核桃壳制备生物炭及其对矿井水中铜、锌、铬离子的吸附研究

Preparation of Biochar from Walnut Shell and Its Adsorption Research of Cu(Ⅱ),Zn(Ⅱ)and Cr(Ⅵ)in Mine Water

以核桃壳为原料,在绝氧制备生物炭后利用盐酸进行改性处理。利用响应面设计法考察了改性时间、盐酸浓度、固液比对生物炭性能的影响,最后利用改性生物炭对矿井水中几种重金属进行吸附研究。用原子吸收分光光度计测定吸收前后重金属离子含量。结果发现,改性生物炭对Cu(Ⅱ)的吸附率在96.71%~97.63%,对Zn(Ⅱ)的吸附率在69.25%~99.90%,对Cr(Ⅵ)的吸附率在72.51%~93.38%。响应面分析发现,当盐酸浓度为2 mol/L,固液比为1∶100(g/mL),改性24 h时,改性生物炭对三种重金属综合吸附率最高。

Using walnut shell as raw material,biochar is prepared by anaerobic method and modified by hydrochloric acid.The effects of modification time,hydrochloric acid concentration and solid-liquid ratio on the properties of biochar are studied by response surface design method.Finally,the adsorption of heavy metals in simulated mine water by modified biochar is studied.The content of heavy metal ions before and after absorption is determined by atomic absorption spectrophotometer.The results show that the adsorption rate of Cu 2+by modified biochar is 96.71%~97.63%.The adsorption rate of Zn 2+is 69.25%~99.90%.The adsorption rate of Cr 6+is 72.51%~93.38%.The response surface analysis shows that when the concentration of hydrochloric acid is 2 mol/L,the solid-liquid ratio is 1∶100,and the modification time is 24 h,the modified biochar has the highest comprehensive adsorption rate for the three heavy metals.