Kaolinite properties and advances for solid acid and basic catalyst synthesis

Abstract

Historically, clay mineral catalysts have found industrial applications since the early 1930s. However, inherent limitations such as impurities, porosity, low surface area and acidity hindered their wide and sustained acceptability, this is despite their economic advantages. Interestingly, the use of kaolinite as precursor in active catalyst synthesis has been a breakthrough for several industrial processes such as petrol chemistry; especially in catalytic refining and bulk chemistry. The same is also true for processes that require solid acid catalysts, catalyst support, co-catalyst or promoter application for positive environmental impact and economic viability. Therefore, this article reviews the physicochemical properties of kaolinite and their amenability to modification towards enhancing their catalytic properties. The article also discussed modification methods such as mechanochemical activation (dealumination), thermal activation, intercalation and chemical activation. With more advances in technology and long-term commitment to investments, kaolinite will become the ideal catalyst and precursor for synthesizing novel catalysts for a sustainable “greener” future.