastewater treatment. Batch adsorption experiment results showed that the optimal pH, temperature, initial Cd(Ⅱ) concentration, ...Mixed bacteria were enriched from heavy metals mine soil for cadmium(Cd(Ⅱ))-containing wastewater treatment. Batch adsorption experiment results showed that the optimal pH, temperature, initial Cd(Ⅱ) concentration, and biomass dosage were 6.0, 30 ℃, 20 mg/L, and 1 g/L, respectively. Living biomass exhibited better Cd(Ⅱ) removal efficiency(91.97%) than autoclaved biomass(79.54%) under optimal conditions. The isotherms and kinetics of living biomass conformed to the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. FTIR results implied that amine groups, hydroxyl groups and phosphoric acid play an important role in the Cd(Ⅱ) adsorption process, while XRD results showed that crystalline Cd(OH)and CdO were obtained. After Cd(Ⅱ)-containing wastewater treatment exposure, the dominant bacteria genera included Comamonas(39.94%), unclassified_f__Enterobacteriaceae(34.96%), Ochrobactrum(14.07%), Alcaligenes(4.84%), Bordetella(2.07%), Serratia(1.04%), and Bacillus(1.01%). Function prediction showed that the abundance of metabolic genes changed significantly. This study proposes the potential application of mixed bacteria for Cd(Ⅱ)-containing wastewater treatment.展开更多
Zinc and cadmium pollutants cause a significant environmental effect that cannot be ignored.Due to their considerable amount in an aqueous environment,industries are seeking suitable adsorbents that are environmentall...Zinc and cadmium pollutants cause a significant environmental effect that cannot be ignored.Due to their considerable amount in an aqueous environment,industries are seeking suitable adsorbents that are environmentally friendly and inexpensive for removing metals from wastewater before disposing of them in surface waters.This research employed original MXene(MX)and chitosan-modified MXene(CSMX)to extract zinc(Zn(Ⅱ))and cadmium(Cd(Ⅱ))metal ions from water-based solutions.The composite material produced was analyzed using techniques such as X-ray Diffraction(XRD),Scanning Electron Microscopy(SEM),Fourier Transform Infrared Spectroscopy(FTIR),and Brunauer-Emmett-Teller(BET).The effects of contact duration,p H of the solution,and initial concentration of metal ions on the adsorption process of Zn(Ⅱ)and Cd(Ⅱ)onto both MX and CSMX composites were investigated.MX and prepared CSMX composite presented a high adsorption capacity for both studied heavy metals,which were 91.55 and 73.82 mg/g for Zn(Ⅱ)and Cd(Ⅱ)onto MX,106.84 and 93.07 mg/g for Cd(Ⅱ)and Zn(Ⅱ)onto CSMX composite,respectively.Furthermore,the maximum competitive adsorption capacities for Zn(Ⅱ)onto MX and CSMX composites are 77.29 and 93.47 mg/g,and for are Cd(Ⅱ)60.30 and 79.66 mg/g,respectively.Hence,the removal capacities for both single and competitive metal ions were superior to CSMX composite.However,the adsorption capacities after five successive regeneration sequences were only dropped by 13.2%for Zn(Ⅱ)and 17.4%for Cd(Ⅱ)onto the CSMX composite compared to the first cycle.These results confirm that both metals could be efficiently terminated from wastewater,which makes the prepared CSMX composite a favorable candidate adsorbent in practical applications.展开更多
基金supported by the National Natural Science Foundation of China (No. 52170164)the Open Project of Key Laboratory of Environmental Biotechnology,CAS (No. kf2018001)the Scientific Research Foundation for Returned Scholars at the University of South China (No. 2018XQD25)
文摘Mixed bacteria were enriched from heavy metals mine soil for cadmium(Cd(Ⅱ))-containing wastewater treatment. Batch adsorption experiment results showed that the optimal pH, temperature, initial Cd(Ⅱ) concentration, and biomass dosage were 6.0, 30 ℃, 20 mg/L, and 1 g/L, respectively. Living biomass exhibited better Cd(Ⅱ) removal efficiency(91.97%) than autoclaved biomass(79.54%) under optimal conditions. The isotherms and kinetics of living biomass conformed to the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. FTIR results implied that amine groups, hydroxyl groups and phosphoric acid play an important role in the Cd(Ⅱ) adsorption process, while XRD results showed that crystalline Cd(OH)and CdO were obtained. After Cd(Ⅱ)-containing wastewater treatment exposure, the dominant bacteria genera included Comamonas(39.94%), unclassified_f__Enterobacteriaceae(34.96%), Ochrobactrum(14.07%), Alcaligenes(4.84%), Bordetella(2.07%), Serratia(1.04%), and Bacillus(1.01%). Function prediction showed that the abundance of metabolic genes changed significantly. This study proposes the potential application of mixed bacteria for Cd(Ⅱ)-containing wastewater treatment.
文摘Zinc and cadmium pollutants cause a significant environmental effect that cannot be ignored.Due to their considerable amount in an aqueous environment,industries are seeking suitable adsorbents that are environmentally friendly and inexpensive for removing metals from wastewater before disposing of them in surface waters.This research employed original MXene(MX)and chitosan-modified MXene(CSMX)to extract zinc(Zn(Ⅱ))and cadmium(Cd(Ⅱ))metal ions from water-based solutions.The composite material produced was analyzed using techniques such as X-ray Diffraction(XRD),Scanning Electron Microscopy(SEM),Fourier Transform Infrared Spectroscopy(FTIR),and Brunauer-Emmett-Teller(BET).The effects of contact duration,p H of the solution,and initial concentration of metal ions on the adsorption process of Zn(Ⅱ)and Cd(Ⅱ)onto both MX and CSMX composites were investigated.MX and prepared CSMX composite presented a high adsorption capacity for both studied heavy metals,which were 91.55 and 73.82 mg/g for Zn(Ⅱ)and Cd(Ⅱ)onto MX,106.84 and 93.07 mg/g for Cd(Ⅱ)and Zn(Ⅱ)onto CSMX composite,respectively.Furthermore,the maximum competitive adsorption capacities for Zn(Ⅱ)onto MX and CSMX composites are 77.29 and 93.47 mg/g,and for are Cd(Ⅱ)60.30 and 79.66 mg/g,respectively.Hence,the removal capacities for both single and competitive metal ions were superior to CSMX composite.However,the adsorption capacities after five successive regeneration sequences were only dropped by 13.2%for Zn(Ⅱ)and 17.4%for Cd(Ⅱ)onto the CSMX composite compared to the first cycle.These results confirm that both metals could be efficiently terminated from wastewater,which makes the prepared CSMX composite a favorable candidate adsorbent in practical applications.
