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INTRODUCTION Eutrophication of surface water is a significantly increasing worldwide problem (Ma and Liu, 2002). Mesocyclops leukarti, a kind of Cyclops, is a water-borne animal propagating prolifically in eutrophic water reservoirs or fresh water lakes in China. Some reservoirs such as Dahuofang Reservoir (Liaoning Province), East Taihu Lake (Jiangsu Province), Gaozhou, Qiyeshi and Xinfengjiang Reservoir (Guangdong Province), Miyun Reservoir (Beijing), etc. are sources of drinki… 相似文献
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探索了臭氧投加量对O3/UV组合工艺处理兰州石化公司二级出水中常规指标去除效果的影响。研究结果表明,当其他因素确定时,臭氧投加量在50mg/L时,O3/UV对CODcr和UV254的去除率最高,达到了39.55%和58.21%,说明O3/UV工艺对处理兰州石化二级出水有一定的效果,具有良好的应用前景。 相似文献
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采用US／Cu^2＋／H2O2体系,超声催化降解罗丹明B模拟废水溶液。考察了超声功率、超声频率、超声时间、初始pH值、H2O2的用量、CuSO4的投加量以及罗丹明B溶液的初始浓度对脱色率的影响。通过正交实验,得出了主次因素,并得出了最佳反应条件。还对单独使用H2O2、H2O2／CuSO4体系,单独使用超声技术以及US／H2O2体系的处理效果进行了分析。 相似文献
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WANG Kun-ping GUO Jin-song YANG Min JUNJI Hirotsuji DENG Rong-sen LIU Wei 《重庆大学学报(英文版)》2008,7(3):171-178
We studied the decomposition of two haloacetic acids （HAAs）, dichloroacetic acid （DCAA） and trichloroacetic acid （TCAA）, in water by single oxidants ozone （O3） and ultraviolet radiation （UV） and the advanced oxidation processes （AOPs） constituted by the combinations of O3/UV, H2O2/UV, O3/H2O2, and O3/H2O2/UV. The concentrations of HAAs were analyzed at specified time intervals to track their decomposition. Except for O3 and UV, the four combined oxidation processes remarkably enhance the decomposition of DCAA and TCAA owing to the generated very reactive hydroxyl radicals. The fastest decomposition process is O3/H2O2/UV, closely followed by O3/UV. DCAA is much easier to decompose than＇ TCAA. The kinetics of HAA decomposition by O3/UV can be described well by a pseudo first-order reaction model under a constant initial dissolved O3 concentration and fixed UV radiation. Humic acids and HCO3 in the reaction system both decrease the decomposition rate constants for DCAA and TCAA. The amount of H2O2 accumulates in the presence of humic acids in the O3/UV process. 相似文献
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The efficiency of chlorine and chloramines disinfection on biofilm development in a simulated drinking water distribution system was investigated by using heterotrophic bacterial spread plate technique. The experiments were carried out with four annular reactors （ARs） with stainless steel （SS） or copper （Cu） material slides. The results showed that there were fewer bacteria attached to Cu slides without a disinfectant compared with those attached to SS slides. When the water was disinfected with chloramines, the heterotrophic plate counts （HPCs） on the biofilm attached to the Cu slides were significantly lower （by 3.46 log CFU/cm^2） than those attached to the SS slides. Likewise, the biofilm HPC numbers on the Cu slides were slightly lower （by 1.19 log CFU/cm^2） than those on the SS slides disinfected with chlorine. In a quasi-steady state, the HPC levels on Cu slides can be reduced to 3.0 log CFU/cm^2 with chlorine and to about 0.9 log CFU/cm^2 with chloramines. The addition of chloramines resulted in a more efficient reduction of biofilm heterotrophic bacteria than did chlorine. We concluded that the chlorine and chloramines levels usually employed in water distribution system were not sufficient to prevent the growth and development of microbial biofilm. The combination of copper pipe slides and chloramines as the disinfectant was the most efficient combination to bring about diminished bacterial levels. 相似文献
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YANG Wei CHEN Jie LI Xing LIANG Heng HE Wen-jie LI Gui-bai 《浙江大学学报(A卷英文版)》2007,8(9):1475-1481
Considering that contaminated raw water mostly contains high Ammonia-N and a majority of water treatment plants use prechlorination process in China,efficiency of chloramines as a coagulant aid in enhancing coagulation was investigated by Jar stirring and pilot-scale tests,using Yellow River water containing high concentration of natural organic matters (NOM) and bromide in winter. The jar tests results showed that,compared with no preoxidation,preformed chloramine apparently decreased the turbidity of settled and filtered water with low dosage (2.0 mg/L),and the aid-coagulation efficiency was further enhanced with the increase of chlorine (Cl2) to Ammonia-N (N) ratio. Pilot-scale studies indicated that,in comparison to the case without pre-oxidation,the turbidity removal efficiency of flotation and filtration effluent water was significantly improved,the particle counts of filtered water were decreased 63.4%,the average rate of filter head loss was reduced 18.2%,and filter run time was prolonged 15.7%. Therefore,chloramine preoxidation may substantially enhance the particle separation efficiency. 相似文献
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浸泡法是降低蔬菜中硝酸盐含量的有效途径之一。本文以芹菜为试验材料,研究了利用H2O2溶液浸泡后在不同条件下的硝酸盐去除率,结果表明:在温度为303K时,用浓度为0.01mol/L的H2O2溶液浸泡50min,去除率可达71.9%,效果最好。 相似文献
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We evaluated several different pre-oxidation treatments, namely the introduction of either potassium permanganate （KMnO4）, chlorine （Cl2）, or both to remove manganese （Mn） from the Qiantang River source water. Our results showed that Mn removal percentages were 12.7%, 71.0%, 17.4% and 58.7% when none of the oxidants, KMnO4 only, Cl2 only, or both oxidants were added, respectively. Furthermore, a field study showed that when the available Mn concentration in the source water was 0.14 mg/L, it could be reduced to less than 0.05 mg/L when a solution of KMnO4 （0.47 mg/L） was added as the oxidant. 相似文献
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卢静 《泰州职业技术学院学报》2012,12(2):25-27
当传统的3P词汇教学模式受到抨击后,新的词汇教学理念纷纷涌现,但高职学生并未因此而从如何记忆词汇的困惑中解放出来。笔者在多年的词汇教学中,通过研究学生课堂学习和自主学习词汇的过程和结果,总结出了一些适合高职学生的词汇教学方法。 相似文献
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This paper analyses the changing rule of indoor ozone concentration and its influencing factors. A formula of indoor-outdoor
concentration ratio (I/O ratio) was deduced based on the indoor ozone mass-balance equation. The ozone I/O ratio in different
kinds of buildings was studied. Results show that I/O ratio is much related to air-exchange rate, which is well compatible
with the theoretical calculation results. 相似文献
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通过调节硫酸铜溶液浓度,采用恒电位沉积方法,在玻碳电极表面制备了三种形貌的Cu-Cu2O壳核纳米粒子．比较研究了Cu-Cu2O壳核纳米粒子的形貌和结构对过氧化物的催化效果,发现立方八面体形的Cu-Cu2O壳核纳米粒子的催化效率较高．循环伏安法研究表明过氧化物在Cu-Cu2O修饰玻碳电极的还原电位在．0．23V,随着过氧化物浓度的增加,还原峰电流明显增大．用计时电流法,控制电位在．0．17Vcu．Cu20修饰玻碳电极可以检测过氧化氢异丙苯（CHP）、叔丁基过氧化氢（t-BHP）、过氧化丁酮（2-BP）和过氧化氢． 相似文献
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以H3PW12O40为催化剂,30%H2O2为氧源,催化氧化环己酮合成己二酸.探讨了H3PW12O40对氧化反应的催化活性,较系统地研究了磷钨酸用量、反应温度、H2O2用量、KHSO4用量等因素对产物收率的影响.实验表明：H3PW12O40是合成己二酸的良好催化剂;在n（环己酮）∶n（H2O2）∶n（H3PW12O40）∶n（KHSO4）=100∶388∶0.035∶0.74（固定环己酮用量为0.10 mol,磷钨酸用量0.1g,H2O2用量40 mL,KHSO4用量0.1 g）,反应温度为100℃,反应时间6 h的最佳条件下,己二酸的收率可达49.5%. 相似文献
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自行制备负载型TiO2催化剂,对苯胺水样进行了光助催化。探讨了初始底物浓度、催化剂用量、光照强度及微量H2O2对降解率的影响。结果显示,TiO2光助催化降解苯胺效果良好,当苯胺浓度低于2mmol.L-1时,降解率在98%以上,催化剂量、光源强度和微量H2O2都可提高苯胺的降解率。进一步研究可知苯胺经催化降解后,苯环被打开,有助于后续的生化处理。 相似文献
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本文研究了在FeCl_3-CuCl_2-HCl混合液催化H_2O_2分解的反应动力学。测定了25、30、35、40℃下的速率常数k,其值分别为0.01524、0.02936、0.05751、0.10233 min~(-1)。直线lnκ～1/T的线性相关系数为-0.99994。由此可知,该反应为一级反应,其活化能E_(25～40)加=98.323KJ·mol(-1)。 相似文献
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Azo dyes discharged in the environment are persistent organic pollutants （POPs）, which are very difficult to remove. We developed a microwave-assisted Fenton-like process to degrade methyl orange （MO）, an azo dye, with hydrogen peroxide （H2O2） catalyzed by chromium compounds coexisting with MO in the solution. Comparison between the Cr（Ⅲ）-H2O2 and Cr（Ⅵ）-H2O2 systems shows＂ that Cr（Ⅵ） has a stronger and more stable catalytical activity than Cr（Ⅲ）, and Cr（Ⅲ） is more susceptible to a change in the acidity or alkalinity of the reaction system. With a Cr（Ⅵ） concentration of 10 mmol L^-1 or a Cr（Ⅲ） concentration of 12 mmol L^-1 in the solution under the microwave irradiation of a power larger than 300 W for 3 min, 10 mmol L^-1 H2O2 can degrade more than 95% of 1 000 mg L^-1 methyl orange; when the microwave power is increased to 700 W, the same amount of H2O2 can degrade all methyl orange in the solution with the same amount of Cr（Ⅵ ） catalyst. Ultraviolet-visible spectrography indicates the cleavage of the azo bond in methyl orange after treatment, suggesting the potential o of this Fenton-like process to degrade azo dye POPs. Reusing waste chromium compounds coexisting with dyestuff in wastewater to catalyze the degradation of azo dyes could be a cost-effective technique for azo dyes and chromate manufacturers and/or users to treat their wastewater and prevent POPs from endangering the environment. This is of particula importance to controlling the water quality of the Three Gorges Reservoir. 相似文献
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用碳酸氢铵和氨水的混合溶液来作复合沉淀剂,采用共沉淀法制备了Tb3＋共掺杂Al2O3：Eu粉体.用X射线衍射（XRD）对其相结构进行了研究,通过荧光分光光度计分析了Tb3＋离子共掺杂浓度对Al2O3：Eu的发光性能的影响.研究结果表明：Tb3＋掺杂提高了γ-Al2O3的热稳定性.并观察到Tb3＋→Eu3＋的能量传递,最佳掺杂浓度为5 mol%,提高了Al2O3：Eu的发光强度. 相似文献
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Lei Li Nai-yun Gao Yang Deng Juan-juan Yao Ke-jia Zhang Hai-jun Li Di-di Yin Hua-se Ou Jian-wei Guo 《浙江大学学报(A卷英文版)》2009,10(11):1660-1669
The degradation of Microcystin-LR （MC-LR） in water by hydrogen peroxide assisted ultraviolet （UV/H2O2） process was investigated in this paper. The UV/H2O2 process appeared to be effective in removal of the MC-LR. MC-LR decomposition was primarily ascribed to production of strong and nonselective oxidant-hydroxyl radicals within the system. The intensity of UV radiation, initial concentration of MC-LR, MC-LR purity, dosages of H2O2, the initial solution pH, and anions present in water, to some extent, influenced the degradation rate of MC-LR. A modified pseudo-first-order kinetic model was developed to predict the removal efficiency under different experimental conditions. 相似文献
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利用金电极上自组装的3-巯基丙酸自组装膜,通过DCC和NHS共价连接辣根过氧化物酶（HRP）,构建了一种稳定性好、寿命长的过氧化氢电化学生物传感器.HRP在该电极上实现了直接电子传递,其氧化还原峰电位差为250mV,式量电位为-231 mV.该传感器对过氧化氢表现出良好的电催化活性,还原峰电流与过氧化氢含量在1.5-1000μmol/L之间呈现良好的线性关系,灵敏度达到1185μA/mM,检出限为0.5μmol/L.该传感器具有良好的稳定性、重现性,已用于合成样品中过氧化氢含量的测定,准确度良好. 相似文献