Recent Advances in Modification of Biochar for Removal of Emerging Contaminants from Water Bodies

Abstract

Emerging Contaminants (ECs) are a group of pollutants that occurs synthetically or naturally in trace amounts in the environment with high-toxicity, have attracted attention in recent years. These ECs are mainly composed of pharmaceuticals and personal-care products (PPCPs), flame retardants, surfactants, plasticizers, pesticides etc. With the continuous increase of humans' needs, the threat to the ecological environment and human health has become a matter of concern. Low concentrations and complex structures of these pollutants make them untraceable and difficult to remove by present conventional system of waste treatment. Some of the water treatment methods used for removal of ECs from water are chemical precipitation, ion exchange and adsorption. The modern advanced water treatment methods such as the Advanced Oxidation Process (AOP), and Nano-Filtration (NF)/Reverse Osmosis (RO) membrane technology have proved to be effective for the removal of contaminants, but most of these methods are very expensive, and sometimes produce secondary chemical pollutants. To overcome this situation a readily available, cost effective and eco-friendly method is required for the new class of these emerging contaminants. Biochar (BC) adsorption has become the most suitable technique because of the simple operating design, its low cost, and high efficiency to treat ECs in water. In this regard, various modifications of biochar to improve its utility has been developed and reported. It consists of physical and chemical modification. Physical modification mainly includes steam and gas purging while chemical modification is composed of acid modification, alkalinity modification, oxidizing agent modification, carbonaceous materials modification and metal salts or oxidizing agent modifications. In this chapter, different types of biochar and its modification for the detection and removal of ECs from water bodies have been included.