排序方式: 共有29条查询结果,搜索用时 328 毫秒
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赤铁矿生物可利用性弱、污染物去除效率低,但因其具有价格低廉、存在广泛的特点而常被用于环境污染治理与修复.本研究通过向赤铁矿生物还原体系中添加硝酸改性后的活性炭,以强化矿石中Fe(Ⅲ)的生物可利用性.同时,以Fe(Ⅲ)还原率与有机物降解率为响应值,通过响应曲面法探究了赤铁矿浓度、有机物浓度与硝酸改性剂浓度对赤铁矿生物可利用性的影响机制.结果表明,硝酸改性活性炭可以提高赤铁矿的生物可利用性,促进有机物的降解,赤铁矿浓度对反应的影响最为显著.生物反应过程的最佳条件为:赤铁矿初始浓度8.35 mmol·L~(-1)、有机物初始浓度13.41 mmol·L~(-1)、硝酸改性剂浓度5.07%.硝酸改性活性炭强化赤铁矿生物体系虽能降解高浓度有机物,但有机物去除效率仅为20%~50%,证明该体系适用于低有机物浓度的水环境.本研究对促进水、土壤环境中有机物的降解具有重要科学意义. 相似文献
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Caihong Xu Jianmin Chen Zhikai Wang Hui Chen Hao Feng Lujun Wang Yuning Xie Zhenzhen Wang Xingnan Ye Haidong Kan Zhuohui Zhao Abdelwahid Mellouki 《Frontiers of Environmental Science & Engineering》2021,15(3):37
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Yu Jiang Beidou Xi Rui Li Mingxiao Li Zheng Xu Yuning Yang Shaobo Gao 《Frontiers of Environmental Science & Engineering》2019,13(6):89
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Qing Xia Rui Liang Yuxiang Mao Yuning Hong Lili Ding Hongqiang Ren Mingyu Zhao 《Frontiers of Environmental Science & Engineering》2009,3(3):369-374
Batch experiments were conducted to study the short-term biological effects of rare earth ions (La3+, Ce3+) and their mixture on the nitrogen removal in a sequencing batch reactor (SBR). The data showed that higher NH4 +-N removal rate, total inorganic nitrogen removal efficiency, and denitrification efficiency were achieved at lower concentrations of rare earth elements (REEs) (<1 mg/L). In the first hour of the aeration stage of SBR, the presence of REEs increased the total inorganic nitrogen removal efficiency and NH4 +-N removal efficiency by 15.7% and 10%–15%, respectively. When the concentrations of REEs were higher than 1 mg/L, the total inorganic nitrogen removal efficiency decreased, and nitrate was found to accumulate in the effluent. When the concentrations of REEs was up to 50.0 mg/L, the total inorganic nitrogen removal efficiency was less than 30% of the control efficiency with a high level of nitrate. Lower concentrations of REEs were found to accelerate the nitrogen conversion and removal in SBR. 相似文献
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Production and emission of phosphine gas from wetland ecosystems 总被引:2,自引:1,他引:1
Chao Han Xueyuan Gu Jinju Geng Yuning Hong Rui Zhang Xiaorong Wang Shixiang Gao 《环境科学学报(英文版)》2010,22(9):1309-1311
Phosphine is a part of an atmospheric link of phosphorus cycle on earth, which could be an important pathway for phosphorus transport in environment.Wetland ecosystems are important locations for global biogeochemical phosphorus cycle.In this study, production and emission fluxes of free phosphine from four wetlands types in southern China were observed in different seasons.The results showed that the concentration of phosphine liberated from wetlands was at pg/m3-ng/m3 level.The emission concentrations of different wetlands followed the sequence:paddy field(51.83 ± 3.06) ng/m3 marsh(46.54 ± 20.55) ng/m3 lake(37.05 ± 22.74) ng/m3 coastal wetland(1.71 ± 0.73) ng/m3, the positive phosphine emission flux occurred in rice paddy field(6.67 ± 5.18) ng/(m2·hr) and marsh(6.23 ± 26.9) ng/(m2·hr), while a negative phosphine flux of(-13.11 ± 35.04) ng/(m2·hr) was observed on the water-air interface of Lake Taihu, suggesting that paddy field and marsh may be important sources for phosphine gas in atmosphere, while lake may be a sink of atmospheric phosphine gas during the sampling period.Atmospheric phosphine levels and emission flux from Yancheng marsh and rice paddy field varied in different seasons and vegetational zones.Both diffusion resistance in aqueous phase and temperature were dominating factors for the production and transportation of phosphine to atmosphere. 相似文献
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为解决煤矿风井防爆门研发中的设计爆炸载荷取值问题,采用理论分析和数值模拟方法,研究MFBL防爆门在被冲击波冲飞过程中的能量转化、传递、耗损关系,以及空气阻力因素的影响;改进拉断钢丝绳消耗能量的算法,着重考虑空气阻力影响因素,重新建立基于事故中防爆门的飞起高度计算防爆门设计爆炸载荷的方法,并以典型案例进行验证。结果表明:防爆门在拉断牵引钢丝绳的过程中,传递给配重的能量相较于拉断钢丝绳所消耗能量较小,可忽略不计;MFBL防爆门的空气阻力系数接近于1,其以较大速度飞行时受空气阻力影响显著,故考虑克服空气阻力作功是必要的;鉴于计算结果,推荐根据20~50 m飞起高度设计防爆门爆炸载荷,并提出根据防爆门飞起高度划分安全防护等级等建议和应用指南,其可提高计算方法的可靠性和可用性,可为防爆门研发等提供参考依据。 相似文献
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Can Wu Gehui Wang Jiayuan Wang Jianjun Li Yanqin Ren Lu Zhang Cong Cao Jin Li Shuagshuang Ge Yuning Xie Xinpei Wang Guoyan Xue 《环境科学学报(英文版)》2018,30(9):179-187
Fireworks burning releases massive fine particles and gaseous pollutants, significantly deteriorating air quality during Chinese Lunar New Year(LNY) period. To investigate the impact of the fireworks burning on the atmospheric aerosol chemistry, 1-hr time resolution of PM_(2.5) samples in Xi'an during the winter of 2016 including the LNY were collected and detected for inorganic ions, acidity and liquid water content(LWC) of the fine aerosols. PM_(2.5) during the LNY was 167 ± 87 μg/m~3, two times higher than the China National Ambient Air Quality Standard(75 μg/m~3). K~+(28 wt.% of the total ion mass) was the most abundant ion in the LNY period, followed by SO_4~(2-)(25 wt.%) and Cl-(18 wt.%). In contrast, NO_3~-(34 wt.%) was the most abundant species in the haze periods(hourly PM32-2.5 75 μg/m), followed by SO_4(29.2 wt.%) and NH_4~+(16.3 wt.%), while SO_4~(2-)(35 wt.%) was the most abundant species in the clean periods(hourly PM_(2.5) 75 μg/m~3), followed by NO_3~-(23.1 wt.%) and NH_4~+(11 wt.%). Being different from the acidic nature in the non-LNY periods, aerosol in the LNY period presented an alkaline nature with a pH value of 7.8 ± 1.3. LWC during the LNY period showed a robust linear correlation with K_2SO_4 and KCl, suggesting that aerosol hygroscopicity was dominated by inorganic salts derived from fireworks burning. Analysis of correlations between the ratios of NO--3/SO_4~(2-) and NH_4~+/SO_4~(2-) indicated that heterogeneous reaction of HNO_3 with NH_3 was an important formation pathway of particulate nitrate and ammonium during the LNY period. 相似文献
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新冠肺炎封城对南京污染排放的影响 总被引:1,自引:0,他引:1
2020年初新冠肺炎疫情爆发以后,为了有效防止疫情扩散和蔓延,全国主要城市都相继停工停产,人类活动和污染排放强度大幅降低.本文针对新冠肺炎爆发前后南京地区污染排放变化,利用南京及周边地区的逐时污染观测资料,基于在线区域化学传输模式WRF-Chem和集合平方根滤波同化系统,在同时同化污染物浓度初始场和污染源排放的框架下,在1 km的高分辨率条件下进行了逐时同化实验模拟.结果表明,由于疫情管控,2月南京市区的PM2.5气溶胶和NO源排放分别较1月减少4.4%和30%,减少的区域主要位于工业区和南京城区.该结果显示同化系统在反演高时空分辨率的污染源方面具有很好的潜力. 相似文献