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51.
研究了Fe2+活化过硫酸钠产生的硫酸根自由基降解土壤中十溴联苯醚(PBDE-209)的效果,分别考察了Na2S2O8的用量、初始pH值、Na2S2O8与Fe2+摩尔比例、反应时间4个因素对降解效果的影响。通过正交实验确定了降解污染物的最优条件。结果表明,在Na2S2O8用量为0.8 mmol·kg-1,初始pH为5,Na2S2O8与Fe2+摩尔比为2:1,反应时间为30 min的最优条件下,降解率达96.36%。分子探针竞争实验表明体系中产生了硫酸根自由基。Fe2+活化过硫酸钠降解PBDE-209反应过程符合一级反应动力学。 相似文献
52.
53.
聚硫氯化铝絮凝效果及在水处理中的应用 总被引:8,自引:0,他引:8
采用聚硫氯化铝(PACS)为絮凝剂进行废水处理试验,对其絮凝效果及影响因素进行了研究,试验结果表明,PACS的SO4^2-含量,碱化度,投加量和水的pH对絮凝效果有影响,当Al^3+/SO4^2-(摩尔比)为14 ̄16,碱化度为65% ̄70%,pH为6 ̄9、PACS投加量为2 ̄4mg/L时,絮凝效果最佳,试验结果还表明,PACS比聚氯化铝(PAC)的絮凝效果好。 相似文献
54.
利用天然矿石毒重石对硫酸盐废水进行吸附处理,在废水的pH=9,停留时间为80min左右时,该吸附剂具有较好的吸附效果。且该离子交换吸附法具有成本低、操作简单、无二次污染的优点。 相似文献
55.
Removal of arsenic from wastewater using iron compound: Comparing two different types of adsorbents in the context of LCA 总被引:1,自引:0,他引:1
Gjergj Dodbiba Teiji Nukaya Yousuke Kamioka Yuji Tanimura Toyohisa Fujita 《Resources, Conservation and Recycling》2009,53(12):688-697
A study was carried out in order to compare the environmental performance of two different types of adsorbents in removing arsenic (As) from wastewater. A FeCl3-based adsorbent and a poly-Fe-based adsorbent were first synthesized and their abilities in adsorbing As from wastewater were investigated in terms of the adsorption density and the rate of adsorption. Here, it should be noted that the main material being used in the synthesis of the poly-Fe-based adsorbent was a waste product, known as polyferric sulfate or poly-Fe in short, which exits the manufacturing process of titanium dioxide.Both adsorbents were then compared in the context of life-cycle assessment (LCA). In other words, the experimental results (i.e. the value of the adsorption density and the rate of adsorption) were input into the LCA model in order to assess the environmental performance of each adsorbent in removing arsenic. An estimate for the environmental burden of each option was finally calculated as the sum of the depletion of abiotic resources (ADP), the global warming potential (GWP), the acidification potential (AP), the photo-oxidant formation potential (POCP), the eutrophication potential (EP), and the human toxicity potential (HTP). The main finding of this study was that the adsorption of arsenic by using the poly-Fe-based adsorbent is more attractive treatment option in the environmental protection point of view than the adsorption by using the FeCl3-based adsorbent, which generates a relatively larger environmental burden. 相似文献
56.
研究了用聚合氯化铝(PAC)、聚合硫酸铁(PFS)、聚丙烯酰胺(PAM)及改性蒙托石等不同无机—有机高分子絮凝剂复配使用处理炼钢厂连铸含油废水的除油效果,考察了不同絮凝剂的复配以及絮凝剂的不同复配比例对处理效果的影响。试验结果表明,用聚合氯化铝(PAC)+聚合硫酸铁(PFS)+聚丙烯酰胺(PAM)3种絮凝剂复配使用除油效果最佳,当3种絮凝剂的复配比为2∶2∶3时除油效果最好,除油率达到88.2%,达到国家排放标准。 相似文献
57.
Richard H. Fuller Robert C Averett 《Journal of the American Water Resources Association》1975,11(5):946-952
ABSTRACT: Copper sulfate has been used extensively in the California Aqueduct to control phytoplankton and the alga Cladophora. Since 1969 more than 250,000 pounds of copper sulfate has been added to a part of the aqueduct. Although copper sulfate is effective in controlling algae, copper tends to accumulate in the system in which it is applied. Samples of water, biota including plants, clams, and snails, as well as sediment were analyzed for copper. Results of these analyses showed that copper concentrations in the water, with three exceptions, were less than 10 micrograms per litre. Samples of plant tissue showed a 198 percent increase in copper concentration in the treated reach of the aqueduct, and clam tissue showed a 68 percent increase. Snails in the treated reach had 77 percent more copper than in the untreated reach whereas copper concentrations in the sediment doubled. None of the concentrations found are considered to be harmful to the biota. 相似文献
58.
A. S. Rogowski 《Journal of the American Water Resources Association》1983,19(6):983-992
ABSTRACT: Large variability of water quality data often makes it difficult to judge whether or not the conditions in an aquifier or a stream are deteriorating or not the conditions in an aquifer or a stream are deteriorating or improving. A technique for separation of variograms into positive and negative difference components is proposed. This technique was applied to water quality data from a requality improved with time on the stripmined and undisturbed areas, declined in a seep and an adjoining stream and remained about the same in the deep mined zone. 相似文献
59.
Yongsung Cho K. William. Easter Laura M.J. McCann Frances Homans 《Journal of the American Water Resources Association》2005,41(3):729-740
ABSTRACT: The concentrations of iron and sulfate in community water supplies are a concern for a number of areas in southwestern Minnesota. This study used the contingent valuation method to determine how much consumers would be willing to pay to improve their drinking water quality. On average, individuals were willing to pay US$5.25 per month (in 1995 U.S. dollars) to reduce the level of iron and US$4.33 per month to reduce the level of sulfate in their water to the USEPA's secondary standards for drinking water quality. Respondents with negative perceptions of their drinking water quality were willing to pay more to improve water quality. The aggregate annual willingness to pay (WTP) for all consumers in community water systems in southwestern Minnesota that were out of compliance with water quality standards were estimated to be US$2.4 million and US$2.0 million (in 1995 dollars) for reducing the levels of iron and sulfate, respectively. Yet the total WTP of consumers who use small community water systems may not be enough to pay the full cost of providing improved water in those systems. Economies of scale in water treatment and difficulties in financing improvements mean that technical innovation, government assistance, or institutional changes may be needed to improve water quality in these areas. 相似文献
60.
ABSTRACT: A study was conducted to elucidate some of the chemical factors affecting the rate and pathways of N transformations in lake sediments. The main emphasis was placed on modifying a noncalcareous sediment with CaCO3 to approximate the composition of a calcareous sediment. Additionally, the effects of Ca2+, CO32-, Mg2+ and OH- were evaluated by using appropriate chemicals. Further, the effect of aluminum sulfate was evaluated with both sediment types. Sediment pH at 7 days was not affected by CaCO3, but was decreased by aluminum sulfate. The CaCO3 treatment increased the rate of ammonification, nitrification, reduction of acetylene to ethylene and methane formation, while with few exceptions the other treatments decreased the rate of the transformations studied. Aluminum sulfate, which has been proposed as a lake restoration treatment, increased ammonification but decreased most of the other transformations. 相似文献