改性铁覆膜砂的制备及吸附性能研究

制备了4种改性铁覆膜砂,并对其吸附性能进行了全面的实验,分析比较了4种改性剂的作用和效果.实验中发现,添加改性剂对铁覆膜砂吸附性能的促进作用各不相同,改性剂和铁氧化物的性质共同决定了改性铁覆膜砂的性质.吸附等温线和连续动态过滤实验结果表明,活性炭和硅藻土对提高铁覆膜砂吸附性能有促进作用,但膨润土和粉煤灰的作用不明显,甚至还可能降低吸附容量.活性炭改性铁覆膜砂的吸附等温式符合Langmuir模型,硅藻土改性铁覆膜砂、膨润土改性铁覆膜砂和粉煤灰改性铁覆膜砂对Langmuir模型和Freundlich模型都有较好的相关性.改性铁覆膜砂对天然有机物(NOM)的吸附属于单分子层吸附,吸附的主要机理为静电相互作用、配位交换-表面络合作用和疏水/憎水作用等.溶液pH值对改性铁覆膜砂吸附NOM有很大的影响,表现为低"pH值去除效率高,高pH值去除效率低"的特点,其变化规律取决于添加物质的性质.磷酸盐会和腐殖酸在改性铁覆膜砂表面产生竞争吸附,磷酸盐对粉煤灰改性铁覆膜砂的吸附能力影响最大.     

废铸砂作为建筑材料资源化再利用研究进展

废铸砂是铸造工业在金属制品的生产过程中次生出来的一种细颗粒固体废弃物。研究其作为一种资源进行合理再利用是当前处置废铸砂、保护生态环境的良好对策。本文对废铸砂的环境特征、物理性质及废铸砂作为建筑材料在多种建筑制品及工程中的资源化再利用进行了综述研究,涉及的再利用领域包括混凝土、热拌沥青混合料、低强度填料、水泥、路基、路堤、阻水帷幕（屏障）和衬垫。调查发现,次生于黑色金属（铁和钢）铸造生产线的废铸砂是一种无害固体废弃物,正确处置和科学利用,对环境不会产生二次污染,在以上建筑制品及工程中的应用能满足相关技术、性能要求,可以替代相关的材料进行资源化再利用。     

Simulating Direct and Indirect Damages to Commercial Fisheries from Marine Sand Mining: A Case Study in Korea

Rapid growth in marine sand mining for construction and other uses poses environmental challenges to coastal nations virtually worldwide. Yet the development of management policies, such as a system of fees imposed on operators for damage caused by mining, has been frustrated by a lack of studies to support such measures. Adapting a Beverton-Holt bioeconomic model, this paper attempts to contribute to the estimation of external costs to commercial fisheries due to marine mining. Using the major mining area of Ongjin in Korea as a case study, we estimate economic losses in use value of commercial fisheries through the time to recovery of the injured resource stocks. Present value of lost catch over a 1-year period from mining to resource recovery is estimated at $38,851 for a single “prototype” mining site. Estimated cumulative damages due to recurring mining for 5 and 10 years are $1.5 million and $2.2 million, respectively, at 20 mining sites. Sensitivity analyses are used to examine the effects of alternative assumptions to assess the many sources of uncertainty. Using a form of meta-analysis, dose-response information is used to assess the excess mortality the mining sediment plume has on eggs and larvae and, ultimately, on the value of lost catch ($841). Also addressed is the importance of specifying the appropriate “premining” conditions against which to assess environmental losses at the mining site. Damages estimated with premining fish populations are $23,066 higher than is the case using postmining conditions. Overall, the illustrative results suggest the variety of complex conditions which influence damage to fisheries from mining and which can benefit from further study to improve management guidelines. An erratum to this article can be found at     

Sand Fences in the Coastal Zone: Intended and Unintended Effects

Sand-trapping fences modify the character of the coastal landscape and change its spatial structure, image, and meaning. This paper examines the relationship between these changes and fence usage at the municipal level, where most decisions about fence deployment are made. Use of fences in 29 municipalities on the developed coast of New Jersey is examined over a 6-year period. Interviews with municipal officers indicate that wooden slat sand-trapping fences are used primarily to build dunes to provide protection against wave uprush and flooding, but they are also used to control pedestrian traffic and demarcate territory. These uses result in changes in landforms and habitats. An aerial video inventory of fences taken in 2002 indicates that 82% of the shoreline had fences and 72% had dunes. Single and double straight fence rows are the most commonly used. Fences are often built to accomplish a specific primary purpose, but they can cause many different and often unanticipated changes to the landscape. The effects of a sand fence change through time as the initial structure traps sand, creates a dune that is colonized by vegetation, and becomes integrated into the environment by increasing topographic variability and aesthetic and habitat value. Sand fences can be made more compatible with natural processes by not placing them in locations where sources of wind blown sand are restricted or in unnatural shore perpendicular orientations. Symbolic fences are less expensive, are easy to replace when damaged, are less visually intrusive, and can be used for controlling pedestrian access.     

Adaptation of Nitraria sphaerocarpa to wind-blown sand environments at the edge of a desert oasis

This study addresses the adaptation of Nitraria sphaervcarpa to blown sand at the edge of a desert oasis with regard to the aspects of soil seed banks, seedlings, and population. Horizontally, the total number of seeds per unit area decreased from the shrub canopy center to intershrub areas, and most seeds were found under shrub canopies. Vertically, the highest proportion of seeds was found at depths of 5-10 cm. The emergence percentage, seedling mass, and seedling height, which were significantly affected by both burial depth and seed size, were highest at the optimal burial depth of 2 cm, and decreased with increasing burial depth in each seed size-class. Although seedling mass was usually greatest for large seeds and least for small seeds at each burial depth, little difference was observed in seedling height at shallow burial depths of 0-3 cm. The population shows a patchy and discontinuous distribution pattern. Population height increases with increasing sand depth. Also the density increases with increasing depth of sand in the desert; however, there is a steady decrease when the depth of sand is more than 100 cm. This result indicates that the depth of sand that is most suitable for the growth of Nitraria sphaervcarpa is 100 cm. The size of the population is significantly correlated with the sand depth, which increases with increasing depth in the desert.     

Mann-Kendall检验及其在河流悬沙浓度时间序列分析中的运用

探讨了Mann-Kendall非参数秩次相关检验在时间序列分析方面的应用,并以云南省文山州盘龙河为例,把它运用到河流悬沙浓度时间序列的趋势分析和突变分析研究中。结果表明：①M-K检验同样适用于河流悬沙浓度的趋势与突变分析;②盘龙河自20世纪60年代初至90年代末河流悬沙浓度一直表现为波动上升趋势,1999年后有下降的迹象;③盘龙河的河流悬沙浓度自20世纪60年代以来存在着两个明显的突变点,其一在1973年,其二在1999年。     

垃圾渗滤液预处理实验研究

在总结以往研究成果的基础上,选用絮凝沉淀和沙滤方法对垃圾渗滤液进行预处理,实验得出了各自最佳的处理条件,并提出了一个成本低效果好的处理方案。     

饮用水砂滤池中微生物对微量污染物的降解潜力与途径

砂滤池已广泛应用于饮用水处理中,已有研究证明砂滤池能有效降解部分微量污染物,但对其降解途径和降解微生物缺乏深入探讨.据此,本研究首先采集2个实际饮用水厂滤池中的石英砂和锰砂滤料,通过宏基因组分析了滤料对阿替洛尔、阿特拉津、磺胺嘧啶和卡马西平的降解基因和相关降解微生物.结果表明,锰砂滤池生丝微菌科和石英砂滤池中的假单胞菌属具有将阿特拉津转化为羟基阿特拉津的潜力;砂滤池含多种分泌阿替洛尔酰胺水解酶的微生物,具有将阿替洛尔转换为阿替洛尔酸的能力;在滤池中广泛存在单、双加氧酶和细胞色素P450,能将阿特拉津、磺胺嘧啶和卡马西平氧化.进一步通过培养实验验证了滤料对这4种微量污染物的降解途径.本研究最后对其它9个实际水厂砂滤池滤料的宏基因组分析发现所有砂滤池都含有丰富的酰胺水解酶、加氧酶和细胞色素P450,说明饮用水砂滤池都具有降解多种微量污染物的潜力.     

Laboratory-scale column study for remediation of TCE-contaminated aquifers using three-section controlled-release potassium permanganate barriers

A laboratory-scale study with a sand column was designed to simulate trichloroethylene(TCE) pollution in the aquifer environment with three-section controlled-release potassium permanganate(CRP) barriers.The main objective of this study was to evaluate the feasibility of CRP barriers in remediation of TCE in aquifers in a long-term and controlled manner.CRP particles with a 1:3 molar ratio of KMnO 4 to stearic acid showed the best controlled-release properties in pure water,and the theoretical release time was 138.5 days.The results of TCE removal in the test column indicated that complete removal efficiency of TCE in a sand column by three-section CRP barriers could be reached within 15 days.The molar ratio of KMnO 4 to TCE in the three-section CRP barriers was 16:1,which was much lower than 82:1 as required when KMnO 4 solution is used directly to achieve complete destruction of TCE.This result revealed that the efficiency of CRP for remediation of TCE was highly improved after encapsulation.     

含砂海水对40Cr钢加速冲刷腐蚀性能影响

目的研究40Cr钢在实际海水中的冲刷腐蚀性能。方法采用自制旋转冲刷实验装置,模拟实际海洋环境对40Cr钢进行实验。试验介质为含有质量分数为0.15%、0.3%、1%石英砂(300目左右)的青岛海域天然海水,冲刷流速分别为1、3、5 m/s。用交流阻抗谱和极化曲线测试检测其冲刷腐蚀性能,采用失重法测量冲刷腐蚀速率,并用扫描电镜观察其表面形貌,用XRD、EDS技术检测腐蚀产物成分。结果当流速一定,石英砂的质量分数为0.3%时,腐蚀速率最小,交流阻抗谱和极化曲线结合分析显示,此时最耐腐蚀,腐蚀产物成分为FeO(OH)。当含砂量一定时,随着流速的增加,试样腐蚀速率快速增加,耐蚀性逐渐下降,腐蚀产物主要成分为Fe O(OH)。结论流速对40Cr的冲刷腐蚀速率影响较大,而含砂量对冲刷腐蚀速率的影响较小。