Abstract
Day by day, the water sources are increasingly being adulterated due to various reasons including the uncontrolled discharge of pollutants from the point and nonpoint sources. Therefore, it is a timely need to develop suitable, inexpensive and efficient treatment techniques for water purification. This review aims at evaluating different water treatment technologies, their basic principles, cost and suitability for pollutants' removal from wastewater. Among various water treatment technologies, adsorption technique appears to be techno-economically more attractive due to its inexpensiveness, universality and environment friendliness. Here, wide varieties of adsorbents (silica gel, activated alumina, clays, limestone, chitosan, activated carbon, zeolite, etc.) and their capacities for pollutant removal are described. The limitations of conventional adsorbent applications for water treatment are also discussed. Recently, nanotechnology has introduced nanoadsorbents, which have drawn additional attention due to their unique properties and are considered to be the viable alternative to conventional adsorbents. The potential applications, separation and regeneration of nanoadsorbents for wastewater treatment are also included in this review. Furthermore, prospects including commercial and health aspects of nanoadsorbents are also added.