摘要
通过加热和亚铁离子2种方法活化过硫酸钠产生强氧化性的硫酸根自由基,利用硫酸根自由基氧化难降解有机污染物.以对氯苯酚(4-CP)为目标污染物,研究了温度、pH值、亚铁离子浓度、过硫酸钠浓度、柠檬酸浓度对4-CP降解率的影响.结果表明,升高温度可以显著地提高4-CP降解率.反应4h后,在30℃,4-CP降解率只有2.5%;在50℃,4-CP降解率能够达到43.5%;而在60℃,4-CP降解率为100%.pH值对4-CP降解率的影响较大,依次为pH4.0>pH7.0>pH10.0.在室温下,亚铁离子是促使4-CP降解的必要条件,并且对反应条件进行了优化,分子探针实验证实了硫酸根自由基的存在.在过硫酸钠/亚铁离子体系加入适量的柠檬酸能够有效利用溶液中的亚铁离子,在等量的过硫酸钠存在条件下,常温下过硫酸钠/亚铁离子/柠檬酸体系对4-CP降解率为50.9%,优于50℃下过硫酸钠体系对4-CP降解率43.5%.
The heat and ferrous ion-activated sodium peroxydisulfate （ PDS） for the oxidation of 4-chlorophenol （ 4-CP） was investigated. These processes are based on the generation of sulfate radicals,which are powerful oxidizing species found in nature. The effects of temperature,pH,the initial concentrations of Fe（Ⅱ）,PDS and citric acid on the degradation efficiencies of 4-CP were studied. The results show that the degradation efficiency of 4-CP is significantly enhanced as temperature increases. The degradation efficiencies of 4-CP are 2. 5% and 43. 5% within 4 h at 30℃ and 50℃,respectively. Moreover,4-CP is degraded completely at 60℃. The degradation efficiency of 4-CP follows the order： pH 4. 0 〉pH 7. 0〉 pH 10. 0. In the PDS/Fe（Ⅱ） system,ferrous ion played an important role in generating sulfate radicals at ambient temperature. The optimum experimental condition is established and the addition of probe compounds proves the formation of sulfate radicals. Furthermore,the iron availability in the aqueous solution is manipulated with the optimum amount of citric acid,as a chelating agent. The degradation efficiency of 4-CP is 50. 9% in the PDS/Fe （Ⅱ） /citric acid system,which is superior to 43. 5% at 50℃ under the same initial concentration of PDS.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2010年第5期1233-1238,共6页
Environmental Science
基金
国家自然科学基金项目(20837001)
关键词
硫酸根自由基
高级氧化技术
过硫酸钠
对氯苯酚
柠檬酸
sulfate radical anion
advanced oxidation process
sodium peroxydisulfate
4-chlorophenol
citric acid
