Carbon from plastic: Synthesis, characterization, and application in dye wastewater treatment

Plastic is one of the threats to the environment and human health, though it has contributed to the development of society in the past 150 years. Due to its diverse properties, lightweight, strong, heat resistant, highly convenient, waterproof, corrosion-resistant, non-biodegradable, and economical, it is popular in many applications. However, its non-biodegradable nature makes it a hazardous substance, and thus, it should be eliminated. The researchers have tried to convert this waste into valuable products from carbon-based material. These carbon-based materials include carbon nanotubes, carbon spheres, carbon nanosheets, carbon nanorods, mesoporous carbons, porous carbon, carbon-spheres, graphene, and activated carbon with diverse applications. One of the applications is used in wastewater treatment. Based on the research gap, this article focuses on synthesizing carbon-based material from PET water bottles and its application in methylene blue (MB) dye adsorption. Two catalysts, citric acid and ferric nitrate, were used for carbon synthesis, which shows a maximum Langmuir adsorption capacity of 14.90 mg/g (C_CA) and 13.22 mg/g (C_Fe), respectively. The adsorption kinetics follow PSO kinetics. The surface area observed was 8.06 and 2.12 m²/g for C_CA and C_Fe, respectively. The synthesized carbon has a good potential for removing MB from aqueous solutions, but further research is required to find other applications of the C_CA and C_Fe. PRACTITIONER POINTS: The article reviews the diverse synthesis methods of listed carbon-based materials and their possible applications Carbon was prepared from waste PET waste bottles using citric acid and ferric nitrate as catalysts Equilibrium isotherms, adsorption kinetics, and process thermodynamics were studied for the removal of methylene blue dye onto synthesized carbon The maximum Langmuir adsorption capacity of 14.90 mg/g (C_CA) and 13.22 mg/g (C_Fe) was achieved The surface area observed was 8.06 and 2.12 m²/g for C_CA and C_Fe, respectively.