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941.
通过对兼氧-好氧染料废水处理系统兼氧生物膜中脱氢酶、脂肪酶和酯酶的活性分析,研究了3种酶的作用特性以及最佳条件优化。试验结果表明,脱氢酶作为一种胞内酶,在出水水样中仍能检测到2.2%的活性存在;82.5%脂肪酶和79.9%的酯酶分布在生物膜中,这说明绝大多数脂肪酶和酯酶是与细胞相连或固定在细胞外多聚絮体基质中。0.4 mmol/L的抑制剂EDTA对脱氢酶活性有促进作用,而对脂肪酶和酯酶的抑制率分别达到59.8%和18.9%。正交试验结果表明,待测3种酶有最大活性的条件均为:温度为60℃,底物浓度为50 μmol/L,pH为8,在优化条件下待测酶活性可达常规作用条件的2.58~6.44倍。各因素对待测酶活性的影响强弱排序为:温度>底物浓度>pH。 相似文献
942.
943.
Ling Zhang Lu Wang Kedong Yin Ying Lv Derong Zhang 《Environmental pollution (Barking, Essex : 1987)》2009,157(11):2957-2963
In this study, the natural Cu background concentration and Cu natural and anthropogenic contamination in soil, water and crop were investigated systematically in Huangshi area. The results show that regional geology is the dominant factor controlling the natural Cu background concentration in soil and water, and that pH is important to control the vertical distribution of Cu in soil under the same geographical and climatic conditions. The mineralization of rock bodies causes the natural Cu increase in soil and water, whereas, a large number of mining–smelting plants and chemical works are the main sources of Cu anthropogenic contamination. Cu in naturally and anthropogenically polluted soil displays differences in total and available contents, vertical distribution patterns and physico-chemical properties, the same happens in water. 相似文献
944.
Xuebin Yin Chunxia Yao Zhibo Li Wei Qian Chenxi Li Longhua Wu Yongming Luo 《Environmental pollution (Barking, Essex : 1987)》2009,157(6):1787-1793
In the present study, we aim to investigate the extent of soil contamination by Hg, particularly by anthropogenic Hg, and tentatively estimate the total Hg (HgT) accumulation in topsoils (0-15 cm) in Fuyang, Zhejiang Province—a secondary Cu smelter of China. The results show that the levels of soil Hg in the vicinity of the smelters have been substantially elevated following local smelting activities. The spatial distribution of soil Hg in this area reveals a rapid decrease as the distance from the smelter reaches 1.5 km, which is probably due to the quick deposition process of particulate Hg and reactive gaseous Hg emitted from the smelters. The total accumulation of HgT in the topsoils of the study area of 10.9 km2 is approximately 365-561 kg and of which 346-543 kg might be contributed by anthropogenic emission alone with an annual emission of 17.3-27.2 kg Hg to the topsoils. 相似文献
945.
在传统OCO工艺基础上设计了一体化OCO工艺,在厌氧区放置填料,将二沉池和生物反应器合建,并就水力停留时间(HRT)对生物反应器脱氮除碳的影响进行研究。在进水COD为260~360 mg/L,好氧区DO为2 mg/L左右,缺氧区<0.5 mg/L,MLSS为4 500 mg/L左右时,分别研究了不同HRT下的脱氮除碳效果。研究结果表明:随着HRT的逐渐增大,出水COD值无明显波动,COD去除率达到90%以上,出水氨氮随着HRT的增大而降低;但仅当HRT为12 h左右时,氨氮和总氮均有良好的去除效果,去除率分别可达到93%和80%。 相似文献
946.
947.
Organic chemicals usually coexist as a mixture in the environment, and the mixture toxicity of organic chemicals has received increased attention. However, research regarding the joint effects of reactive chemicals is lacking. In this study, we examined two kinds of reactive chemicals, cyanogenic toxicants and aldehydes and determined their joint effects on Photobacterium phosphoreum. Three factors were found to influence the joint effects of multicomponent mixtures containing reactive chemicals, including the number of components, the dominating components and the toxic ratios. With an increased number of components, the synergistic or antagonistic effects (interactions) will weaken to the additive effects (non-interactions) if the added component cannot yield a much stronger joint effect with an existing component. Contrarily, the joint effect of the mixture may become stronger instead of weaker if the added components can yield a much stronger joint effect than the existing joint effect of the multicomponent mixture. The components that yield the strongest interactions in their binary mixture can be considered the dominating components. These components contribute more to the interactions of multicomponent mixtures than other components. Moreover, the toxic ratios also influence the joint effects of the mixtures. This study provides an insight into what are the main factors and how they influence the joint effects of multicomponent mixtures containing reactive chemicals, and thus, the findings are beneficial to the study of mixture toxicology. 相似文献
948.
通过溶胶-凝胶法制备出可漂浮于水面的膨胀珍珠岩(EP)负载型TiO2,研究其在水中对罗丹明B(RB)的去除效果、吸附降解动力学以及最佳工艺条件,并研究其多次回收再生后的降解效果。结果表明,浸渍3次的负载型TiO2光催化活性最高,回收5次后活性变化很小,降解率下降不到8%;光催化剂用量为0.2 g,20 mL初始浓度为10 mg/L和15mg/L RB溶液光照6 h后降解率分别达98%和74%。在实验浓度范围内,该光催化反应可用一级反应动力学方程描述。 相似文献
949.
为了实现城市污水厂二级出水的回用,将La3+、Fe3+共掺杂TiO2/浮石光催化用于二级出水中有机物的去除。在优化工艺条件下,该方法对TOC的去除率为49.0%,对UV254的去除率为76.5%;出水BDOC/DOC值大幅度提高,由最初的0.21提高到0.56,增加了出水的可生化性;二级出水中存在着影响光催化去除有机物的因素,其中阴离子对有机物的去除有一定的抑制作用;光催化反应在通过O3强化后对有机物的去除率得到提高,TOC的去除率达到75.0%,光催化和O3氧化对有机物的去除具有协同效应;随着光催化反应次数的增加,催化剂活性有下降趋势,使用10次后TOC去除率下降到第一次使用时的16.7%,再生能够使催化活性恢复到使用前的95%,催化剂在使用15次以内稳定性较好。 相似文献
950.