科研之友
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摘要
This study successfully synthesized a new adsorbent cerium impregnating fibrous protein (CeFP) to remove fluoride, arsenate and phosphate from aqueous solutions. The sorbent was characterized by the SEM, FTIR, BET specific surface area and other physical measurements. FTIR showed that the hydroxyl group of hydrous metal oxide (Ce-OH) of CeFP occurred at 1122 cm(-1), and the pH of zero point charge (pH) increasing up to 9.0 after Ce impregnation was benefit for electrostatic attraction for anions. Batch experiments results indicated that sorption properties of three anions were strongly dependent on solution pH. The maximum sorption capacity of fluoride was evaluated to be 5.59 mmol/g at pH = 3.0, and the optimum adsorption capacity for arsenate reached 2.3 mmol/g in the pH range of 3.0-7.0 and 2.11 mmol/g for phosphate in pH 4.0-7.0 at 303 K respectively, better than those of most sorbents available in the market. And the increase of solution pH after adsorption revealed a possible ligand exchange mechanism and the surface hydroxyl group of CeFP played an important role in the adsorption. The Langmuir isotherm equation described all the three anions' sorption equilibrium well at 303 K, 313 K and 323 K, and the thermodynamic parameters such as Delta G degrees, Delta H degrees and Delta S degrees indicated that the nature of fluoride sorption was spontaneous and exothermic while arsenate and phosphate adsorption were endothermic. The pseudo-second-order rate model fitted the adsorption kinetics of three anions perfectly. The competitive adsorption experiment indicated that CeFP had a stronger affinity to arsenate than to fluoride and phosphate.
- 出版日期2012-3-1
- 单位东华大学
