不同改性生物炭对溶液中Cd的吸附研究

Adsorption of Cd in Solution By Different Modified Biochar

为研究生物炭对溶液中重金属Cd的吸附去除效果,进一步提升生物炭对Cd的吸附性能,以玉米芯、玉米秸秆、木屑为原料,分别在400℃、500℃、600℃和700℃密闭缺氧条件下热解制备生物炭,通过微波改性、Na OH改性方法对生物炭进行改性处理,研究初始浓度、溶液p H、吸附时间等因素对生物炭吸附Cd效果的影响,筛选出适合用于处理镉污染水体的生物炭品种。结果表明：当Cd浓度为100 mg/L时,玉米秸秆-600℃-Na生物炭（B-6-Na）对Cd的吸附可用Langmuir方程拟合,吸附量可达78.7 mg/g,去除率为78.7%,基本达到吸附平衡的时间为60~120 min;当溶液p H达到7时,三种生物炭对Cd吸附率均超过80%以上;600℃条件下经Na OH溶液改性制备的玉米秸秆生物炭能够更好地吸附溶液中的Cd。该研究结果为制备对污染物具有高效、深度净化功能的生物炭方法提供参考,在深入研究生物炭在重金属Cd污染修复的可行性方面提供理论支撑。

In order to study the adsorption removal effect of Cd by biochar in solution,and further enhance the Cd adsorption property of biochar,this experiment took corn cob,cornstalk,sawdust as raw material,and manufactured biochar under sealed hypoxia pyrolysis conditions of 400℃,500℃,600℃ and 700℃,respectively. The biochar was modified by microwave and Na OH methods. Studies were conducted on adsorption effects of Cd by biochar from the factors of initial concentration,solution p H and adsorption time. Suitable biochar varieties for treating cadmium pollution of water bodies were selected. The results showed that when the Cd concentration was 100 mg/L,the adsorption of Cd by B-6-Na treatment could match by Langmuir equation. Its adsorption capacity was 78.7 mg/L and the removal rate was 78.7%,basically reaching adsorption equilibrium time was about 60 min ~ 120 min. When the solution p H value was 7,the adsorption rate of Cd by these 3 biochars were over than 80%. Cornstalk biochar under600℃ condition modified and prepared by Na OH solution had a better absorption of Cd in solution. The result has provided reference for preparing highly efficient,with deep purification function biochar on pollutants,and also theoretical support for in-depth studies on the feasibility of remediation using biochar for Cd pollution.