基于废弃茄科植物的纳米铁/生物炭制备及其对含铬(Ⅵ)废水的吸附净化研究

Preparation of Nano-Iron/Biochar Based on Waste Solanaceae Plants and Its Adsorption and Purification of Chromium(Ⅵ)-Containing Wastewater

利用农业废弃物烟梗为原料,选用两种改性方法制备改性生物炭,对比前体混合法和共沉淀法制备的生物炭对铬的吸附效果。利用SEM、EDS、FT-IR、BET、XRD、TEM对生物炭进行表征。探究反应pH、反应时间、Cr(Ⅵ)初始浓度、生物炭添加量等单因素对生物炭吸附效果的影响,同时利用动力学模型和等温吸附模型等拟合参数。结果表明:pH=2时,生物炭对Cr(Ⅵ)的吸附效果最好,反应时间为4 h时对Cr(Ⅵ)的吸附接近饱和,Cr(Ⅵ)初始浓度越低吸附效果越好,生物炭添加量在0.1 g时吸附效果接近饱和更利于节约成本。Fe_(2)SO_(4)改性的生物炭对Cr(Ⅵ)的去除率高达97%,吸附过程更接近准二级动力学模型和Langmuir模型,吸附理论值也更接近实际值。

Using agricultural waste tobacco stems as raw materials,two modified methods were selected to prepare modified biochar,and the adsorption effects of biochar prepared by precursor mixing method and co-precipitation method on chromium were compared.SEM,EDS,FT-IR,BET,XRD,TEM were used to characterize biochar.The effects of single factors such as reaction pH,reaction time,initial concentration of Cr(Ⅵ)ions,and biochar addition on the adsorption effect of biochar were explored,and the fitting parameters such as kinetic model and isothermal adsorption model were used.The results showed that when pH=2,the adsorption effect was the best,the reaction time was close to saturation at 4 h,the lower the initial concentration of Cr(Ⅵ)ions,the better the adsorption effect,and the adsorption effect was close to saturation when the biochar addition amount was 0.1 g,which was more conducive to cost saving.The removal rate of Fe_(2)SO_(4)modified biochar can be as high as 97%,the adsorption process is closer to the quasi-second-order kinetic model and the Langmuir model,and the theoretical value of adsorption is closer to the actual value.