摘要
系统研究了锆铁氧化物颗粒吸附剂(GZI)对As(Ⅴ)的去除性能,考察了反应时间、溶液pH、初始As(Ⅴ)浓度、共存离子等反应条件的影响.同时评价了吸附后材料的脱附性能及动态处理后材料的安全性.实验结果显示,初始浓度低于20 m.gL-1时,5 h后As(Ⅴ)在GZI吸附剂上达到平衡,初始浓度为50 m.gL-1时,24 h内As(Ⅴ)在GZI吸附剂上未达到平衡.吸附过程符合准二级速率方程,吸附开始3.0 h内,吸附主要受颗粒内扩散控制.在pH 3.0—9.0的范围内,As(Ⅴ)在GZI表面吸附不受pH影响,显示出良好的pH适用性,意味着在地下水常见的pH范围内,吸附效率不受pH影响.在pH=7.0时,As(Ⅴ)平衡浓度为13.8 m.gL-1时,该颗粒吸附剂对As(Ⅴ)的去除容量为20.75 m.gg-1,优于多数已报道的颗粒除砷吸附剂.共存离子实验结果显示,HCO-3、F-、腐殖酸对As(Ⅴ)的去除存在不同程度影响,其余共存离子在中性pH条件下对As(Ⅴ)去除影响不大.碱液脱附实验表明,3.0%的NaOH适合于对吸附后的GZI进行脱附.对使用后的吸附剂颗粒进行的TCLP测试证实其是惰性的、可以安全填埋.以上结果显示GZI吸附剂是一种能应用于实际处理的除砷吸附剂.
Arsenic（Ⅴ）adsorption on a granular zirconium-iron oxide（GZI）adsorbent was investigated under various conditions of adsorption time,initial solution pH,initial arsenic（Ⅴ） concentration and co-existing substances.Kinetic results revealed that the adsorption reached equilibrium after 5 h with an initial concentration of As（Ⅴ） below 20 mg·L^-1,and the adsorption did not achieve equilibrium after 24 h at an initial concentration of 50 mg·L^-1.The adsorption process was well described by a pseudo-second-order kinetic model.During the initial 3 h,the adsorption was controlled by intrapatical diffusion.The optimum operation pH for As（Ⅴ） removal was in a broad range,from 3.0 to 9.0,which meant As（Ⅴ） removal would not be affected under natural pH conditions found in common groundwater.A maximum adsorption capacity of 20.75 mg·g^-1 was achieved at pH 7.0,which was much higher than those of many reported sorbents.The As（Ⅴ） desorption was inhibited to some extent in the presence of HCO-3,F-,and humic acid,while little effect was found in the presence of other matters.The best desorption concentration of NaOH for GZI adsorbents regeneration was about 3.0%.In the column tests,with an influent As（Ⅴ） concentration of 500 μg·L-1 and SV of 2 h^-1,2433 bed volumes of water was treated before As（Ⅴ） concentration in effluent reached 10 μg·L^-1.The toxicity characteristic leaching procedure（TCLP） test showed that the used granular adsorbent was inert and could be safely land filled.The results indicated that this granular adsorbent was material for As（Ⅴ） removal in practical use.
出处
《环境化学》
CAS
CSCD
北大核心
2011年第8期1396-1404,共9页
Environmental Chemistry
基金
中央高校基本科研业务费专项资金资助(YX2011-13)
北京市科技新星计划(2008A33)
教育部科学技术重点项目(108018)
863探索课题(2007AA06Z301)资助
