羧甲基淀粉吸附剂对水溶液中铬和铝离子的吸附研究

RESEARCH ON ADSORBING OF CHROMIUM AND ALUMINIUM IONS IN AQUEOUS SOIUTION BY CARBOXYMETHYL STARCH ADSORBENT

羧甲基淀粉 (CMS)吸附剂是将氯乙酸接枝到交联淀粉骨架上研制而成的。先用静态法和动态法研究羧甲基淀粉吸附剂对 Cr3+、Al3+的吸附效果以及 p H值对吸附效果的影响 ,然后用不同浓度的 HCl溶液 (0 .3～ 1 .2 mol/L)进行解吸 ,研究解吸后 Cr3+、Al3+的回收情况 ,并探讨了吸附剂的吸附机理 ,结果表明 :CMS吸附剂的静态等温吸附符合 Freundilich吸附等温式 ,动态吸附的吸附时间大大缩短 ,明显优于静态吸附 ,吸附的 p H值范围宽 ,为 4.0～1 0 .0 ,在解吸过程中 ,使用 0 .6mol/L HCl溶液效果最佳 ,Cr3+、Al3+的最大回收率分别可达96.1 %～ 97.0 %。

Water insoluble Carboxymethyl starch (CMS) adsorbent was prepared by grafting monochloroacetic acid onto the cross linked starch. First, the adsorptive efficiency of carboxymethyl starch adsorbent to Cr 3+ and Al 3+ as well as the effect of pH in the adsorbate solution on the adsorption were studied by static and dynamic adsorption. Then the adsorbent adsorbing Cr 3+ and Al 3+ was desorbed with HCl solution with various concentrations( 0.3 - 1.2 mol/L) , thus the recovery condition of Cr 3+ and Al 3+ could be observed. Moveover, the adsorption mechanisn was also explored. It could be concluded that the static isotherms adsorption of the CMS adsorbent is in conformity with Freundlich isotherm adsorption. And, dynamic adsorption prevailed over the static adsorption because of its rapid adsorption. The optimum pH value of adsorption lay in a wide range of 4.0 and 10.0. The maximum recoval rate of Cr 3+ and Al 3+ could reach 96.1% and 97.0%, respectively, when 0.6mol/L HCl agueous solution was used in the desorption process.