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181.
To reveal the basic characteristics and controlling factors of water quality change in the project Wenyu to Chaobai reclaimed water diversion, the water quality in the study area was monitored for one year at seven monitoring sites. Inverse geochemical models of the statistical groups were developed using PHREEQC to elucidate the hydrochemistry characteristics of reclaimed water and the factors. The monitoring results indicated that nitrogen and phosphorus contents were significantly reduced along the river mainly caused by seasonal and location variation. The pH ranged from 7.44 to 9.81. Photosynthesis of algae and denitrification in anaerobic microenvironment ultimately led to a sudden p H increase after the Jian River and the Chaobai River confluence. Mg~(2+)and SO_4~(2-) levels dropped obviously in the summer and increased in winter seasons after intersection. Na+and Cl-are relatively stable, and marked drop in the concentration only after the two rivers meet. And there is a decrease of Ca~(2+) and HCO~(3-) and increase in CO_3~(2-) during monitoring period. As a whole, the primary ions and nutrient components, including nitrogen and phosphorus, had high levels in winter. Algae's photosynthesis and respiration were observed to have an impact on the river water quality; there was precipitation–dissolution of minerals and denitrification from upstream to downstream. Inverse geochemical PHREEQC modeling confirmed that there was precipitation of aragonite or calcite, and gypsum or anhydrite in summer, and dissolution in winter; as well as precipitation of dolomite in winter, and cationic exchange and denitrification along the river. 相似文献
182.
论文探讨A型沸石对废水中磷的吸附性能,影响A型沸石对磷吸附的主要因素有吸附温度、灰水比、吸附时间和pH值。通过单因素和正交试验确定在水样体积30mL,A型沸石投加量3g,吸附时间为40~50min,吸附温度25oC,pH值4~5范围内,初始磷浓度小于20 mg/L,A型沸石对磷都有很好的吸附效果。TP去除率达99%以上,对磷的吸附容量约为0.44mg/g,适用于工业废水处理和生活污水的深度除磷。 相似文献
183.
地震灾害一直是人类社会所面临的重大自然灾害之一,在灾害发生之后,为了能够让灾区较短时间内恢复正常的生产生活和社会运行,高效率的恢复重建机制不可或缺.在所有的震后恢复重建项目中,灾区原有的工业企业的恢复重建是一大重点,这些工业企业在灾前往往是当地政府税收的主要来源,也为当地人口提供了大量的就业岗位.然而,能够投入到灾区用... 相似文献
184.
赵江涛 《防灾科技学院学报》2010,12(3):26-28,141
我国是世界上荒漠面积大、分布广、危害严重的国家之一。目前,我国每年由于荒漠化造成的直接经济损失高达500亿元。本文介绍了我国荒漠化防治立法概况及法律制度存在的问题,并针对这些问题,进行了一些完善我国荒漠化防治法律制度的思考。 相似文献
185.
Min Zhou Liping Qiao Shuhui Zhu Li Li Shengrong Lou Hongli Wang Qian Wang Shikang Tao Cheng Huang Changhong Chen 《环境科学学报(英文版)》2016,28(10):151-160
In this work, a one-year observation focusing on high time resolution characteristics of components in fine particles was conducted at an urban site in Shanghai. Contributions of different components on visibility impairment were also studied. Our research indicates that the major components of PM2.5 in Shanghai are water-soluble inorganic ions and carbonaceous aerosol, accounting for about 60% and 30% respectively. Higher concentrations of sulfate (SO42−) and organic carbon (OC) in PM2.5 occurred in fall and summer, while higher concentrations of nitrate (NO3−) were observed in winter and spring. The mass concentrations of Cl− and K+ were higher in winter. Moreover, NO3− increased significantly during PM2.5 pollution episodes. The high values observed for the sulfate oxidizing rate (SOR), nitrate oxidizing rate (NOR) and secondary organic carbon (SOC) in OC indicate that photochemical reactions were quite active in Shanghai. The IMPROVE (Interagency Monitoring of Protected Visual Environments) formula was used in this study to investigate the contributions of individual PM2.5 chemical components to the light extinction efficient in Shanghai. Both NH4NO3 and (NH4)2SO4 had close relationships with visibility impairment in Shanghai. Our results show that the reduction of anthropogenic SO2, NOx and NH3 would have a significant effect on the improvement of air quality and visibility in Shanghai. 相似文献
186.
北京平原夏垫断裂沉积旋回研究 总被引：3，自引：0，他引：3
通过对夏垫断裂下降盘(上盘)第四纪堆积物逐层分析和对比,定性的分析出夏垫断裂下降盘(上盘)距地表10 m范围内,各层的沉积环境和相应的沉积韵律特征。研究发现:由探槽所揭露的地层可以分为7个沉积旋回,每个沉积旋回由上部的细粒层和下部的粗粒层组成,粒度上细下粗;细粒层均为含碳粘土和粉砂质粘土,具有湖相沉积的特点,其沉积环境多为还原环境或弱还原环境;粗粒层一般为细砂、粗砂层,具有快速堆积的特点,其沉积环境多为氧化环境或弱氧化环境;分析认为,断塞沉积所显示的韵律性结构是地震周期性活动的结果,这一研究是揭示夏垫断裂的古地震事件,反演古地震活动并预测其未来行为的基础。 相似文献
187.
乔寿锁 《城市环境与城市生态》1992,5(3):30-34
为解决工业污染问题,我国早有“把污染消除在生产过程之中”的提法,在有关法规中也已有明文,但是防止污染的思想并没有成为有组织的社会行动,污染处理(控制)的管理思想仍然占据着环境管理的主导地位.由此而引发的把末端处理处置作为追求目标的控制污染的社会行为不能不引起忧虑.本文从对我国现行污染控制政策评述出发,剖析了环境管理实践中现行污染控制政策遇到的障碍,提出了我国工业污染防治政策的调整方向和行动计划的建议. 相似文献
188.
Xin Pang Shixiang Xue Tong Zhou Mingtao Qiao Huaxing Li Xue Liu Quanlong Xu Gang Liu Wanying Lei 《Advanced Sustainable Systems》2023,7(1):2100507
Developing highly efficient, robust, and noble metal-free photocatalytic systems is essential for the large-scale implementation of solar-to-chemical energy conversion. Herein, a novel sandwich-like hierarchical heterostructure of Ti3C2 MXene/WO3 is created by in situ growth of ultrathin WO3 nanosheets onto the surface of few-layer Ti3C2 nanosheets via a one-pot solvothermal synthesis strategy. The resultant Ti3C2/WO3 heterostructure holds a large interface contact area, an intimate electronic interaction, and a short carrier migration distance, which is beneficial for bulk-to-surface and interfacial charge transfer. Meanwhile, the excellent electrical conductivity of Ti3C2 and the Schottky junction at the interface of WO3 and Ti3C2 expedites the spatial charge separation and transportation. As expected, the as-prepared Ti3C2/WO3 nanohybrids exhibit a superior visible-light-driven photoactivity and stability toward tetracycline hydrochloride (TC) decomposition. Across a range of Ti3C2 concentrations, 3 wt% Ti3C2/WO3 achieves the greatest photodegradation rate of 16.08 × 10−3 min−1 that is approximately ninefold larger than that of pristine WO3. In addition to the underlying photocatalytic mechanism, three TC degradation pathways are identified, highlighting the important roles of ·O2− and h+. This study shows the potential of earth-abundant MXene family materials in the fabrication of high-performance and low-cost photocatalysts applicable for environment purification. 相似文献
189.
190.