SiO_2-TiO_2纳米管的制备及其光催化性能的研究

文章采用水热法制备SiO2-TiO2纳米管,通过扫描电镜(SEM)和透射电镜(TEM)考察了该纳米管的结构形态,并用X-射线衍射考察其晶体结构。实验结果表明所制得的纳米管是锐钛晶型,其两端开口,具有多层管壁;管径为8nm左右,管壁厚1～2nm。光催化降解酸性橙Ⅱ实验表明:SiO2-TiO2纳米管光催化速率比TiO2纳米管高出10%。这可能是因为Si元素的存在增大了钛纳米管的比表面积,同时SiO2的存在能降低光生电子和空穴的复合率。     

兰炼烷基化废酸处理工艺选择

对目前四种烷基化硫酸处理工艺进行了分析比较，认为兰炼应依托现有硫酸装置，采用裂解制硫酸工艺来处理烷基化废酸。     

新型负载型纳米TiO_2光催化降解苯酚的试验研究

以岩棉为载体制备一种新型负载型纳米TiO2,对有机污染物苯酚的降解效果较好。岩棉对苯酚有一定的吸附作用。经过120min的处理,苯酚基本上被完全降解。流速对降解率的影响较大,本试验选择流速为5mL/min。初始浓度越小,苯酚的降解效果越好。通入O2和加入适量H2O2均有利于苯酚的降解,且少量的H2O2可使苯酚的降解率大大提高。苯酚在pH=4.5时降解效果最好。     

过程模拟法在清洁生产研究中的应用

以醋酸清洁生产为例，介绍了过程模拟法在清洁生产研究中的应用。利用现代过程模拟技术，可在较小人力、物力投入的前提下，获得更多的系统信息，有利于清洁生产工艺的确定及操作参数的优化。     

Complex behaviour of trivalent rare earth elements by humic acids

ＣｏｍｐｌｅｘｂｅｈａｖｉｏｕｒｏｆｔｒｉｖａｌｅｎｔｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｂｙｈｕｍｉｃａｃｉｄｓＧｅｎｇＡｎｃｈａｏＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＥｎｖｉｒｏｎｍｅｎｔａｌＥｎｇｉｎｅｅｒｉｎｇ，ＦｕｓｈｕｎＰｅｔｒｏｌｅ...     

Effects of low pH on zooplankton in some suburban waterbodies of Chongqing City

ＥｆｆｅｃｔｓｏｆｌｏｗｐＨｏｎｚｏｏｐｌａｎｋｔｏｎｉｎｓｏｍｅｓｕｂｕｒｂａｎｗａｔｅｒｂｏｄｉｅｓｏｆＣｈｏｎｇｑｉｎｇＣｉｔｙＺｈｕａｎｇＤｅｈｕｉ（ＩｎｓｔｉｔｕｔｅｏｆＨｙｄｒｏｂｉｏｌｏｇｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃ...     

Vitamins,folic acid and neural tube defects: Comments on investigations in the United States

No clear answer concerning whether multivitamin/folate supplementation prevents neural tube defects (NTDs) is provided by three studies in the United States. All these studies are occurrence in nature, no recurrence studies having been conducted. The Atlanta Birth Defects Study is subject to pronounced memory and recall biases, the length between event and interview being as long as 16 years. In a second study (Boston University), objections can be raised to certain aspects of the experimental design, and the claim that 22 per cent of women started vitamins sufficiently early after pregnancy diagnosis to influence NTD formation is suspicious. Our NICHD case control study of 541 women in California and Illinois revealed no evidence for multivitamins or folic acid preventing NTDs. U.S. public policy-makers face difficulties in applying results of recurrence or occurrence studies in high-risk areas to low-risk areas in the U.S.     

味精废水处理研究

味精废水具有浓度高、粘性大、pH值低、SS含量高等特点 ,其中SO42 及NH3 N含量高 ,使味精废水处理难度大。用Ca(OH) 2 中和味精废水 ,从而找出味精废水进入生化段的最佳条件     

湿法烟气脱硫添加剂的试验研究

采用我校自主设计研制的水浴脱硫设备,以石灰石为脱硫剂,通过模拟烟气净化冷态模型试验研究了甲酸,乙酸,已二酸,草酸作为有机添加剂对湿法烟气脱硫的影响,并讨论了其机理.试验结果表明,有机酸添加剂能减缓脱硫液pH值的降低过程,能在较低的pH值时得到较高的脱硫率.实验结果为有机添加剂在湿法脱硫中的应用提供了理论依据.     

Acid resistance of methanogenic bacteria in a two-stage anaerobic process treating high concentration methanol Wastewater

In this study, the two-stage upflow anaerobic sludge blanket (UASB) system and batch experiments were employed to evaluate the performance of anaerobic digestion for the treatment of high concentration methanol wastewater. The acid resistance of granular sludge and methanogenic bacteria and their metabolizing activity were investigated. The results show that the pH of the first UASB changed from 4.9 to 5.8 and 5.5 to 6.2 for the second reactor. Apparently, these were not the advisable pH levels that common methanogenic bacteria could accept. The methanogenic bacteria of the system, viz. Methanosarcina barkeri, had some acid resistance and could still degrade methanol at pH 5.0. If the methanogenic bacteria were trained further, their acid resistance would be improved somewhat. Granular sludge of the system could protect the methanogenic bacteria within its body against the impact of the acidic environment and make them degrade methanol at pH 4.5. The performance of granular sludge was attributed to its structure, bacteria species, and the distribution of bacterium inside the granule. Translated from Acta Scientiae Circumstantiae, 2004, 24(4): 633–636 [译自: 环境科学学报]