藻细胞内外有机物氯消毒后典型消毒副产物的生成潜能

为探究藻细胞内外有机物氯化后典型消毒副产物的生成潜能,选取小球藻为研究对象,采用加氯消毒法研究了在不同生长时期及不同氯投加量下典型含碳类消毒副产物(THMs)和含氮类卤代消毒副产物(TCNM)的生成规律,并对二者的生成势进行了对比.结果表明:细胞外有机物(EOM)和细胞内有机物(IOM)提取液的总有机碳(TOC)和有机氮(DON)较高,而芳香结构和不饱和双键的有机质质量浓度很低;从对数生长期到衰亡期,EOM经氯化后TCNM的生成量逐渐增加,IOM的TCNM生成量则呈现先增加后降低的趋势;THMs的生成规律与TCNM相似,但其生成量明显高于TCNM.增加氯投量,EOM的TCNM生成量逐渐升高,IOM的TCNM生成量则先升高后下降;在氯投量为30 mg/L时,IOM的TCNM生成量最高;稳定生长期小球藻细胞的EOM和IOM在氯投量由20 mg/L升高到30 mg/L时,THMs的生成量稳定增加,当氯投量超过30 mg/L时,THMs的生成势显著升高,且三氯甲烷为THMs的主导物种.     

氨基糖氯消毒后典型卤代碳、氮消毒副产物生成势研究

本研究以典型氨基糖类物质D-(+)-葡萄糖胺为研究对象,采用氯消毒方式,探究了D-(+)-葡萄糖胺是否是卤代碳、氮消毒副产物三卤甲烷(THMs)和三氯硝基甲烷(TCNM)的前驱物,明确其THMs和TCNM生成势及投氯量、p H值、溴离子浓度、亚硝酸根离子浓度这对其生成势的影响。结果表明:D-(+)-葡萄糖胺是THMs和TCNM的主要前驱物,三氯甲烷是氯消毒过程中主要的THMs物种。增大投氯量,HNMs和TCNM的生成势均升高;随着p H值的增大,THMs的生成势升高,TCNM的生成势先升高后降低;随着溴离子浓度和亚硝酸根离子浓度的增大,THMs的生成势均为先升高后降低,而TCNM生成势在高溴离子和高亚硝酸根离子浓度下则表现出被抑制的趋势。     

Determination of several common disinfection by-products in frozen foods

Disinfected water and/or disinfectants are commonly used by the freezing industry in such processes as sanitising, washing, blanching, cooling and transporting the final product. For this reason, disinfection by-products (DBPs) can be expected in frozen foods. This study focused on the presence of DBPs in a wide variety of frozen vegetables, meats and fish. For this purpose, the 14 halogenated DBPs more prevalent in disinfected water were selected (four trihalomethanes, seven haloacetic acids, two haloacetonitriles and trichloronitromethane). Up to seven DBPs were found in vegetables, whereas only four DBPs were present in meats and fish, and at lower concentrations, since their contact with disinfected water is lower than in frozen vegetables. It is important to emphasise that trichloronitromethane (the most abundant nitrogenous DBP in disinfected water) was found for the first time in foods. Finally, it was concluded that the freezing process can keep the compounds stable longer than other preservation processes (viz. sanitising, canning) and, therefore, frozen foods present higher DBP concentrations than other food categories (minimally processed vegetables, or canned vegetables and meats).     

沉后水中典型含氮消毒副产物TCNM的生成势研究

为了明确不同季节特征下实际水厂水氯胺消毒的TCNM生成规律,选取富营养化程度较高的夏季和藻类、植物集中消亡的秋季两个典型季节某水厂沉后水为研究对象,考察了氯胺消毒后其三氯硝基甲烷(TCNM)的生成特性及不同影响因素(消毒时间、p H值和溴离子浓度)对该沉后水TCNM生成势的影响。结果表明:两个典型季节的沉后水经氯胺消毒后均有TCNM生成,且夏季沉后水的TCNM生成势高于秋季;延长消毒时间,该沉后水的TCNM生成势升高;升高p H值,沉后水氯胺消毒后TCNM的生成量先升高后降低,p H=8时其TCNM生成量有最大值;增加溴离子浓度,TCNM的生成量大幅降低。