title: Removal of Pb(II) from water by the activated carbon modified by nitric acid under microwave heating.
abstract: The rice husk based activated carbon (RH-AC) was treated by nitric acid under microwave heating, in order to improve its capability for the removal of heavy metal ions from water. The optimal conditions for the modification of RH-AC (M-RH-AC) were determined by means of orthogonal array experimental design, giving those as the concentration of nitric acid of 8mol/L, modification time of 15min, modification temperature of 130°C and microwave power of 800W. The characteristics of the M-RH-AC and RH-AC were examined by BET, XRD, Raman spectrum, pH titration, zeta potential, Boehm titration and FTIR analysis. The M-RH-AC has lower pore surface area, smaller crystallite, lower pHIEP and more oxygen-containing functional groups than the RH-AC. Removal capacity of Pb(II) ions by the M-RH-AC and RH-AC from water solution was estimated concerning the influence of contact time, pH value, and initial concentration. The equilibrium time of Pb(II) removal was found to be around 90min after modification process. Two kinetic models are adopted to describe the possible Pb(II) adsorption mechanism, finding that the adsorption rate of Pb(II) ions by the M-RH-AC is larger than that of RH-AC.
authors.affiliation: Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, PR China.
authors.forename: Shuheng
authors.initials: S
authors.lastname: Yao
authors.affiliation: School of Energy, Environment and Agrifood, Cranfield University, College Road, Bedfordshire, United Kingdom.
authors.forename: Jiajun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, PR China; State Key Laboratory of Motor Vehicle Biofuel Technology, Nanyang 473000, PR China. Electronic address: 101011398@seu.edu.cn.
authors.forename: Dekui
authors.initials: D
authors.lastname: Shen
authors.affiliation: Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Xiao
authors.affiliation: School of Energy, Environment and Agrifood, Cranfield University, College Road, Bedfordshire, United Kingdom.
authors.forename: Sai
authors.initials: S
authors.lastname: Gu
authors.affiliation: Electric Power Research Institute, Yunnan Electric Power Test and Research Institute (Group), Kunming 650217, PR China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Electric Power Research Institute, Yunnan Electric Power Test and Research Institute (Group), Kunming 650217, PR China.
authors.forename: Junyu
authors.initials: J
authors.lastname: Liang
keywords: Activated carbon; Adsorption kinetics; Heavy metal ions; Microwave heating; Nitric acid