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921.
922.
Fe~(3+)掺杂TiO_2/凹凸棒复合材料的光催化性能 总被引:2,自引:1,他引:1
采用酸催化的溶胶-凝胶法制备了一系列Fe3+掺杂TiO2/凹凸棒(Fe3+-TiO2/ATP)复合光催化剂材料。在可见光条件下,以亚甲基蓝(MB)溶液的光催化降解反应,评价了样品的光催化性能,研究了TiO2负载量、Fe3+掺杂量和焙烧温度对复合材料光催化性能的影响。在单因素实验的基础上,采用正交实验设计(L25(53))优化了催化剂的制备条件。光催化实验结果表明,MB在复合材料上的光催化降解反应遵循Langmuir-Hinshelwood(L-H)动力学模型。正交实验结果表明,当TiO2负载量为15%、Fe3+掺杂量为0.5%和焙烧温度为550℃时,得到的复合材料对MB的光催化降解效率最佳,测得表观反应速率常数kapp为6.09×10-3min-1,反应4 h后MB的降解率(Dt)可达75.88%,相同实验条件下与P25(1.51×10-3min-1)相比较,反应速率提高了4.03倍,降解率提高了45.05%。另外,复合材料的沉降性能优于P25,易于分离,是一类有应用前景的复合光催化剂。 相似文献
923.
Wei Luo Yonglong Lu Yan Zhang Wenyou Fu Bin Wang Wentao Jiao Guang Wang Xiaojuan Tong John P. Giesy 《Journal of environmental management》2010,91(12):2599-2607
Concentrations of As and selected metals were determined in surface soils of the Miyun Reservoir watershed of Beijing, China. The degree to which concentrations of As and metals exceeded the corresponding background concentration of soils was: Cr > Cu > Zn > As > Ni with no apparent anthropogenic contamination with Cd and Pb. Based on the results of a combination of multivariate statistics and geostatistical analysis, greater concentrations of Cr and Ni in soils were determined to be primarily from iron ore mining near where the Chaohe River enters the northeast portion of the reservoir. Agricultural activities were responsible for the observed elevated concentrations of Cu and Zn in soils. Relatively great concentrations of As were found in soils near the upstream regions of the Baihe River in Chicheng County where small gold mining activities have taken place. The greatest potential for adverse effects of Cr and Cu occurred along the eastern shore of Miyun Reservoir. 相似文献
924.
为了提高有机物的臭氧化降解效率,工作中利用浸渍法制备了一种新型的三组分催化剂(记为V2O5-TiO2-AlF3/Al2O3)。催化臭氧化降解2,4-滴丙酸的实验结果表明,该催化剂能有效提高臭氧化的效率,体系可能遵循羟基自由基的作用机理。利用相对法计算结果表明,与单独臭氧化相比,V2O5-TiO2-AlF3/Al2O3催化臭氧化体系具有更大的Rct值。重复实验结果表明,该催化剂具有相对较好的稳定性。以上研究结果对推广催化臭氧化技术在实际废水处理中的应用具有重要的实际意义。 相似文献
925.
上海市产业结构和能源结构的变动对碳排放的影响及应对策略 总被引:16,自引:0,他引:16
节能减排是政府工作的一项重要任务,为了给上海碳排放政策的制订提供有效的参考依据并提出合理的应对策略,采用IPCC 2006年提出的各类能源排放二氧化碳量的计算方法,根据近年来上海工业能源消耗和GDP增长及产业结构变化相关数据,分析了上海城市的碳排放变化趋势,探讨了产业结构和能源结构变动对碳排放量的影响。研究表明,能源结构的变动尤其是高排碳的煤类能源比重下降,热、电等能源比重上升,是上海万元GDP碳排放量下降的主要原因。针对能源结构的发展趋势,提出继续优化能源结构,降低煤类能源比重,鼓励使用电、热类能源,促进产业结构升级,尤其是促进第三产业的发展,利用上海周边资源开发潮汐能等新能源促进能源类型的多元化等多种应对策略。 相似文献
926.
Clean processing of copper converter slag to reclaim cobalt and copper could be a challenge. An innovative and environmentally sound approach for recovering valuable metals from such a slag has been developed in the present study. Curing the slag with strong sulphuric acid, without re-smelting or roasting as practiced currently in the industry, render it accessible to leaching, and more than 95% of cobalt and up to 90% of copper was extracted together with iron by water leaching, leaving silica behind in a residue. The copper in the leach liquor was recovered by cementation with iron and the dissolved iron crystallized as ferrous sulphate monohydrate. The cobalt in the mother-liquor rich in iron was recovered by either cementation or sulphide precipitation. Operation variables in the new process were also investigated and optimized. 相似文献
927.
以液晶屏抛光废液为原料制备冰晶石,首先加入碳酸钠,反应生成氟硅酸钠沉淀,去除废液中的氟硅酸根;再向滤液中加入NaOH和NaAlO2混合溶液,反应生成冰晶石。最佳工艺条件为:碳酸钠加入量为理论加入量的2.2倍,冰晶石制备反应温度为80℃,反应原料中n(HF)∶n(NaAlO2)为5.4、n(Na)∶n(Al)为3.4、NaOH和NaAlO2质量分数为20%。在最佳条件下制得的冰晶石产品中n(Na)∶n(Al)为2.84,达到GB/T4291-2007《冰晶石》中牌号CH-1的质量标准。采用该工艺可实现液晶屏抛光废液的资源化综合利用。 相似文献
928.
Julie R. Marentette Grace Wang Stephanie Tong Natalie M. Sopinka Matthew D. Taves Marten A. Koops Sigal Balshine 《Behavioral ecology and sociobiology》2011,65(12):2239-2249
Activity levels are modulated by trade-offs between reducing predation risk and the need to move in order to find food or
mates. Because these trade-offs affect males and females differently, many species show sex-specific movement, dispersal patterns,
and spatial navigation capacities, with the sex that gains the most from territory ownership often dispersing less. Unlike
mammals and birds, sex differences in movement among fishes remain poorly studied, and the connections between tests of movement
propensity in the laboratory and in the field are rarely made. Here, we examine the differences in movement between male and
female round goby (Neogobius melanostomus) in both laboratory and field settings. This fish species is invasive in North America and currently undergoing further range
expansions. In the laboratory, round goby males were more active and explored a novel environment more readily than did females.
A large-scale mark–recapture study in Lake Ontario over two years revealed that males moved more than females between years,
but there were no within-year sex differences. Thus, round goby display male-biased movement patterns, providing a comparison
point to dispersal patterns in other taxa. Understanding sex-specific movement of round goby in the field will also help predict
dispersal and population dynamics, both in areas where round goby have already become established and where they are continuing
to invade. 相似文献
929.
Xiao Tang Zifa Wang Jiang Zhu Alex E. Gbaguidi Qizhong Wu Jie Li Tong Zhu 《Atmospheric environment (Oxford, England : 1994)》2010,44(31):3833-3842
In order to understand the formation mechanisms of high surface ozone and identify the main contributor sources in Beijing, this study investigates the sensitivity of surface ozone to NO, NO2 and nine types of NMVOC emissions during a photochemical smog episode. Monte Carlo sensitivity analysis scheme with fifty simulations is established based on the Nested Air Quality Prediction Model System (NAQPMS). At every simulation, each of the eleven precursor emissions is perturbed with a distinct set of perturbations. The sensitivities of ozone to emissions are identified by multiple linear regressions. The stability of sensitivity results is validated by two experiments with standard deviations of log-normal perturbations set as 30% and 50% respectively. The sensitivity results suggest that the current high surface ozone is strongly stimulated by NMVOC emissions. Among NMVOC emissions, formaldehyde, ethylene and olefins emissions present the greatest impacts on ozone. On the other hand, NOx emissions have a strong inhibitory effect on ozone formation, even after 50% NOx emission reduction. This indicates that the current ozone formation in Beijing is under NOx-saturated conditions. A transition of ozone formation is observed from NOx-saturated to NOx-limited sensitivity behavior with a 75% reduction of NOx emissions. This study gives the implication that abatement of the four NMVOC types mentioned above could be efficient on reducing the high levels of surface ozone in central urban Beijing, while inadequate abatement in NOx emissions probably induces reverse effects. 相似文献
930.