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991.
考察了再生水氯消毒过程中的氯消耗特性及水质特性的变化,发现加氯后5 min,氯消耗速率最大,同时254 nm的紫外吸光度和三维荧光强度的变化最为显著.发现再生水消毒后生物可同化有机碳(AOC)浓度显著增加,说明消毒后水质生物稳定性变差.AOC变化趋势呈现为先增长后降低的趋势,对于不同处理工艺再生水,二级出水的AOC水平普遍高于深度处理出水,但深度出水消毒5 min后AOC的增长率却高于二级出水消毒后的增长率.进一步研究发现,再生水水样消毒后的AOC变化量与三维荧光积分值变化量之间有一定的正相关关系. 相似文献
992.
Robert Liu R.S. Shieh Ruth Y.L. Yeh C.H. Lin 《Waste management (New York, N.Y.)》2009,29(11):2842-2845
The traditional burning process is used to recover copper from scrapped PC board (printed circuit board) but it causes serious environmental problems. In this research a new process was developed which not only prevents pollution problems, but also maximizes the utility of all the materials on the waste board. First, the scrapped PC board was crushed and grounded, then placed in the NH3/NH5CO3 solution with aeration in order to dissolve copper. After distilling the copper NH3/NH5CO3 solution and then heating the distilled residue of copper carbonate, pure copper oxide was obtained with particle size of about 0.2 μm and the shape elliptical. The remaining solid residue after copper removal was then leached with 6 N hydrochloric acid to remove tin and lead. The last residue was used as a filler in PVC plastics. The PVC plastics with PC board powder as filling material was found to have the same tensile strength as unfilled plastics, but had higher elastic modulus, higher abrasion resistance, and was cheaper. 相似文献
993.
Qiu Cai Mei-Li Long Ming Zhu Qing-Zhen Zhou Ling Zhang Jie Liu 《Environmental pollution (Barking, Essex : 1987)》2009,157(11):3078-3082
Cadmium (Cd) and Lead (Pb) are environmental pollutants. Environmental samples and bovine tissues were collected from the areas around a lead–zinc smelter in Guizhou, China for Cd, Pb, zinc (Zn) and copper (Cu) analysis. Cd in soil (10 mg/kg) and feed (6.6 mg/kg) from the polluted areas was 10 times higher than the Chinese Standards, resulting in higher Cd in bovine kidney (38 mg/kg) and liver (2.5 mg/kg). Pb in feed (132 mg/kg) from the polluted area was much higher than unpolluted areas, causing higher Pb levels in bovine tissues. Environmental Zn was elevated, but bovine tissue Zn was normal. Cu in bovine liver decreased with increased Cd and Pb. Metals in drinking water and in bovine muscle were within the Standard range. Thus, in the areas of this lead–zinc smelter, the environment has been contaminated with Cd and Pb, which has been transferred to cattle through the food chain. 相似文献
994.
土壤重金属污染及其修复技术研究 总被引:4,自引:0,他引:4
土壤重金属污染物有汞、镉、铅、锌等,主要来源于交通运输、工业污染和农业污染。土壤重金属污染会导致农作物减产甚至死亡,对人体健康也会产生极大危害。目前土壤重金属污染修复的技术主要包括工程修复法、物理化学修复法、化学修复法和生物修复法。植物修复技术作为一种新兴的绿色、生态、高效的修复技术具有良好的发展前景。 相似文献
995.
Fu-Sheng Liu Zhuo Li Shi-Tao Yu Xiao Cui Cong-Xia Xie Xiao-Ping Ge 《Journal of Polymers and the Environment》2009,17(3):208-211
Alkali-catalyzed methanolysis and hydrolysis of polycarbonate (PC) in a solvent in which PC can substantially dissolve such
as N-methyl-2-pyrrolidone, 1,4-dioxane, tetrahydrofuran and so on were studied. Reaction conditions were optimized for the purpose
of recycling PC in the form of bisphenol A and carbon carbonate. The results showed that both the methanolysis and hydrolysis
of PC could take place under moderate conditions. Under the conditions of reaction temperature 40 °C, m(PC):m(MeOH) = 1:1,
m(PC):m(NaOH) = 50:1, reaction time 35 min and using tetrahydrofuran as solvent, the methanolysis conversion of PC was almost
100% and the yield of bisphenol A was over 95%. Moreover, under the conditions of reaction temperature 100 °C, m(PC):m(H2O) = 1:0.7, m(PC):m(NaOH) = 10:1, reaction time 8 h and using 1,4-dioxane as solvent, the hydrolysis conversion of PC was
almost 100% and the yield of bisphenol A was over 94%. 相似文献
996.
Ionic composition of TSP and PM2.5 during dust storms and air pollution episodes at Xi'an,China 总被引:1,自引:0,他引:1
Zhenxing Shen Junji Cao Richard Arimoto Zhiwei Han Renjian Zhang Yuemei Han Suixin Liu Tomoaki Okuda Shunsuke Nakao Shigeru Tanaka 《Atmospheric environment (Oxford, England : 1994)》2009,43(18):2911-2918
TSP and PM2.5 samples were collected at Xi'an, China during dust storms (DSs) and several types of pollution events, including haze, biomass burning, and firework displays. Aerosol mass concentrations were up to 2 times higher during the particulate matter (PM) events than on normal days (NDs), and all types of PM led to decreased visibility. Water-soluble ions (Na+, NH4+, K+, Mg2+, Ca2+, F?, Cl?, NO3?, and SO42?). were major aerosol components during the pollution episodes, but their concentrations were lower during DSs. NH4+, K+, F?, Cl?, NO3?, and SO42? were more abundant in PM2.5 than TSP but the opposite was true for Mg2+ and Ca2+. PM collected on hazy days was enriched with secondary species (NH4+, NO3?, and SO42) while PM from straw combustion showed high K+ and Cl?. Firework displays caused increases in K+ and also enrichments of NO3? relative to SO42?. During DSs, the concentrations of secondary aerosol components were low, but Ca2+ was abundant. Ion balance calculations indicate that PM from haze and straw combustion was acidic while the DSs samples were alkaline and the fireworks' PM was close to neutral. Ion ratios (SO42?/K+, NO3?/SO42?, and Cl?/K+) proved effective as indicators for different pollution episodes. 相似文献
997.
社会经济和资源禀赋的区域差异导致耕地非农化压力表现出明显的空间异质性。开展耕地非农化压力测算并揭示其时空格局演变,是实现土地资源优化配置的基础。从经济因素、社会因素、产业结构和资源禀赋4个方面构建耕地非农化压力指数评价指标体系,采用熵值法计算各指标权重,继而计算1990~2014年中国31省的耕地非农化压力指数,并在此基础上开展了耕地非农化压力的时空格局分析。结果表明:(1)从空间格局分布来看,中国耕地非农化压力空间分布呈现明显的地理梯度,总体上呈现从东到西依次递减的态势。(2)从时间变化趋势来看,不同地区各省份之间的耕地非农化压力指数变化呈现多元化趋势。东部沿海地区,山东、浙江、江苏的耕地非农化压力指数处于上升阶段,上海、福建的压力指数变化趋势逐渐趋稳,广东的压力指数呈现下降趋势。中部地区,河南、河北、山西、江西的耕地非农化压力指数趋稳,陕西、湖北以及四川、重庆等西南地区省份的压力指数呈上升趋势。西部沿边3省(云南、西藏、新疆)的耕地非农化压力呈现了一致的下降趋势。(3)从时空格局结合来看,耕地非农化压力不同的省份其变化趋势呈现出截然不同的走向。在耕地非农化压力较大的地区,耕地非农化经历了从制度驱动向发展推动的阶段,经济增长的倒"U"型轨迹明显,经济增长与耕地非农化之间的关系逐渐脱钩。在耕地非农化压力居中或较小的地区,产业发展滞后,土地比较收益较低,耕地的社会保障作用、生态作用对耕地非农化的影响较大,从而增加了部分省份的耕地非农化压力。 相似文献
998.
Arsenic contamination and potential health risk implications at an abandoned tungsten mine, southern China 总被引:3,自引:0,他引:3
Chuan-ping Liu Chun-ling Luo Fang-bai Li Lan-wen Lin Xiang-dong Li 《Environmental pollution (Barking, Essex : 1987)》2010,158(3):820-826
In an extensive environmental study, field samples, including soil, water, rice, vegetable, fish, human hair and urine, were collected at an abandoned tungsten mine in Shantou City, southern China. Results showed that arsenic (As) concentration in agricultural soils ranged from 3.5 to 935 mg kg−1 with the mean value of 129 mg kg−1. In addition, As concentration reached up to 325 μg L−1 in the groundwater, and the maximum As concentration in local food were 1.09, 2.38 and 0.60 mg kg−1 for brown rice, vegetable and fish samples, respectively, suggesting the local water resource and food have been severely contaminated with As. Health impact monitoring data revealed that As concentrations in hair and urine samples were up to 2.92 mg kg−1 and 164 μg L−1, respectively, indicating a potential health risk among the local residents. Effective measurements should be implemented to protect the local community from the As contamination in the environment. 相似文献
999.
注浆法治理公路黄土暗穴病害的试验研究 总被引:1,自引:1,他引:0
注浆法是公路工程中治理暗穴的一种新方法.针对湿陷性黄土地区公路工程中大量发育的暗穴病害,通过室内浆液材料物理力学性能试验与工程现场模拟注浆效果试验,分析了以水泥为主剂的注浆材料在不同配合比情况下治理公路工程中暗穴的效果.室内外试验结果分析表明:浆液水灰比在2.5∶1~1.5∶1之间较为适宜;在不影响路基路面的正常压力下有效的加固半径是1.0 m~1.5 m;在特殊情况下为了使浆液快速凝结可以加入一定量的水玻璃作为速凝剂;可以采用二次注浆加强治理的效果. 相似文献
1000.
Jie Liu Junjun Ma Weizhang Zhong Jianrui Niu Zaixing Li Xiaoju Wang Ge Shen Chun Liu 《Frontiers of Environmental Science & Engineering》2023,17(4):51