摘要
用批平衡法研究了污水处理厂进、出污水中提取的可溶性有机物(DOM)和商用腐殖酸(HA)等3种DOM对四溴双酚A(TBBPA)的增溶作用,并用红外、紫外吸收、元素组成、分子大小分布、扫描电镜等对DOM进行结构表征.结果表明,增溶作用受DOM结构、分子大小以及溶液离子强度的影响,并且与TBBPA形态有关.进水DOM和出水DOM对TBBPA的增溶等温曲线呈非线性,可用Langmuir方程描述,结合系数(Kdoc)分别为1.19×105L.kg-1和1.27×105L.kg-1,其中的大分子DOM(相对分子质量>1 000)对TBBPA的增溶等温曲线呈线性,主要机制为分配,非线性变化由小分子DOM(相对分子质量<1 000)造成,进出水中小分子DOM的增溶能力(Kdoc)比大分子高约55%,增溶贡献率也更大(75%～80%).增溶作用同时受溶液离子强度影响,离子强度低时促进增溶作用,随着离子强度增大而引起DOM聚合、絮凝等降低了增溶效果.
Water solubility enhancements by two types of dissolved organic matter （DOM） extracted from a local wastewater treatment plant and by a commercial humic acid （HA） have been studied for tetrabromobisphenol A （TBBPA） using batch equilibrium technique, and the characteristics of DOM were studied with the aid of infrared and ultraviolet absorbance, elemental analysis, dialysis membranes and scanning electron microscope （SEM） . The results showed that the effectiveness of DOM in enhancing solute solubility appeared to be controlled by the structure and molecular size of DOM, the ionic strength of solution and the dissociation ratio of TBBPA. Langmuir Equation could fit the isotherms of the total influent DOM and effluent DOM, and their binding coefficients （ Kdoc ） are 1.19 ×10^5 L·kg^-1 and 1.27×10^5 L·kg^-1 , respectively. The interaction of TBBPA with DOM （relative molecular weight 〉 1 000） can be explained by partition according to the linear isotherms, while the nonideal binding behavior of the total DOM was caused by DOM （relative molecular weight 〈 1 000） which contributed about 75 % to 80 % of the total water solubility enhancement effect and had higher binding coefficients to TBBPA, about 55 %, than those of DOM （relative molecular weight 〉 1 000）. The capability of solubility enhancements by the influent DOM and effluent DOM was greater than that of 14A in which the high molecular weight DOM controlled the effect of solubility enhancement. In addition, it was also found that the capability of solubility enhancements was affected by the ionic strength of solutions. The capability of solubility enhancements was increased when the ionic strength was low, while it was decreased at higher ionic strength due to the aggregation and flocculation of DOM.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2009年第1期184-190,共7页
Environmental Science
基金
国家自然科学基金项目(20737001
20577020)
关键词
可溶性有机物
四溴双酚A
增溶
dissolved organic matter（DOM）
tetrabromobisphenol A （TBBPA）
water solubility enhancements
