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41.
粉煤灰合成分子筛及处理含氟废水的研究 总被引:3,自引:0,他引:3
实验利用工业废渣——循环流化床粉煤灰合成出较高结晶度的X型和P型分子筛,合成过程无须高温焙烧预处理.通过XRD分析表征,发现该法合成分子筛结晶度较高,X型和P型分子筛相对结晶度分别达68%~75%和55%.实验应用合成分子筛进行载铁改性,并对NaF模拟的工业含氟废水进行了除氟实验.结果表明,载铁X型分子筛处理工业含氟废水效果良好,除氟率可达74%~98%,除氟容量达25.0~30.0 mg/g.在处理含氟废水过程中,载铁合成分子筛与其他除氟剂相比较,具有除氟率高、除氟容量大、反应迅速的特点. 相似文献
42.
水体富营养化综合水质模型及其应用研究 总被引:11,自引:0,他引:11
针对水体富营养化问题,探讨了一种多参数水体富营养化的水质生态模型(WASP4)。在阐述其原理和计算方法的基础上结合汉江武汉段1992年性水华事件的实例进行水质模型,其特点是,不仅能够较好地模拟浮游植物的变化过程。而且能够提供发生水华问题的原因和生态机理的解释。 相似文献
43.
Excessive nitrate(NO_3~-) is among the most problematic surface water and groundwater pollutants.In this study,a type of magnetic cationic hydrogel(MCH) is employed for NO_3~-adsorption and well characterized herein.Its adsorption capacity is considerably pHdependent and achieves the optimal adsorption(maximum NO_3~--adsorption capacity is95.88±1.24 mg/g) when the pH level is 5.2-8.8.The fitting result using the homogeneous surface diffusion model indicates that the surface/film diffusion controls the adsorption rate,and NO_3~-approaches the center of MCH particles within 30 min.The diffusion coefficient(D_s) and external mass transfer coefficient(k_F) in the liquid phase are1.15 × 10~(-6) cm~2/min and 4.5 × 10~(-6) cm/min,respectively.The MCH is employed to treat surface water that contains 10 mg/L of NO_3~-,and it is found that the optimal magnetic separation time is 1.6 min.The high-efficiency mass transfer and magnetic separation of MCH during the adsorption-regeneration process favors its application in surface water treatment.Furthermore,the study of the mechanism involved reveals that both-N~+(CH_3)_3 groups and NO_3~-are convoluted in adsorption via electrostatic interactions.It is further found that ion exchange between NO_3~-and chlorine occurs. 相似文献
44.
Ming Dou Qiting Zuo Jinping Zhang Congying Li Guiqiu Li 《Environmental monitoring and assessment》2013,185(9):7501-7516
With rapid economic development, the Pearl River Delta (PRD) of China has experienced a series of serious heavy metal pollution events. Considering complex hydrodynamic and pollutants transport process, one-dimensional hydrodynamic model and heavy metal transport model were developed for tidal river network of the PRD. Then, several pollution emergency scenarios were designed by combining with the upper inflow, water quality and the lower tide level boundary conditions. Using this set of models, the temporal and spatial change process of cadmium (Cd) concentration was simulated. The influence of change in hydrodynamic conditions on Cd transport in tidal river network was assessed, and its transport laws were summarized. The result showed the following: Flow changes in the tidal river network were influenced remarkably by tidal backwater action, which further influenced the transport process of heavy metals; Cd concentrations in most sections while encountering high tide were far greater than those while encountering middle or low tides; and increased inflows from upper reaches could intensify water pollution in the West River (while encountering high tide) or the North River (while encountering middle or low tides). 相似文献
45.
Nitrogen mass flow in China's animal production system and environmental implications 总被引:2,自引:0,他引:2
China's economic boom in recent decades has stimulated consumer demand for animal products and consequently, a vast expansion in animal production. From 1978 to 2006, the number of animals increased by 322% for pigs, 209% for poultry, and 2770% for dairy cattle. The objective of the present study was to quantify nitrogen mass flow in China's animal production system at the national scale and to elucidate potential environmental implications. A comprehensive analysis was performed combining statistical records with data from the scientific literature and supplemental survey information. Results indicate that approximately 18 Mt of N flowed through the Chinese animal production system in 2006. Nitrogen input to the system was from various feed materials, including 6.8 Mt (38% of total) from roughage, 4.4 Mt (24%) from byproducts, 2.3 Mt (13%) from cereal grains, and 1.6 Mt (9%) each from crop residues and oilseed cakes, with the remaining N (16%) obtained from other feedstuffs. Nitrogen outputs from the system included edible animal products (2.4 t, 13% of total), nonedible animal parts (e.g., bones, skins) (3.8 Mt, 21%), and excreta (12 Mt, 66%). At the national level, the excreta would average 28 Mg (as excreted) and 90 kg N ha(-1) of cropland. However, at the provincial level, it varied from 1 Mg ha(-1) (5 kg N ha(-1)) in Qinghai to 97 Mg ha(-1) (243 kg N ha(-1)) in Sichuan. In regions with excreta in the intermediate rate (e.g., Hebei Province, 115 kg N ha(-1)) or high rare (e.g., Sichuan Province, 243 kg N ha(-1)), animal manure contributes significantly to nutrients polluting groundwater and/or surface waters. It is crucial for China to develop and implement proper management practices to maximum the beneficial use of the 12 Mt excreta N while minimizing its environmental footprint. 相似文献
46.
通过分析现阶段我国建筑行业农民工的常见职业性伤害事故以及职业安全健康现状,从教育、技术、监管3个方面提出了引导农民工学会利用法律、通过合法渠道维护自身权益;改善农民工的就业环境,加强个体防护,讲究文明礼貌,遵守职业行为准则,培养科学、文明、健康的生活方式等具体措施,为农村富余劳动力转移提供更多的就业机会,增加农民收入促进城乡经济协调发展,保障建筑行业农民工的职业安全健康提供科学依据。 相似文献
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48.
仪征市可持续发展指标体系研究 总被引:16,自引:0,他引:16
本文采用了隶属度函数及可持续发展的阶段连续性方程,建立了评价可持续发展的复合指标体系,给出了持续发展的水平及揭示了不同时态持续发展的类型,并以此为基础分析了仪征市近,无期的可持续发展状况,提出了调控的措施。 相似文献
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