有机物相对分子质量分布对O3-GAC工艺中臭氧投加量的影响

Impact of the organic molecular weight distribution on ozone dosage in O_3—GAC technique

采用滤膜法测试了不同臭氧投加量下,臭氧活性炭出水中的有机物相对分子质量分布的特性,并对其去除情况进行了分析。结果表明,相对分子质量小于1000的有机物易被臭氧氧化为CO2和H2O而去除。大于10000的大分子有机物被氧化分解为3000-10000的小分子有机物,这部分小分子有机物可被后续活性炭生物降解去除。增加臭氧投加量,大于30000的有机物被氧化为相对分子质量分布范围更广的小分子有机物,使大于30000的有机物易被活性炭降解,但会使小于1000的有机物的去除效果降低。臭氧投加量的确定应考虑水中有机物相对分子质量分布情况。

The organic molecular weight distribution （MWD） in ozone--granular activated carbon （GAC） treatment was investigated and the corresponding removal rates were analyzed by filter membrane method with different ozone dosage. The results showed that： the organic with molecular weight （MW） 〈1 000 Dalton could be removed by ozone by decomposing the organic into CO2 and H2O, the organic with MW〉10 000 Dalton could be decomposed into the organic with MW= 3 000-10 000 Dalton, which could be removed by GAC by adsorption or biodegradation; Increasing ozone dosage, the organic with MW〉30 000 Dalton would be decomposed into organic with smaller size and wider distribution. At the same time, the adsorption and hiodegradation properties of the organic were changed, which induced the adsorbability and biodegradability of the organic with MW〉30 000 Dalton but reduced the removal rate of the organic with MW〈1 000 Dalton. As a result, the MWD in water is a key point for determining the ozone dosage in O3--GAC technique.