南方天然水体DOM的化学分级、变化特征及三卤甲烷生成势(THMFP)特性研究

Fractionation and characterization of DOM and the THMFP feature in the South-China source water

采用XAD树脂吸附法,在春季内(3～5月)连续对南方深圳水库中的水体溶解性有机物(DOM)进行化学分级表征.结果表明,天然水体DOM的总量和单个化学分级组分含量在一个季节会发生一定的波动,但总的分布特征在季节内未发生根本变化,即憎水酸(HoA)和亲水部分(HiM)浓度始终较高,而憎水碱(HoB)、憎水中性物(HoN)、弱憎水酸(WHoA)浓度则相对较低.同时,选取代表性时间点对DOM各化学分级组分进行了消毒副产物三卤甲烷生成势(THMFP)的研究,发现三卤甲烷(THMs)的主要前驱物为憎水和弱憎水有机部分,对THMFP的贡献共占约80%.进一步研究发现,憎水中性物、憎水酸、弱憎水酸的THMs生成能力较强,总体上与紫外吸收能力基本一致;但弱憎水酸表现略有不同,其SUVA(100×UV254/DOC)值并不十分突出,但三卤甲烷生成能力却明显较高,说明DOM的紫外吸收特性不能完全作为THMFP特性的替代指标.亲水物质(HiM)的SUVA值也不高,但其THMs生成能力接近憎水酸部分,值得水处理工艺研究重点关注.

Characterization and fractionation of DOM from South-China natural water by resin adsorption method showed that the basic iractlonal character of DOM didnt change significantly in a season although the amount of total DOM and the single fraction would vary with time in a limited range. The amount of the hydrophobic acids （HoA） and the hydrophilic matter （HiM） was relatively higher all the time than the other fractions. The trihalomethane formation potential （THMFP） was studied and the result showed that the main precursors in the DOM were hydrophobic and weakly hydrophobic fractions, up to 80%. It was also found that fractions which had higher THMs yield ability were FioN（hydrophobic neutrals） , FIoA and WHoA（weakly hydrophoblc acids）, corresponding with the character of SUVA （which is 100× UV254/DOC）. But the WHoA fraction had a special character that its THMs yield ability was super than that of UV absorption, so SUVA couldn＇t be surrogate indicator for THMFP absolutely. So it was with HiM and needed to pay more attention.