滤后水中NOM经臭氧氧化产生的小分子醛、酮和酮酸

以富集、分离得到的滤后水中6种不同特性的天然有机物(NOM)为对象,测定了臭氧氧化NOM各组分后小分子醛、酮及酮酸的生成情况.NOM各组分臭氧氧化后甲醛和丙酮酸产量最大,特别是憎水中性物质(HON)的甲醛产率是其醛、酮总产率的70.58%,单位DOC丙酮酸的产率达103.2 μg/mg;憎水性NOM组分的小分子醛、酮、酮酸产率比亲水性组分的高,特别是憎水中性物质(HON)和憎水酸(HOA)的小分子醛、酮及酮酸类总产率最高,二者之和分别占NOM各组分的醛酮总产率及酮酸总产率的55.56%和60%; NOM碱性组分的醛、酮、酮酸产量最低.用小分子醛、酮、酮酸总量折算DOC占氧化后NOM的DOC的百分比作为衡量氧化后各组分可生物降解性的参考,则臭氧氧化后HON和HOA的可生物降解性比其他组分高得多.

Aldehydes, Ketones, and Ketoacids Produced During Ozonation of NOM Fractions Isolated from Filtrated Water

Natural organic matter (NOM) in the filtrated surface water from a water treatment plant was isolated and fractionated into six types of fractions. These fractions were ozonated at typical ozone dose and reaction time. The yields of several small molecular ozonation by-products, such as, aldehydes, ketones and ketoacids, were monitored after ozonation of the individual NOM fractions. The results showed that formaldehyde and pyruvic acid had the maximal yields among the aldehydes and ketoacids, respectively. Hydrophobic neutral (HON) produced the most significant yield of the ozonation by-products with the specific yield of formaldehyde up to 70.58% of the specific yields and pyruvic acid being 103.2 microg/mg. The hydrophobic NOM fractions produced higher yields of these by-products than the hydrophilic fractions. For example, HON and hydrophobic acid (HOA) produced much higher yields of the ozonation by-products than other fractions. Aldehydes and ketones from HON and HOA and ketoacids from the two fractions accounted for 55.56% and 60% of the ozonation by-products from all the NOM, respectively. Lower production of these by-products was also observed for the basic fractions compared to the acidic and neutral ones. HON and HOA were more biodegradable after ozonation, because their ozonation by-products contributed much higher amount of DOC to the final DOC after ozonation.