A review on the adsorption of heavy metals by clay minerals, with special focus on the past decade

Adsorption has been proved to be the best process of water treatment because of its significant advantages. Clays and their minerals are abundant and cheap material successfully used for decades as an adsorbent for removing toxic heavy metals from aqueous solutions. Clays and their minerals, both in its natural and modified forms, effectively remove various heavy metals from aqueous solution, as extensively discussed in this review. This detailed review compiles thorough literature of current research over the last ten years (2006–2016) and highlights the key findings of adsorption studies that use clay minerals as an adsorbent. This review article presented an outline of the structure, classification, and chemical composition of various clay minerals, and a descriptive analysis of their adsorption behavior. The review confirmed that both natural and modified forms of clay minerals have excellent feasibility in removing different toxic aquatic metal pollutants. However, modification and further development of the synthesis of novel clay materials and their application to adsorb different environmental pollutants, which would enhance pollution control, is still needed.