Amino-functionalized Fe3O4@mesoporous SiO/ core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb（Ⅱ） and Cd（Ⅱ） adsorption. The microspheres were characteriz...Amino-functionalized Fe3O4@mesoporous SiO/ core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb（Ⅱ） and Cd（Ⅱ） adsorption. The microspheres were characterized by transmission electron microscope （TEM）, scanning electron microscope （SEM）, N2 adsorption-desorption, zeta potential measurements and vibrating sample magnetometer. Batch adsorption tests indicated that NH2-MS exhibited higher adsorption affinity toward Pb（Ⅱ） and Cd（Ⅱ） than MS did. The Langmuir model could fit the adsorption isotherm very well with maximum adsorption capacity of 128.21 and 51.81 mg/g for Pb（Ⅱ） and Cd（Ⅱ）, respectively, implying that adsorption processes involved monolayer adsorption. Pb（Ⅱ） and Cd（Ⅱ） adsorption could be well described by the pseudo second-order kinetics model, and was found to be strongly dependent on pH and humic acid. The Pb（Ⅱ）- and Cd（Ⅱ）-loaded microspheres were effectively desorbed using 0.01 mol/L HC1 or EDTA solution. NH2-MS have promise for use as adsorbents in the removal of Pb（Ⅱ） and Cd（Ⅱ） in wastewater treatment processes.展开更多
The removal of dissolved oxygen(DO)from water was studied experimentally in a Pd-resin base catalyst reactor using purified hydrogen gas as a reducing agent.The effects of various operating conditions,such as hydrogen ...The removal of dissolved oxygen(DO)from water was studied experimentally in a Pd-resin base catalyst reactor using purified hydrogen gas as a reducing agent.The effects of various operating conditions,such as hydrogen and waterflow rates,height of the catalytic resin bed,temperature,pH value and run time,on the removal of DO,had been studied extensively.The results shows that DO could be removed by the reactor from ppm to ppb levels at ambient temperature.Increases of temperature,H2 gas rate and the height of the catalytic resin were helpful to improve the DO removal rate.The change of pH value from 4 to 12 resulted in no effect on DO removal.Reaction time was the key factor to control the DO removal efficiency.Only when the reaction time was longer than 2.3 minutes under the experimental conditions,could a very low DO level be achieved.展开更多
基金supported by the National Natural Science Foundation of China (No. 21007048)the Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (No. 2012BAF03B06,2012BAJ25B06)partial fund of the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No. PCRRY11011,PCRRF11003)
文摘Amino-functionalized Fe3O4@mesoporous SiO/ core-shell composite microspheres NH2-MS in created in multiple synthesis steps have been investigated for Pb（Ⅱ） and Cd（Ⅱ） adsorption. The microspheres were characterized by transmission electron microscope （TEM）, scanning electron microscope （SEM）, N2 adsorption-desorption, zeta potential measurements and vibrating sample magnetometer. Batch adsorption tests indicated that NH2-MS exhibited higher adsorption affinity toward Pb（Ⅱ） and Cd（Ⅱ） than MS did. The Langmuir model could fit the adsorption isotherm very well with maximum adsorption capacity of 128.21 and 51.81 mg/g for Pb（Ⅱ） and Cd（Ⅱ）, respectively, implying that adsorption processes involved monolayer adsorption. Pb（Ⅱ） and Cd（Ⅱ） adsorption could be well described by the pseudo second-order kinetics model, and was found to be strongly dependent on pH and humic acid. The Pb（Ⅱ）- and Cd（Ⅱ）-loaded microspheres were effectively desorbed using 0.01 mol/L HC1 or EDTA solution. NH2-MS have promise for use as adsorbents in the removal of Pb（Ⅱ） and Cd（Ⅱ） in wastewater treatment processes.
文摘The removal of dissolved oxygen(DO)from water was studied experimentally in a Pd-resin base catalyst reactor using purified hydrogen gas as a reducing agent.The effects of various operating conditions,such as hydrogen and waterflow rates,height of the catalytic resin bed,temperature,pH value and run time,on the removal of DO,had been studied extensively.The results shows that DO could be removed by the reactor from ppm to ppb levels at ambient temperature.Increases of temperature,H2 gas rate and the height of the catalytic resin were helpful to improve the DO removal rate.The change of pH value from 4 to 12 resulted in no effect on DO removal.Reaction time was the key factor to control the DO removal efficiency.Only when the reaction time was longer than 2.3 minutes under the experimental conditions,could a very low DO level be achieved.
