The synthesized biochars derived from sawdust (SD) SD ozone (SDO) biochar, purified SD (PSD) biochar, and sonicated SD (SSD) biochar, which was employed in the confiscation of methylene blue (MB) dye ion, were characterized employing “Brunauer–Emmett–Teller (BET), scanning electron microscope (SEM), Fourier Transform Infrared (FTIR), and Thermal gravimetrical analysis (TGA).” The impact of various factors, such as pH, biochar dosage, and initial concentration, on MB dye sequestration, was tested in this study. It was found that the biosorption of MB dye to the various biochars was dependent on the solution pH, with optimum confiscation of MB observed at pH 12 for all biochars. Pseudo-second-order (PSO), Freundlich (FRH)- (SDO and SSD biochars), and Langmuir (LNR)- (PSD biochar) models were used to best describe the biosorption process of MB dye to various biochars. Based on the LNR model fitting to the experimental data, the optimum sorption capacities obtained using SDO, SSD, and PSD biochars were 200, 526, and 769 mg/g, respectively. Electrostatic interaction and hydrogen bonding played an important role in the interaction mechanism between the various biochars and MB dye. Hence, these studied SDO, PSD, and SSD biochars prepared from cheap, easily accessible, biodegradable, and non-hazardous agro-waste materials can be effectively used for the removal, treatment, and management of MB dye as well as other industrial effluents before their disposal into the environment.

Carbon nanomaterials are endowed with novel and magnificent optical, electrical, chemical, mechanical, and thermal properties, with a promising prospect in different advanced applications such as electronics, batteries, capacitors, wastewater treatment, membranes, heterogeneous catalysis, and medical sciences. However, macroscopic synthesis of carbon materials for industrial use has been a great challenge. Furthermore, structural nonhomogeneity and indefinite fabrication have hindered vigorous and consistent implementation of these materials in extensive technologies. Nevertheless, they offer exotic physics, and as a result, they have continued to attract great interest from the scientific community in an effort aimed to optimize their properties through innovative synthesis techniques, ensuring macroscopic production and discovering new applications. Hence, this study endeavours to provide a conscious review of these materials via the comprehensive discussion of the various allotropes of carbon (fullerenes, carbon nanotubes, and graphene), synthesis techniques (arc discharge, laser ablation, and chemical vapor deposition), and their applications in energy-related fields (batteries, capacitors, photocells, hydrogen storage, sensors, etc.) and their impending prospects.