磁性生物炭对高砷煤矿酸性废水的净化处理

Purification of High Arsenic Acid Mine Wastewater by Magnetic Biochar

为了获得能高效去除高砷煤矿酸性废水中As(V)的吸附材料,利用生物炭以及铁氧化物与砷离子的强亲和力,以莲蓬、龙葵、稻草为原料,采用共沉淀法,并在该过程中加以微波辅助,制备出磁性生物炭.实验结果表明:当As(V)质量浓度为1 mg/L,磁性生物炭投加量为2 g/L,实验温度为25℃时,以莲蓬、龙葵、稻草为原料制备的磁性生物炭对As(V)的最高去除率分别达到97.46%,96.17%,67.86%,其中以莲蓬为原料制备的磁性生物炭(L-BC@Fe_(3)O_(4))去除效果最佳,6 h达到最大吸附量为0.472 mg/g;吸附动力学和吸附等温模型分别符合准二级动力学方程和Langmuir吸附等温线,这表明吸附主要是受化学作用控制的单分子层吸附;通过比表面积与孔隙度分析(BET)、扫描电子显微镜-元素分析(SEM-Mapping)、X射线衍射(XRD)、磁性表征(VSM)、傅里叶红外光谱(FTIR)等对L-BC@Fe_(3)O_(4)表征分析,表明L-BC@Fe_(3)O_(4)对As(V)的吸附机理包括络合反应、吸附和重金属的共沉淀等化学吸附效应.研究结果为高砷煤矿酸性废水的处理提供了新的解决思路.

In order to obtain an adsorption material that can efficiently remove As(V)in the high arsenic acid mine wastewater,due to the strong affinity of iron oxides and arsenic ions,this study uses the co-precipitation and microwave-assisted methods to prepare magnetic biochar from lotus,nightshade,and rice straw.The experimental results show that when the mass concentration of As(V)is 1 mg/L,the dosage of magnetic biochar is 2 g/L,and the experimental temperature is 25℃,the magnetic biochar prepared with lotus,nightshade,and straw the highest removal rate of As(V)can reach 97.46%,96.17%,67.86%,among which the magnetic biochar(L-BC@Fe 3O 4)prepared with lotus has the best removal effect,reaching the maximum adsorption capacity of 0.472 mg/g in 6 hours.The adsorption kinetics and adsorption isotherm models respectively accord with the quasi-second-order kinetic equation and Langmuir adsorption isotherm,which indicates that the adsorption is mainly monolayer adsorption controlled by chemical action.The characterization results of L-BC@Fe 3O 4 by Brunauer Emmett Teller(BET),Scanning Electron Microscope-Mapping(SEM-Mapping),X-ray diffraction(XRD),Vibrating Sample Magnetometer(VSM),Fourier Transform Infrared Spectrometer(FTIR)show that the adsorption mechanism of L-BC@Fe 3O 4 to As(V)includeschemisorption effects such as complexation reaction,adsorption and co-precipitation of heavy metals.The research results have provided a new solution for the treatment of acid wastewater from high-arsenic coal mines.