焦化废水原水中有机污染物的活性炭吸附过程解析

以焦化废水原水作为研究对象,采用粉末活性炭作为吸附剂,考察活性炭投加量、温度、pH及反应时间对废水中主要有机污染物去除的影响规律,结合UV-Vis吸收光谱及GC/MS对吸附过程中有机物组分的变化进行定性和半定量分析.结果表明,在最佳反应条件即活性炭投加量6g·L-1,温度30, pH=9,反应时间20min的情况下处理废水有机物去除率大于70%,原水中检测出的56种有机物中的45种被去除,如长链烷烃、多环芳香族及氮杂环化合物等的浓度降至检测限以下,剩余的11种有机物中苯胺、苯酚、吲哚、乙酸-2-甲基苯酯的去除率分别达到63.5%、42.6%、88.1%、28.1%,甲苯酚(邻、间)和二甲苯酚(5种)去除率在70%和85%以上.结果分析表明,多组分有机污染物共存体系的焦化废水活性炭吸附过程中,多环芳香族和氮杂环等弱极性且-ΔG°较大的大分子有机物优先被吸附且吸附容量大,构成了快速吸附过程;而苯胺、苯酚等强极性且-ΔG0较小的小分子单苯环有机物则表现为弱吸附过程.

Adsorption Process of Organic Contaminant in Untreated Coking Wastewater by Powdered Activated Carbon

The article investigated the removal of organic contaminant from coking wastewater in adsorption process using powdered activated carbon as adsorbent. The dose of activated carbon, temperature, pH and reaction time were studied, and UV-Vis and GC/MS were used to carry out the qualitative and semiquantitative analysis of organic compositions in wastewater. The results showed that the optimum conditions for pretreatment of coking wastewater were 6 g activated carbon per liter, 30 degrees C, pH = 9 and reaction for 20 min, under which the removal efficiency of organic pollutants are more than 70%. Among the 56 kinds of organic compounds, 45 kinds such as dolichoalkanes, polynucleation aromatic series, azacyclo compounds could be removed, and the removal ratios of amidobenzene, hydroxybenzene, indoleacetic, acid-2-methyl-phenyl-ester are 63.5%, 42.6%, 88.1%, 28.1% respectively, while cresol and xylenol are more than 70% and 85%. In the adsorption process of multi-composition system in wastewater, macromolecules with low-pole and major -delta G0 as polynuclear aromatic hydrocarbons and azacyclo compounds could be adsorbed preferentially and completely in tacho-absorption period, while micromolecule with hadro-pole and inferior -delta G0 as amidobenzene and hydroxybenzene were adsorbed ambly.