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921.
922.
Ruihua Zhang Hongwen Sun Jin Yin 《Frontiers of Environmental Science & Engineering in China》2008,2(2):203-208
The purpose of this study is to estimate the removal efficiency of As and Cr (VI) by one kind of industrial waste — iron chips,
as well as to estimate the effects of typical inorganic anions (sulfate, phosphate, and nitrate), and typical organic anions
(citrate, oxalate, and humate) on As or Cr (VI) removal. The results showed that 98% of As (V) and 92% of As (III) could be
removed from aqueous phase by the iron chips within 60 min. Compared with As species, Cr (VI) was removed much more rapidly
and efficiently with 97% of Cr (VI) being removed within 25 min. The removal efficiency for arsenic was in the order: As (III)
(sulfate), As (III) (nitrate) or As (III), As (III) (humate), As (III) (oxalate), As (III) (citrate), As (III) (phosphate),
and for chromate was in the order: Cr (VI) (sulfate), Cr (VI) (phosphate) or Cr (VI) (nitrate) or Cr (VI) (oxalate), Cr (VI),
Cr (VI) (citrate), Cr (VI) (humate). In all the treatments, pH level increased with time except for As (III), the removal
of which was either without anions or in the presence of humate or nitrate. 相似文献
923.
The formation of toxic nitrogenous disinfection byproducts (N-DBPs), such as nitrosamines, halonitromethanes and haloacetonitriles, from reactions between chlorine/chloramine and dissolved organic nitrogen in drinking water has caused great concern with regarding public health. This study revealed the occurrence of 17 aliphatic amines, some of which have been confirmed to be the precursors of N-DBPs, in source water across China. A sensitive method based on benzenesulfonyl chloride derivatization and liquid-liquid extraction followed by GC-MS analysis was established for the simultaneous analysis of the selected amines in aqueous samples. In total, 37 source water samples from the capital cities of 20 provinces were collected for the survey. Among the 17 amines, 14 were detected with an average frequency of detection of 36%. The most relevant amines in terms of frequency and maximum concentrations detected were dimethylamine (100%, 24.82 μg/L), methylamine (78%, 0.92 μg/L), N-methylethylamine (70%, 8.84 μg/L), propylamine (59%, 10.69 μg/L), diethylamine (54%, 3.76 μg/L), N-methylbutylamine (35%, 3.07 μg/L), N-ethylpropylamine (35%, 0.52 μg/L), and piperidine (32%, 2.35 μg/L). This is the first large scale survey of the aliphatic amines occurrence in source water in the world. The wide presence of nitrosamine precursors like dimethylamine, N-methylethylamine and diethylamine, and the precursors of haloacetonitriles and halonitromethanes like methylamine and propylamine suggests that better source water management is required to ensure the safety of drinking water. 相似文献
924.
胶州湾沉积物氮的环境生物地球化学意义 总被引:5,自引:1,他引:5
利用氮的分级浸取技术,研究了胶州湾不同粒级沉积物中氮的赋存形态.研究表明,胶州湾沉积物中可转化态氮可分为离子交换态、弱酸浸取态、强碱浸取态和强氧化剂浸取态.不同粒级沉积物中各形态氮占可转化态氮的比例各不相同.在细、中和粗粒级沉积物中,强氧化剂浸取态氮是可交换态氮的优势形态,分别占可转化氮的35.38%、44.38%和58.69%.在中、粗粒级沉积物中,强碱浸取态氮是无机氮的主要赋存形态,分别占可转化态氮的26.31%和25.85%.在细粒级沉积物中,离子交换态氮是优势态的无机氮,占可转化态氮的27.67%.相关分析表明,对于胶州湾来说,沉积物的粒度越细,氮的含量就越高,各形态氮大致与细、中粒级沉积物含量呈正相关,而与粗粒级沉积物含量呈负相关.研究还表明,不同粒级沉积物中氮与浮游植物数量、叶绿素a以及上覆水体中硝酸盐的含量大致都在一定程度上呈正相关,这一方面说明了沉积物对上覆水体元素的含量有着不可忽视的影响,另一方面也说明了沉积物中的氮对海水的富营养化水平有着较好的指示和十分重要的环境意义. 相似文献
925.
Metal(Cu,Co,or Zn) loaded ZSM-5 and Y zeolite adsorbents were prepared for the adsorption of hydrogen cyanide(HCN) toxic gas.The results showed that the HCN breakthrough capacity was enhanced significantly when zeolites were loaded with Cu.The physical and chemical properties of the adsorbents that influence the HCN adsorption capacity were analyzed.The maximal HCN breakthrough capacities were about the same for both zeolites at 2.2 mol of HCN/mol of Cu.The Cu2p XPS spectra showed that the possible species present were Cu2O and CuO.The N1s XPS data and FT-IR spectra indicated that CNwould be formed in the presence of Cu+/Cu2+ and oxygen gas,and the reaction product could be adsorbed onto Cu/ZSM-5 zeolite more easily than HCN. 相似文献
926.
采用封闭式采样和气相色谱法分析监测了北京主要树种油松排放的萜烯类化合物,其中包括α和β蒎烯、蒈烯、松油烯、柠檬烯和罗勒烯,以及少量异戊二烯。松油烯、B蒎烯、柠檬烯和蒈烯的排放量之和占油松排放碳氢总量的94%以上。萜烯和异戌二烯排放速率随日照和温度的升高而增加。萜烯等浓度的日变化表明在正午和午夜油松有两个排放高峰。在日均气温为18℃时油松的碳氢化合物平均总排放速率约为8.7μh/h.g。 相似文献
927.
Fenton试剂处理酸性玫瑰红B的研究 总被引:7,自引:0,他引:7
采用Fenton试剂处理酸性玫瑰红B染料废水,考察了FeSO4投加量、H2O2投加量、pH值和反应时间对处理效果的影响,研究了原水的氧化还原电位和TOC的变化规律,评价了它的可生化性。结果表明,最佳pH值为3,FeSO4的适宜投加量为8mmol/L,H2O2最佳投加量为50mmol/L,此时COD去除率和脱色率分别为77.1%和92.8%,处理后该染料废水的可生化性大大提高。 相似文献
928.
磨盘山水库水质富营养化的防治对策研究 总被引:1,自引:0,他引:1
磨盘山水库是哈尔滨市人民重要的饮用水源地。从库区面源污染来源、农业各类面源污染入库量比较、磨盘山水库水质富营养化状况及趋势等方面论述了磨盘山水库水质富营养化防治对策。提出要加强磨盘山水库水质的科学研究,防止水库水质的富营养化发生。 相似文献
929.
Liqun Lv Yunshan Ge Zhe Ji Jianwei Tan Xin Wang Lijun Hao Zhiwei Wang Mengzhu Zhang Chunjie Wang Haidan Liu 《环境科学学报(英文版)》2020,32(2):155-164
On-road driving emissions of six liquefied natural gas(LNG) and diesel semi-trailer towing vehicles(STTVs) which met China Emission Standard IV and V were tested using Portable Emission Measurement System(PEMS) in northern China.Emission characteristics of these vehicles under real driving conditions were analyzed and proved that on-road emissions of heavy-duty vehicles(HDVs) were underestimated in the past.There were large differences among LNG and diesel vehicles, which also existed between China V vehicles and China IV vehicles.Emission factors showed the highest level under real driving conditions, which probably be caused by frequent acceleration, deceleration, and start-stop.NOx emission factors ranged from 2.855 to 20.939 g/km based on distance-traveled and 6.719–90.557 g/kg based on fuel consumption during whole tests, which were much higher than previous researches on chassis dynamometer.It was inferred from tests that the fuel consumption rate of the test vehicles had a strong correlation with NOx emission, and the exhaust temperature also affected the efficiency of Selected Catalytic Reduction(SCR) aftertreatment system, thus changing the NOx emission greatly.THC emission factors of LNG vehicles were 2.012–10.636 g/km, which were much higher than that of diesel vehicles(0.029–0.185 g/km).Unburned CH_4 may be an important reason for this phenomenon.Further on-road emission tests, especially CH_4 emission test should be carried out in subsequent research.In addition, the Particulate Number(PN) emission factors of diesel vehicles were at a very high level during whole tests, and Diesel Particulate Filter(DPF)should be installed to reduce PN emission. 相似文献
930.