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481.
研究了在模拟太阳光下,采用银修饰的碘掺杂二氧化钛光催化剂(Ag/I—TiO2)对某食品厂山核桃加工废水进行光催化预处理的效果。结合x射线衍射(XRD)、比表面积分析(BET)、紫外-可见漫反射光谱(uV—Vis)的表征结果,来分析催化剂结构对于废水处理效果的影响。探讨了Ag含量、废水初始pH(pHi)和光照时间等因素对化学需氧量(COD)去除及水质可生化性(B/C)提高的影响。并得出适宜的反应参数为:3%Ag含量;pHi为6;光照时间为240min。在最佳条件下,COD去除率45%,废水B/C比由0.17上升到0.31。光催化氧化法能够有效降低山核桃加工废水的COD含量,并达到显著提高废水可生化性的目的。 相似文献
482.
483.
CuO / 过硫酸氢钾体系催化氧化苯酚简 总被引:1,自引:0,他引:1
本论文通过直接沉淀法制备了CuO催化剂,结合过硫酸氢钾,在常温常压下催化氧化处理苯酚模拟废水。采用电子显微镜(SEM)、X射线粉末衍射(XRD)对催化剂进行了表征,并研究了反应过程中各影响因素对降解效率的影响。实验结果表明,在催化剂用量为0.2 g/L,氧化剂浓度为0.25 g/L,pH值为7,反应时间为60 min的条件下,浓度为50 mg/L的苯酚降解率可达100%,TOC去除率达84%。进一步实验表明,催化剂具有良好的重复使用能力。最后,通过自由基捕捉实验,考察了体系中的自由基种类,并根据实验结果,讨论了CuO/过硫酸氢钾体系的催化降解机理。 相似文献
484.
485.
阳宗海沉积物中磷的稳定性 总被引:1,自引:0,他引:1
絮凝剂(Fe Cl3)治理阳宗海砷污染的过程中,水体中的磷被大量沉积进入底泥,弄清其是否会在环境条件变化后发生反溶形成二次污染对湖泊富营养化防治具有重要意义。通过模拟实验模拟泥-水界面p H变化、物理扰动和微生物活动的变化,旨在分析这些环境因子变化对沉积物中磷溶出的影响。结果表明,阳宗海水体在目前这种磷浓度下,底泥的磷会随时间的增加而溶出再次造成水体磷污染,当暴露在清洁水条件下时磷的释放率会增加;这种由于絮凝剂吸附沉淀到湖底的磷,在上覆水p H增加0.5时底泥磷解吸附释放速率增加;每年秋季湖泊上下层水的交换活动会造成水体磷浓度的季节性升高,形成不可忽视的磷内源。而夏季水温分层导致湖泊底部厌氧,使厌氧微生物活性增强,这将进一步促进底泥中磷的释放。 相似文献
486.
将废粘土砖加工成粗细骨料,用于配制全废砖再生轻骨料混凝土.检测结果表明:所用废砖粗细骨料属轻骨料范畴,但其吸水率较大,且细骨料级配不良.试验表明:本试验配合比体系中,净水灰比为0.42,体积砂率为50%时最佳;以全废砖配制的再生砖轻骨料混凝土的强度发展规律与普通轻骨料混凝土类似,均有随水泥用量提高而强度提高的趋势,但随着所配制的混凝土强度等级的提高,再生轻骨料混凝土的强度提高趋势下降.以全废砖为骨料适合配制强度等级LC30及以下的再生轻骨料混凝土. 相似文献
487.
Shipeng Dong Liang Mao Siqiang Luo Lei Zhou Yiping Feng Shixiang Gao 《Environmental science and pollution research international》2014,21(3):2358-2366
Concentrations of aqueous-phase nonylphenol (NP), a well-known endocrine-disrupting chemical, are shown to be reduced effectively via reaction with lignin peroxidase (LiP) or horseradish peroxidase (HRP) and hydrogen peroxide. We systematically assessed their reaction efficiencies at varying conditions, and the results have confirmed that the catalytic performance of LiP toward NP was more efficient than that of HRP under experimental conditions. Mass spectrum analysis demonstrated that polymerization through radical–radical coupling mechanism was the pathway leading to NP transformation. Our molecular modeling with the assistance of ab initio suggested the coupling of NP likely proceeded via covalent bonding between two NP radicals at their unsubstituted carbons in phenolic rings. Data from acute immobilization tests with Daphnia confirm that NP toxicity is effectively eliminated by LiP/HRP-catalyzed NP removal. The findings in this study provide useful information for understanding LiP/HRP-mediated NP reactions, and comparison of enzymatic performance can present their advantages for up-scale applications in water/wastewater treatment. 相似文献
488.
Liang Peng Yanqing Ren Jidong Gu Pufeng Qin Qingru Zeng Jihai Shao Ming Lei Liyuan Chai 《Environmental science and pollution research international》2014,21(12):7631-7640
Novel magnetic carbonaceous bio-char was hydrothermal prepared from microalgae under different loadings of iron and its structures and surface chemistry were characterized with Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and nitrogen adsorption-desorption isotherm (BET). The morphology of bio-char changed from sheet to particle as iron loading increased and its surface area also increased. When 3.0 g of dried microalgae and 6.0 mmol iron salt ((NH4)2SO4·FeSO4·6H2O) were mixed and treated, the obtained bio-char possessing the highest amount of oxygen-containing functional groups resulted in the best adsorption performance on tetracycline (TC). This adsorption process was fitted to Langmuir adsorption isotherm and the maximum adsorption capacity was 95.86 mg/g, which is higher than other bio-char reported. The iron loading contributed to the higher adsorption capacity of bio-char, which may be due to three factors, the high surface area, more hydrogen bonding, and bridging effects of the structural Fe for TC. Our data suggest that bio-char may have more important role in stabilization of pollutants in the environment. 相似文献
489.
Effects of di-n-butyl phthalate on the physiology and ultrastructure of cucumber seedling roots 总被引:1,自引:0,他引:1
Ying Zhang Yue Tao Guoqiang Sun Lei Wang 《Environmental science and pollution research international》2014,21(10):6662-6670
Agricultural pollution caused by the use of plastic sheetings has been documented to be a widespread problem in most of the major crop-planting regions of the world. In order to better understand the phytotoxic mechanisms induced by phthalic acid esters involved with this problem, Cucumber sativus L. cv Jinyan No. 4 were sown in pots to the three-leaf-stage in the presence of di-n-butyl phthalate (DBP; 0, 30, 50, 100, and 200 mg L?1) for 1, 3, 5, or 7 days. Physiology, biochemistry, and ultrastructure of seedling roots were examined. The results indicated that activities of three antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD)) were stimulated at low-DBP treatments and decreased under higher levels (>100 mg L?1) compared to the controls. On the other hand, SOD and POD provided a better defense against DBP-induced oxidative damage in the roots of cucumber seeding, compared to CAT. The productions of both malondialdehyde (MDA) and proline (Pro) were promoted under DBP stress. Visible impact on the cytoderm, mitochondrion, and vacuole was detected, possibly as a consequence of free radical generation. These results suggested that activation of the antioxidant system by DBP led to the formation of reactive oxygen species that resulted in cellular damage. 相似文献
490.
Co-composting of livestock manure with rice straw: Characterization and establishment of maturity evaluation system 总被引:5,自引:0,他引:5
Xiaoyong Qian Genxiang Shen Zhenqi Wang Chunxia Guo Yangqing Liu Zhongfang Lei Zhenya Zhang 《Waste management (New York, N.Y.)》2014,34(2):530-535
Composting is considered to be a primary treatment method for livestock manure and rice straw, and high degree of maturity is a prerequisite for safe land application of the composting products. In this study pilot-scale experiments were carried out to characterize the co-composting process of livestock manure with rice straw, as well as to establish a maturity evaluation index system for the composts obtained. Two pilot composting piles with different feedstocks were conducted for 3 months: (1) swine manure and rice straw (SM–RS); and (2) dairy manure and rice straw (DM–RS). During the composting process, parameters including temperature, moisture, pH, total organic carbon (TOC), organic matter (OM), different forms of nitrogen (total, ammonia and nitrate), and humification index (humic acid and fulvic acid) were monitored in addition to germination index (GI), plant growth index (PGI) and Solvita maturity index. OM loss followed the first-order kinetic model in both piles, and a slightly faster OM mineralization was achieved in the SM–RS pile. Also, the SM–RS pile exhibited slightly better performance than the DM–RS according to the evolutions of temperature, OM degradation, GI and PGI. The C/N ratio, GI and PGI could be included in the maturity evaluation index system in which GI > 120% and PGI > 1.00 signal mature co-composts. 相似文献