Recent advances in organotemplate-free synthesis of zeolites

Abstract

Green and sustainable synthesis of zeolites has been continuously developed because of the requirement of environmental concerns. Among these efforts, it is very successful for organotemplate-free synthesis of aluminophosphate and silicoaluminophosphate molecular sieves and pure silica zeolites. In general, for the synthesis of aluminophosphate-based molecular sieves and many aluminosilicate zeolites, it is necessary to use organic templates, resulting in the formation of a huge amount of polluted wastes, which are environmentally unfriendly. In 2008, we show first example for organotemplate-free synthesis of aluminosilicate Beta, where the organic template of tetraethylammonium hydroxide in the conventional synthesis is completely avoided. However, it still has a challenge for organotemplate-free synthesis of other important aluminophosphate-based molecular sieves and pure silica zeolites. In this short review, it is briefly summarized recent advances in organotemplate-free synthesis of aluminophosphate and silicoaluminophosphate molecular sieves and pure silica zeolites, which are green and sustainable compared with those synthesized in the presence of organic templates.