A review on the application of clay minerals as heavy metal adsorbents for remediation purposes

Clay minerals are affordable, abundant, naturally occurring minerals found in many parts of the world that have been used effectively for remediation of many contaminants. This review article is aimed at studies involving the use of clay minerals for the remediation of soils and water contaminated with heavy metals. All relevant scientific literature using science direct online database from the year 2000 till 2019 were evaluated. The review highlighted the properties of clay minerals which make them good adsorbents and the processes necessary for adsorption to take place. It revealed that clay minerals are quite effective for remediation purposes, confirmed that clay minerals are very affordable, reliable, and environmentally friendly remediation materials for heavy metal contaminated media. Also, several methods are available for the modification of clay minerals in order to increase their adsorption capacity. However, in order to establish the use of clay minerals as heavy metal remediation materials compared to other established methods, more investigations are required, to determine the best modification type for clay minerals as well as the standard dosage of clay minerals required for the adsorption of heavy metals. (C) 2020 Elsevier B.V. All rights reserved.