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排序方式: 共有2223条查询结果,搜索用时 15 毫秒
61.
Effect of pH on phosphine production and the fate of phosphorus during anaerobic process with granular sludge 总被引:6,自引:0,他引:6
The effect of pH on phosphine formation during anaerobic cultivation of granular sludge was investigated. The sludge was taken from full-scale anaerobic reactors treating brewery wastewater. Acetate and phosphate were used as the carbon source and phosphorus source respectively. After 10 days cultivation in the dark, results showed that acidic conditions were more favorable for free phosphine production. At pH 5, the optimum concentration 86.42 ng PH3 m-3 of free phosphine was obtained. The level at pH 7 was reduced to 18.53 ng PH3 m-3, about 1/5 of the maximum. The maximum concentration of matrix-bound phosphine of 3.30 ng PH3 kg-1 wet sludge was achieved at pH 6. More than 83% of the total phosphine was matrix-bound phosphine, which accounted for 0.003-0.009 per thousand of the phosphate removal, while free phosphine comprised 0.00002-0.001 per thousand of the phosphate removal. Most of the phosphorus removal from solution was turned into chemical precipitation or was adsorbed by sludge. The mechanism of the phosphate reduction-step in the formation of phosphine production is still unknown. The promotion of phosphine formation by low pH is compatible with an acidic bio-corrosion mechanism of metal particles in the sludge or of metal phosphides which form phosphine at low pH. 相似文献
62.
不同粒径泥沙理化特性对磷吸附过程的影响 总被引:1,自引:0,他引:1
以北京大兴南海子湖表层沉积物为研究对象,测试分析了0.147~0.246 mm(细砂)、0.074~0.147 mm(极细砂)、0.0385~0.0740 mm(粉粒)和<0.0385 mm(粉粒粘粒混合物)4种粒径泥沙对磷的吸附行为,并采用相关分析及逐步回归分析探讨不同粒径沉积物中有机质(OM)、Fe、Al、Ca、Mn和TP含量对磷吸附过程的影响。结果表明,二级动力学方程和Langmuir模型能较好地描述南海子不同粒径泥沙的吸附动力学及等温吸附过程(R2>0.90)。粒径对单位质量泥沙吸附磷量具有明显影响,粉粒粘粒混合物>粉粒>细砂>极细砂。总体上,泥沙有机质(OM)、TP、Fe、Al、Ca和Mn含量随粒径的减小而增大,且粘粒对其影响较大。不同粒径泥沙(OM)、Fe、Al、Ca和Mn含量之间存在极显著正相关关系(P<0.01),且均对单位质量泥沙最大吸附量(Xm)和饱和吸附量(Cse)具有正效应,其中Al含量对该参数的影响更为显著。这说明泥沙对磷的吸附行为可能受到粒径和化学成分的共同影响。 相似文献
63.
Shi-Ling Ding Xi-Kui Wang Wen-Qiang Jiang Xia Meng Ru-Song Zhao Chen Wang Xia Wang 《Environmental science and pollution research international》2013,20(5):3195-3201
This work aimed to investigate the effectiveness of ultraviolet (UV) radiation on the degradation of the antimicrobial triclocarban (TCC). We investigated the effects of several operational parameters, including solution pH, initial TCC concentration, photocatalyst TiO2 loading, presence of natural organic matter, and most common anions in surface waters (e.g., bicarbonate, nitrate, and sulfate). The results showed that UV radiation was very effective for TCC photodegradation and that the photolysis followed pseudo-first-order kinetics. The TCC photolysis rate was pH dependent and favored at high pH. A higher TCC photolysis rate was observed by direct photolysis than TiO2 photocatalysis. The presence of the inorganic ions bicarbonate, nitrate, and sulfate hindered TCC photolysis. Negative effects on TCC photolysis were also observed by the addition of humic acid due to competitive UV absorbance. The main degradation products of TCC were tentatively identified by gas chromatograph with mass spectrometer, and a possible degradation pathway of TCC was also proposed. 相似文献
64.
65.
在人工配制的污水中投入一定量的基质,不同条件下振荡培养,评价沸石、炉渣和陶瓷滤料3种基质在不同因素影响下对氨氮(NH4+-N)和总磷(TP)的吸附能力。结果表明,不同吸附时间时,沸石对NH4+-N的吸附效果最好,陶瓷滤料对TP的吸附效果最好;进水浓度对沸石吸附NH4+-N的影响较大,其吸附量随进水浓度的增大而增大,进水浓度对炉渣和陶瓷滤料吸附NH4+-N及炉渣吸附TP影响不大;3种基质对NH4+-N和TP的吸附量均是随吸附剂量的增加而降低,要达到较好的去污效果,应根据实验结果考虑基质投入量;pH值对沸石吸附NH4+-N影响显著,pH值6~7范围内吸附效果最好,pH值8~12的碱性条件有利于基质对TP的吸附。 相似文献
66.
The nitrous oxide emissions were measured at three tundra sites and one snowpack on the Fildes Peninsula in the maritime Antarctic in the summertime of 2002. The average fluxes at two normal tundra sites were 1.1 ± 2.2 and 0.6 ± 1.7 μg N2O m−2 h−1, respectively. The average flux from tundra soil site with penguin dropping addition was 3.7 ± 2.0 μg N2O m−2 h−1, 3–6 times those from the normal tundra soils, suggesting that the deposition of fresh droppings enhanced N2O emissions during penguin breeding period. The summer precipitation had an important effect on N2O emissions; the flux decreased when heavy precipitation occurred. The diurnal cycle of the N2O fluxes from Antarctic tundra soils was not obtained due to local fluky weather conditions. The N2O fluxes through four snowpack sites were obtained by the vertical N2O concentration gradient and their average fluxes were 0.94, 1.36, 0.81 and 0.85 μg N2O m−2 h−1, respectively. The tundra soils under snowpack emitted N2O in the maritime Antarctic and increased local atmospheric N2O concentrations; therefore these fluxes could constitute an important part of the annual N2O budget for Antarctic tundra ecosystem. 相似文献
67.
Occurrence and behavior of wastewater indicators in the Santa Ana River and the underlying aquifers.
The occurrence and behavior of wastewater indicator compounds in the Santa Ana River (SAR) water and the underlying aquifer recharged by the SAR has been studied. The SAR contains a high proportion of tertiary treated wastewater effluents, up to 100% during summer and fall. The following water quality parameters were quantified: four specific wastewater indicator compounds, ethylene diaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), a naphthalene dicarboxylate (NDC) isomer, alkylphenol polyethoxy carboxylates (APECs), and selected haloacetic acids (HAAs), nitrate, dissolved oxygen (DO), DOC, total carbohydrate, and phenolic substances. Statistical analysis indicated that normal distribution was adequate to describe the probability distribution of the constituents in most cases. In the river, the concentrations of wastewater indicator compounds decreased as the fraction of storm runoff increased. EDTA and NDC were detected in a monitoring well near the river and in two production wells 1.8 and 2.7 km down gradient with little apparent attenuation. By contrast, NTA, APECs, bromochloro- and dibromoacetic acids appeared to be attenuated significantly during infiltration of river water and groundwater transport. 相似文献
68.
研制了一种新型有害物质环境测试组合舱,该测试舱由舱体系(内舱和外舱)、恒温恒湿空气处理系统、空气循环装置和信号控制与处理软件组成。该测试舱具有可分别使用内舱和外舱对样品进行测试的特点,并采用美国FLUNT公司开发的air pack软件包对内舱和外舱的气流进行模拟与计算,并划分出内舱的层流区域,同时也对舱体系的性能进行了测试与评价。结果表明,有害物质环境测试组合舱的温湿度的相对标准偏差分别为0.04℃和0.7%,混合性达到90.7%。因此,该有害物质环境测试组合舱对温湿度控制精准,气流稳定,混合性能良好,能为室内空气污染研究提供条件稳定的室内仿真环境。 相似文献
69.
70.
水溶性巯基壳聚糖对污染土壤吸附态汞的解吸作用研究 总被引:1,自引:0,他引:1
用两种巯基化试剂半胱氨酸(Cys)和硫代乙醇酸(Thi)与壳聚糖(CTS)反应,制备了两种水溶性巯基壳聚糖,即Cys-CTS和Thi-CTS,对比研究了这两种巯基壳聚糖与CTS对被染毒土壤中吸附态汞的提取能力.结果表明,Thi-CTS在pH=3、质量浓度为0.5g/L、用量为20 mL的条件下.对汞的提取率为59.44%,相同条件下CTS和cys-CTS对汞的最高提取率只有31.81%和10.15%. 相似文献