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21.
分别利用重铬酸钾法、重铬酸钾紫外分光光度法和紫外分光光度法测定污水的COD极差分别为2.43mg/L、1.19 mg/L和4.72 mg/L,RE%分别为0.84%、0.53%和1.36%,重铬酸钾紫外分光光度法和紫外分光光度法的线性范围分别在0~280 mg/L和0~400 mg/L.结果表明:重铬酸钾紫外分光光度法测定的准确度和精密度最高,简化了用标准溶液进行标定的步骤,缩短了实验时间;紫外分光光度法测定的结果准确度和精密度相对差一些,但是快速、操作简单、节省试剂,为广大环境工作者提供借鉴参考的实例。 相似文献
22.
城市再生水生产工艺中典型紫外防晒剂的去除 总被引:2,自引:0,他引:2
随着紫外防晒剂在个人护理用品中的大量使用,其环境及健康风险效应开始得到人们的关注.采用固相萃取-气相色谱-质谱联用(SPE-GC-MS)技术对天津某再生水厂不同处理单元中4种典型紫外防晒剂4-甲氧基肉桂酸-2-乙基己基酯(ethylhexylmethoxycinnamate,EHMC),羟苯甲酮(benzophenone-3,BP-3),3-(4-甲苯基亚甲基)-d-1-樟脑(4-methylbenzylidene,4-MBC),2-氰基-3,3-二苯基丙酸-(2-乙基)己基酸(octocylene,OC)的分布及去除情况进行了检测.结果表明,污水处理厂二级出水中4种目标化合物的浓度范围在34ng·L-1 ̄2128ng·L-1之间;4种物质在夏秋季(7月和9月)的浓度普遍高于冬季(2月).污水处理厂二级出水中的这4种紫外防晒剂在经过混凝-絮凝处理、连续膜过滤和臭氧氧化处理后出水中的浓度呈下降趋势,总去除率为28.3% ̄43.1%,其中臭氧氧化阶段对目标物的去除率最大(16% ̄29%),而连续膜过滤阶段去除率最小(3.6% ̄8.5%),混凝-絮凝阶段去除率介于2者之间(8% ̄21%).由此可见,紫外防晒剂在再生水处理过程中并未得到完全去除,因此再生水的使用需经周密规划,以免对人体健康和生态环境造成威胁. 相似文献
23.
应用原子力显微镜研究盐度对棕囊藻生长的影响 总被引:4,自引:1,他引:3
研究不同盐度梯度下棕囊藻的生长,实验设计了10个盐度梯度,结果表明:在盐度8~32范围内,棕囊藻的生长正常,最佳生长盐度为16,当盐度低于8或高于32时,藻的生长明显受到抑制,细胞数量增长缓慢,最大细胞数远低于16盐度组。研究发现:棕囊藻在盐度为0的环境下仍能缓慢生长,说明海洋中的棕囊藻赤潮在内陆的淡水湖也可能暴发,用原子力显微镜研究比较盐度为0及36的棕囊藻细胞表面形态,发现两者差异较显著,前者藻细胞的直径大于后者,且后者藻细胞表面形成了明显的塌陷。 相似文献
24.
Yapeng Song Hui Gong Jianbing Wang Fengmin Chang Kaijun Wang 《Frontiers of Environmental Science & Engineering》2020,14(4):64
25.
UV Spectroscopic Monitoring of Vaporized Monoaromatic Hydrocarbons from Petroleum-Contaminated Soils
Fast and simple systems using ultraviolet (UV) absorbance were examined for on-line monitoring of monoaromatic hydrocarbons from petroleum-contaminated soils in this research. Since soil particles hinder the UV light transmittance, the absorbance measurement of vaporized monoaromatic hydrocarbons in soil gas extracted from petroleum-contaminated soils was proposed. In the fixed system that exhibited higher sensitivity than the portable one, the absorbance intensity of benzene, toluene, ethylbenzene, and xylene increased in proportion to the concentration of the contaminants. The portable system, however, was suitable for screening purpose, while it exhibited faster response. There was no interference from water, which helps the applicability of the proposed systems to the actual fields. 相似文献
26.
27.
超滤处理洗涤污水循环利用的中试研究 总被引:3,自引:0,他引:3
采用不同材质国产超滤膜聚丙烯(PP)、聚丙烯腈(PAN)和聚砜(PS),进行了洗涤污水处理循环利用的现场中试研究.结合超滤工艺出水水质和膜污染分析,3种膜材质中PAN膜较优,有效去除了水中浊度、悬浮物、油脂等污染物,一定程度保留了游离阴离子表面活性剂(LAS),长期循环洗涤对衣物的白度无不良影响.根据相关性分析,超滤出水较高COD值很大程度上是由水中LAS引起的.超滤膜对细菌、大肠菌群的去除率较低,出水通过紫外消毒,当紫外线密度≥3?750 J/m2时,微生物水平能够达到国家饮用水水质标准.根据不同水力反冲洗条件下膜渗透通量和净产水量比较,PAN膜最佳水力反冲洗条件为0.5 h反冲洗2 min.长期运行时超滤膜化学清洗方法采用碱洗法方便有效. 相似文献
28.
The degradation of polyacrylamide (PAM) in simulate wastewater was studied in UV/Fenton/C4H4O62? system. The factors such as molecular ratio of H2O2/Fe2+/C4H4O62?, pH, and the dosage of Fenton reagent that could affect the PAM degradation in the UV/Fenton/C4H4O62? system were investigated. The experimental results showed that adding C4H4O62? to UV/Fenton system could form photosensitive ferrous complexes, which led to higher degradation efficiency of PAM. The degradation rate of PAM could be up to 95.2% under the following conditions: the concentration of H2O2, Fe2+, and C4H4O62? were 22.5, 2.25, and 2.25 mmol/L, respectively (i.e., molecular ratio of H2O2/Fe2+/C4H4O62? was 10:1:1), the pH value was 3.0. 相似文献
29.
Sukhendu Kumar Pramanik Soumen Joarder Saktipada Das Sankhajit Roy 《Journal of environmental science and health. Part. B》2016,51(5):287-297
The phototransformation of Oryzalin was studied under UV light (λmax ≥ 290 nm) and sunlight (λmax ≥ 250 nm) in aqueous isopropanol and acetonitrile solution in absence and presence of TiO2 as sensitizer. The rate of photodegradation of Oryzalin in different solvent system followed first-order kinetics, and calculated half-lives were found to be in the range of 23.52-53.75 h for UV light and 41.23-61.43 h for sunlight. From this study, total 12 photoproducts were identified and characterized on the basis of column chromatography and Q-Tof micromass spectral data. The plausible mechanism of phototransformation involved was hydrolysis, breaking of sulfonic bond, and loss of amino and sulfonic acid group. 相似文献
30.
This study reports on the effect of microwave radiation for inactivation of Ascaris lumbricoides eggs in 25 g of soil compared to ultraviolet irradiation and ozone expose. Microwave radiation at 700 W with 14% water content (w/w) achieved approximately 2.5 log inactivation of eggs in soil within 60 s. On the other hand, UV irradiation at 3 mW cm−2 with and without shaking soil for 3600 s achieved approximately 0.32 and 0.01 log inactivation of eggs, respectively. In ozone treatment, 0.13 log inactivation of eggs was achieved with 5.8 ± 0.7 mg L−1 of dissolved ozone dose for 30 min in a continuous diffusion reactor. In addition, the inactivation of eggs by three disinfection techniques was conducted in water in order to compare the inactivation efficiency of eggs in soil. The inactivation efficiency of microwave radiation was found to be no significant difference between in soil and water. However, the inactivation efficiency of UV irradiation was significantly increased in water while in ozone expose there was no significant difference between in soil and water. Microwave treatment thus proved to be the most efficient method in controlling A. lumbricoides eggs in soil. 相似文献