Characterization and modification of porous ceramic sorbent for arsenate removal

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• 作者：Rongzhi Chen ; ^{RZ.Chen@aist.go.jp} ; Zhongfang Lei ; Shengjiong Yang ; Zhenya Zhang ; Yingnan Yang ; Norio Sugiura
• 关键词：Ceramic adsorbent ; Modification ; Arsenate(V) removal ; Equilibrium isotherms ; Possible mechanism
• 刊名：Colloids and Surfaces A: Physicochemical and Engineering Aspects
• 出版年：2012
• 出版时间：20 November, 2012
• 年：2012
• 卷：414
• 期：Complete
• 页码：393-399
• 全文大小：1262 K

文摘

Porous ceramic sorbent, synthesized with a mixture of akadama mud, wheat starch, and Fe₂O₃, has been used for the removal of arsenic, which is an extremely toxic contaminant even at very low concentrations. Acid washing process using dilute HCl solvent and iron impregnation using ferric and ferrous solutions were applied to modify the ceramic for enhancing arsenic removal performance. The batch results indicated that ferric impregnated ceramic (ceramic/FeCl₃) exhibited the best arsenic adsorption efficiency at room temperature (25 ¡ãC) under neutral conditions (pH 6.9). And its maximum adsorption capacity for arsenic removal was 7.12 mg/g, estimated by the Langmuir-Freundlich equation with correlation coefficient of 0.984. The equilibrium data also well fitted to Dubinin-Radushkevich adsorption isotherms with a sorption energy E = 8.11 kJ/mol, indicating that the mechanism for As(V) adsorption on ceramic/FeCl₃ was a combination of chemical ion exchange and physical electrostatic attraction, in which chemisorption seemed to be a little stronger. No secondary pollution (toxic sludge and leached iron) caused by the ceramic/FeCl₃ was observed.