%0 Journal Article
%T Modification of Silica Rice Husk Ash to Solid Ammonium Sulphate for Second Generation Biofuels Productions
%A Kasim Mohammed Hello
%A Majid Jari Mohammed
%A Asstabraq Mohsen Yasser
%A Farook Adam
%A Zinab Farag
%J Journal of Catalysts
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/128547
%X A new approach has been demonstrated for the synthesis of solid ammonium sulphate attached to silica rice husk ash. The 3-(aminopropyl)triethoxysilane was immobilized onto silica at room temperature to functionalize the silica with ammine end groups (¨CNH2). The amine group was sulphated with sulphuric acid to produce a novel micro-rod-like shaped acidic catalyst (as seen with TEM) designated RHNH3SO4H (RH = rice husk). The TGA analysis shows that the catalyst is stable at temperatures below 200¡ãC. The acidity measurement of the catalyst indicates that it has Br£¿nsted acid sites. Cellulose extracted from waste of rice husk and cellulose extracted from office paper were hydrolysed to glucose in 6£¿h, and the glucose was hydrolysed afterwards to other products within 13£¿h. The catalyst is reusable many times without a significant loss of catalytic activity. 1. Introduction Until recently, most ionic catalysts were synthesised and used for different purposes in liquid solutions. These ionic liquids were showing very good catalytic activity compared with the commercial strong acids such as H2SO4, HCl, and H3PO4, which have limitations due to a tedious work-up procedure and the necessity of postneutralization of the strongly acidic media leading to production of undesired wastes. Therefore many challenges are facing the researcher regarding the characterization and the recycling of these ionic liquid catalysts. We have recently reported the synthesis of a new type of ionic catalysts in solid state form with less environmental concerns. Those catalysts are recyclable and can be used for the same purposes as where the ionic liquids catalysts are used [1]. Rice husk (RH) is a major by-product of the rice-milling industries and it is causing disposal problems. Moreover, after its burning approximately 20% ash content comprises over 95% of amorphous silica which has very fine particle size, very high purity, high surface area, and high porosity. These properties would give rice husk utilization a very economically attractive perspective [2, 3]. One important application of silica is due to its ability to be modified with different silylating agents, which can introduce basic groups through an anchored pendant chain. The traditional procedure for immobilization of 3-(aminopropyl)triethoxysilane (APTES) onto different types of silica involves long reaction times, nonenvironmentally friendly organic solvents, harsh refluxing condition, and multiple steps [4¨C6]. Moreover, the vast majorities of these protocols call for expensive chemicals and techniques and cause
%U http://www.hindawi.com/journals/jcat/2014/128547/