Synthesis of 4A zeolites from kaolin for obtaining 5A zeolites through ionic exchange for adsorption of arsenic

Synthesis, characterization, and mercury adsorption properties of hybrid mesoporous aluminosilicate sieve prepared with fly ash

“…Three peaks mean three structures of silicon atoms from left to right side. These structures are indexed as Q 2 , Q 3 , and Q 4 according to the Q n  = Si [ n Si, (4 −  n ) OH], or Si [ n Si, (4 −  n ) Al], n  = 1–4 [24]. Q 4 : Q 3 of HMAS was about 10.36.…”

“…The precursors of A zeolite were prepared as previously reported in the synthesis of A zeolite [24]. The main process is as follows: the chemicals Na 2 SiO 3 ·9H 2 O, NaOH, and NaAlO 2 with molar ratio of Na 2 O:Al 2 O 3 :SiO 2 :H 2 O equal to 3.165:1:1.926:128 were mixed in distilled water in the boiling state and stirred for 1 h. After that, aged at 298 K in a static state for 24 h to form the precursors of A zeolite.…”

Use of Brazilian Kaolin as a Potential Low-cost Adsorbent for the Removal of Malachite Green from Colored Effluents

“…Kaolin is a clay predominantly composed by kaolinite (Al 2 Si 2 O 5 (OH) 4 ) 25 , which has been widely used in a variety of technological applications [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] . Due to the low-cost and large availability, the use of clays like kaolin becomes the adsorption process an attractive and promising technology.…”

Synthesis of Na-A zeolite from coal gangue with the in-situ crystallization technique

“…Thus, the direct synthesis method of zeolites from natural aluminosilicate minerals without those intermediate chemicals has received wide attention [16]. Moreover, extensive efforts have been made to search cheaper mineral materials and solid wastes, such as kaolin/metakaolinite [17][18][19], sugarcane bagasse [20,21], fly ash [22,23], low-grade natural zeolite [24,25], palygorskite [26], attapulgite [27], oil shale ash [28] and cupola slag [29], to replace those synthetic chemicals in the synthesis of NAZ for economic considerations. However, in some synthesis methods, the synthetic zeolite products still contain impurities.…”