A comparative investigation of NdSrCu_(1-x) Co_x O_(4-δ) and Sm_(1.8) Ce_(0.2) Cu_(1-x) Co_x O_(4-δ) (x:0–0.4) for NO decomposition

A series of single-phase T-structured NdSrCu 1-x Co x O 4-δ with oxygen vacancies and T -structured Sm 1.8 Ce 0.2 Cu 1-x Co x O 4-δ (x: 0–0.4) with oxygen excess were prepared using ultrasound-assisted citric acid complexing method, and characterized by means of techniques such as thermogravimetric analysis and NO temperature-programmed desorption (NO-TPD). The catalytic activities of these materials were evaluated for the decomposition of NO. It was found that the NdSrCu 1-x Co x O 4-δ catalysts were of oxygen vacancies whereas the Sm 1.8 Ce 0.2 Cu 1-x Co x O 4-δ ones possessed excessive oxygen (i.e., over-stoichiometric oxygen); with a rise in Co doping level, the oxygen vacancy density of NdSrCu 1-x Co x O 4-δ decreased while the over-stoichiometric oxygen amount of Sm 1.8 Ce 0.2 Cu 1-x Co x O 4-δ increased. The NO-TPD results revealed that NO could be activated much easier over the oxygen-deficient perovskite-like oxides than over the oxygen-excessive perovskite-like oxides, with the NdSrCuO 3.702 catalyst showing the best efficiency in activating NO molecules. Under the conditions of 1.0% NO/helium, 2800 hr -1 , and 600–900°C, the catalytic activity of NO decomposition followed the order of NdSrCuO 3.702 NdSrCu 0.8 Co 0.2 O 3.736 NdSrCu 0.6 Co 0.4 O 3.789 Sm 1.8 Ce 0.2 Cu 0.6 Co 0.4 O 4.187 Sm 1.8 Ce 0.2 Cu 0.8 Co 0.2 O 4.104 Sm 1.8 Ce 0.2 CuO 4.045 , in concord with the sequence of decreasing oxygen vacancy or oxygen excess density. Based on the results, we concluded that the higher oxygen vacancy density and the stronger Cu 3+ /Cu 2+ redox ability of NdSrCu 1-x Co x O 4-δ account for the easier activation of NO and consequently improve the catalytic activity of NO decomposition over the catalysts.     

Sm_xCe_(1-x)VO_4纳米粒子对四环素抗生素的光降解机制

以硝酸钐、硝酸铈和钒酸钠为原料,采用共沉法制备不同Sm/Ce摩尔比的Sm_xCe_(1-x)VO_4纳米复合材料,考察其可见光降解四环素抗生素的催化性能。利用XRD、SEM、TEM、HRTEM、XPS、N_2-sorption和UV-vis DRS等手段表征样品。与Sm VO_4和Ce VO_4纳米粒子相比,Sm_xCe_(1-x)VO_4纳米复合物对四环素抗生素具有更好的可见光催化活性,且对四环素的光降解效率随着Sm/Ce摩尔比的减小先增大后减小。Sm/Ce摩尔比2∶3的Sm_(0.4)Ce_(0.6)VO_4纳米复合材料表现出最好的可见光催化活性,且在相同实验条件下循环使用5次后的光催化活性轻微降低。这归因于Sm_(0.4)Ce_(0.6)VO_4纳米复合材料有利于增强可见光区域的光电子捕获能力,降低光生电子-空穴对的复合和提高光生电子在异质结界面的快速传递。超氧自由基(·O~(2-))和空穴(h~+)是参与Sm_(0.4)Ce_(0.6)VO_4纳米催化剂可见光降解四环素的主要活性物质,其中超氧自由基的影响作用更为显著。     

Photoreaction of 1-(2-chlorobenzoyl)-3-(4-chlorophenyl) urea in simulated atmosphere

Thephotoreactionofl-(2-chlorobenzoyl)-3-(4-chlorophenyl)urea(ccu)in simulated atmosphere was studkd．Rate constants and half-lives of this compound in nitrogen，air and oxygen，upon irradiation with Xenon lamp，were determined．Statistical treatment ofexperimental results indicated that photoreactions in nitrogen and air were of the first order，while that in oxygen was closer to the second order．The main products of photoreaction of this compound were 2-chlorobenzamide，4-chlorophenyl urea，4-chloro aniline，and 2-chloro-N-(4-chlorophenyl)benzamide，and the possible pathways of photodecomposition were suggested．     

Study on the photoreaction of 1-(2-chlorohenzoyl)-3-(4-chlorophenyl 1 urea in methanol

A photoreaction of 1-(2-chlorobenzoyl)-3-(4-chlorophenyl)urea(CCU)m methanol was studied．Rate constants of its reactions，which are found both of the first order，in methanol solution saturated with N₂ or O₂ upon irradiation with xenon lamp,are determined to be O,118 and O.129 h^-1，respectively．Its half life changes from 5.37 to 4.42 h when the light intensity is changed from O.50 to O.62 cal/cm²．min．The main photoproducts identified arc 2-chloro-benzamide．N-phenyl methylearbamate，N-(4-chlorophenyl) methylcarbamate，4-chlorophenyl urea and others．Meanwhile．the mechanism of the photochemical reaction of this compound in methanol was discussed．     

Review the environm ental heimviour of insecticide 1-(2-chlorobenzoyl)-3-(4-chlorophenyl)urea

The environmental behaviour of insecticide 1-(2-chlorobenzoyl)-3-(4-chlorophenyl)urea(CCU) were studied．The results indicated that the insecticide concerning the risk assessment and safe for application of the chemical was not a long-persistent compound in the environment and degraded fastly in plant，soil，water and air．The maior degradation products of CCU were found to bc 4-chloroaniline，4-chlorophenyl urea， 2-chlorobenzamide， 2-chlorobenzoic acid， chloroisocyanatobenzene and 2-chloro-N-chlorophenyl benzamide．The study demonstrated that the insecticide would not be harmful to environment，especmuy to groundwater．However，attention should be paid to the potential problem caused by its degradation products．     

用1-苯基-3-甲基-4-苯甲酰吡唑酮-5(PMBP)从磷酸溶液中萃取铀(Ⅳ)

<正> 本文研究用萃取光度法测定磷酸溶液中的铀含量。为了达到这一目的,已经研究了几种技术。其中之一是测定低量铀(0.02—0.2克/升)的方法,它是用二(2-乙基已基)磷酸(DEHPA)和三辛基氧化膦(TOPO)协同萃取铀(Ⅵ),再用每升含20克铁(Ⅱ)的8.6M磷酸反萃取铀(Ⅳ),最后在醋酸盐缓冲溶液     

钙钛矿La_(1-x)B_xCoO_3光催化降解SDBS的研究

文章采用了溶胶-凝胶法制备了钙钛矿催化剂La1-x Bx CoO3(B=Mg、Ca、Sr;x=0,0.1,0.3,0.5,0.7,0.9,1)并以X衍射线对其结构进行表征,以甲基橙光催化降解率来评价所制备的催化剂的活性。结果表明SrCoO3对甲基橙的降解有较高的活性。在紫外光下,催化剂的量为2.5 g/L、pH=8.0、30%H2O2的量为2 mL/L,SrCoO3对SDBS溶液有较好的降解效果,降解率达到96%。     

结构可控磁性Co_xCu_(1-x)Fe_2O_4对水中五氯苯酚的吸附研究

该文采用溶剂热法合成了不同微结构特性的磁性Co_xCu_(1-x)Fe_2O_4纳米吸附剂,通过透射电子显微镜(TEM)、X-射线衍射(XRD)、BET比表面积仪、磁强计等手段研究了材料的特性,并将此应用于水中五氯苯酚的吸附。结果表明,Co_xCu_(1-x)Fe_2O_4具有良好的吸附能力和磁性能。最合适的调控制备条件是Co含量(x)为0.5,处理温度为200℃。吸附剂对五氯苯酚的吸附符合Langergren一级动力学模型,平衡吸附量为21.55 mg/g;吸附等温线符合Freundlich模型。此外,Co_xCu_(1-x)Fe_2O_4具有良好磁性,容易回收,经O_3再生处理,可重复使用。     

La_xSr_(1-x)NiO_3对水溶液染料的光电催化活性研究

用甘氨酸 硝酸盐燃烧合成法 ,制备LaxSr1 -xNiO3复合氧化物的陶瓷粉末。并以此为光电催化剂对不同水溶液染料进行光催化降解和光电催化降解实验。利用红外、紫外 可见光谱、循环伏安曲线研究LaxSr1 -xNiO3的催化性能。结果表明 :LaxSr1 -xNiO3(x =0 .1 5、0 .6、0 .7、0 .75、1 )复合氧化物都具有较强光催化特性 ,La0 .7Sr0 .3NiO3也具有光电催化降解特性 ;LaxSr1 -xNiO3的光催化活性高于LaNiO3,这与A位离子 (La3+ 、Sr2 + )的电子构型有关 ;Sr2 + 的加入可使LaNiO3的光催化活性有所提高     

基于δ~(15)N和δ~(18)O的农业区地下河硝酸盐污染来源

为研究岩溶区农业活动为主导的地下河流域硝酸盐污染来源,于2017年5~10月每24d左右对重庆青木关流域6个采样点进行监测,利用15N和18O同位素技术对示踪硝酸盐来源进行解译,应用IsoSource模型计算出不同端元硝酸盐的贡献率。结果表明:(1)青木关农业区地下河系统存在较大的硝酸盐污染风险,大部分采样点出现不同程度NO3--N浓度超标现象。(2)空间上,青木关地下河中NO3--N浓度整体呈现由上游向下游升高的趋势。时间上,上游鱼塘和岩口落水洞以及下游姜家泉样点NO3--N浓度在5~6月因受农业施肥的影响,均呈上升趋势,6~9月受降水影响而出现不同程度升高或降低,9月之后随着农业活动减少而逐渐降低;中游土壤点NO3--N浓度保持较高值;中下游大鹿池NO3--N浓度较低且变幅不大。(3)通过硝酸盐15N和18O同位素分析,表明上游鱼塘和岩口落水洞的硝酸盐源于土壤有机氮、动物粪便及污废水混合;中游土壤点硝酸盐源于土壤有机氮、降水和肥料中NH4+;中下游大鹿池中硝酸盐来源于动物粪便及污废水、土壤有机氮、降水和肥料中NH4+的混合作用。地下河出口处姜家泉硝酸盐污染严重,其源于土壤有机氮、降水和肥料中NH4+、动物粪便及污废水、大气沉降的综合作用。(4)基于IsoSource模型对地下河出口处硝酸盐来源进行定量分析,发现动物粪便及污废水贡献率占46.4%,土壤有机氮占32.6%,降水与肥料中NH4+占18.6%,大气沉降仅占2.4%。     

Numerical sim ulation of transport and transform ation of insecticide 1-(2-chlorobenzoyl)-3-(4-chlorophenyl) urea in unsaturated soil

A numerical simulation model of pesticide transport and transformation in unsaturated soil is presented in this paper．The model was developed under basic principles of movement of water and solute in soil under transient condition and overall consideration water flow：pesticide convection，diffusion, dispersion，sorption and degradation．The model was tested for the persistence and leaching of 1-(2-chlorobenzoyl)-3-(4-chlorophenyl)urea(CCU)using data from soil columns under laboratory conditions．The results of the test indicate that the modeling approach is simple and effective in describing movement and transformation of pesticides in soils．     

Adsorption leaching of l-(2-chlorobenzoyl)-3-(4-chlorophenyl)urea in soil

A study of adsorption of l-(2-chlorobenzoyl)-3-(4-chlorophenyl)urea(ccu)on fourtypes of soil was performed by using the batch slurry method．Freundlich adsorption isotherm equations of CCU in each soil were obtained and the method and the procedure were described in detail．At the same time，Freundlich adsorption coeffacient(K_{d)and organic carbon adsorption coefficient(Koc)were given for each soil．The leaching of CCU on different soils was also investigated under laboratory conditions．The results showed that CCU possesses a weak tendency of leaching to the deep layer of soil or contaminating the underground water．}     

δ~(15)N和δ~(18)O指标识别环境中N_2O生成机理

δ15N和δ18O指标在识别环境N2 O生成机理中具有重要的作用。本文主要讨论δ15N指标在识别海洋、土壤和污染水体N2 O生成机理中的作用 ;分析硝化和反硝化作用引起的同位素分馏特征 ;并对δ18O指标的应用进行了探讨。     

1991年总目次(第4卷 第1—4期)

研究报告紫外光降解RDX的研究············一,·,,··,······……太湖地区农村生态经济协调发展途径的探讨蚌埠市大气污染源布局问题研究】··一·一荆马河沉积物的污染·····1,·一卜宜昌市城市环境地质灾害地质研究与控制对策武汉市大气污染物排放标准的研究与制订····,·二·········,·…1(1)··,·····,··二1(5) ’几(1) 3(10)····,·,一4(1)······‘··…4(6) 调查研究徐州市小造纸发展现状及其污染防治‘········……乡镇工业对徐州市农村环境质量的影响分析·徐州…     

安图红松树轮稳定δ~(13)C、δ~(18)O序列记录的气候变化信息

测定了安图红松树轮稳定碳、氧同位素组成。选取与安图县毗邻的敦化市气象记录 ,分析了气象记录与树轮稳定碳、氧同位素的相关关系 ,发现红松树轮碳、氧同位素对气候变化均有显著的响应。合成了复合温湿指标 (TH) ,相关分析表明树轮碳、氧同位素对复合温湿指标的响应更加灵敏 ,而且碳同位素和氧同位素均对 5～ 8月的平均复合温湿指标有显著的响应。建立了碳、氧同位素对气候因子的响应函数 ,重建了安图地区近 2 0 0年来的气候变化。功率谱分析发现碳、氧同位素组成在 95 %的置信水平上存有准 2 0 0年、准 11年、准 4年和准 2年的变化周期。前两个周期变化基本上与太阳活动周期变化一致 ,后两个周期分别对应于“厄尔尼诺现象”和东亚夏季风的“准 2年振荡”。     

金堆城超大型钼矿床水-岩δD-δ~(18)O同位素交换体系理论模型及成矿流体来源

基于水-岩δD-δ18O同位素交换体系理论模型的建立和计算，对金堆城超大型斑岩钼矿四个不同成矿期中成矿流体的演化和来源进行了研究，发现在成矿前期和早期，成矿流体为岩浆水与围岩在较低水／岩比值（0．1W／R＞0．001）和中、高温（t=250～500℃）条件下反应后的残余流体，而主成矿期和成矿晚期的成矿流作为大气降水在相对较高水／岩比值（0．5＞W／R0．1）和中、低温（t＝150～310℃）条件下与围岩反应后的残留流体。大气降水在金堆城钼矿成矿过程中起了重要作用。在主成矿期水／岩比值达到最高。     

A comparative investigation of NdSrCu1-xCoxO4-σ and Sm1:8Ce0:2Cu1-xCoxO4-σ(x: 0-0.4) for NO decomposition

A series of single-phase T-structured NdSrCu1??xCoxO4?? with oxygen vacancies and T0-structured Sm1:8Ce0:2Cu1??xCoxO4?? (x: 0–0.4) with oxygen excess were prepared using ultrasound-assisted citric acid complexing method, and characterized by means of techniques such as thermogravimetric analysis and NO temperature-programmed desorption (NO-TPD). The catalytic activities of these materials were evaluated for the decomposition of NO. It was found that the NdSrCu1??xCoxO4?? catalysts were of oxygen vacancies whereas the Sm1:8Ce0:2Cu1??xCoxO4?? ones possessed excessive oxygen (i.e., over-stoichiometric oxygen); with a rise in Co doping level, the oxygen vacancy density of NdSrCu1??xCoxO4?? decreased while the over-stoichiometric oxygen amount of Sm1:8Ce0:2Cu1??xCoxO4?? increased. The NO-TPD results revealed that NO could be activated much easier over the oxygen-deficient perovskite-like oxides than over the oxygen-excessive perovskite-like oxides, with the NdSrCuO3:702 catalyst showing the best e ciency in activating NO molecules. Under the conditions of 1.0% NO/helium, 2800 hr??1, and 600–900°C, the catalytic activity of NO decomposition followed the order of NdSrCuO3:702 > NdSrCu0:8Co0:2O3:736 > NdSrCu0:6Co0:4O3:789 > Sm1:8Ce0:2Cu0:6Co0:4O4:187 > Sm1:8Ce0:2Cu0:8Co0:2O4:104 > Sm1:8Ce0:2CuO4:045, in concord with the sequence of decreasing oxygen vacancy or oxygen excess density. Based on the results, we concluded that the higher oxygen vacancy density and the stronger Cu3+/Cu2+ redox ability of NdSrCu1??xCoxO4?? account for the easier activation of NO and consequently improve the catalytic activity of NO decomposition over the catalysts.     

Ce_(0.65-x)Co_xK_(0.15)Zr_(0.2)O_2催化碳烟燃烧活性研究

采用柠檬酸络合燃烧法制备了不同铈钴摩尔比的Ce_(0.65-x)Co_xK_(0.15)Zr_(0.2)O_2(x=0,0.15,0.23,0.30,0.38,0.45,0.65)催化剂,采用XRD、SEM、FT-IR与H_2-TPR等技术对催化剂进行表征,并通过程序升温氧化反应(TPO)考察了催化剂不同Ce/Co比对碳烟颗粒物催化燃烧活性的影响。研究结果表明:在松散接触条件下,该系列催化剂催化碳烟颗粒物燃烧活性较高,T_m均小于400℃,当x=0.23时活性最高,T_i与T_m分别为321℃与355℃,催化剂所表现出的高活性受益于样品表面具有大量高活性的细小Co_3O_4颗粒物。     

Cl~-、SO_4~(2-)和PO_4~(3-)对异养反硝化污泥的胁迫效应

反硝化菌是反硝化作用的驱动者,探明Cl~-、SO_4~(2-)和PO_4~(3-)对异养反硝化污泥(HDS)的胁迫效应,有助于含盐废水生物脱氮技术的研发和优化.选用硝酸盐还原酶(周质酶)和碱性磷酸酯酶(胞内酶)作为指标,考察了不同Cl~-、SO_4~(2-)和PO_4~(3-)浓度对HDS酶活的影响;通过观测HDS中的活菌水平和细胞形态,考察了不同Cl~-、SO_4~(2-)和PO_4~(3-)浓度对HDS微生物细胞结构的影响.结果表明,Cl~-、SO_4~(2-)和PO_4~(3-)对HDS硝酸盐还原酶的半抑制浓度分别为0.15、0.12和0.05mol/L,对碱性磷酸酯酶的半抑制浓度为1.14、0.75和0.49mol/L;高浓度Cl~-、SO_4~(2-)和PO_4~(3-)导致HDS微生物细胞膜结构破损,通透性增加,细胞物质外泄.阴离子对HDS的胁迫可分为渗透胁迫和电荷胁迫,渗透胁迫造成HDS中功能酶失活,电荷胁迫造成HDS中细胞膜破损,细胞物质外泄.     

ABR反应器中COD/SO_4~(2-)值和硫酸盐负荷对SO_4~(2-)去除影响

利用厌氧折流板反应器,分别考察了反应器启动,及不同COD/SO42-比值和硫酸盐负荷对模拟废水中SO42-去除的影响。实验在(32±0.1)℃,pH为6.0⁶.5的条件下连续运行。结果表明:ABR经过约90 d的启动驯化阶段后,进水硫酸盐及COD浓度分别为1 500 mg/L和3 000 mg/L,水力停留时间为12 h条件下,硫酸盐去除率达到了92%。固定COD/SO42-比值为2.5时,随着进水SO42-浓度的增加(1 5006.5的条件下连续运行。结果表明:ABR经过约90 d的启动驯化阶段后,进水硫酸盐及COD浓度分别为1 500 mg/L和3 000 mg/L,水力停留时间为12 h条件下,硫酸盐去除率达到了92%。固定COD/SO42-比值为2.5时,随着进水SO42-浓度的增加(1 500³ 500 mg/L),SO42-去除率逐渐下降,最低为60%,相反SO42-去除速率随着硫酸盐浓度的增加而增加,最大为7.98 kg(/m3.d);维持恒定的硫酸盐浓度(1 500 mg/L),逐渐缩短水力停留时间以提高反应器中硫酸盐负荷,SO42-去除率呈现先上升后下降的复杂变化趋势,当水力停留时间为6 h时,SO42-去除率达到最大;随着COD/SO42-比值的提高,硫酸盐去除能力增强,且反应体系对硫酸盐负荷的耐受能力也逐渐增强。