title: Kinetics and equilibrium of adsorption of dissolved organic matter fractions from secondary effluent by fly ash.
abstract: Fly ash was used as a low-cost adsorbent for removing dissolved organic matter (DOM) in secondary effluent. Batch experiments were conducted under various adsorbent dosages, pH, contact time, temperatures and DOM fractional characteristics. Under the optimum conditions of fly ash dosage of 15 g/L, temperature of 303 K and contact time of 180 min, a removal of 22.5% of the dissolved organic carbon (DOC), 23.7% of UV-254, 25.9% of the trihalomethanes precursors in secondary effluent was obtained. The adsorption of DOM fractions onto fly ash all followed the pseudo second-order kinetic model, and the hydrophilic fraction adsorption by fly ash also fitted the intraparticle diffusion model quite well. Freundlich and Langmuir models were applicable to the fly ash adsorption and their constants were evaluated. The maximum adsorption capacities of the adsorptions revealed that fly ash was more effective in adsorbing hydrophilic fraction than the acidic fractions. Structure changes of the DOM fractions after fly ash adsorption were also characterized via spectrum analyzing. Those mechanisms presented critical step toward improved efficiencies of fly ash adsorption via further surface-modification.
authors: School of Municipal & Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China. llwei1985@126.com
authors: Liangliang
authors: L
authors: Wei
authors: Kun
authors: K
authors: Wang
authors: Qingliang
authors: Q
authors: Zhao
authors: Chunmei
authors: C
authors: Xie
authors: Wei
authors: W
authors: Qiu
authors: Ting
authors: T
authors: Jia
mesh_terms: D000327:Adsorption; D005591:Chemical Fractionation; D060729:Coal Ash / Q000737:chemistry*; D007700:Kinetics
chemical_list: D060729:Coal Ash