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我国高砷地下水分布广泛,经济、高效地饮用水除砷技术受到广泛关注.静态批实验采用资源丰富、价格便宜的天然菱铁矿为主要原材料,考虑灼烧温度、时间及添加黏合剂等因素确定最优改性条件使除砷效果达到最佳.结果表明,在加铝量为10 mg.g-1、350℃下恒温灼烧90 min后造粒达到强度要求并除砷效果较优.25℃、固液比为0.5 g∶50 mL、As(Ⅲ)和As(Ⅴ)初始浓度为5 mg.L-1时,吸附后溶液中残留As浓度均<10μg.L-1.静态吸附批实验结果表明,25℃时,接触反应时间为12 h可达到吸附平衡,吸附过程较好地符合Lagergren假二级吸附速率方程;最优改性天然菱铁矿对砷的吸附规律可用Langmuir和Freundlich等温吸附模型很好地描述,As(Ⅲ)、As(Ⅴ)饱和吸附容量分别可以达到1 039、1 026μg.g-1.结合XRD、SEM等研究方法和比表面及孔结构分析初步探讨天然菱铁矿改性以及除砷的主要机制.分析表明,改性后天然菱铁矿比表面积大幅度增大,孔径减小,且在表面活化生成一层圆球状的含Fe(Ⅱ)和Fe(Ⅲ)的化合物.改性天然菱铁矿是一种值得进一步研究并实际应用的除砷材料.
A wide range of high-arsenic groundwater in China is distributed widely and economically and efficiently, arsenic removal technology for drinking water has received widespread attention.Static batch experiments use natural siderite with rich resources and cheap price as the main raw materials, taking into account factors such as burning temperature, time and adding binders The results showed that the optimal conditions for the removal of arsenic to achieve the best results show that the amount of aluminum in 10 mg.g-1,350 ℃ constant temperature burning 90 min after the grain strength requirements and better arsenic removal. The concentration of residual As in the solution after adsorption was <10μg.L-1 at 25 ℃, the solid-liquid ratio was 0.5 g:50 mL, the initial concentrations of As (Ⅲ) and As (Ⅴ) were 5 mg.L- The experimental results show that the adsorption equilibrium can be achieved when the reaction time reaches 12 h at 25 ℃, and the adsorption process accords well with Lagergren pseudo-second-order adsorption rate equation. The adsorption of arsenic by the optimized modified natural siderite can be described by Langmuir and Freundlich adsorption isotherm model well described, As (Ⅲ), As (Ⅴ) saturation adsorption capacity can reach 1 039,1 026μg.g-1. Combined with XRD, SEM and other methods and specific surface area and pore structure analysis of preliminary study Natural siderite modified and the main mechanism of arsenic removal The apparent specific surface area of natural siderite increases greatly, the pore diameter decreases, and the surface is activated to form a spherical compound containing Fe (Ⅱ) and Fe (Ⅲ). The modified natural siderite is worth further Research and practical application of arsenic removal materials.