Advances in biosorbents for removal of environmental pollutants: A review on pretreatment, removal mechanism and future outlook

Highlights: • Removal of hazardous pollutant from wastewater using biosorbent was establish to be efficient and eco-friendly approach. • Significant enhancement of biosorbent capacity by different modification methods was summarized. • Microbial biomass display greater ability to transform toxic hazardous compounds into less toxic form. • Desorption studies elucidates that high reusability potential of biosorbent as a less-expensive material. • Economic value, scope of biosorbent for large scale application and future perspectives are discussed. Environmental pollutants are a serious threat for decades causing contamination of soil and water systems. The release from various industries is the main source of these pollutants. Biosorption has been accepted as an alternative eco-friendly green technology for the removal of various pollutants utilizing microbes such as bacteria, fungi and algae, and yeasts. This review features on overview of studies on materials as biosorbents, their pretreatment process, desorption of adsorbed pollutants from biosorbents, and safe disposal of biosorbent material in detail. Pretreatment is mainly performed for increasing the efficiency and adsorption rate which can be performed using various methods. Desorbing eluents can be used for recovering adsorbed pollutants and regeneration of biosorbents can be performed chemically, thermally, or electrochemical methods. In the case of large-scale commercial utilization of biosorbents, final disposal of biosorbents without any effects has paid better attention. Cost is also one of the major factors and it has an impact on the overall economy of the biosorption process. Additional efforts are required for discovering novel biosorbent materials and desorbing eluents for an economically feasible and efficient treatment process.