考察了时间、pH、温度、吸附剂投加量、无机阴离子等因素对磁黄铁矿去除As(V)过程的影响.同时,对去除过程的动力学和等温线进行分析,并探究了动态去除的效果.结果显示:磁黄铁矿对As(V)的去除在24 h达到平衡;在pH值3~9范围内去除率都达到80%以上;温度升高和吸附剂用量增加都对As(V)去除具有促进作用;PO_4~(3-)、SiO_3~(2-)、CO_3~(2-)对吸附有较强的抑制作用;在As(V)初始浓度为2 mg·L~(-1)时动态吸附出水浓度在150个吸附床体积(BV)内能达到国家饮用水标准;吸附去除过程符合拟二级动力学方程和Langmuir等温方程.能谱仪和X射线电子能谱分析表明,去除过程是一个自发吸热的配位离子交换反应.本实验表明,天然磁黄铁矿是一种有潜力的除砷吸附剂.
Effects of reaction time,p H,temperature,pyrrhotite dosage,and inorganic anions on the As( V) removal from water with natural pyrrhotite were investigated. The kinetics and isotherms of the As( V) removal process were analyzed,and the removal effects of dynamic test were conducted. The results show that adsorption of As( V) on natural pyrrhotite reached the equilibrium stage within 24 h. in the p H 3 ~ 9,As( V) removal rates were above80%. As( V) removal increased with increasing temperature and dosage. PO_4~(3-),SiO_3~(2-),CO_3~(2-)had stronger inhibition on As( V) removal. Under the condition of 2 mg·L~(-1)of the initial As( V) concentration,As( V) concentration in the effluent could meet the national drinking water standards,10μg·L~(-1),within 150 BV in the dynamic adsorption test. Pseudo second-order kinetics and Langmuir isotherm equation could well fit the As( V) removal process. EDS and XPS analysis confirm that the As( V) removal process is a spontaneous endothermic ligand exchange reaction. This study demonstrates that natural pyrrhotite was a promising arsenic removal adsorbent.