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341.
为探讨纳米Fe0粒子对产乙烯脱卤菌群脱氯性能和物种多样性的影响,采用纳米Fe0粒子与产乙烯脱卤菌群联合脱氯,并通过气相色谱、PCR-DGGE和TEM等技术手段进行相关表征.结果表明:当纳米Fe0粒子浓度为0~0.50 g·L-1时,体系的脱氯速率提高较小,低于40%,且菌种数量无明显变化;当其浓度为0.50~1.00 g·L-1时,体系的脱氯速率由0.31μmol·h-1提高到0.77μmol·h-1,体系的脱氯速率提高了60%,部分DGGE条带消失,多样性减少.TEM结果显示,产乙烯脱卤拟球菌在与纳米Fe0粒子接触部位有轻度破损,但细胞没有破裂.纳米Fe0粒子浓度较高时对产乙烯脱卤菌群的脱氯有明显的促进作用,但会使产乙烯脱卤菌群物种多样性减少. 相似文献
342.
钙、氯对磷酸盐稳定污染土壤中铅的促进作用研究 总被引:1,自引:0,他引:1
为探讨促进磷酸盐稳定污染土壤中铅的方法,在全铅含量为517 mg·kg-1的铅冶炼污染土壤中加入5 mmol·kg-1磷酸盐,同时加入10mmol·kg-1硝酸钙或5 mmol·kg-1氯化钾,在15%或30%的含水率下培养40 d,之后种植黑麦草.结果表明,与单独施用磷酸盐相比,采用磷酸盐与钙、氯结合或增加培养期间的土壤含水率后,土壤DTPA-Pb含量下降3.92%~26.1%;对于同一添加剂处理,培养期间土壤含水率从15%增加到30%,土壤有效铅(DTPA-Pb)含量下降8.83%~24.4%.增加土壤含水率后,土壤有效磷(Olsen-P)含量均显著升高(p0.05).土壤铅的EXAFS分析表明,与未施用磷酸盐的对照相比,土壤中加入磷酸盐后矿物态铅的比例由57%上升至81%,加施钙、氯或增加土壤含水率后,多数处理矿物态铅的比例有所下降,而有机结合态铅比例上升.与对照相比,污染土壤中施用磷酸盐后,植物产量大幅增加,但施用钙、氯或增加培养期间含水率后,部分处理植物产量有所下降.以上结果表明,在铅冶炼污染土壤中加入磷酸盐时,加入钙、氯或者增加土壤含水率均有利于铅的稳定,但以上措施可能对植物生长产生不利影响. 相似文献
343.
For phosphorus (P) recovery from wastewater, the effect of humic substances (HS) on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate (as P) and 20 mg/L HS (as dissolved organic carbon, DOC) at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium (Ca) and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction (XRD) and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0, the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite (HAP) by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate. 相似文献
344.
Zihao Li Yang Geng Lei Ma Xiaoyin Chen Junhua Li Huazhen Chang Johannes W. Schwank 《Frontiers of Environmental Science & Engineering》2020,14(4):65
345.
Romário J. da Silv Lizeth Carolina Mojica-Sánchez Filipe D.S. Gorz Graciela C. Pedro Bruna G. Maciel Gabriela P. Ratkovski Hérica D. da Roch Kamila T.O. do Nascimento Juan C. Medina-Llamas Alicia E. Chávez-Guajardo José J. Alcaraz-Espinoz Celso P. de Melo 《环境科学学报(英文版)》2021,33(2):62-73
We report the preparation of poly(3,4-ethylene dioxythiophene) (PEDOT)-modified polyvinylidene fluoride electrospun fibers and their use as a novel adsorbent material for the removal of the anionic dye Methyl Orange (MO) from aqueous media. This novel adsorbent material can be used to selectively remove MO on a wide pH range (3.0–10.0), with a maximum capacity of 143.8 mg/g at pH 3.0. When used in a recirculating filtration system, the maximum absorption capacity was reached in a shorter time (20 min) than that observed for batch mode experiments (360 min). Based on the analyses of the kinetics and adsorption isotherm data, one can conclude that the predominant mechanism of interaction between the membrane and the dissolved dye molecules is electrostatic. Besides, considering the estimated values for the Gibbs energy, and entropy and enthalpy changes, it was established that the adsorption process is spontaneous and occurs in an endothermic manner. The good mechanical and environmental stability of these membranes allowed their use in at least 20 consecutive adsorption/desorption cycles, without significant loss of their characteristics. We suggest that the physical-chemical characteristics of PEDOT make these hybrid mats a promising adsorbent material for use in water remediation protocols and effluent treatment systems. 相似文献
346.
Yifei Wang Wending Pan Kee Wah Leong Yingguang Zhang Xiaolong Zhao Shijing Luo Dennis Y.C.Leung 《绿色能源与环境(英文)》2023,(5):1380-1388
Low-cost, flexible and safe battery technology is the key to the widespread usage of wearable electronics, among which the aqueous Al ion battery with water-in-salt electrolyte is a promising candidate. In this work, a flexible aqueous Al ion battery is developed using cellulose paper as substrate. The water-in-salt electrolyte is stored inside the paper, while the electrodes are either printed or attached on the paper surface,leading to a lightweight and thin-film battery prototype. Currently, ... 相似文献
347.
Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene (PS) bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as "purge and trap" and analysed by gas chromatograph-mass spectrometer (GC/MS). Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 μg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 μg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks. 相似文献
348.
Paul A.Steenhof 《中国人口.资源与环境(英文版)》2005,3(2)
1 INTRODUCTIONEnergy and environmental issues in China have receivedsignificant attention in both the peer-reviewed literatureand in international energy and environmental policymaking in the last number of years. China's coal dominatedenergy consumption results in significant regional pollutionproblems, most notably acid rain that affects nearly 1/3rdof China's landmass and air pollution that plagues manyof its major cities. China now ranks as the top emitterof sulphur dioxide (SO2) pol… 相似文献
349.
Profile of Methane Concentrations in Soil and Atmosphere in Alpine Steppe Ecosystem on Tibetan Plateau 总被引:1,自引:1,他引:0
Pei Zhiyong Ouyang Hua Zhou Caiping Xu Xingliang . The Administrative Center for China’s Agenda Beijing China . Interntional Center for Integrated Mountain Development Kathm a Nepal . Institute of Geographical Sciences Natural Resources Research CAS Beijing 《中国人口.资源与环境(英文版)》2009,7(1):3-10
The methane concentration profile from -1.5m depth in soil to 32m height in air was measured in alpine steppe located in the permafrost area. Methane concentrations showed widely variations both in air and in soil during the study period. The mean concentrations in atmosphere were all higher than those in soil, and the highest methane concentration was found in air at the height of 16m with the lowest concentration occurring at the depth of 1.5m in soil. The variations of atmospheric methane concentrations did not show any clear pattern both temporally and spatially, although they exhibited a more steadystable state than those in soil. During the seasonal variations, the methane concentrations at different depths in soil were significantly correlated (R^2〉0.6) with each other comparing to the weak correlations (R^2〈0.2) between the atmospheric concentra- tions at different heights. Mean methane concentrations in soil significantly decreased with depth. This was the compositive influence of the decreasing production rates and the increasing methane oxidation rates, which was caused by the descent soil moisture with depth. Although the methane concentrations at all depths varied widely during the growing season, they showed very distinct temporal variations in the non-growing season. It was indicated from the literatures that methane oxidation rates were positively correlated with soil temperature. The higher methane concentrations in soil during the winter were determined by the lower methane oxidation rates with decreasing soil temperatures, whereas methane production rates had no reaction to the lower temperature. Relations between methane contribution and other environmental factors were not discussed in this paper for lacking of data, which impulse us to carry out further and more detailed studies in this unique area. 相似文献
350.
大型相连容器中火焰传播的研究 总被引:1,自引:1,他引:0
为了进一步了解相连装置中粉尘爆炸的火焰传播行为和压力发展,为该结构的安全防护设计提供有价值的信息,采用大型实验装置对相连容器中玉米淀粉/空气混合物爆炸时的火焰传播行为进行了实验研究,同时采用已开发的数值模型对实验进行仿真计算。实验表明:粉尘浓度的变化对粉尘爆炸的火焰传播行为有重要影响;在粉尘浓度很低的情况下,火焰仍然能够在管道中加速传播且爆炸发展的最终结果相当猛烈。数值模型采用欧拉-拉格朗日方法模拟两相流现象,通过求解非稳态的湍流两相反应流守恒方程对实验进行二维仿真,计算结果与实验结果符合性较好,表明该模型可以很好地应用于粉尘爆炸火焰传播的研究。 相似文献