2. Algal Biochar for Removal of Refractory Pollutants

Biochar has recently emerged as one of the promising alternative to conventional methods employed for the remediation of different pollutants in the environment. The physiochemical properties of these carbonaceous materials along with their porous nature and the presence of functional groups on the surface make biochars an effective adsorbent of various pollutants. Hence, biochars produced from various organic sources are extensively researched for the removal of various refractory pollutants. Algae-based biochars are efficient adsorbents due to their enhanced porosity, active functional groups and large surface area. Therefore, this chapter discusses in detail, the application of biochars produced from algal biomass for the removal of pollutants that are persistent in the environment. Various studies have demonstrated the algal biochar synthesized from biomass of Rhizoclonium riparium, Saccharina japonica, Sargassum fusiforme, Scenedesmus dimorphus, and others can effectively remove hazardous metals such as uranium, cadmium, cobalt and even copper and zinc through electrostatic interactions, precipitation as well as complexation with the surface functional groups. Likewise, organic pollutants which include toxic dyes and antibiotics can also be removed by biochar generated from algal biomass of Eucheuma spinosum, Ascophyllum nodosum, Chlorella sp., Cystoseira barbata, Enteromorpha prolifera, Sargassum crassifolium, and Ulva ohnoi through various removal mechanisms. Thus, additional research on the feasibility of utilizing algal biochar for remediation of refractory pollutants can help in developing powerful strategy to ensure effective treatment of industrial effluents before releasing them in the environment.