Bleaching Properties of Alumina-Pillared Acid-Activated Montmorillonite

Abstract

Abstract--The bleaching of cottonseed oil by alumina-pillared (Al-pillared) acid-activated clays was investigated. Acid activation of a Ca-rich montmorillonite (CMS STx-I) following treatment with 1, 4, and 8 eq/L sulfuric-acid solutions, as well as subsequent pillaring with alumina, produces new materials. These materials have bleaching properties dependent upon the extent of activation of the clay prior to pillaring. The pillared acid-activated montmorillonites possessed higher bleaching efficiency compared to pillared products of the untreated clay. Mild activation of the montmorillonite matrix, pillaring with the Keggin ion [Al~30~(OH)24(H20)t2] 7+, and calcination temperatures to 500~ produced materials with the best fractional degree of bleaching. Direct comparison to the performance of a commercial bleaching earth (Tonsil Optimum 214, Sud-Chemie AG. Moosburg, Germany) show's that the efficiency of the A1-pillared acid-activated montmorillonite may be improved. The optimization of the bleaching process is achieved via a judicious utilization of intermediate surface area, relatively high acidity, and enhanced pore volume.

Influence of Acid Activation on Natural Calcium Montmorillonite Clay

“…1 It shows bleaching action 2,3 and also can be effectively used as adsorbent for adsorption of harmful substances like dye 4,5 , heavy metal ions 6,7 from their sources. Its adsorption capacity as adsorbent and bleaching action can be increased manifold if it is activated particularly with acid.…”

Synthesis of Alumina-Containing Hexagonal Mesoporous Silica and Its Application in the Adsorption of Gossypol

“…It can be inferred that the acidity was increased on increasing the Al loading on hexagonal mesoporous silica content. Falaras et al 9 reported that adsorption phenomenon in cottonseed oil is mainly involves the pigment such as gossypol, carotene and so on; the pigment attraction to the acid sites in the adsorbent.…”

“…In order to efficiently removal gossypol from cottonseed oil, a number of studies have been carried out, usually through caustic reining 7 and adsorption on solids, such as activated alumina 8 and activated montmorillonite-containing clays 9 . Richard et al 10 investigated that aluminas and silicas as adsorbents for reducing the gossypol from cottonseed oil, they found gossypol has a high affinity for alumina surface.…”

Activation oF Trass Rock aS Bleaching Palm Oil (CPO)

“…Through this process, the appearance of oil product can be improved. Its color becomes clearer and its production stability might be improved (Falaras, 2000). Bleaching earth can also remove chlorophyll, carotenoids, phosphorlipids, metals.…”