Synthesis of Na–A and –X zeolites from oil shale ash

The use of synthesized zeolites from power plant rice husk ash obtained from Thailand as adsorbent for cadmium contamination removal from zinc mining

“…1) in 2003 by the Department of 10 Agriculture (DOA), Ministry of Agriculture (MOA) and Department 11 of Pollution Control (DPC) [1]. Cadmium usually occurs in 12 association with zinc ore and is a by-product of zinc mining. 13 Cadmium is a toxic heavy metal which causes environmental 14 problems and can be accumulated in human body through the food 15 chain, and also can causes damage to the ecosystem [2].…”

“…Due to the above reasons, much research work has been 51 undertaken to develop new techniques of ash utilization. The rice 52 husk ash (RHA) is mainly composed of high silica content and some 53 alumina content typically used in zeolite synthesis [9], such as coal 54 fly ash [10,11], oil shale ash [12] and bagasse fly ash [13]. Zeolites [14], where generally x is equal to or greater than 2 because AlO À 4 63 tetrahedra are joined only to SiO À 4 tetrahedra, y is the water 64 contained in the voids of the zeolite and n is the cation valence.…”

Using the Response Surface Methodology to Optimize the Extraction of Silica and Alumina from Coal Fly Ash for the Synthesis of Zeolite Na-A

“…Recently, microwave-assisted thermal fusion of CFA and sodium hydroxide resulting in sodium silicate has been reported [6]. Generally sodium silicate is an important ingredient and the source of soluble silica for the preparation of zeolites [4,5,[7][8][9][10] and mesoporous materials [11,12], which are expected to be high-value industrial materials. Zeolites have wide applications amongst which are included adsorbents, reaction catalysts, catalyst support and filtering agents [13][14][15][16][17][18].…”

Conventional hydrothermal synthesis of Na-A zeolite from cupola slag and aluminum sludge

“…For example, the hydrothermal treatment of coal fly ash [3][4][5][6][7][8][9][10], paper sludge ash [11], oil shale ash [12] and metakaolin [13] under alkaline conditions have been reported. By fusing a mixture of fly ash and NaOH (weight ratio of 1:1.2) at 550 • C, followed by hydrothermally heating at 60-100 • C for 6-24 h, the fused powder was converted into the faujasite type zeolites X and Y [14].…”