Production of silver‐doped analcime by isomorphous substitution technique

BACKGROUND: Metal‐exchanged zeolites have been reported to have significant limitations on cayalytic activity, such as counterbalancing the negative framework charges and limitation of active space. Alternative methods of incorporating silver ions into the framework of zeolites are therefore necessary. This paper reports on a technique for producing silver doped analcime by isomorphous substitution of silver ion into the framework of analcime. The amount of aluminium in the gel composition was reduced by a factor of 5%, 10% and 20% and an equivalent amount of silver was added to the gel and treated in a conventional manner for zeolite crystallisation. Some of the aluminium in the reaction gel was replaced with the silver. The silver‐doped analcime samples where characterised by X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐rays (EDX), Fourier transform infrared (FTIR) spectroscopy and inductively coupled plasma‐atomic emission spectroscopy (ICP‐AES) analysis. RESULTS: The amount of silver ions loaded for each reduction of aluminium as determined by EDX were found to be (w/w) 0.29%, 1.41% and 2.10%, respectively. XRD pattern SEM images of the silver‐doped analcime showed the presence of zeolite P in addition to analcime. CONCLUSION: Silver‐doped analcime was successfully produced with different silver loadings and may exhibit higher anti‐microbial activities than silver‐exchanged counterparts. Copyright © 2008 Society of Chemical Industry     

Stretchable Gold Tracks on Flat Polydimethylsiloxane (PDMS) Rubber Substrate

A process to fabricate stretchable gold tracks on silicone rubber substrates is studied by XPS, static water contact angle measurement, AFM, and SEM. The process involves several steps: removing uncured oligomers by hexane Soxhlet extraction; pre-stretching the substrate; activating the strained silicone surface by an oxygen plasma treatment; coating the strained substrate with 5 nm titanium and 80 nm gold layers; and finally releasing the sample. The plasma treatment creates a thin brittle silica-like layer that temporarily increases the substrate's surface energy. Indeed, the plasma treatment is followed by a hydrophobic recovery. As a consequence, the delay between plasma treatment and metal deposition has to be reduced as much as possible. The silica-like layer can be nicely observed after release. The entire process allows us to obtain stretchable metallized samples that remain conductive even after an excessive deformation leading to electrical failure.     

Biosorption of heavy metals by Saccharomyces cerevisiae: Effects of nutrient conditions

Studies took place to investigate the effects of different nutrient conditions on the biosorption ability and selectivity of heavy metals by Saccharomyces cerevisiae. After having grown in media supplemented with additional glucose, ammonium, phosphate or cysteine, the yeast was exposed to an equimolar solution of lead, cadmium, zinc and copper. Lead removal from a mixed solution was significantly higher than that of copper, followed by zinc and cadmium. Generally, yeasts from cysteine-rich media showed greatest sorption capacity whereas phosphate addition influenced zinc selectivity. In addition, glucose, fructose and sucrose as carbon sources were examined. Cultures grown in glucose had a better uptake than those cultivated with fructose at an incubation time of 30 min.     

Trifluoromethanesulphonic acid catalysed transalkylation between tetrabromobisphenol-a and toluene for the production of 2,6-dibromophenol

The preparation of 2,6-dibromophenol is described. This compound, useful as raw material for brominated poly(phenyleneoxide) and pyrogallol or derived pharmaceuticals/pesticides, was prepared in 80% (isolated) yield by a transalkylation reaction between tetrabromobisphenol-A and toluene. The catalyst, trifluoromethanesulphonic acid, can be simply recovered and recycled. Perfluorinated resin sulphonic acid (NAFION-H®, DuPont) did not effectively catalyse this transalkylation.     

计算机硬盘坏磁道修复的思路与技巧

本文通过隐藏坏磁道分区的方法,着重介绍了硬盘坏磁道的修复技术及注意事项,同时还介绍了逻辑坏磁道、0磁道损坏的修复方法。     

PRO/Ⅱ软件在硫磺回收中的二次开发应用

硫磺回收装置的设备需要有较大的操作弹性。针对其过程气进口压力低，手工计算难于进行严格的全程压降计算，现以PRO／Ⅱ软件为开发平台，通过扩充数据库和建立模拟流程，成功地将其用于硫磺回收装置的设备选型和核算，为工程设计提供了先进的计算手段。     

Simultaneous recovery of copper and surfactant by an electrolytic process from synthetic solution prepared to simulate a concentrate waste stream of a micellar-enhanced ultrafiltration process

Electroplating method was employed to recover copper and surfactant simultaneously from synthetic solutions prepared to simulate concentrated waste stream generated from micellar-enhanced ultrafiltration. Effects of surfactant and copper (II) concentrations, surfactant to copper (II) molar ratio (S/M), electroplating voltage and time, solution pH, and ionic strength on metal recovery and electrical current efficiency were investigated. Results show that at a fixed S/M ratio of 5, the first-order kinetic constant for Cu (II) removal by electroplating increases with decreasing SDS concentration. At fixed SDS concentration of 8.5 mM, increasing initial Cu (II) concentration increases both Cu (II) recovery and current efficiency. Electrolyte pH has profound effects on the metal recovery and current efficiency due to the difference in solution conductivity after pH adjustment and the extent of Cu (II) adsorption onto SDS at different pHs.     

Nitrogen fertilizer use in rainfed agriculture

Agronomic efficiency (AE) is defined as the increase in economic yield of a crop per unit fertilizer applied. Components of AE are physiological efficiency and apparent recovery fraction. The latter can be further separated into uptake efficiency and availability index. Ways to increase the nitrogen fertilizer use efficiency in rainfed agriculture through fertilizer management are discussed.     

基于Jpcap的Webmail邮件还原技术

基于Smtp和Pop3的邮件还原技术已经日臻成熟,而由于主要Webmail邮件格式不同,Webmail邮件还原技术一直是难点。通过对主要Webmail的内容格式分析,针对不同网站的Webmail建立相应的还原模块,实现对主要Webmail的内容还原。实验结果验证了该技术的有效性。     

丙烯腈生产中噁唑控制方法的研究

本文介绍了丙烯腈生产过程中影响杂质噁唑产生的因素，并对噁唑超标的处理方法进行了研究，成功地将侧线产品中噁唑的含量控制在10^-6之内。