堆肥过程中胡敏素的变化及其对五氯苯酚(PCP)吸附能力的影响

The change of humin in sewage sludge composting and its influence on the adsorption of pentachlorophenol(PCP)

以城市污泥为堆肥原料,分别以药渣和木屑为辅料,探讨了为期120d堆肥过程中胡敏素的变化及其对五氯苯酚(PCP)吸附的影响.结果表明,随着堆肥时间的延长,堆料的总有机碳和胡敏素含量降低;堆料比表面积和孔容变小,而从堆料中提取的胡敏素的比表面积和孔容随堆肥时间的延长逐渐增大,堆料有机组分随时间的延长芳构化程度增加.吸附试验表明,堆置不同时间的堆料和其中的胡敏素对PCP的吸附均符合Freundlich模型,胡敏素的吸附能力占堆料总吸附能力的比例随堆肥时间的延长逐渐增加.但是由于堆肥的总有机碳含量下降,比表面积和孔容减小,以及胡敏酸含量的升高造成了竞争吸附作用增强,使得2种堆料对PCP的吸附能力随着堆肥时间的延长逐渐降低.

The change of humin in sewage sludge composting and its influence on the adsorption of Pentachlorophenol （PCP） were studied to understand the role of humin on the adsorption ability of the compost. It can help us to devel- op strategies for reducing the risks of pentachlorophenol （PCP） when sewage sludge-based composts are applied to soils. Aerobic cocomposting of sewage sludge mixed with dregs of a decoction and saw dust was carried out for 120 d. The results show that the contents of total carbon and humins decreased during the composting process. The surface areas, pore volume of composts reduced with the prolonged time. However, the surface area, pore volume, pore size of humin increased during the composting process, and the degree of aromatization of humin increased with the prolonged time. The adsorption experiment results show that the sorption data fitted the Freundlich model well, the sorption capacity of PCP on humin and the contribution of humin to the total sorption of composts increased during the composting process. But due to the decline of total organic matter content and the increased contents of HA molecules, the competition with PCP for sorption sites was enhanced, which blocked some of the micropores that contribute to the sorption. Therefore, the sorption capacity and nonlinear degree of PCP on two composts decrease with the prolonged composting time.