零价金属对土壤中五氯苯酚的脱氯研究

Study on Dechlorination of Pentachlorophenol in Soils by Zero-valent Mental Systems

五氯苯酚(PCP)目前仍为国内外普遍而大量采用的防腐剂、杀虫剂和除莠剂,由于它的化学稳定性致使残留不易消失,给环境造成严重污染。本文以恒温培养为方法,气相色谱-质谱联用仪(GC-MS)为检测手段,研究了三种零价金属对在不同土壤中五氯苯酚的脱氯规律。结果表明,五氯苯酚可被Fe、Zn、Sn还原降解成四氯苯酚,产物为1,2,3,4-四氯苯酚和1,2,4,5-四氯苯酚;在相同土壤中,脱氯性能与零价金属的还原性成正比关系,Fe-Zn混合物的不同质量比对PCP的降解没有协同催化的作用;不同理化性质的土壤,其脱氯效果存在一定的差异,主要讨论了土壤酸度和有机质含量的影响。

Pentachlorophenol （PCP） is currently used ubiquitously as a wood preservative, an insecticide and a phytocide because of its well - known properties of excellent chemical and thermal stability. PCP degrades extremely slowly in nature and can cause severe environmental pollution problems. At ambient temperature and pressure, the dechlorination of PCP in 3 different soils by 3 zero-valent mentals （ZVIs） was investigated in the laboratory with isothermal incubation and gas chromatography mass spectrometry （GC- MS） as the primary analytical method. Results from GC- MS analysis indicated that PCP in soil with the 3 ZVIs underwent dechlorination and was transformed to i, 2,3, 4 - trachlorophenol and 1,2,4,5 - trachlorophenol. Experimental data showed that in congeneric soils, the rate of dechlorination of PCP was in direct proportion to the reductive power of the mentals with Zn〉Fe〉Sn. Soil properties exerted some influences on the dechlorination of PCP, and soil acidity and organic matter contents seemed to be the major factors. There were no observable synergetic catalytic effects on the dechlorination between Fe and Zn mixed in soils.