废板栗壳、核桃壳对水溶液中锌离子的吸附条件研究

Study on Adsorption Condition of Zn^(2+) on Waste Chestnut Shell and Walnut Shell

由于重金属废水对环境具有较强的危害,日前针对重金属废水的处理研究日趋增多。吸附法是一种典型的对重金属废水的处理方法,其中吸附剂的选用是重中之重。文章采用农业废弃物板栗壳和核桃壳作为吸附剂,以锌离子溶液模拟重金属废液,探讨溶液pH、反应时间、吸附剂投加量、模拟废液浓度和混合比例等参数对板栗壳和核桃壳吸附性能的影响。实验结果表明:当溶液浓度为20 mg/L,pH值为6.03,振荡反应时间为120 min,核桃壳投加量为0.85 g时,锌离子的去除率可达到97.38%。而板栗壳在相同条件下,投加量仅为0.7 g,锌离子的去除率就可达到98.78%。当2种吸附剂按照1∶3的比例混合时,锌离子的去除率可达到99.75%,明显高于单独使用时的去除效果。

Due to the hazardous nature of the heavy metal waste water to the environment, the studies on the treatment of it are increasing gradually. Among all the treatments, adsorption method is a typical way to deal with the heavy metal waste water, and the most important thing in this method is the selection of adsorbent. In this paper, waste walnut shell and chestnut shell were utilized as the raw materials of adsorbent. The effect of pH, reaction time, adsorbent dosage and mixture ratio on adsorption capacity and the removal rates of Zn2+in aqueous solution were studied. The adsorption rate of the walnut shell to Zn2+in 50 mL 20 mg/L Zn2+polluted water could be up to 96.26%, when the adsorbent dosage was 0.85 g, the pH was 6.03,and the adsorption time was about 120 min. Under the same condition, the removal rate of Zn2+was up to 98.78% when the chestnut shell dosage was 0.7 g. The analysis shows that different proportions of chestnut and walnut shell have different effects of adsorption. The best ratio was 1∶3 and the removal rate of Zn2+was up to 99.75%, which is much effective than just using one of the raw materials.