Carbon Xerogel nanocomposites for wastewater treatment and energy applications for advancing sustainability

Abstract Water pollution caused by heavy metal ions, which are both hazardous and nontoxic, as well as radioactive, constitutes a significant environmental challenge and a source of substantial concern in the contemporary world, attributable to the swift advancement of the economy and industry. The Scopus digital database was investigated in order to carry out this investigation. The PICO framework and a systematic review approach were used to search for, assess, and interpret information on adsorption technology, adsorption-influencing factors, the performance of various adsorbent materials, and the benefits and downsides of adsorption isotherms. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement’s requirements were utilized to filter the data, enabling the selection of papers that answered the study’s research goals. Researchers are exploring methods for extracting and recycling heavy metal ions from wastewater, including chemical precipitation, biological treatment, coagulation, filtration, ion exchange, reverse osmosis, and physical adsorption. Metal oxide-based carbon xerogel is being explored for its use in energy and wastewater applications. Based on the results, the previous studies demonstrate the CX-based materials exhibit excellent performance in both energy applications and wastewater treatment applications. In energy application, gravimetric capacitance values ranged from 105 to 612 F.g⁻ 1 , with high retention rates after thousands of charge/discharge cycles and energy densities reaching up to 7014 Wh.m⁻ 3 .. Concurrently, in pollutant removal, CX composites either doped with metal oxides or hybridized with graphene achieved high adsorption efficiencies up to 99% for diverse pollutants such as heavy metals, pharmaceuticals, and dyes with adsorption capacities of 300 mg/g under optimized conditions. Finally, the green synthesis of CX is used in wastewater treatment and energy applications; they can offer high performance.