Recent Advances in Nano-metal Oxide-Biochar Composites for Efficient Removal of Environmental Contaminants

Abstract

Along with global industrialization and rapid urbanization, the perpetual conception of sustainable environmental remediation is to be delivered as its utmost priority. For many years, metal oxide-biochar has followed biochar in the removal of harmful pollutants from natural resources and issues. The relatively lower effectiveness and efficiency of standard biochar (BCs) and metal biochar composites (MBCs) result in the continuation of further research efforts, as nano-metal oxide biochar composites and nano-metal–metal oxide biochar composites (NMOBCs) have emerged as environmental remediation pioneers in recent days. The novel NMOBCs have more flexible physicochemical properties and enhance the removal efficiency of environmental contaminants through adsorption and photocatalytic degradation. The absence of a complete description of adsorption and a systematic summary of NMOBC catalytic processes is still being investigated. Therefore, in this review, efforts have been made to fill these gaps to some extent by emphasizing synthetic methods, properties, and characterization of raw materials, a comprehensive overview of adsorptive properties, and a systematic summary of the catalytic activities of novel NMOBCs. Also, the meager challenges and recent developments up to the mark are discussed. Further, suggestions and recommendations for the modifications of physicochemical properties of NMOBCs are proposed to make them potentially applicable in the enhanced adsorption and photocatalytic degradation of various inorganic and organic environmental contaminants.