磷酸改性核桃壳作为Cr(Ⅵ)吸附剂的改性工艺优化研究

Optimization of modification technics of phosphoric acid modified walnut shell as Cr(Ⅵ)adsorbent

磷酸改性核桃壳能显著提高对Cr(Ⅵ)的吸附率,改性工艺简单、环保。研究了磷酸改性核桃壳的改性工艺,详细探讨了磷酸浓度、核桃壳颗粒度、改性时间、改性温度和核桃壳用量等因素对吸附效果的影响,并通过正交试验和对比实验进一步优化改性工艺。实验确定的最佳工艺条件为:在100mL改性溶液中,磷酸质量分数为15%,核桃壳颗粒度为60目,改性温度为室温,改性时间为5h,核桃壳用量为10g。采用最佳工艺条件制备了磷酸改性核桃壳,在改性核桃壳用量为1.0g、pH=2条件下,处理150mL质量浓度为50mg/L的含Cr(Ⅵ)废水,吸附率达97.23%,吸附量为7.29mg/g。

As Cr(Ⅵ)ions adsorbent,phosphoric acid modified walnut shell has characteristics including environmental friendly and simple modification process,and high adsorption rate for Cr(Ⅵ)ions.Some factors,including phosphoric acid concentration,particle size of walnut shell,reaction time,reaction temperature,and walnut shell dosage,were investigated in detail.Based on single factor experiments,the modification technics were further optimized through orthogonal experiments and comparative experiments.Optimum modification technics were as follows:in 100 mL of solution,phosphoric acid concentration was 15%,particle size of walnut shell was 60 mesh,reaction temperature was 20℃,reaction time was 5 h,and walnut shell dosage was 10 g.The adsorbent of 1.0 g prepared under the optimal conditions selected was used to dispose 150 mL of 50 mg/L simulated wastewater containing Cr(Ⅵ)ions.The adsorption rate of Cr(Ⅵ)ions was 97.23%and the adsorption capacity of adsorbent was 7.29 mg/g.