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101.
In an attempt to convert the carcinogenic benzene which is almost restricted for its use in gasoline, alkylation reaction with olefin 1-hexene has been conducted on various zeolites. Four zeolites having different pore topology and pore size have been applied as solid acid catalysts for effective production of alkylate in a liquid phase, solvent-less low temperature reaction. The textural properties of all the four zeolites (ZSM-5, MOR, BEA, HY) have been characterized for crystal morphology by TEM, crystal structure by XRD and FTIR, BET for surface area, N2 sorption for porosity and TPD for acidity. Among the zeolite, BEA possessed high surface area (600.61 m2/g) and enhanced meso pores volume (0.3956 cm3/g) as compared to other zeolite samples. The performance of BEA was also observed to be superior in the liquid phase alkylation of benzene with 1-hexene in a batch reactor under autogenous pressure without using any solvent. At the optimum reaction conditions, the benzene conversion was 86.6 wt% and 3-Phenylhexane, 2-Phenylhexane yield were about 47.9 wt% and 38.7 wt% respectively on this catalyst. The BEA also exhibited longer time-on-stream and reusability performance, thus offers an attractive route for converting benzene into valuable (3-Phenylhexane, 2-Phenylhexane) alkylate product useful for the manufacturing of fine chemicals, dyestuff, detergents and scents. 相似文献
102.
Mustafa T. Yagub Tushar Kanti Sen Sharmeen Afroze H.M. Ang 《Advances in colloid and interface science》2014
In this review article the authors presented up to-date development on the application of adsorption in the removal of dyes from aqueous solution. This review article provides extensive literature information about dyes, its classification and toxicity, various treatment methods, and dye adsorption characteristics by various adsorbents. One of the objectives of this review article is to organise the scattered available information on various aspects on a wide range of potentially effective adsorbents in the removal of dyes. Therefore, an extensive list of various adsorbents such as natural materials, waste materials from industry, agricultural by-products, and biomass based activated carbon in the removal of various dyes has been compiled here. Dye bearing waste treatment by adsorption using low cost alternative adsorbent is a demanding area as it has double benefits i.e. water treatment and waste management. Further, activated carbon from biomass has the advantage of offering an effected low cost replacement for non-renewable coal based granular activated carbon provided that they have similar or better adsorption on efficiency. The effectiveness of various adsorbents under different physico-chemical process parameters and their comparative adsorption capacity towards dye adsorption has also been presented. This review paper also includes the affective adsorption factors of dye such as solution pH, initial dye concentration, adsorbent dosage, and temperature. The applicability of various adsorption kinetic models and isotherm models for dye removal by wide range of adsorbents is also reported here. Conclusions have been drawn from the literature reviewed and few suggestions for future research are proposed. 相似文献
103.
随着检测需求的提高与分析技术的发展,简单、自动化、环保与小型化的微型样品前处理技术越来越受到关注。针阱微萃取(NTME)是在固相微萃取(SPME)技术的理论基础上发展起来的一种新型微型萃取技术,其萃取装置将吸附剂填充到不锈钢针内制得,可避免固相微萃取纤维易碎及涂层脱落的问题,而且通过动态萃取,可使目标物被彻底萃取,具有更好的耐用性和富集能力。近年NTME结合气相色谱法在挥发性和半挥发性有机污染物分析中获得广泛应用,已有诸多关于NTME的研究被报道。吸附剂是影响NTME萃取性能的核心,本文简要概述了近年NTME的吸附剂种类,并综述了其在环境、食品、生物领域的应用进展。 相似文献
104.
Screening acidic zeolites for catalytic fast pyrolysis of biomass and its components 总被引:2,自引:0,他引:2
David J. MihalcikCharles A. Mullen Akwasi A. Boateng 《Journal of Analytical and Applied Pyrolysis》2011,92(1):224-232
Zeolites have been shown to effectively promote cracking reactions during pyrolysis resulting in highly deoxygenated and hydrocarbon-rich compounds and stable pyrolysis oil product. Py/GC-MS was employed to study the catalytic fast pyrolysis of lignocellulosic biomass samples comprising oak, corn cob, corn stover, and switchgrass, as well as the fractional components of biomass, i.e., cellulose, hemicellulose, and lignin. Quantitative values of condensable vapors and relative compositions of the pyrolytic products including non-condensable gases (NCG's) and solid residues are presented to show how reaction products are affected by catalyst choice. While all catalysts decreased the oxygen-containing products in the condensable vapors, H-ZSM-5 was most effective at producing aromatic hydrocarbons from the pyrolytic vapors. We demonstrated how the Si/Al ratio of the catalysts plays a role in the deoxygenation of the vapors towards the pathway to aromatic hydrocarbons. 相似文献
105.
106.
Rapid crystallization and morphological adjustment of zeolite ZSM-5 in nonionic emulsions 总被引:1,自引:0,他引:1
Zeolite ZSM-5 was synthesized for the first time in a nonionic emulsion composed of polyoxyethylated alkylphenol, butanol, cyclohexane and tetraethylammonium hydroxide (TEAOH)-containing zeolite synthesis mixture. The crystallization kinetics in the emulsion was investigated and the ZSM-5 product was characterized in detail by XRD, SEM, FT-IR, TG, N2 adsorption and CHN analysis techniques. Compared with the conventionally hydrothermal synthesis with the same structure directing agent TEAOH, the emulsion system allows rapid crystallization of ZSM-5. The ZSM-5 product exhibits unusual agglomerated structure and possesses larger specific surface area. The FT-IR, TG results plus CHN analysis show the encapsulation of a trace of emulsion components in the emulsion ZSM-5. Control experiments show the emulsion system exerts the crystallization induction and morphological adjustment effects mainly during the aging period. The effects are tentatively attributed to the confined space domains, surfactant-water interaction as well as surfactant-growing crystals interaction existing in the emulsion. 相似文献
107.
Bassam Alfeeli Vaibhav Jain Richard K. Johnson Frederick L. Beyer James R. Heflin Masoud Agah 《Microchemical Journal》2011,98(2):240-245
This work aims at evaluating poly(2,6-diphenyl-p-phenylene oxide) (Tenax TA), in the form of thin films, as an adsorbent material for various analytical applications. The physical properties of the polymer were studied with regard to surface topography, crystal structure, and thermal stability. Films deposited from solution at different substrate temperatures were studied and compared to the granular form of the polymer. It was found that Tenax TA deposited from solution have a different topography compared to their granular counterpart. The films possess a complex phase composition that includes crystalline and amorphous phases. The films showed high thermal stability (400 °C) similar to the granular form. The adsorption performance of the polymer compared to other possible adsorbent films such as polydimethylsiloxane (PDMS) and layer-by-layer assembled gold nanoparticles (GNPs) were also investigated. Representative volatile organic compound samples were used to compare the adsorption properties of Tenax TA films to that of the granules. 相似文献
108.
High silica zeolite SSZ-13 with Si/Al ratios varying from 11 to 17 was characterized by aluminum-27 and silicon-29 NMR spectroscopy. Aluminum-27 MAS and MQMAS NMR data indicated that in addition to tetrahedral aluminum sites, a fraction of aluminum sites are present in distorted tetrahedral environments. Although in samples of SSZ-13 having high Si/Al ratios all aluminum atoms are expected to be isolated, silicon-29 NMR spectra revealed that in addition to isolated aluminum atoms (Si(1Al)), non-isolated aluminum atoms (Si(2Al)) exist in the crystals. To model these contributions of the various aluminum atoms, a mixed-domain distribution was developed, using double-six membered rings (D6R) as the basic building units of SSZ-13. A combination of different ideal domains, one containing isolated and the other with non-isolated aluminum sites, has been found to describe the experimental silicon-29 NMR data. 相似文献
109.
X. -M. Lu X. -Q. Yun C. -S. Zhang D. -M. Kou C. -X. Fu S. -H. Xiang H. -X. Li 《Chromatographia》1996,43(3-4):211-214
Summary The preparation of a zeolite membrane PLOT column by in-situ synthesis is described. The advantages of this new column are discussed. Some analytical applications to alkanes, arenes, esters, alkyl halides and ethers on the zeolite membrane PLOT column compared with those on a coated zeolite PLOT column are reported. 相似文献
110.
Allen W. Burton Stacey I. Zones Saleh Elomari 《Current Opinion in Colloid & Interface Science》2005,10(5-6):211-219
In this review we discuss the roles that inorganic and organic components play in the synthesis of high-silica zeolites. We discuss the effects that heteroatom identity, heteroatom substitution, and SDA shape have on synthesis products. Then we summarize recent developments in zeolite synthesis that have been made by performing syntheses in concentrated fluoride media and by using germanium as a tetravalent heteroatom. Finally, we examine the combined roles that framework stability, framework/SDA interactions, and silanol defects may have in determining phase selectivity. 相似文献