A general approach to halloysite clay mineral

Abstract

Halloysite is a natural clay mineral that belongs to the kaolin group. Its chemical formula is Al2(OH)4Si2O5.nH2O. When n is equal to 2, it is hydrated, and when n is equal to 0, the halloysite is dehydrated. Generally, halloysite has a tubular structure; however, as a result of different deposits and crystallization conditions, this mineral can consist of spheroidal and plate-like particles. Its main deposits are in the United States, China, New Zealand, Mexico, Brazil, and Turkey where halloysite is formed by weathering or hydrothermal alteration of pumice, ultramafic, and volcanic rocks. Halloysite can be used in various fields due to its characteristic features. Primarily, this mineral is an ideal nanofiller for polymer composites. It is also utilized in the manufacture of ceramic wares and encapsulation of drugs in the pharmaceutical industry. Moreover, its higher specific surface area makes halloysite a good candidate for catalyst support. © 2020 Nova Science Publishers, Inc. All rights reserved.