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891.
Wenjuan Han Guiying Luo Bin Luo Chenchen Yu Hai Wang Jie Chang Ying Ge 《环境科学学报(英文版)》2019,31(3):229-237
Wastewater with relatively high nitrogen concentrations is a major source of nitrous oxide (N2O) and methane (CH4) emissions and exerts multiple stresses on the environment. Studies have shown that plant diversity plays an important role in ecosystem functioning. However, the effects of plant species diversity on CH4 and N2O emissions under high ammonium (NH4+-N) loading rates remain unclear. In this study, a microcosm experiment simulating vertical constructed wetlands supplied with high NH4+-N water levels was established. The treatments included four species richness levels (1, 2, 3, 4) and 15 species compositions. There was no significant relationship between species richness and N2O emissions. However, N2O emissions were significantly reduced by specific plant species composition. Notably, the communities with the presence of Rumex japonicus L. reduced N2O emissions by 62% compared to communities without this species. This reduction in N2O emissions may have been a result of decreased N concentrations and increased plant biomass. CH4 emissions did not respond to plant species richness or species identity. Overall, plant species identity surpassed species richness in lowering N2O emissions from constructed wetlands with high NH4+-N water. The results also suggest that communities with R. japonicus could achieve higher N removal and lower greenhouse gas emissions than other wetland species. 相似文献
892.
电化学高级氧化技术是处理有机染料废水的有效技术方法之一,但其应用受传统贵金属电极成本高、易毒化失活等缺陷的限制.本研究采用廉价易得的石墨粉材料,制备氧化石墨烯(GO)催化剂,用于活性黑5(RBk5)染料废水的电催化氧化降解研究.利用透射电子显微镜、X射线光电子能谱、红外光谱、拉曼光谱、循环伏安法和电化学阻抗谱分析材料的结构特性及电化学性能.结果显示,氧化石墨烯具有较高的电子迁移速率,良好的亲水性和电催化活性.不同的RBk5浓度、外加电流、电解质、初始pH值等条件对RBk5的降解效率也有一定程度的影响.其中,电解质因素对材料性能影响最为显著.在RBk5浓度为10mg/L、外加电流为20mA、反应时间为35min、电解质为NaCl的条件下,电催化降解效率可以达到100%. 相似文献
893.
张铁 《安全.健康和环境》2014,14(8):33-36
根据烟气脱硝装置工艺特点,利用臭氧腐蚀性测试装置,开展了金属材质的腐蚀性研究。通过扫面电镜对不同材质腐蚀前后的表面形貌进行表征,确定了臭氧对不同材质的腐蚀特性,通过理论计算确定了臭氧分解的绝热温升。结合脱硝装置工艺特点对氧气管道流速控制方面进行了分析和总结,根据分析结果给出了建议。 相似文献
894.
改性聚合硫酸铁的絮凝特性及其应用 总被引:15,自引:0,他引:15
本文较详细地介绍了改性聚合硫酸铁的絮凝机理、净水性能、质量指标、应用范畴及其注意事项,并使用珠江水对几种主要的无机高分子絮凝剂进行了性能测试,结果表明,改性聚合硫酸铁的生产成本最低,净水效果却最显著. 相似文献
895.
二氧化锰体系中环丙沙星的氧化转化研究 总被引:1,自引:0,他引:1
为了更全面的了解环丙沙星在自然界中的环境化学行为,采用批处理实验方法研究了环丙沙星在二氧化锰作用下的氧化转化过程,并讨论了溶液的pH对反应的影响。结果表明,在无二氧化锰的条件下,环丙沙星的质量浓度在1周内检测没有明显的变化。在二氧化锰存在的条件下,环丙沙星对二氧化锰的氧化作用具有较强的反应感受性。pH一定的条件下,当环丙沙星相对过量时,环丙沙星去除率随自身质量浓度的增大而减小,随二氧化锰质量浓度的增大而增大。此外,随着溶液pH值由3.5升至5.9时,环丙沙星的去除率显著上升。 相似文献
896.
897.
La2O3—ZrO2缺陷萤石型燃烧催化剂的制备 总被引:7,自引:0,他引:7
缺陷萤石型La2O3-ZrO2固溶体的催化燃烧活性受制备条件的影响,本文通过对其共沉淀前体的表面结构和热分解过程的分析,发现共沸蒸馏的办法可以有效地控制前体表面羟基的缩合过程,减少团聚,保持前体中金属离子均匀分散,为生成缺陷有序的烧结石型的La2Zr2O7复氧化物提供了可能。复合氧化物固溶体的表面阳离子配置情况与样品的催化氧化性能密切相关,软团聚前体的烧结产物对甲烷燃烧反应具有更高的催化活性。 相似文献
898.
Wei Meng Yuan LuVictor H. Carreto-Vazquez Qingsheng Wang M. Sam Mannan 《Journal of Loss Prevention in the Process Industries》2012,25(1):202-208
Methyl ethyl ketone peroxide (MEKPO) is a widely used initiator for polymerization reaction and hardener in glass-reinforced plastic. However, MEKPO is an unstable reactive chemical and has caused several serious accidents all over the world. This work studied the thermal stability of MEKPO in the presence of ferric oxide as the contaminant through calorimetric and kinetic studies. The calorimetry was performed using Automatic Pressure Tracking Adiabatic Calorimeter (APTAC) to identify the effects of ferric oxide (different concentration) on important reactive hazards such as onset temperature and pressure hazard. Kinetic modeling was then performed to study the kinetics of the runaway reaction and estimate important kinetic parameters. The results indicate that in the low concentration range (<0.3%), ferric oxide has no significant effect on the thermal stability of MEKPO. However, in the high and intermediate concentration range of ferric oxide (i.e., 10%), the negative effect on the thermal stability of MEKPO was observed. This result is in agreement with the kinetic study result that the activation energy and frequency factor decrease dramatically in the high ferric oxide concentration range. The results provide necessary process safety information for the handling of MEKPO and also technical basis for the further study in this area. 相似文献
899.
Zhichao Wu Chang Zhang Kaiming Peng Qiaoying Wang Zhiwei Wang 《Frontiers of Environmental Science & Engineering》2018,12(3):15
900.
Naoto Mihara Dalibor Kuchar Yoshihiro Kojima Hitoki Matsuda 《Journal of Material Cycles and Waste Management》2007,9(1):21-26
From the point of view of a sustainable and environment-friendly society based on the recycling of material resources, it
is preferable to utilize waste gypsum as a substitute for lime, which is currently produced by the calcination of limestone.
In the present work, the reductive decomposition of CaSO4 was investigated under an atmosphere of CO: 2 vol%, CO2: 30 vol%, with N2 as a carrier gas without and with the addition of SiO2, Al2O3, or Fe2O3. It was found that the decomposition temperature of CaSO4 was significantly reduced from 1673 K to 1223 K when only 5 wt% Fe2O3 was added to CaSO4. In the case of the addition of SiO2 or Al2O3 to CaSO4, the decomposition temperature was reduced from 1673 K to 1623 K. This was due to the formation of composite oxides (calcium
ferrite, calcium silicate, or calcium aluminate) during the reaction of CaSO4 with the additives at a lower temperature. In addition, the formation of unfavorable product CaS was inhibited in the presence
of 5 wt% Fe2O3, and this inhibition effect further increased as the addition of Fe2O3 was increased. In contrast, no significant effect on the inhibition of CaS formation was observed on the addition of SiO2 or Al2O3. 相似文献