Polymer-based biochar materials for environmental remediation: A review
Pritesh Gole, Kabir Raut, Balasubramanian Kandasubramanian
Abstract
The prodigious consumption of an extensive array of plastic products have engendered an enormous amount of plastic wastes. Incineration of waste plastic in the open atmosphere serves to be one of the predominant sources of air pollution, due to the liberation of various noxious gases like Polychlorinated biphenyls, mercury, dioxins, and furans into the atmosphere. Conversion of the generated waste plastics into biochar serves to address dual concerns associated with mitigating plastic pollution concerns, while also opening up avenues for extensive environmental remediation applications. The synthesis of biochar, a carbonaceous substance possessing greater specific surface area, porosity, total pore volume, and abundant surface functionalities obtained by the thermochemical conversion of waste plastic distinctively, along with mixtures containing biomass feedstock can be utilized for as an adsorbent for the elimination of toxic gases from the atmosphere, while also being applicable for effluent treatment. In this regard, the present review is the first that analytically contemplates the conversion of pristine plastic wastes via pyrolysis, and hydrothermal carbonization, and plastic wastes mixed with other biomass feedstock via co-pyrolysis, and co-hydrothermal carbonization techniques, and activated plastic-derived char modified by physical, or chemical methodologies to adsorb an extensive array of detrimental contaminants spanning from dyes, heavy metal ions, pharmaceutical compounds, and other organic compounds from wastewater, while also capturing toxic gases from the atmosphere. Various adsorption advanced characterization methodologies, kinetics models, isotherm models, and underlying mechanism governing the sorption of these pollutants are also accentuated in this review. Furthermore, the prospects of regenerability of the spent plastic char adsorbents along with a roadmap leading to the future directives in this domain for heading towards a green, and sustainable environment are also presented here.