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1.
Dental personnel manually handle methacrylate-based restorative materials, which can cause skin irritation and allergies. The protection given by different types of medical gloves is not well known. Breakthrough time (BTT, min) was used as a measure of protection according to a European standard, using 2 test mixtures consisting of respectively 3 and 5 monomers. Fourteen gloves representing natural rubber latex, synthetic rubber, and synthetic polymeric material were tested. The BTT ranged from some minutes to more than 2 hrs for the 4 monomers with a molecular mass less than 300. The longest protection was recorded for Nitra Touch (nitrile rubber), Tactylon (synthetic rubber), and Metin (PVC).  相似文献   
2.
In this article, the technical feasibility of the use of activated carbon, synthetic resins, and various low-cost natural adsorbents for the removal of phenol and its derivatives from contaminated water has been reviewed. Instead of using commercial activated carbon and synthetic resins, researchers have worked on inexpensive materials such as coal fly ash, sludge, biomass, zeolites, and other adsorbents, which have high adsorption capacity and are locally available. The comparison of their removal performance with that of activated carbon and synthetic resins is presented in this study. From our survey of about 100 papers, low-cost adsorbents have demonstrated outstanding removal capabilities for phenol and its derivatives compared to activated carbons. Adsorbents that stand out for high adsorption capacities are coal-reject, residual coal treated with H3PO4, dried activated sludge, red mud, and cetyltrimethylammonium bromide-modified montmorillonite. Of these synthetic resins, HiSiv 1000 and IRA-420 display high adsorption capacity of phenol and XAD-4 has good adsorption capability for 2-nitrophenol. These polymeric adsorbents are suitable for industrial effluents containing phenol and its derivatives as mentioned previously. It should be noted that the adsorption capacities of the adsorbents presented here vary significantly depending on the characteristics of the individual adsorbent, the extent of chemical modifications, and the concentrations of solutes.  相似文献   
3.
Biocomposites were made by a novel high volume processing technique named biocomposite sheet molding compound panel (BCSMCP) manufacturing process. This process design was inspired by the commercial glass fiber–polyester resin composite fabrication method called sheet molding compounding (SMC). This process yields continuous production of biocomposites on a large scale, and thus can be easily adopted in industries. A unique fiber dispersion method, which enabled uniform distribution of natural fibers, was used in this process. Consistency of the process was tested by evaluating the repeatability of the resultant materials mechanical properties. The low cost biocomposites produced as a result of the processing will be used for various panel applications such as housing and transportation. The molded samples were tested for various mechanical and thermal properties, in accordance with ASTM procedures. The biocomposites were made with various natural fibers including, big blue stem grass, jute, and industrial hemp. By combining different natural fibers in varying mass fractions, hybrid biocomposites were made using this process. Grass fiber reinforced polyester biocomposites processed by the SMC line showed very promising results.  相似文献   
4.
从原料的危害,有机物的挥发量,人员的个人防护等方面对脲醛树脂胶粘剂的职业安全问题进行了探讨,并指出了其安全环保的发展方向。  相似文献   
5.
带希夫碱和酰肼基团的壳聚糖螯合树脂的合成及其吸附性能   总被引:21,自引:1,他引:21  
刘芳  董世华 《环境化学》1996,15(3):207-213
本文利用壳聚糖C2位上活泼氨基与水杨醛进行大分子反应,再以环硫氯丙烷作交联剂,合成了带有邻羟基希夫碱基团的交联型壳聚糖螯合树脂;利用带有游离氨基的交联壳聚糖与丙烯腈进行大分子反应,合成了带有氰基的功能聚合物,再由CT-CN与水合肼进一步反应,制得了带有酰肼基轩物壳聚糖螯合树脂。  相似文献   
6.
SCOPE: The detection and investigation of metal ions bound in strong complexes in natural waters is a difficult task, due to low concentration of the metal ions themselves, and also of the strong ligands, which, moreover, are often not of a well-defined composition. Here, a method is proposed for the investigation of the speciation of metal ions in natural waters. OBJECTIVE AND METHOD: It is based on the sorption of metal ions on strongly sorbing ion exchange resins, i.e. complexing resins. For this reason the method is called Resin Titration. It has been shown in previous investigations that the concentration of metal ion totally sorbed by a particular resin, and its reaction coefficient in the solution phase in the presence of the resin, can be determined from the sorption data using a simple relationship. Here, a data treatment (the Ruzic linearization method) is proposed for also determining the concentration of the ligands responsible for the complex in equilibrium with the resin. RESULTS: The method was applied to data obtained by Resin Titration of a freshwater and a seawater. Copper(II) and aluminium(III) were considered, using Chelex 100 as a titrant, due to its strong sorbing properties towards these metal ions. The results were: the total metal concentration in equilibrium with the resin, the side reaction coefficients, and the concentration of ligands. In all these cases the ligands forming very strong complexes were found to be at concentration lower than that of the metals. CONCLUSION: The Ruzic linearization method allows the determination of the concentration of the ligands forming very strong complexes in equilibrium with Chelex 100. The reaction coefficient was better determined by the calculation method previously proposed for RT. The ligands responsible for the strong complexes were found to be at low concentration, often lower than that of the metal ions considered. The metal in the original sample is partly bound to these ligands, since the complexes are very strong. Only a part of the metal is linked to weaker ligands, or free.  相似文献   
7.
包南  高连存  王吉顺  王淑仁 《环境科学》1995,16(2):73-77,66
以乙腈-水-醋酸(31:68:1,V/V/V)为流动相的反相HPLC-UV法,可以方便地对水中酚类进行直接分离和分析。采用树脂吸附法为HPLC的预富集步骤,选用国产吸附树脂GDX-502为富集剂,二氧六环为洗脱剂,可以定量测定水中μg/L级以下的多种酚。在实验条件下,9种一元酚的平均变异系数为2.4%,其中8种酚的富集回收率大于90%。用本法测得的地面水的总酚含量与4-氨基安替比林法具有可比性。  相似文献   
8.
为分析不饱和聚酯树脂在内衬改造应用中存在的引燃风险,阐述加油站埋地罐内衬改造工艺,测试不饱和聚酯树脂固化放热特性、与玻璃钢摩擦的滚刷及装树脂绝缘桶的表面静电电位。结果表明:不饱和聚酯树脂与固化剂混合后的放热不足以引起树脂自燃;滚刷、树脂与绝缘桶间摩擦可导致桶表面静电位超过7 kV,带电绝缘体表面与金属凸出物间存在静电放电现象、甚至引起挥发苯乙烯局部闪燃风险。油罐内衬改造时需强化通风以及增加静电防护措施,避免静电放电引起罐内燃爆事故。  相似文献   
9.
Waste cooking oil is a potential substitution of refined vegetable oil for the production of biodiesel due to the low cost of raw material and for solving their disposal problem. In this study, optimization of esterification process of free fatty acids in artificially acidified soybean oil with oleic acid has been carried out using methanol as an agent and ion exchange resin as a heterogeneous catalyst. The esterification reaction has been investigated based on the mass balance of the developed model. The model has been validated against experimental data and effects of temperature and catalyst weight have been analyzed. Thereafter, optimization process has been fulfilled for two different objective functions as conversion of acid oil and benefit. Optimization results indicated that the maximum conversion of acid is 95.95%, which is achievable at 4.48-g catalyst loading and reaction temperature of 120°C. Maximum benefit was obtained as US$0.057 per batch of reaction at a catalyst amount of 1 g and temperature of 120°C.  相似文献   
10.
稠油降解菌的筛选、鉴定与菌群构建   总被引:1,自引:1,他引:0  
分别以烷烃、芳烃、胶质沥青质为唯一碳源,从稠油污染过的土壤里分离、筛选可培养的降解菌,将16株组合构建SL-16稠油降解菌群,通过室内摇瓶实验测得该菌群在最佳条件下对陈庄油田稠油降解率可达68%,其适宜的生长及降解温度为35~45℃,pH值为7.0~9.0,含盐量为4 000~14 000 mg/L,接种量为2%,稠油...  相似文献   
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