title: Removal of 2-chlorophenol from water using rice-straw derived ash.
abstract: Removal of 2-chlorophenol from water using rice-straw derived ash (RSDA) was evaluated in this study to compare with commercial activated carbon. RSDA was obtained by burning rice-straw at 400 °C and 700 °C for 1 h. This ash can provide a better adsorbent for 2-chlorophenol. The adsorption capacities of RSDA at 400 °C and 700 °C are 37 and 52 mg g⁻¹ at pH 4, respectively, and decrease to 9.0 and 40 mg g⁻¹ at pH 10. Adsorption of either neutral or anionic 2-cholorphenol by the RSDA are shown as L-shaped nonlinear isotherms, suggesting surface adsorption rather than partitioning is occurring. At higher-burning temperatures, the surface area, porosity, point of zero charge and aromaticity of the resultant RSDA increase, but the oxygen content and surface acidity decrease. The combined effects result in a higher 2-chlorophenol adsorption of RSDA at 700 °C, which shows a slight pH effect on the adsorption of 2-chlorophenol, due to the lower content of oxygen-containing functional groups. Oxygen-containing functional groups contribute to surface acidity and H-bonding sites for adsorbed water, which compromises the interaction between 2-chlorophenol and the adsorbents. Thus, it suggests that rice-straw derived carbon (RSDC) can be used as an effective low-cost substitute material for activated carbon for removal of chlorophenols from wastewater.
authors.affiliation: Department of Soil and Environmental Sciences, National Chung-Hsing University, Taichung, Taiwan.
authors.forename: Rung R
authors.initials: RR
authors.lastname: Chang
authors.forename: Shan L
authors.initials: SL
authors.lastname: Wang
authors.forename: Yu M
authors.initials: YM
authors.lastname: Tzou
authors.forename: Yue M
authors.initials: YM
authors.lastname: Chen
authors.forename: Ming K
authors.initials: MK
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D002733:Chlorophenols / Q000737:chemistry*; D006358:Hot Temperature; D012275:Oryza / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014877:Water Pollution, Chemical; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D002733:Chlorophenols; D014874:Water Pollutants, Chemical; C030683:2-chlorophenol