title: Removal of dieldrin from aqueous solution by a novel triolein-embedded composite adsorbent.
abstract: In this study, a novel triolein-embedded activated carbon composite adsorbent (CA-T) was prepared and applied for the adsorption and removal of dieldrin from aqueous systems. Experiments were carried out to investigate the adsorption behavior of dieldrin on CA-T, including adsorption isotherms, adsorption kinetics, the influence of initial concentration, temperature, shaking speed, pH and the addition of humic acid (HA) on adsorption. The adsorption isotherms accorded with Freundlich equation. Three kinetics models, including pseudo-first-order, pseudo-second-order and intraparticle diffusion models, were used to fit the experimental data. By comparing the correlation coefficients, it was found that both pseudo-second-order and intraparticle diffusion models were used to well describe the adsorption of dieldrin on CA-T. The addition of HA had little effect on dieldrin adsorption by CA-T. Results indicated that CA-T appeared to be a promising adsorbent for removing lipophilic dieldrin in trace amount, which was advantageous over pure granular activated carbon (GAC). The adsorption rate increased with increasing shaking speed, initial concentration and temperature, and remained almost unchanged in the pH range of 4-8. Thermodynamic calculations indicated that the adsorption reaction was spontaneous with a high affinity and the adsorption was an endothermic reaction.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China. rujia_china@hotmail.com
authors.forename: Jia
authors.initials: J
authors.lastname: Ru
authors.forename: Huijuan
authors.initials: H
authors.lastname: Liu
authors.forename: Jiuhui
authors.initials: J
authors.lastname: Qu
authors.forename: Aimin
authors.initials: A
authors.lastname: Wang
authors.forename: Ruihua
authors.initials: R
authors.lastname: Dai
mesh_terms: D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D004026:Dieldrin / Q000737:chemistry*; D006812:Humic Substances; D013696:Temperature; D013816:Thermodynamics; D014304:Triolein / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014873:Water Pollutants / Q000737:chemistry*
chemical_list: D006812:Humic Substances; D014873:Water Pollutants; D014304:Triolein; D002606:Charcoal; D004026:Dieldrin