排序方式: 共有77条查询结果,搜索用时 375 毫秒
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Hong He Guangyan Xu Wenpo Shan Yunbo Yu Yulong Shan Xiaodong Wu Ye Wu Shaojun Zhang Liqiang He Shijin Shuai Hailong Pang Xuefeng Jiang Heng Zhang Lei Guo Shufen Wang Feng-Shou Xiao Xiangju Meng Feng Wu Dongwei Yao Yan Ding Hang Yin 《环境科学学报(英文版)》2023,123(1):15-29
Diesel vehicles have caused serious environmental problems in China. Hence, the Chinese government has launched serious actions against air pollution and imposed more stringent regulations on diesel vehicle emissions in the latest China VI standard. To fulfill this stringent legislation, two major technical routes, including the exhaust gas recirculation (EGR) and high-efficiency selective catalytic reduction (SCR) routes, have been developed for diesel engines. Moreover, complicated aftertreatment technologies have also been developed, including use of a diesel oxidation catalyst (DOC) for controlling carbon monoxide (CO) and hydrocarbon (HC) emissions, diesel particulate filter (DPF) for particle mass (PM) emission control, SCR for the control of NOx emission, and an ammonia slip catalyst (ASC) for the control of unreacted NH3. Due to the stringent requirements of the China VI standard, the aftertreatment system needs to be more deeply integrated with the engine system. In the future, aftertreatment technologies will need further upgrades to fulfill the requirements of the near-zero emission target for diesel vehicles. 相似文献
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Pt/BaO/Al_2O_3 catalysts with different BaO loadings prepared from Al_2O_3 nanorods(Pt/BaO/Al_2O_3-nr) and irregular Al_2O_3 nanoparticles(Pt/BaO/Al_2O_3-np) were investigated for NOx storage and reduction(NSR). The Pt/BaO/Al_2O_3 materials derived from Al_2O_3 nanorods always exhibited much higher NOx storage capacity(NSC) over the whole temperature range of 100–400°C than the corresponding Pt/BaO/Al_2O_3-np samples containing the same BaO loading, giving the maximum NSC value of 966.9 μmol/gcatat 400°C, 1.4 times higher than that of Pt/BaO/Al_2O_3-np. Higher catalytic performance of nanorod-supported NSR samples was also observed during lean-rich cyclic conditions(90 sec vs. 5 sec), giving more than 98% NOx conversion at 300–450°C over the Pt/BaO/Al_2O_3-nr sample with 15% BaO loading. To reveal this dependence on the shape of the support during the NSR process, a series of characterization techniques including the Brunauer–Emmett–Teller(BET) method,X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), H_2 temperature programmed reduction(H2-TPR), and in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) were also conducted. It was found that intimate contact of Ba–Al and Ba–Pt sites was achieved over the Pt/BaO/Al_2O_3 surface when using Al_2O_3-nr as a support.This strong interaction among the multi-components of Pt/BaO/Al_2O_3-nr thus triggered the formation of surface nitrite and nitrate during the lean period, and also accelerated the reverse spillover of ad-NOxspecies onto the Pt surface, enhancing their reduction and leading to high NSR performance. 相似文献
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重金属(Hg,As,Pb)污染对蚕豆根尖细胞微核的诱变研究 总被引:1,自引:0,他引:1
采用蚕豆根尖细胞微核检测技术,分别探讨不同浓度的HgCl2、As2O3、Pb(NO3)2对蚕豆根尖细胞微核率的影响。以蒸馏水处理作为阴性对照实验。结果表明不同浓度的HgCl2可使蚕豆根尖细胞微核率明显上升,说明HgCl2对蚕豆根尖具有明显的毒性效应——诱发突变(微核)。不同浓度As2O3可使蚕豆根尖细胞微核率明显上升。说明三氧化二砷(As2O3)对蚕豆根尖具有明显的毒性效应——诱发突变(微核)。蚕豆根尖微核率在铅离子浓度0—25mg/L范围内,随着硝酸铅处理浓度的升高而升高,说明硝酸铅是一种较强的诱变剂。 相似文献
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为了对PVA(聚乙烯醇)溶液中PVA去除进行研究,采用UV/Fenton氧化技术氧化处理PVA溶液。探究了UV/Fenton氧化PVA溶液的影响因素,主要研究了反应时间、初始p H、H2O2/COD和H2O2/Fe2+,获得了各个因素对PVA溶液COD去除率的影响规律以及PVA溶液经处理后的B/C(BOD5/COD)变化规律。实验表明,随着H2O2/COD投加比的增加,COD去除率不断增加,B/C呈现先增加后减少的现象;随初始p H的增加,COD去除率以及B/C均呈现先增加后减少的现象;随着H2O2/Fe2+不断增加,COD去除率以及B/C均呈现先增加后减少的现象;随反应时间的增加,COD去除率以及B/C均增加之后趋于稳定。当H2O2/COD=1.5,p H=4,H2O2/Fe2+物质的量之比为10,T=30 min时COD去除率效果比较好,经过处理之后溶液的B/C由0.1增至0.6,可生化性提高,为后续生物处理创造条件。 相似文献