水中天然有机物的臭氧强化光催化降解研究

研究了饮用水源中大分子天然有机物（NOM）的臭氧强化光催化降解,考察了臭氧投加量、反应时间和HCO3^-浓度对NOM降解速率的影响;分析了臭氧强化光催化过程中NOM相对分子质量的变化,并比较不同相对分子质量大小NOM的降解速率.研究结果表明,臭氧强化光催化比单独臭氧氧化、光催化能更有效地降解NOM,同时增加臭氧投加量和反应时间才能有效提高臭氧强化光催化对TOC的去除率,而单独增加臭氧投加量可显著提高生物可降解性;HCO3^-显著降低光催化的降解效果,臭氧强化光催化能有效地减弱HCO3^-的不利影响;臭氧强化光催化过程中大分子NOM分解为小分子,SUVA值迅速下降,且相对分子质量越大矿化速度越快.

Ozone-enhanced photocatalytic degradation of natural organic matter in water

Ozone-enhanced photocatalytic degradation of macromolecular natural organic matter (NOM) in drinking water source was investigated. The influences of ozone dosage, reaction time and bicarbonate concentration on NOM degradation rate were studied. The change of molecular weight distribution of NOM caused by ozone-enhanced photocatalysis was analyzed, as well as the degradation rate of NOM with different molecular weight. It was showed that, ozone-enhanced photocatalysis was much better than sole ozonation or photocatalysis for NOM degradation. Increase of both ozone dosage and reaction time could effectively increase TOC removal rate, while the biodegradability could be improved by increase of ozone dosage solely. The existence of bicarbonate significantly reduced the photocatalytic degradation rate of NOM, however its impact was effectively offset by addition of ozone into the photocatalytic process. Macromolecular NOM was transformed into smaller molecules, and the larger NOM was much faster mineralized than smaller NOM by ozone-enhanced photocatalysis.