TY - JOUR ID - 10.1016/S1001-0742(12)60100-4 TI - Removal of Pb(II) from aqueous solution by hydrous manganese dioxide: Adsorption behavior and mechanism AU - Meng Xu AU - Hongjie Wang AU - Di Lei AU - Dan Qu AU - Yujia Zhai and Yili Wang VL - IS - 3 PB - SP - 479 EP - 486 PY - JF - Journal of Environmental Sciences JA - J. Environ. Sci. UR - http://www.jesc.ac.cn/jesc_en/ch/reader/view_abstract.aspx?file_no=2013250308&flag=1 KW - adsorption;mechanism;heavy metal;manganese dioxide KW - adsorption;mechanism;heavy metal;manganese dioxide AB - Hydrous manganese dioxide (HMO) synthesized by redox of potassium permanganate and hydrogen peroxide was used as an adsorbent for Pb(II) removal. The specific surface area, pore volume and BJH pore diameter of the HMO were 79.31 m2/g, 0.07 cm3/g and 3.38 nm, respectively. The adsorption equilibrium at 298 K could be well described by the Langmuir isotherm equation with qmax value of 352.55 mg/g. The negative values of ΔG and the positive values of ΔH and ΔS indicated the adsorption process was spontaneous and endothermic. The pseudo second-order equation could best fit the adsorption data. The value of the calculated activation energy for Pb(II) adsorption onto the HMO was 38.23 kJ/mol. The uptake of Pb(II) by HMO was correlated with increasing surface hydroxyl group content and the main adsorbed speciation was PbOH+. The final chemical state of Pb(II) on the surface of HMO was similar to PbO. HMO was a promising candidate for Pb(II) removal from aqueous solution. ER -