期刊文献+
共找到1,328篇文章
< 1 2 67 >
每页显示 20 50 100
Research on the impact of manufacturing servitization on environmental pollution:spatial econometric analysis of sulfur dioxide based on 284 prefecture-level cities
1
作者 Qiu Xia Zhibin Zhou 《Chinese Journal of Population,Resources and Environment》 2024年第3期258-267,共10页
Using China’s regional input–output table,the paper constructs indicators of manufacturing servitization,matches manufacturing servitization at the regional level with city data,and uses spatial econometrics to empi... Using China’s regional input–output table,the paper constructs indicators of manufacturing servitization,matches manufacturing servitization at the regional level with city data,and uses spatial econometrics to empirically analyze the impact of manufacturing servitization on urban sulfur dioxide(SO_(2))emissions within the classical Environmental Kuznets Curve(EKC)framework.The results show that manufacturing servitization can reduce SO_(2) emissions.Producer servitization and consumptive services can both significantly reduce industrial SO_(2) emissions.Transportation and warehousing servitization,information servitization,leasing,and commercial servitization,technology research and development servitization significantly reduce SO_(2) emissions;technology research and development servitization,in particular,have the largest influence coefficient,while the reduction effect of servitization in the wholesale and retail and finance sectors is not significant.The study also found that servitization reduced the SO_(2) emissions through technological innovation and industrial structure upgrading. 展开更多
关键词 SERVITIZATION Environmental pollution SO_(2)emission EKC framework Spatial econometrics
下载PDF
Fe^(2+)/Mn^(2+)活化亚硫酸盐降解盐酸土霉素的机理研究
2
作者 贾艳萍 阴东旭 +2 位作者 徐静仪 张海丰 张兰河 《化工学报》 EI CSCD 北大核心 2024年第2期647-658,共12页
盐酸土霉素常被用于治疗畜禽疾病,但是它不能被畜禽完全代谢,残留的盐酸土霉素进入水体危害水环境的健康。铁锰作为常见的过渡金属,通常以二价态活化亚硫酸盐来降解有机污染物,反应条件温和、操作简单,但是单独的二价铁与二价锰氧化还... 盐酸土霉素常被用于治疗畜禽疾病,但是它不能被畜禽完全代谢,残留的盐酸土霉素进入水体危害水环境的健康。铁锰作为常见的过渡金属,通常以二价态活化亚硫酸盐来降解有机污染物,反应条件温和、操作简单,但是单独的二价铁与二价锰氧化还原电势低,活化亚硫酸盐效果较差。本研究采用Fe^(2+)/Mn^(2+)共活化Na_(2)SO_(3)降解水中的盐酸土霉素,考察药剂用量、pH、溶解氧、氯离子、碳酸根及腐殖酸对Fe^(2+)/Mn^(2+)/Na_(2)SO_(3)体系降解盐酸土霉素的影响;通过焦磷酸盐实验、自由基淬灭实验和EPR实验分析Fe^(2+)/Mn^(2+)/Na_(2)SO_(3)体系中的活性物种;利用紫外可见光谱、傅里叶红外光谱、气相色谱-质谱联用仪识别盐酸土霉素的官能团及其降解中间产物的变化,推断盐酸土霉素的降解途径。结果表明:当Fe^(2+)/Mn^(2+)/Na_(2)SO_(3)浓度比为1∶4∶20(浓度分别为0.1、0.4和2 mmol/L)时,在反应45 min、pH为9.0条件下,盐酸土霉素的去除率和矿化率最高,分别达到94%和49%。随着溶解氧从9 mg/L下降至1.89 mg/L,盐酸土霉素去除率从94%下降至17%;氯离子、腐殖酸和碳酸根均对盐酸土霉素的降解产生抑制作用。Mn(Ⅲ)和SO_(4)·^(-)是降解盐酸土霉素的主要活性氧化剂,盐酸土霉素的降解经过电子转移、开环与酰基化等过程。 展开更多
关键词 Fe^(2+)/Mn^(2+)/Na_(2)SO_(3)体系 盐酸土霉素 活化 自由基 氧化
下载PDF
电协同Fe^(2+)活化过硫酸盐处理偶氮染料废水的研究
3
作者 李亚峰 崔可清 王艺霖 《环境科学与技术》 CAS CSCD 北大核心 2024年第8期44-52,共9页
偶氮染料废水会对自然环境和人类健康产生巨大危害。文章研究电协同Fe^(2+)活化过硫酸盐体系高效处理偶氮染料废水,以金橙G废水为处理对象,考察不同反应条件例如pH、Fe^(2+)投加量、过二硫酸盐(PDS)投加量、电流密度等因素对处理效果的... 偶氮染料废水会对自然环境和人类健康产生巨大危害。文章研究电协同Fe^(2+)活化过硫酸盐体系高效处理偶氮染料废水,以金橙G废水为处理对象,考察不同反应条件例如pH、Fe^(2+)投加量、过二硫酸盐(PDS)投加量、电流密度等因素对处理效果的影响,采用响应曲面法优化反应条件并确定最佳反应条件下的处理效果。结果表明,在pH为3、极板间距为9 cm、电流密度为15 mA/cm^(2)、PDS投加量为6.66 mmol/L、Fe^(2+)投加量为2 mmol/L、Na_(2)SO_(4)投加量为89.39 mmol/L的条件下,金橙G废水色度平均去除率为93.03%,COD平均去除率为85.80%。分析电协同Fe^(2+)活化过硫酸盐体系起主要作用的自由基及降解机理,证实了电和Fe^(2+)的协同作用。该研究可为电协同Fe^(2+)活化过硫酸盐体系在偶氮染料废水处理领域的应用提供技术支撑。 展开更多
关键词 过硫酸盐 金橙G废水 Fe^(2+)离子 响应曲面法
下载PDF
Fe^(2+)、Cu^(2+)诱导工艺对柞木表板颜色变化规律的影响
4
作者 侯豪杰 齐华春 +3 位作者 王宏兴 黄茹 李春风 刘明利 《东北林业大学学报》 CAS CSCD 北大核心 2024年第1期124-127,共4页
木材中的木质素、抽提物等物质具有能与金属盐溶液产生颜色反应的特性。利用这一特性以硫酸亚铁、硫酸铜溶液作为诱导剂,通过正交试验得到色差最大时的工艺参数,探究金属Fe^(2+)、Cu^(2+)的诱导剂质量分数、诱导时间、干燥时间、干燥温... 木材中的木质素、抽提物等物质具有能与金属盐溶液产生颜色反应的特性。利用这一特性以硫酸亚铁、硫酸铜溶液作为诱导剂,通过正交试验得到色差最大时的工艺参数,探究金属Fe^(2+)、Cu^(2+)的诱导剂质量分数、诱导时间、干燥时间、干燥温度对实木复合地板柞木表板颜色变化的影响。结果表明:Fe^(2+)、Cu^(2+)的诱导剂质量分数对柞木表板色彩色调的影响极为显著(F值分别为20.4453、8.8442);柞木表板的明度色品指数(L^(*))、红绿轴色品指数(a^(*))、黄蓝轴色品指数(b^(*))均随着Fe^(2+)、Cu^(2+)的诱导剂质量分数、诱导时间、干燥时间的增加而逐渐减少,总色差(ΔE^(*))逐渐增大,最大为31.53、9.90,表板色调逐渐偏暗、偏绿、偏蓝;随着干燥温度的增加,Fe^(2+)、Cu^(2+)诱导时的柞木表板总色差都逐渐减小。 展开更多
关键词 柞木表板 Fe^(2+) Cu^(2+) 诱导变色
下载PDF
外源Fe^(2+)浓度和矿物粒径对生物浸铀的影响
5
作者 辛燕 王世俊 +3 位作者 刘勇 张益硕 李龙祥 周仲魁 《有色金属(冶炼部分)》 CAS 北大核心 2024年第2期64-71,共8页
为改善以往生物浸铀效率不高的缺陷,通过添加外源Fe^(2+)及改变矿物粒径来提高生物对铀的浸出率。研究结果表明:外源Fe^(2+)浓度分别为0、0.5、1.0和2.0 g/L时,铀浸出率分别为87.34%、88.27%、91.23%、89.13%,当浸出体系中Fe^(2+)浓度为... 为改善以往生物浸铀效率不高的缺陷,通过添加外源Fe^(2+)及改变矿物粒径来提高生物对铀的浸出率。研究结果表明:外源Fe^(2+)浓度分别为0、0.5、1.0和2.0 g/L时,铀浸出率分别为87.34%、88.27%、91.23%、89.13%,当浸出体系中Fe^(2+)浓度为1.0 g/L时,铀矿石会产生部分溶解且表面粗糙孔隙明显,有利于铀的浸出,溶浸液中存在适量的Fe^(2+)对生物浸铀的能力具有提升效果。另外,外源Fe^(2+)对铀矿生物浸出符合固体产物层控制模型,浸出过程主要受扩散控制。当粒径<-2 mm和-5 mm时铀浸出率分别为91.23%和83.70%,矿物粒径适当减小可增大颗粒比表面积,同样利于铀的浸出。 展开更多
关键词 生物浸出 外源Fe^(2+) 粒径
下载PDF
Fe^(2+)螯合剂对羟脯氨酸发酵的影响
6
作者 龚雨 李长庚 +1 位作者 李旭 徐庆阳 《食品与发酵工业》 CAS CSCD 北大核心 2024年第9期50-55,共6页
为解决反式-4-羟基脯氨酸发酵过程中Fe^(2+)供应不足、产酸效率低等问题。该研究以大肠杆菌HYP-08为供试菌株,首先通过单因素实验探究Fe^(2+)螯合剂种类及添加量对羟脯氨酸发酵生产的影响,并通过5 L发酵放大验证,以羟脯氨酸产量、生物量... 为解决反式-4-羟基脯氨酸发酵过程中Fe^(2+)供应不足、产酸效率低等问题。该研究以大肠杆菌HYP-08为供试菌株,首先通过单因素实验探究Fe^(2+)螯合剂种类及添加量对羟脯氨酸发酵生产的影响,并通过5 L发酵放大验证,以羟脯氨酸产量、生物量,糖酸转化率为指标,进一步探究其在放大过程中的影响,结果表明葡萄糖酸亚铁对羟脯氨酸发酵效果最好,流加发酵生产中,最终确定了10 h开始持连续流加的补料方式,反式-4-羟基脯氨酸生物量及产量达到最高,分别为146.2、118.6 g/L,较优化前提高了12.1%和4.2%,副产物乙酸减少到1.05 g/L,葡萄糖酸亚铁的添加有效增强了菌体活力,提高了羟脯氨酸的产量和糖酸转化率,为微生物发酵生产羟脯氨酸提供了依据。 展开更多
关键词 Fe^(2+)螯合剂 羟脯氨酸 连续流加 大肠杆菌 葡萄糖酸亚铁
下载PDF
以研促教:利用荧光探针检测Fe^(2+)的实验设计
7
作者 杨晓朋 姬小明 来苗 《广东化工》 CAS 2024年第19期211-214,共4页
本文以荧光探针的设计合成和监测亚铁离子(Fe^(2+))应用于分析化学拓展实验教学为主题,介绍了一种新型的荧光探针DCM-Fe,其通过引入N-氧化物基团有效抑制了分子内电荷转移的发生,实现了对Fe^(2+)荧光“turn on”型检测。本文还阐述了在... 本文以荧光探针的设计合成和监测亚铁离子(Fe^(2+))应用于分析化学拓展实验教学为主题,介绍了一种新型的荧光探针DCM-Fe,其通过引入N-氧化物基团有效抑制了分子内电荷转移的发生,实现了对Fe^(2+)荧光“turn on”型检测。本文还阐述了在实验教学中,通过本实验的设计和实施,学生可以深入理解荧光探针的设计合成原理和荧光检测技术的应用,在实践中掌握荧光探针的合成、分析和应用,并培养了学生的实验技能和创新意识。本实验教学可为分析化学实验教学的拓展提供一种新思路和方法。 展开更多
关键词 荧光探针 Fe^(2+) 苯并吡喃腈 分析检测
下载PDF
N Cycle, N Flow Trends in Japan, and Strategies for Reducing N_2O Emission and NO_3^- Pollution 被引量:11
8
作者 K.MINAMI 《Pedosphere》 SCIE CAS CSCD 2005年第2期164-172,共9页
To feed an increasing population, large amounts of chemical nitrogen fertilizer have been used to produce much of our food, feed and fiber thereby increasing nitrogen levels in soils, natural waters, crop residues, li... To feed an increasing population, large amounts of chemical nitrogen fertilizer have been used to produce much of our food, feed and fiber thereby increasing nitrogen levels in soils, natural waters, crop residues, livestock wastes,and municipal and agricultural wastes, with national and international concern about its potential adverse effects on environmental quality and public health. To understand these phenomena and problems, first the nitrogen cycle and the environment are described. Then recent trends for nitrogen cycling through the food and feed system, N2O emissions from fertilized upland and paddy soils, and NO-3 pollution in ground water in Japan are reported. Finally, mitigation strategies in Japan for reducing N2O emission and NO-3 pollution are proposed, including nitrification inhibitors, controlled release fertilizers, utilization of plant species that could suppress nitrification, utilizing the toposequence, government policy, and appropriate agricultural practices. Of all the technologies presented, use of nitrification inhibitors and controlled release fertilizers are deemed the most important with further development of these aspects of technologies being expected. These practices, if employed worldwide, could help reduce the load, or environmental deterioration, on the Earth's biosphere. 展开更多
关键词 mitigation strategy N2O emission NO3- pollution nitrogen cycle
下载PDF
营养液不同浓度Fe^(2+)对水培小白菜生长发育及品质的影响
9
作者 毛丹 张鑫月 +3 位作者 李嘉琪 周君蔓 孙灵灵 翟玉莹 《上海蔬菜》 2024年第2期31-33,共3页
为筛选适宜水培小白菜生长的Fe^(2+)浓度,该文以苏州青为试验材料,开展了不同浓度Fe^(2+)对小白菜生长发育及品质的影响试验。试验结果表明,水培营养液Fe^(2+)浓度为0.03 mmol/L处理,水培小白菜株高、茎粗均显著高于其他处理,地上部鲜... 为筛选适宜水培小白菜生长的Fe^(2+)浓度,该文以苏州青为试验材料,开展了不同浓度Fe^(2+)对小白菜生长发育及品质的影响试验。试验结果表明,水培营养液Fe^(2+)浓度为0.03 mmol/L处理,水培小白菜株高、茎粗均显著高于其他处理,地上部鲜质量、地上部干质量、地下部鲜质量、地下部干质量最大,较对照分别提高92.5%、266.7%、115.5%、357.9%,叶绿素含量(57.12 mg/g)、维生素C含量[92.15 mg/(100 g)]、可溶性糖含量(0.43%)最高,较对照分别提高77.67%、50.44%、30.30%,小白菜丙二醛含量最低(11.06 nmol/g),较对照降低39.33%。综上,营养液Fe2+浓度为0.03 mmol/L时,水培小白菜生长势最旺、品质最佳、抗逆性最强。 展开更多
关键词 水培小白菜 营养液 Fe^(2+)浓度 生长发育 品质 抗逆性
下载PDF
Association between Air Pollution and Type 2 Diabetes Mellitus in Developing Countries:A Systematic Review and Meta-Analysis 被引量:3
10
作者 Zihan Chen Zhou Zhao +1 位作者 Chuiwen Deng Naishi Li 《Chinese Medical Sciences Journal》 CAS CSCD 2022年第3期218-227,I0007,共11页
Objective In recent years,many studies have reported that air pollution is a risk factor for type 2 diabetes mellitus(T2DM).The aim of this systematic review and meta・analysis is to summarize the evidence about the as... Objective In recent years,many studies have reported that air pollution is a risk factor for type 2 diabetes mellitus(T2DM).The aim of this systematic review and meta・analysis is to summarize the evidence about the association between exposure to air pollution andT2DM in developing countries.Methods The databases,including PubMed,EMBASE and Web of Science,were systematically searched for studies published up to 31 March 2022.Studies about the association between air pollution andT2DM prevalence or incidence in developing countries were included.The odds ratio(OR)was used as effect estimate.We synthesized the included studies in the meta-analysis.Results We included 8 cross-sectional studies and 8 cohort studies,all conducted in developing countries.Meta-analysis of 8 studies on PM_(2.5)(particulate matter ≤2.5 μm in diameter)showed that T2DM prevalence was significantly associated with PM_(2.5)exposure(OR=1.12;95%CI:1.07,1.17;P<0.001).The association between air pollutants andT2DM incidence was not estimated due to the limited relevant studies.Conclusions The exposure to PM_(2.5)would be positively associated with an increased prevalence of T2DM in developing countries.Some effective measures should be taken to reduce air pollutant exposure in people who are vulnerable to diabetes. 展开更多
关键词 Air pollutants PM_(2.5) type 2 diabetes mellitus
下载PDF
甲基磺酸盐电镀液中Fe^(2+)质量浓度对镀锡板的影响
11
作者 贾宁 王悦鼎 +3 位作者 宋乙峰 岳重祥 朱广永 李建中 《材料与冶金学报》 CAS 北大核心 2024年第5期491-496,504,共7页
采用扫描电镜(SEM)、X射线衍射(XRD)、塔费尔曲线及循环伏安曲线等测试方法,研究了在甲基磺酸盐体系镀锡工艺中,Fe^(2+)质量浓度对镀锡板的耐蚀性、电镀过程中Sn^(2+)扩散系数及电流效率的影响.结果表明:Fe^(2+)质量浓度增加会导致镀锡... 采用扫描电镜(SEM)、X射线衍射(XRD)、塔费尔曲线及循环伏安曲线等测试方法,研究了在甲基磺酸盐体系镀锡工艺中,Fe^(2+)质量浓度对镀锡板的耐蚀性、电镀过程中Sn^(2+)扩散系数及电流效率的影响.结果表明:Fe^(2+)质量浓度增加会导致镀锡板表面孔隙数量增多,抑制镀层中的锡粒向(200)晶面生长,致使镀锡板耐蚀性下降,当Fe^(2+)质量浓度超过8.0 g/L时,镀锡板耐蚀性明显降低;同时,Fe^(2+)质量浓度增加会导致电镀锡过程中Sn^(2+)扩散系数减小、电流效率降低. 展开更多
关键词 镀锡板 甲基磺酸 Fe^(2+) 耐蚀性 Sn^(2+)扩散系数
下载PDF
Impact of air pollution on urbanization:evidence at China’s city level
12
作者 Yanchun Yi Yixin Geng +1 位作者 Jiawen Wu Yinling Liu 《Chinese Journal of Population,Resources and Environment》 2024年第3期268-274,共7页
This paper investigates the effect and transmission mechanism of air pollution on urbanization based on data from China’s 107 cities during 2005–2018.In order to identify the impact of air pollution on China’s urba... This paper investigates the effect and transmission mechanism of air pollution on urbanization based on data from China’s 107 cities during 2005–2018.In order to identify the impact of air pollution on China’s urbanization,we utilized night light data to represent the level of urbanization and used temperature inversion as an instrumental variable to mitigate endogeneity within the two-stage least squares framework.The results suggest that air pollution significantly slowed China’s urbanization process with economic growth acting as the transmission mechanism.The heterogeneity analyses revealed that air pollution had a greater negative impact on urbanization in northern regions than that in southern regions,and a greater negative impact in resource-oriented cities than that in non-resource-based cities.We also find that air pollution was to the detriment of urbanization in larger cities,which have more than 3 million residents,while it did not have a significant impact on Type II large cities,which have fewer than 3 million residents. 展开更多
关键词 Air pollution URBANIZATION Influencing mechanism 2SLS Night light data Instrumental variable
下载PDF
不同因素对Fe^(3+)-TiO_(2)/ACF降解NH_(3)的影响
13
作者 徐伟 万家豪 +1 位作者 张兴惠 贾冠冠 《化工新型材料》 CAS CSCD 北大核心 2024年第7期194-198,203,共6页
为了探究不同因素对Fe^(3+)-TiO_(2)/活性炭纤维(ACF)降解氨气(NH_(3))的影响规律,采用Fe^(3+)-TiO_(2)/ACF复合材料,以NH_(3)为目标降解物,研究初始浓度、流速、光催化剂负载量以及光照强度对Fe^(3+)-TiO_(2)/ACF降解NH_(3)的影响,并... 为了探究不同因素对Fe^(3+)-TiO_(2)/活性炭纤维(ACF)降解氨气(NH_(3))的影响规律,采用Fe^(3+)-TiO_(2)/ACF复合材料,以NH_(3)为目标降解物,研究初始浓度、流速、光催化剂负载量以及光照强度对Fe^(3+)-TiO_(2)/ACF降解NH_(3)的影响,并进行了相应的反应动力学分析。结果表明:随着初始浓度的增加,NH_(3)降解率呈现略微降低的趋势,光催化过程基本符合L-H一级反应动力学模型;随着流速的增加,NH_(3)降解率表现为先升高后降低,其光催化过程也基本符合L-H一级反应动力学模型;随着光催化剂负载量以及光照强度的增加,NH_(3)降解率表现为略微增加的趋势。 展开更多
关键词 Fe^(3+)-TiO_(2)/活性炭纤维 降解 不同因素 影响规律 NH_(3)
下载PDF
Correlation between Cr^(6+) and Mn^(2+) Adsorption in Rock-soil Medium with Combined Pollution 被引量:1
14
作者 YU Xiao-ying ZOU Sheng-zhang +1 位作者 CAI min-qi LU Hai-ping 《Meteorological and Environmental Research》 CAS 2011年第9期49-50,72,共3页
[Objective] The aim was to study the correlation between Cr6+ and Mn2+ adsorption in rock-soil medium with combined pollution. [Method] Combining single Cr6+ and Mn2+ adsorption test with combined pollution test, the ... [Objective] The aim was to study the correlation between Cr6+ and Mn2+ adsorption in rock-soil medium with combined pollution. [Method] Combining single Cr6+ and Mn2+ adsorption test with combined pollution test, the adsorption laws of Cr6+ and Mn2+ were studied, and the correlation between Cr6+ and Mn2+ adsorption was analysed by using correlation analysis and regression analysis. [Result] According to the comparative analysis on adsorption tests, the adsorption time, adsorption amount and adsorption speed of Cr6+ and Mn2+ were obviously distinct in single adsorption test and combined adsorption test. Correlation analysis revealed that there was a significantly positive correlation between Cr6+ and Mn2+, and there existed addition effects between Cr6+ and Mn2+ in regression analysis, that is, the adsorption of Cr6+ by the soil tested would be enhanced by Mn2+. [Conclusion] The research could provide scientific references for environmental control and environmental management. 展开更多
关键词 Cr6+ Mn2+ Combined pollution ABSORPTION CORRELATION China
下载PDF
Secondary effect of SO_2 pollution: enhanced growth of the army worm, Mythimna separata (Walker)
15
作者 Wu Kunjun, Gong Peiyu, Li Xiuzhen, Shu Jianmin and Cao HongfaInstitute of Zookogy,Academia Sinica,Beijing 100080,ChinaInstitute of Zookogy,Chinese Research Academy of Environmental Science,Beijing 100012,China 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1990年第4期51-60,共10页
Effects of SO2 pollution on growth of the army worm, Mythimna separata, were investigated by rearing the larvae for 12 days on the wheat plants being exposed to SO2 levels ranged from 50 to 200 ppb in the field open-t... Effects of SO2 pollution on growth of the army worm, Mythimna separata, were investigated by rearing the larvae for 12 days on the wheat plants being exposed to SO2 levels ranged from 50 to 200 ppb in the field open-top fumigation devices. Larval period shortened while their mean relative growth rate (MRGR) increased as SO2 dose elevated. Similar experiment with the insect on the artificial diet excluded the possibility that SO2 pollution directly stimulated growth of the army worm.The patterns of change in amino acid hydrolysates in the host foliage suggested that contents of methionine, and perhaps, arginine in food material exposed to unpolluted air were at such levels that they could only support sub-optimum growth of the insect, and SO2 pollution increased concentrations of these limiting amino acids, resulting in better performance of the larvae. 展开更多
关键词 environmental pollution SO2 wheat plant amino acids army worm (Mythimna separata).
下载PDF
Air Pollution Monitoring System Using Micro Controller Atmega 32A and MQ135 Gas Sensor at Chandragiri Municipality of Kathmandu City
16
作者 Rajesh Shrestha Manik Maharjan Mahesh Sharma 《Semiconductor Science and Information Devices》 2022年第2期35-44,共10页
Air is one of the essential elements of human’s surroundings.The earth’s atmosphere is full of air which contains gases such as Nitrogen,Oxygen,Carbon Monoxide and traces of some rare elements.But quality of the air... Air is one of the essential elements of human’s surroundings.The earth’s atmosphere is full of air which contains gases such as Nitrogen,Oxygen,Carbon Monoxide and traces of some rare elements.But quality of the air has been degrading for some decades due to various activities conducted by the human beings that directly or indirectly affect the atmosphere leading to the air pollution.There are different techniques to measure air quality.However,with the evolution of time the expensive and less efficient analog devices have been replaced by more efficient and less expensive electronics device.In this research,MQ135 sensor is used to measure air quality of a particular location.I2C display is used to monitor the data.Indeed,with the increasing in number of vehicles,unplanned urbanization and rapid population growth,air pollution has considerably increased in the last decades in various areas of Kathmandu.Thus,this project‘Air Pollution Monitoring System’was focused on collection of the data specific location of Chandragiri municipality of Kathmandu city.In conclusion,analysis of the data is done with the help of origin software which shows that the Arduino device in this device works perfectly for measuring the air pollution.Air quality of the selected area is found to be less than 500 PPM which concludes that the air quality of this area is normal. 展开更多
关键词 Arduino Uno MQ135 sensor Air pollution I2C display Atmosphere
下载PDF
Fe^(2+)与Fe^0活化过二硫酸盐降解活性艳蓝KN-R 被引量:18
17
作者 于辉 金春姬 +2 位作者 王鹏远 刘明 贾红丽 《环境科学研究》 EI CAS CSSCI CSCD 北大核心 2015年第1期88-95,共8页
为了解Fe2+与Fe0在活化PDS(过二硫酸盐)降解活性艳蓝KN-R时的差异,通过序批试验,考察了Fe2+/PDS和Fe0/PDS体系中c(Fe2+)、ρ(Fe0)、c(PDS)和初始p H对KN-R降解的影响.结果表明:在Fe2+/PDS体系中,最佳反应条件〔初始pH为3.0,c(Fe2+)为1.0... 为了解Fe2+与Fe0在活化PDS(过二硫酸盐)降解活性艳蓝KN-R时的差异,通过序批试验,考察了Fe2+/PDS和Fe0/PDS体系中c(Fe2+)、ρ(Fe0)、c(PDS)和初始p H对KN-R降解的影响.结果表明:在Fe2+/PDS体系中,最佳反应条件〔初始pH为3.0,c(Fe2+)为1.0 mmol/L,c(PDS)为2.0 mmol/L〕下,180 min后KN-R的去除率达到96.55%;过高的p H和c(Fe2+)对KN-R的降解均有明显的抑制作用.在Fe0/PDS体系中,当p H和ρ(Fe0)过高时,KN-R的去除率仍维持在较高水平,当p H为9.0时,180 min后KN-R的去除率为90.53%;当ρ(Fe0)为448 mg/L时,50 min后KN-R的去除率就能达到94.35%.在2个体系中,c(PDS)的升高均能显著提高KN-R的去除率,当c(PDS)由0.5 mmol/L增至8.0 mmol/L时,KN-R的去除率由47.25%(Fe2+/PDS体系)和57.00%(Fe0/PDS体系)增至100%.动力学分析显示,KN-R的降解均遵循一级反应动力学;最佳反应条件下2个体系中的活性自由基均以硫酸根自由基(SO4-·)为主.因此,在降解KN-R过程中,Fe0/PDS体系的性能明显优于Fe2+/PDS体系. 展开更多
关键词 活性艳蓝KN-R FE^2+ Fe^0 过二硫酸盐 降解动力学
下载PDF
Fe^(2+)-H_2O_2法处理DSD酸生产氧化母液的研究 被引量:48
18
作者 祝万鹏 杨志华 +1 位作者 王利 杨吉生 《环境科学》 CAS CSSCI CSCD 北大核心 1995年第1期19-22,共4页
为改善DSD酸氧化母液的可生化降解性,将废液先用有机絮凝剂TS-1(一种季胺盐)处理,TS-1的投加量为3g/L,其后用Fe2+-H2O2法氧化,Fe2+和H2O2的量分别为150mg/L,7g/L,废液COD和色度... 为改善DSD酸氧化母液的可生化降解性,将废液先用有机絮凝剂TS-1(一种季胺盐)处理,TS-1的投加量为3g/L,其后用Fe2+-H2O2法氧化,Fe2+和H2O2的量分别为150mg/L,7g/L,废液COD和色度的去除率分别可达64%和62%。经处理后的废水,其BOD5/COD≈0.3,可以认为已达到生化处理的要求。当H2O2的投量为2g/L,经Fe2+-H2O氧化处理后的废液,再用FeCl3进行两级混凝处理(FeCl3的投加量分别为sg/L和2g/L),则COD和色度的去除率可达90%和95%。 展开更多
关键词 Fe^2+-H2O2 DSD酸 废水处理
下载PDF
模拟酸雨对赤红壤磷素及Ca^(2+)、Al^(3+)、Fe^(2+)淋失特征的影响 被引量:12
19
作者 徐华勤 章家恩 +3 位作者 余家瑜 谢俊芳 毛丹鹃 杨滔 《植物营养与肥料学报》 CAS CSCD 北大核心 2011年第5期1172-1178,共7页
本研究通过室内土柱试验,研究了不同强度和持续时间的模拟酸雨淋溶下赤红壤磷素淋失量及部分阳离子(Ca2+、Al3+、Fe2+)的释放程度和特征。结果表明,经pH 2.0、pH 3.0、pH 4.0、pH 5.0模拟酸雨持续淋溶34 d后,淋溶液pH值变化并不明显(P&g... 本研究通过室内土柱试验,研究了不同强度和持续时间的模拟酸雨淋溶下赤红壤磷素淋失量及部分阳离子(Ca2+、Al3+、Fe2+)的释放程度和特征。结果表明,经pH 2.0、pH 3.0、pH 4.0、pH 5.0模拟酸雨持续淋溶34 d后,淋溶液pH值变化并不明显(P>0.05),而对Ca2+、Fe2+的溶出有显著的促进作用,Ca2+、Al3+、Fe2+溶出量均随pH值的降低而升高,Al3+和Fe2+淋失量在pH 2.0时均有骤增现象。随淋溶时间的增加,土壤可溶态磷的淋失量表现为先增加后逐渐降低;随着pH值的降低,土壤磷淋失总量也表现为先增加后降低,pH>4.0的酸雨有助于促进土壤磷的释放,pH<4.0时土壤磷的淋失减少。相关分析发现淋溶液中磷淋失总量与Al3+和Fe2+溶出量均呈显著负相关(r1=-0.6531,r2=-0.5107),和Ca2+总溶出量相关关系不显著(r3=-0.1287),表明高强度酸雨降低了土壤磷淋失量,这可能与酸雨导致活性铁、铝的大量释放,增加了磷的活性吸附点位,因而增加了对磷酸根离子配位吸附与固定有关。 展开更多
关键词 酸雨 赤红壤 磷素 Ca^2+ AL^3+ FE^2+
下载PDF
Fe^(2+)/H_2O_2体系内各种自由基在氧化NO中的作用 被引量:14
20
作者 赵海谦 高继慧 +2 位作者 周伟 王忠华 吴少华 《化工学报》 EI CAS CSCD 北大核心 2015年第1期449-454,共6页
Fe2+/H2O2体系可分解产生多种氧化性自由基,主要包括O-2·、·OH和HO2·。本文实验研究了O-2·、·OH及HO2·在Fe2+/H2O2体系氧化NO气体过程中的作用。结果表明:在本实验条件下,O-2·对NO气体的氧化作用不... Fe2+/H2O2体系可分解产生多种氧化性自由基,主要包括O-2·、·OH和HO2·。本文实验研究了O-2·、·OH及HO2·在Fe2+/H2O2体系氧化NO气体过程中的作用。结果表明:在本实验条件下,O-2·对NO气体的氧化作用不明显;·OH及HO2·是该体系氧化NO气体的主要活性物质,其中·OH的氧化作用更大。加快自由基的生成速率可以增强Fe2+/H2O2体系对NO气体的氧化能力,但O2的生成速率同时加快。只有少量·OH及HO2·参与NO的氧化,·OH与HO2·之间的快速反应是Fe2+/H2O2体系氧化NO过程中H2O2利用率低的主要原因。 展开更多
关键词 Fe^2+/H2O2体系 自由基 无效分解
下载PDF
上一页 1 2 67 下一页 到第
使用帮助 返回顶部