活性炭吸附石化二级出水有机物去除特性研究

Adsorption characteristics of organics from petrochemical secondary effluent by activated carbon

采用活性炭对某石化二级出水进行吸附研究,考察了静态和动态试验下,活性炭对石化废水二级出水COD的去除效果,并讨论了吸附前后水中有机物的组分和相对分子质量的变化.结果表明:静态试验中,活性炭对石化废水二级出水的COD的饱和吸附量为1.1 mg·g-1,吸附速率为0.7 mg·min-1;通过动态试验得到了吸附的最佳条件,即HRT=1 h,水力负荷为0.76 m3·m-2·h-1,此时COD的去除率可达49.9%,出水COD低于50 mg·L-1.相对分子质量分级和树脂分级分析结果表明,活性炭对石化废水二级出水中相对分子质量小于5000的小分子有机物有较好的吸附效果,该组分被活性炭吸附的COD所占比例为59.72%,活性炭吸附作用对水中不同相对分子质量有机物分布影响不大;活性炭对石化废水中有机物组分的去除效果排序依次为:疏水碱性物质(HOB)>疏水酸性物质(HOA)>亲水中性物质(HIS)>疏水中性物质(HON),对HOB和HOA的去除率可达到79%和61%,对HIS和HON的去除效果不佳.

In this study,static and dynamic adsorptions of petrochemical secondary effluent by activated carbon were studied conditions. COD removal,the relative molecular weight distribution and the components of organics in wastewater were investigated. The static adsorption results show that the saturated adsorption capacity of the activated carbon was 1. 1 mg·g-1and the adsorption rate was 0. 7 mg·min-1for COD. Dynamic adsorption results show that the optimal operating conditions were： hydraulic retention time（ HRT） 1 h and hydraulic loading 0. 76 m3·m-2·h-1. The effluent COD of adsorption was lower than 50 mg·L-1withthe removal efficiency of 49. 9%. The dissolved organics in petrochemical secondary effluent were mainly organics with relative molecular weight lower than 5000,59. 72% of which was removed by activated carbon adsorption,without change in the relative molecular weight distribution of organics. The results of resin classification assay show that the adsorption capacity of activated carbon for organic constituents was in the following order： hydrophobic bases（ HOB） 〉hydrophobic acids（ HOA）〉 hydrophilic substances（ HIS） 〉hydrophobic neutrals（ HON）. The removal rates of HOB and HOA were 79% and 61%,respectively,but the adsorption of HIS and HON by activated carbon was very poor.