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171.
以煤矸石为原料,采用碱熔后水热合成法制备X型分子筛并进行XRD、SEM、BET和Zeta电位分析。研究其对水中Co2+、Cu2+、Cd2+和Cr3+4种离子的吸附性能,包括吸附等温线、吸附动力学以及初始金属离子浓度、pH值对吸附性能的影响。所合成的矸石基X型分子筛的BET比表面积为676.02 m2/g,微孔孔容为0.263 cm3/g。吸附实验表明,矸石基X型分子筛能有效去除上述4种离子,同时实现煤矸石的资源化和金属离子的去除。4种离子的平衡吸附量均随初始浓度的增大而增大,相同条件下平衡吸附量的大小顺序为Cd2+>Cr3+>Cu2+>Co2+。准二级动力学模型能很好地描述4种离子的吸附动力行为。Langmuir模型对Co2+、Cu2+和Cd2+吸附的拟合较Freundlich模型高,说明其主要表现为物理吸附过程。4种离子的吸附速率均由液膜扩散和颗粒内扩散共同控制。 相似文献
172.
水葱修复土壤镉污染潜力的研究 总被引:10,自引:1,他引:10
野外观察与研究发现水葱(Scirpus tabernaemontani G.)可以耐受土壤中高浓度的重金属污染,并对镉(Cd)有很高的生物富集量.实验室水培试验研究了两个主要因素,营养液pH与Cd含量,对水葱生物量以及Cd富集效果的影响.结果表明,它可耐受高浓度Cd (30 mg/L)和大范围pH变化 (3.7~7.7).当营养液pH为4.7, Cd为25 mg/L时,水葱富集的Cd达到最大值:地上部分264.71 mg/kg,地下部分234.39 mg/kg,平均转运系数1.13.这显示了它用于植物修复Cd污染土壤的潜力. 相似文献
173.
Screening 31 endocrine-disrupting pesticides in water and surface sediment samples from Beijing Guanting reservoir 总被引:13,自引:0,他引:13
For screening 31 potential or suspected endocrine-disrupting pesticides in water and surface sediments, a multiresidue analysis method based on gas chromatography with electron capture detection (GC/ECD) was developed. Solid phase extraction (SPE) technology with Oasis® HLB cartridge was also applied in sample extraction. The relevant mean recoveries were 70–103% and 71–103% for water and sediment, respectively. Relative standard deviations (RSD) are 2.0–7.0%, 4.0–8.0% for water and sediment, respectively. Thirty one pesticides (-HCH, β-HCH, γ-HCH, δ-HCH, hexachlorobenzene (HCB), aldrin, heptachlor, endosulfan I & II, p,p′-DDD, o,p′-DDT, p,p′-DDT, p,p′-DDE, endrin aldehyde, endosulfan sulphate, methoxychlor, hepachlor epoxide, -chlordane, γ-chlordane, dieldrin, endrin, dicofol, acetochlor, alachlor, metolachlor, chlorpyriphos, nitrofen, trifluralin, cypermethrin, fenvalerate, deltamethrin) in water and surface sediment samples from Beijing Guanting reservoir were analyzed. Concentrations of pesticides ranged from 7.59 to 36.0 ng g−1 on a dry wt. basis for sediment samples, from 279.3 to 2740 ng l−1 for pore waters and from 48.8 to 890 ng l−1 for water samples, respectively, with a mean concentration of 10.7 ng g−1 in sediment, 735 ng l−1 in pore water and 295 ng l−1 in water, respectively. The data obtained provides information on the levels and sources of endocrine-disrupting pesticides in Guanting reservoir. These results underscore the need to improved environmental protection measures in order to reduce the exposure of the population and aquatic biota to these endocrine-disrupting compounds. 相似文献
174.
Fate and transformation of naphthylaminesulfonic azo dye Reactive Black 5 during wastewater treatment process 总被引:1,自引:0,他引:1
Xingzu Wang Xiang Cheng Dezhi Sun Yiwei Ren Guihua Xu 《Environmental science and pollution research international》2014,21(8):5713-5723
Certain aromatic amines generated by the decolorization of some azo dyes are not removed substantially by conventional anaerobic–aerobic biotreatment. These aromatic amines are potentially toxic and often released in the wastewater of industrial plants. In this study, the fate and transformation of the naphthylaminesulfonic azo dye Reactive Black 5 (RB5) during different phases of a sequencing batch reactor were investigated. The major products of RB5 decolorization during the anaerobic phase include 2-[(4-aminophenyl)sulfonyl]ethyl hydrogen sulfate (APSEHS) and 1-2-7-triamino-8-hydroxy-3-6-naphthalinedisulfate (TAHNDS). During the aerobic phase, APSEHS was hydrolyzed and produced 4-aminobenzenesulfonic acid, which was further degraded via dearomatization. TAHNDS was transformed rapidly via auto-oxidation into TAHNDSDP-1 and TAHNDSDP-2, which were not further removed by the activated sludge during the entire 30-day aerobic phase. In contrast, different behaviors of TAHNDS were observed during the anoxic phase. The transformation of TAHNDS was initiated either by deamination or desulfonation reaction. TAHNDS was then converted into 3,5-diamino-4-hydroxynaphthalene-2-sulfonic acid, which was subsequently removed via ring cleavage reaction under aerobic condition. In conclusion, complete degradation of TAHNDS by activated sludge occurs only during anoxic/aerobic processes instead of the conventional anaerobic/aerobic processes. 相似文献
175.
Haiming Wu Jufeng Liu Jian Zhang Cong Li Jinlin Fan Xiaoli Xu 《Environmental science and pollution research international》2014,21(2):1071-1078
Understanding oxygen release by plants is important to the design of constructed wetlands for wastewater treatment. Lab-scale systems planted with Phragmites australis were studied to evaluate the amount of oxygen release by plants using electrode techniques and oxygen consumption model. Oxygen release rate (0.14 g O2/m2/day) measured using electrode techniques was much lower than that (3.94–25.20 gO2/m2/day) calculated using the oxygen consumption model. The results revealed that oxygen release by plants was significantly influenced by the oxygen demand for the degradation of pollutants, and the oxygen release rate increased with the rising of the concentration of degradable materials in the solution. The summary of the methods in qualifying oxygen release by wetland plants demonstrated that variations existed among different measuring methods and even in the same measuring approach. The results would be helpful for understanding the contribution of plants in constructed wetlands toward actual wastewater treatment. 相似文献
176.
Photocatalytic oxidation of heptane in the gas-phase over TiO2. 总被引:6,自引:0,他引:6
In this paper, gas-phase photocatalytic oxidation (PCO) of heptane over UV-illuminated TiO2 was carried out at ambient temperature in a batch reactor. Complete oxidation of heptane with almost stoichiometric production of CO2 and H2O was observed. The intermediates detected were propanal, butanal, 3-heptanone, 4-heptanone and carbon monoxide. A scheme of the possible mechanism for PCO of heptane over TiO2 was suggested. Langmuir-Hinshelwood kinetics equation was obtained from the results at different initial concentrations of heptane, oxygen, moisture and light intensity. The photocatalytic activity of TiO2 can be sustained indefinitely. This can be attributed to the production of water in the system, which can replenish the consumed hydroxyl radicals. 相似文献
177.
城市河流水质常规评价技术研究 总被引:11,自引:0,他引:11
运用综合水质标识指数法,对我国河流水质评价面临的关键技术问题,包括水质评价方法、水质评价项目,水质级别评价,水环境功能区达标评价、水质定性评价、河流及水系整体水质比较、水质随时间和空间变化等作了明确界定,并介绍了在上海河流水质评价中的应用。 相似文献
178.
179.
以高压汞灯为光源 ,采用浸涂 -烧结法制备的负载型纳米TiO2 作为光催化剂 ,通过对水中微量溶解性间二甲苯的光催化氧化过程的研究表明 ,初始浓度在 6 .6 8— 17.36mg/L的范围内 ,间二甲苯的光催化反应遵循表观一级反应动力学规律 ,反应的表观速率常数随溶液初始浓度的增大而减小 ,半衰期则随初始浓度的增大而增加 ,经 1.5h反应后 ,溶液中间二甲苯的去除率从 17.36mg/L的 5 4 .4 4 %增加到 6 .6 8mg/L的 75 .90 %。 相似文献
180.
模拟煤灰渣垂直潜流人工湿地的除磷性能分析 总被引:10,自引:0,他引:10
为确定煤灰渣作为垂直潜流人工湿地基质的可行性,通过静态吸附实验和煤灰渣去除生活污水中的磷素实验,表明煤灰渣对污水中磷素的吸附平衡时间较短,吸附速率较快.当温度降低时,煤灰渣的磷素吸附容量对吸附平衡浓度依赖性和吸附强度随之降低,最大理论吸附容量亦降低 83.10% .在处理0.5 m 3 /(m2·d)的生活污水中,煤灰渣对TP的平均去除率达86.03%,吸附方式包括物理吸附和化学吸附,同时得出煤灰渣最大磷素解析量占最大理论吸附容量的0.73%,在实际人工湿地应用中应注意磷素解析而形成的二次污染. 相似文献