title: Comparison of two adsorbents for the removal of pentavalent arsenic from aqueous solutions.
abstract: Two adsorbents, magnesia-loaded fly ash cenospheres (MGLC) and manganese-loaded fly ash cenospheres (MNLC), were prepared by wet impregnation of fly ash cenospheres with MgCl(2) solution or a mixed solution of MnCl(2) and KMnO(4), respectively. Their physicochemical properties were characterized by scanning electron microscopy, X-ray diffractometry, X-ray fluorescence spectrometry, and Fourier transform infrared spectrometry. Sorption experiments were conducted to examine the effects of adsorbent dosage, pH, time, temperature, ionic strength and competing anions on As(V) removal by MGLC and MNLC. Both MGLC and MNLC had greater pH buffering capacity and were less affected by changes in ionic strength. Competing anions (carbonate and dihydric phosphate) had a larger impact on As(V) removal by MNLC than by MGLC. Adsorption on MNLC reached equilibrium at 60 min, while adsorption on MGLC reached equilibrium at 120 min. The Langmuir adsorption isotherm was a good fit for the experimental data of As(V) adsorption on MGLC and MNLC, and the adsorption kinetics for both followed the pseudo-second-order rate equation. MGLC and MNLC had a larger removal capacity for As(V) than the cenospheres. Compared with MNLC, MGLC is a better absorbent.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
authors.forename: XiaoTian
authors.initials: X
authors.lastname: Xu
authors.forename: Hao
authors.initials: H
authors.lastname: Cui
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Pang
authors.forename: ZhongBo
authors.initials: Z
authors.lastname: Wei
authors.forename: Zengqing
authors.initials: Z
authors.lastname: Sun
authors.forename: Jianping
authors.initials: J
authors.lastname: Zhai
mesh_terms: D000327:Adsorption; D000838:Anions / Q000737:chemistry; D001151:Arsenic / Q000302:isolation & purification*; D060729:Coal Ash / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008277:Magnesium Oxide / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D009994:Osmolar Concentration; D013696:Temperature; D014873:Water Pollutants / Q000302:isolation & purification*
chemical_list: D000838:Anions; D060729:Coal Ash; D014873:Water Pollutants; D008277:Magnesium Oxide; D008345:Manganese; D001151:Arsenic