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671.
研究了位于北京郊区的北运河中游9个断面的沉积物对磷的吸附行为,分析了沉积物组成及其理化性质与磷吸附特征的关系.实验结果表明,不同断面沉积物对磷的最大吸附量在0.11 ~9.45 mg/g之间,而各断面沉积物的临界平衡磷浓度(EPC0)范围在0.33~ 1.85 mg/L之间,统计分析显示EPC0与河水中的总磷和可溶性无机磷呈显著负相关,但与沉积物中的金属和有机质含量相关性较差;根据临界平衡磷浓度定义的推断,新华大街桥、玉带桥、运河大街桥、六环路桥、宋梁路桥、湿地和甘棠橡胶坝7个断面的沉积物表现为磷的“汇”,而丰子沟和减运沟2个点表现为磷的“源”,并且各点沉积物释放和吸附磷的趋势较大. 相似文献
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673.
Sulfur-containing amino acid methionine as the precursor of volatile organic sulfur compounds in algea-induced black bloom 总被引:2,自引:0,他引:2
After the application of methionine, a progressive and significant increase occurred in five volatile organic sulfur compounds (VOSCs): methanethiol (MeSH), dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS) and dimethyl tetrasulfide (DMTeS). Even in the untreated control without a methionine addition, methionine and its catabolites (VOSCs, mainly DMDS) were found in considerable amounts that were high enough to account for the water’s offensive odor. However, blackening only occurred in two methionine-amended treatments. The VOSCs production was observed to precede black color development, and the reaching of a peak value for total VOSCs was often followed by water blackening. The presence of glucose stimulated the degradation of methionine while postponing the occurrence of the black color and inhibiting the production of VOSCs. In addition, DMDS was found to be the most abundant species produced after the addition of methionine alone, and DMTeS appeared to be the most important compound produced after the addition of methionine+glucose. These results suggest that methionine acted as an important precursor of the VOSCs in lakes suffering from algea-induced black bloom. The existence of glucose may change the transformation pathway of methionine into VOSCs to form larger molecular weight compounds, such as DMTS and DMTeS. 相似文献
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676.
Comparison of quartz sand, anthracite, shale and biological ceramsite for adsorptive removal of phosphorus from aqueous solution 总被引:1,自引:0,他引:1
The choice of substrates with high phosphorus adsorption capacity is vital for sustainable phosphorus removal from waste water in constructed wetlands. In this study, four substrates were used: quartz sand, anthracite, shale and biological ceramsite. These substrate samples were characterized by X- ray diffractometry and scanning electron microscopy studies for their mineral components (chemical components) and surface characteristics. The dynamic experimental results revealed the following ranking order for total phosphorus (TP) removal efficiency: anthracite 〉 biological ceramsite 〉 shale 〉 quartz sand. The adsorptive removal capacities for TP using anthracite, biological ceramsite, shale and quartz sand were 85.87, 81.44, 59.65, and 55.98 mg/kg, respectively. Phosphorus desorption was also studied to analyze the substrates' adsorption efficiency in wastewater treatment as well as the substrates' ability to be reused for treatment. It was noted that the removal performance for the different forms of phosphorus was dependent on the nature of the substrate and the adsorption mechanism. A comparative analysis showed that the removal of particulate phosphorus was much easier using shale. Whereas anthracite had the highest soluble reactive phosphorus (SRP) adsorptive capacity, biological ceramsite had the highest dissolved organic phosphorus (DOP) removal capacity. Phosphorus removal by shale and biological ceramsite was mainly through chemical adsorption, precipitation or biological adsorption. On the other hand, phosphorus removal through physical adsorption (electrostatic attraction or ion exchange) was dominant in anthracite and quartz sand. 相似文献
677.
Shaofeng Wang Yongfeng Ji Shuying Wang Xin Wang He Wang Zhixi Zhao Bingzhu Liu 《环境科学学报(英文版)》2010,22(1):23-31
This work investigated the distribution and speciation of Cd, Cu, Pb, Fe and Mn in the shallow sediments of Jinzhou Bay, Northeast China, which has been heavily contaminated by nonferrous smelting activities. The concentrations of Cd, Cu and Pb in sediments were found to be 100, 13 and 7 times, respectively, being higher than the national guideline (GB 18668-2002). Sequential extraction test showed that 39%-61% of Cd were exchangeable fractions, indicating that Cd in the sediments posed a high risk to local... 相似文献
678.
铁铜双金属有机骨架MIL-101(Fe,Cu)活化双氧水降解染料性能 总被引:1,自引:0,他引:1
针对非均相芬顿传质效率低和Fe(Ⅲ)Fe(Ⅱ)转化慢导致活性低等问题,采用溶剂热法制备铁铜双金属有机骨架材料[MIL-101(Fe,Cu)],并研究了材料界面性质、催化降解染料(亚甲基蓝)性能以及活化催化机制.结果表明,MIL-101(Fe,Cu)晶体结构完整且呈三维八面体形状;比表面积和平均孔径分别为667.2 m2 ·g-1和1.9 nm,可充分暴露反应活性位点.MIL-101(Fe,Cu)在广谱pH范围可活化H2 O2高效降解亚甲基蓝.当pH=5、反应20 min,MIL-101(Fe,Cu)/H2 O2对20 mg ·L-1亚甲基蓝的去除率为100%,较MIL-101(Fe)/H2O2和单独H2 O2分别提高43.1%和88.9%.自由基猝灭实验与反应前后铁和铜价态变化结果表明,羟基自由基(·OH)是MIL-101(Fe,Cu)/H2 O2催化降解亚甲基蓝的主要活性物种;Cu(Ⅱ)掺杂引入新的活性位点,且Cu(Ⅱ)/Cu(Ⅰ)循环和Fe(Ⅲ)/Fe(Ⅱ)循环可协同产生·OH,进而提高催化效率.MIL-101(Fe,Cu)作为新型非均相类芬顿催化剂,无需复杂pH调节即可获得良好催化效果,在工业废水处理上具有较好地应用前景. 相似文献
679.
用缺氧生物滤池与UASB相串联的工艺对杭州市天子岭垃圾填埋场惨滤液进行了中试试验。通过实验,总结了缺氧生物滤池的挂膜特性及UASB起动的成功经验。最终的试验结果表明:出水COD、BOD、SS分别稳定在900mg/L、150mg/L、250mg/L以下,缺氧生物滤池对渗滤液具有很好的预处理效果,不仅能脱吸部分NH3、CO2、H2S,而且能提高它的可生化性,为UASB的高效运行创造了良好的条件。 相似文献
680.
Dan Yao Guiqian Tang Jie Sun Yinghong Wang Yuan Yang Yiming Wang Baoxian Liu Hong He Yuesi Wang 《环境科学学报(英文版)》2022,34(2):210-217
High loads of ground-level ozone have occurred with the implementation of the Air Pollution Prevention and Control Action Plan. However, the long temporal variation in precursor nonmethane hydrocarbons(NMHCs) has rarely been studied. In this study, we examined the evolution of NMHCs in Beijing based on ambient measurements from 2000 to 2019. The results indicated that the annual variation of ambient NMHCs during 2000 and 2019 could be divided into two stages. The mixing ratios of NMHCs rapidly r... 相似文献