Surface modification of low-cost bentonite adsorbents-A review

The growth of science and technology over the world has led to the establishment of various industries which has helped the industrial, technological, and agricultural development of many nations. Environmental pollution from a variety of toxic derivatives, particularly heavy metals and minerals, aromatic molecules and dyes in wastewater posed a great danger to human, plants, and aquatic creatures. Adsorption appears to be the most widely used method among other techniques for the removal of toxic compounds from wastewater. The use of different adsorbents for heavy metal removal has become a subject of great interest, and there have been continuous efforts to develop new, low-cost, and efficient adsorbent materials. Bentonite, in natural and modified forms, has been applied in the removal of different water contaminants. This paper provides a review on recent progress of surface modifications of bentonite and their applications in the removal of organic and inorganic water pollutants. A comparison on the physicochemical characteristics and removal performance was presented. The adsorption mechanisms in relation to the bentonite properties were briefly discussed to offer readers some insight on the usefulness of this clay mineral in wastewater treatment. The challenges encountered and remarks on future prospects were highlighted.