Regeneration, recycling, and disposal of spent biochars

Abstract

Among the technologies that are employed to immobilize and degrade both organic and inorganic contaminants in vari ous polluted environmental compartments, biomass-based biochar has been demonstrated to be an effective and environmentally friendly strategy (Crini et al., 2019; Liao et al., 2022; Nguyen et al., 2023; Rasheed et al., 2020; Wang et al., 2020). In addition, biochar has several other advantages, for instance, high-cost efficiency due to the abundance of low-cost feedstock, as well as simplicity of preparation methods (Barquilha & Braga, 2021). To further improve the biochar pollutant removal efficiency and capture capacity, increasing efforts are currently being carried out to design and develop biochar with improved properties for the immobilization of both organic and inorganic pollutants (Dutt et al., 2020; Liao et al., 2022). However, the main drawback is the management of the spent biochar loaded and concentrated with various pollutants (Hossain et al., 2020). Several technologies are available for the recovery of spent biochar, including filtration, sedimentation, centrifugation, and magnetic separation (Kar et al., 2022). The spent biochar is then either regenerated for reuse or safe disposal via landfilling or incineration (Kozyatnyk et al., 2020), as illustrated in Fig. 20.1. Regeneration of spent biochar for several other decontamination cycles further lowers the running and operational cost of remediating the contaminated environmental media. In essence, biochar’s high recycling and reuse capabilities are fundamental for the economic management of polluted environments (Herath et al., 2021