Application of biochar for the removal of methylene blue from aquatic environments

Incessant advancement of industry and agriculture has amplified organic pollutants contents in recent years causing grave threat to environmental well-being. With time, adsorption has established as an effective and financially advantageous process for the elimination of organic contaminants, like dyes, phenolics, pesticides, polynuclear aromatics and antibiotics. Biochar (BC), a carbon-rich material (70% approximate), prepared predominately by pyrolysis of waste materials such as biomass of agriculture and timber origin, is assumed by far the cleanest form of the charcoal. BC can have important physicochemical features like high carbon content as well as elevated surface chemistry heterogeneity, elevated textural features (specific surface area and pores volume), stable structure, cation exchange capacity, and recyclability. These features in combination with BCs low cost since they can be obtained from abundantly naturally available raw material, establish them as prosperous candidates for applications such as energy source (biofuel), as additives for soil amendment, to sequester carbon, pollution remediation and waste management by recycling agricultural by-products. Principal parameters on which BCs’ properties depend are the temperature and atmosphere of pyrolysis, heat transfer rate, feedstock, type and residence time. This article examines in detail the sources, production, characteristics and modification of BC, along with special emphasis on research published in recent 5 years particularly regarding the removal of a benchmark cationic organic dye, Methylene Blue.