Integrated Bi2O3 nanostructure modified with Au nanoparticles for enhanced photocatalytic activity under visible light irradiation

An integrated Bi_2O_3(i-Bi_2O_3) nanostructure with a particle size 10 nm inducing agglomerated structure were synthesized by dissolving bismuth nitrate pentahydrate in diethylene glycol at 180 ℃ with post heat treatment.The prepared i-Bi_2O_3 nanostructures were employed for the construction of Au/i-Bi_2O_3 composite system and characterized by X-ray diffraction pattern,UV-visible diffuse reflectance spectroscopy(DRS),and transmission electron microscopy,X-ray photoemission spectroscopy(XPS) and Energy dispersive X-ray spectroscopy(EDS).The i-Bi_2O_3 nanostructure and Au/i-Bi_2O_3 composite system were found to exhibit high photocatalytic activity than commercial Bi_2O_3 in decomposing salicylic acid under visible light irradiation.The high catalytic activity of i-Bi_2O_3 nanostructure was deduced to be caused by charge separation facilitated by electron hopping between the particles within the integrated structure and space-charge separation between i-Bi_2O_3 and Au.The charge separation behavior in i-Bi_2O_3 nanostructure was further bolstered by comparing the measured.OH radical produced in the solution with i-Bi_2O_3 nanostructure,commercial Bi_2O_3 and Au/i-Bi_2O_3 composite which readily react with 1,4-terephthalic acid(TA) inducing 2-hydroxy terephthalic acid(TAOH) that shows unique fluorescence peak at 426 nm.The space-charge separation between i-Bi_2O_3 and An was confirmed by measuring the electron spin resonance(ESR) spectra.     

The distribution of acid deposition in Germany

Summary The distribution of acid deposition by atmospheric precipitation in the Federal Republic of Germany is discussed, based on investigations of the wet H⁺-deposition during the five years 1980–1984, using a network of 16 automated samplers of our own construction located in various categories of ecosystems. Analytical problems of sampling and the electrometric determination of pH in rainwater are briefly discussed. Results for the average amounts of precipitation, the average H⁺-concentrations and average H⁺-depositions in the 16 typical regions of the Federal Republic of Germany are compared and the influences of meteorological parameters are discussed. An increase of the H⁺-concentration and H⁺-deposition values has been observed from 1980 onwards with a maximum in 1981 and a slow decrease in the next two years. The comparison of the values found for rural regions with those for more significantly polluted regions shows that in the latter regions the removal of H⁺-ions by wash-out is more effective. Whereas in the Ruhr region the pH is shifted to more acid values, due to the wash-out of acid particles and aerosols, in regions with metallurgical industry the pH is shifted to more alkaline values due to the wash-out of alkaline particles. In general the free acid in rain and snow is rather uniformly distributed over the whole area as a result of mesoscalic transport of the acid precursors SO₂ and NO_x and the concomitant formation of acid in the cloud droplets leading to acid deposition by rain-out. The composition of rainwater and the possibility of determining the proportion of the acid anions in rain which are of anthropogenic origin is briefly discussed.Deseased (May 12th, 1985).     

关于紫棕土的性状及其分类命名商榷

本文报导了作者在全国第二次土壤普查中于江西省广丰等县查到了一种由玄武岩风化物发育的土壤,介绍了这种土壤的成土条件、形态特征和基本属性(剖面各层颗粒组成、养分状况、pH值和代换性能、粘粒化学组成、腐殖质组成及粘土矿物组成等)都与红壤显著不同,认为应在分类中单独分出。就此,作者提出这种土壤的分类命名商榷,拟命名为“紫棕土”。     

加载速率对红砂岩力学效应的试验研究

采用伺服刚性试验机对５４块红砂岩试件进行了９级不同应变加载速率下的单轴压缩室内测试，定量分析了应变速率对材料单轴抗压强度、与峰值强度对应的应变、破坏后的变形模量，以及破裂形式等物理力学性态的影响，按实测数据回归得出的经验公式可用于估算应速率变化剧烈状况下岩石的修正强度和变形量。     

气相色谱法测定工业废水厌氧反应中的挥发性脂肪酸

文章介绍了应用气相色谱法测定挥发性脂肪酸(VFA)的方法,挥发性脂肪酸是厌氧反应器运行中重要的控制指标,该方法试样预处理简便、快速,所采用的色谱柱(GDX-103)对脂肪酸分离效果好,保留时间短,回收率高,变异系数小。     

用活性炭吸附和TiO2光催化降解法处理酸性红G染色废水

用活性炭吸附、二氧化钛光催化降解处理酸性红G染色废水．用正交试验法研究了活性炭用量、吸附时间、二氧化钛用量、紫外灯照射时间对酸性红G去除率的影响．结果表明：若使用活性炭吸附,在20mL浓度为5．26×10^-5mol／L的废水中加0．8g活性炭,搅拌30min,废水中酸性红G去除率达97．1％．若用二氧化钛光催化降解,则在20mL相同浓度的废水中加二氧化钛0．05g,在300W紫外灯下照20min,废水中酸性红G去除率为99．2％．     

高比表面积煤系高岭土材料的制备及其结构表征

高比表面积改性煤系高岭土具有优异的性能,现已被广泛地应用于多种行业。本文以内蒙煤系高岭土为原料,将其高温煅烧制得偏高岭土后,再经盐酸改性用以制备高比表面煤系高岭土材料;通过X射线衍射(XRD)、差热-热重分析(DTA-TGA)和N2吸附-脱附等手段对改性前后煤系高岭土的晶体结构及比表面积进行了表征,实验考察了煅烧温度、煅烧时间、盐酸用量、盐酸浓度及反应时间对煅烧煤系高岭土比表面积的影响,确定了酸改性煤系高岭土的最佳工艺条件;在最佳工艺条件下制备的盐酸改性煤系高岭土材料的比表面积高达465 m2/g。     

一种新β—二酮螯合剂的酸离解常数和两相分配常数的测定

在水-乙醇及水-二氧六环混合溶剂体系中,用pH电位滴定法,测定了新β-酮螯合剂1-苯基-3-甲基-4-(α-呋喃甲酰基)-5-吡唑酮(简称HA)在不同有机溶剂含量(x)时的酸离解常数(K_a),建立了K_a与x的关系式,通过外推,求出HA在纯水中的酸离解常数pK_a=4.18±0.02(I=0.10,t=25±0.5℃),采用两相滴定法,测定了HA在七种有机溶剂与水相间的两相分配常数。用Hildebrand正规溶液理论解释了实验结果,进而建立了溶度参数(δ)与两相分配常数的关系式:log K_d=log(1000d/M)+3.07-0.248(δ-9.80)~2,式中d和M分别是溶剂的密度及摩尔质量。     

红线协定：美国石油资本进驻海湾地区的起点

随着第一次世界大战的爆发,石油从一般性商品跃为战略性物质。美国借战争之机成为世界经济和军事大国,提出＂十四点原则＂意欲争霸世界,海湾丰富的石油资源引起美国的＂关注＂。战后,美国政府积极支持本国石油资本向海湾地区扩张,迫使中东霸主英国签订＂红线协定＂,插足伊拉克,打破了英国对海湾石油资源的垄断。     

红泥聚氯乙烯复合材料热稳定性的机理

各种红泥对PVC都有优良热稳定作用,其热稳定性机理为:1)红泥中的基因Al-O能与PVC分子链上的活泼叔碳氢及—CO—CH=CH—CHCl—基团中的活泼氯发生取代反应消除PVC链上易脱HCl的始发点,从而使PVC链稳定;2)红泥中的游离碱、碱性金属氧化物与碱性金属盐能及时与PVC初脱出来的HCl起反应或吸收,从而阻止PVC继续分解HCl;3)红泥中的铁组分不论以FeCl_3或Fe_2O_3存在,都有显著加速PVC热分解速度,其作用机理可能是Fe_2O_3能促进PVC链生成反常结构-CO-CH=CH-CHCl-,它是促使PVC易脱HCl的一个主要反常结构因素。