摘要
采用熔化成型法,以环境友好型材料石蜡和硅砂为复合材料制备复合型高锰酸钾缓释体,研究其在水中和TCE溶液中的缓释性能及缓释过程.研究结果表明:当固定高锰酸钾含量为6g,蜡砂比在1∶4～1∶6之间时,复合型高锰酸钾缓释体成型度适中,高锰酸钾的缓释量随着时间的延长逐渐增大,13d高锰酸钾累积释放百分数分别为28.3%和58.8%,可以作为缓释材料,实现高锰酸钾的持续可控释放.当固定蜡砂比,释放速率随着高锰酸钾百分含量的增大而增大.SEM分析结果表明,复合型高锰酸钾缓释体在水中和TCE溶液中的释放机理:首先表层外露的高锰酸钾晶体遇水快速溶解留下一些孔洞和缝隙,然后水分子通过这些孔洞进入缓释体内部溶解高锰酸钾,最后由浓度梯度差将高锰酸钾扩散到水相中,与溶液中TCE发生氧化降解反应.蜡砂比为1∶4和1∶6的缓释体4h对TCE的去除率分别为90%和100%;实际的高锰酸钾释放量分别约为理论所需高锰酸钾总量的1.7倍和2.6倍,说明该法制备得复合型高锰酸钾缓释体可通过控制蜡砂比来持续释放高锰酸钾,用于氯代烃的去除.
The preparation of the controlled-release potassium permanganate （CRP） composite mixed with paraffin and silica sand by melting and cooling method and the control-release mechanism of CRP in water and trichloroethylene （TCE） were studied. The results show that CRP composite with the paraffin-to-silica sand mass ratios of 1 ： 4 and 1 ： 6 had a good shape and excellent releasing performance. The release rate increased with the increasing releasing time and the accumulated releasing percents of KMnOs reached 28.3% and 58.8% after 13 days in releasing test. When the mass ratio was fixed, the release rate increased with increasing of the accumulated releasing percent of KMnO4 in CRP composite. SEM analysis results showed that the mechanism of the KMnO4 released from CRP composite in water and TCE solution was ： firstly, KMnO4 exposed on the surface of CRP composite dissolved into water quickly with some holes and cracks left on the surface; secondly, water passed though the holes and cracks into the CRP composite, resulting in further release of inside KMnO4 ; finally the TCE degraded by KMnO4 released from the CRP composite. The TCE removal efficiency can reach 90% and 100% after 4 h of reaction time by CRP with the paraffin-to-silica sand mass ratio of 1 ： 4 and 1 ： 6, and the amount of released KMnO4 is 1.7and 2. 6 folds of the calculated KMnO4 , respectively. With easy preparation and low cost, CRP composite obtained by this method could be applied in the remediation of TCE contamination in soil or groundwater.
出处
《环境科学学报》
CAS
CSCD
北大核心
2013年第5期1249-1255,共7页
Acta Scientiae Circumstantiae
基金
国家自然科学基金面上项目(No.50978059
51178117)
华侨大学高层次人才科研启动基金(No.11BS434)~~
关键词
高锰酸钾
石英砂
石蜡
氯代烃
控制释放
地下水
permanganate
silica
paraffin
chlorinate hydrocarbon
controlled release
ground water
