饮用水除砷材料吸附特性及影响因素分析

Analysis on absorbents for sorption characteristic and factors affecting As(Ⅴ) removal from drinking water

采用活性氧化铝、零价铁粉和载铁沸石作为吸附剂,通过静态吸附实验,研究3种饮用水除砷材料的吸附特性及影响因素。结果表明,在pH值为6.5,砷浓度为1 mg/L,投加量为2 g/L,25℃恒温的条件下,活性氧化铝、零价铁粉和载铁沸石分别在90 min、150 min和90 min达到吸附平衡状态,均较好符合langmuir等温吸附模型,对砷的最大吸附容量依次为7.3、3.3和3.9 mg/g。pH值和竞争性阴离子对砷的去除均有显著影响。降低溶液pH值能明显提高3种材料的除砷效率;水中磷酸根离子的存在,能够明显降低活性氧化铝和零价铁粉的除砷效率;水中硅酸根离子的存在,能够明显降低零价铁粉和载铁沸石的除砷效率。

Batch experiments were conducted to investigate the sorption characteristic and the factors affecting As（ V ） removal from drinking water for activated alumina, zero-valent iron and iron-oxide coated zeolite （IOCZ）. The experimental results suggest that the highest As（ V ） removal efficiency of activated alumina, zerovalent iron and IOCZ was reached after 90 min, 150 min and 90 rain, respectively. The adsorption of As（ V ） on Activated alumina, zero-valent iron and IOCZ was found to follow the Langmuir isotherm. The maximal sorption capacity of activated alumina, zero-valent iron and IOCZ was 7.3 rag/g, 3.3 mg/g and 3.9 rag/g, respectively with the dosage of absorbents were 2 g/L, the initial concentration of As （ V ） was 1 mg/L, the pH value was 6.5, at 25℃. The As（ V ） removal efficiency from the drinking water is dramatically affected by pH value and competitive ions. The removal efficiency of As（ V ） can be increased by the decreasing the pH value, the presence of phosphate decreased the efficiency of arsenic removal for both batch activated alumina, and zero-valent iron ; while the presence of silicate decreased the efficiency of arsenic removal for both zero-valent iron and IOCZ.