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991.
992.
污水处理中,自动控制系统的运行方式关系到污水处理是否达标的关键,尤其是在运行细节中,运行控制考虑得不周全,往往会影响到污水处理的效果。生物制药污水处理中,设备在运行细节控制方法中的有效解决,保证了出水稳定可靠。 相似文献
993.
Chengrun Wang Kegui Zhang Mei He Chuanjun Jiang Liumin Tian Yuan Tian Xiaorong Wang 《环境科学学报(英文版)》2012,24(2):214-220
Effects of mineral nutrient imbalance, DNA lesion and DNA-protein crosslink on growth of Vicia faba L. seedlings hydroponically cultivated in concentrations of extraneous lanthanum (La) for 20 days were investigated in the present experiment. The results showed that contents of La, Cu or K elements in roots generally changed synchronously with those in leaves, while Ca, Fe, Zn, Mg, Mn or P in the roots altered inversely to those in the leaves. Thus, the extraneous La led to redistribution and imbalance of mineral nutrient elements in the roots and leaves. DNA lesion and DNA-protein crosslink were investigated by single cell gel electrophoresis (SCGE) and sodium dodecyl sulfate/potassium (SDS/K+) precipitation methods, respectively. The results demonstrated that the increasing La induced DNA break and DNA-protein crosslinks (DPCs) in the seedlings. These results suggested that mineral nutrient imbalance, DNA lesion and DNA-protein crosslink were involved in the growth retardation and growth alteration of the seedlings, which may help to understand the mechanisms of rare earth elements (REEs) on plant growth. 相似文献
994.
Flaky and nanospherical birnessite and birnessite-supported Pt catalysts were successfully prepared and characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and N2 adsorption-desorption. Effects of the birnessite morphology and Pt reduction method on the catalytic activity for the complete oxidation of formaldehyde (HCHO) were investigated. It was found that flaky birnessite exhibited higher catalytic activity than nanospherical birnessite. The promoting effect of Pt on the birnessite catalyst indicated that the reduction method of the Pt precursor greatly influenced the catalytic performance. Flaky birnessite-supported Pt nanoparticles reduced by KBH4 showed the highest catalytic activity and could completely oxidize HCHO into CO2 and H2O at 50℃, whereas the sample reduced using H2-plasma showed lower activity for HCHO oxidation. The differences in catalytic activity of these materials were jointly attributed to the effects of pore structure, surface active sites exposed to HCHO and the dispersion of Pt nanoparticles. 相似文献
995.
Manhong Huang Shixuan Tian Donghui Chen Wei Zhang Jun Wu Liang Chen 《环境科学学报(英文版)》2012,24(9):1594-1599
Removal characteristics of sulfamethazine (SMZ) by sludge and a bacterial strain using an aerobic sequence batch reactor (ASBR) were studied. Operating conditions were optimized by varying the reaction time and sludge retention time (SRT). An Achromobacter sp. (S-3) with the ability to remove SMZ was isolated from the ASBR. The effects of different operating parameters (pH and temperature) on the biodegradation of SMZ by S-3 were determined. The results indicate that, between 0.5 and 4 hr, reaction time of the ASBR had a significant effect on the SMZ removal efficiency in the system. The SMZ removal efficiency also increased from 45% to 80% when SRT was prolonged from 5 to 25 days, although longer SRT had no impact on SMZ removal. The SMZ adsorption rate decreased with increasing temperature, which fitted Freundlich isotherm well. The removal of SMZ in the ASBR was due to the combined effects of adsorption and degradation, and degradation played a leading role. 相似文献
996.
997.
The high content of alkali chlorides in municipal solid waste incineration(MSWI) fly ash limit its resource reuse due to the potential environmental risks.In this paper, with superheated steam as the gasifying agent and inducer, chlorides in fly ash were removed by thermal treatment within a moderate temperature range.Thermal treatment experiments were performed under different conditions: temperature(500–800℃), steam addition(mass ratio of steam to fly ash = 0.25–1) and residence time(0.5–3 hr).Iron and aluminum powders were added to fly ash to improve the chlorine removal efficiency.Water-soluble chlorides included Na Cl and KCl, and insoluble chlorides mainly included Ca(OH)Cl.The heating process with the addition of water steam was more efficient than that without steam in terms of the removal performance of water-soluble chlorides.The removal efficiency of soluble chlorides reached 75.25% for a mass ratio of 1:1 after 1-hr thermal treatment at 700℃.When the residence time was increased above 1 hr, the total dechlorination efficiency was not increased dramatically.Moreover, adding iron and aluminum powder into the fly ash improved the removal of water-insoluble chlorides, and the total dechlorination efficiency was increased by 11.41%–16.64%. 相似文献
998.
Yi Li Hua Zhang Zongshan Zhao Yong Tian Kun Liu Feifan Jie Liang Zhu Huanwen Chen 《环境科学学报(英文版)》2018,30(5):287-293
Particulate matters(PMs) emitted by automobile exhaust contribute to a significant fraction of the global PMs. Extractive atmospheric pressure chemical ionization mass spectrometry(EAPCI-MS) was developed to explore the molecular dependence of PMs collected from exhaust gases produced at different vehicle engine speeds. The mass spectral fingerprints of the organic compounds embedded in differentially sized PMs(e.g., 0.22–0.45, 0.45–1.00, 1.00–2.00, 2.00–3.00, 3.00–5.00, and 5.00–10.00 μm) generated at different engine speeds(e.g., 1000, 1500, 2000, 2500, and 3000 r/min) were chemically profiled in the mass range of mass to charge ratio(m/z) 50–800. Organic compounds,including alcohols, aldehydes, and esters, were detected in all the PMs tested, with varied concentration levels for each individual PM sample. At relatively low engine speeds(≤ 1500 r/min), the total amount of organic species embedded in PMs of 0.22–1.00 μm was greater than in PMs of other sizes, while more organic species were found in PMs of5.00–10.00 μm at high engine speeds(≥ 3000 r/min), indicating that the organic compounds distributed in different sizes of PMs strongly correlated with the engine speed. The experimental data showed that the EAPCI-MS technique enables molecular characterization of PMs in exhaust, revealing the chemical dependence of PMs on the engine speeds(i.e., the combustion conditions) of automobiles. 相似文献
999.
Myat Sandar Win Zhengyang Tian Hui Zhao Kai Xiao Jiaxian Peng Yu Shang Minghong Wu Guangli Xiu Senlin Lu Shinich Yonemochi Qingyue Wang 《环境科学学报(英文版)》2018,30(9):13-31
Atmospheric humic-like substances(HULIS) are not only an unresolved mixture of macroorganic compounds but also powerful chelating agents in atmospheric particulate matters(PMs); impacting on both the properties of aerosol particles and health effects by generating reactive oxygen species(ROS). Currently, the interests of HULIS are intensively shifting to the investigations of HULIS-metal synergic effects and kinetics modeling studies, as well as the development of HULIS quantification, findings of possible HULIS sources and generation of ROS from HULIS. In light of HULIS studies, we comprehensively review the current knowledge of isolation and physicochemical characterization of HULIS from atmospheric samples as well as HULIS properties(hygroscopic, surface activity, and colloidal) and possible sources of HULIS.This review mainly highlights the generation of reactive oxygen species(ROS) from PMs, HULIS and transition metals, especially iron. This review also summarized the mechanism of ironorganic complexation and recent findings of OH formation from HULIS-metal complexes. This review will be helpful to carry out the modeling studies that concern with HULIS-transition metals and for further studies in the generation of ROS from HULIS-metal complexes. 相似文献
1000.
对长江中下游 南黄海地震带地震活跃期、幕划分及其发展趋势进行了研究,对江苏及其邻区今后几年的地震大形势及重点危险区进行了判定。分析认为,长南带从1971年以来进入第二活跃期的第3幕,该幕地震活动将持续到2010年前后,最高活动水平为6.5级左右。今后几年江苏东部至南黄海海域发生5~6级或6级以上地震的可能性较大。 相似文献