Investigating Kitchen Waste Based Activated Carbon for the Abatement of Cd(II) from Synthetic Wastewater

Abstract

Cd(II) is classified as a heavy metal, poses severe threats to human health, the environment, and various species. Its pervasive presence in water sources necessitates efficient removal methods. In Pakistan alone, approximately 50 million individuals face the risk of heavy metal poisoning due to contaminated groundwater. The adverse health effects of Cd(II) include the potential to induce skin, bladder, and lung cancer. Additionally, the abundance of solid waste exacerbates environmental challenges. To counteract these issues, we employed pyrolysis to convert solid waste into biochar. Specifically, kitchen waste served as the primary source for this biochar. Leveraging food waste as an adsorbent proves advantageous due to its ready availability, cost-effectiveness, and high adsorption capabilities. The process involves activating the kitchen waste biochar with hydrogen peroxide, resulting in an efficient removal of Cd(II) from water, thereby contributing to a more environmentally sustainable solution. This study focuses on the modification of kitchen waste biochar into a novel adsorbent by treating it with hydrogen peroxide for the removal of Cd(II) ions from aqueous solutions. The kitchen waste, comprised of vegetable and fruit peels, undergoes a deposition process with hydrogen peroxide, as confirmed by FTIR and XRD analysis. Optimization of adsorption conditions revealed the most effective parameters to be a pH of 6, a contact time of 4 hours, a dosage of 1g, and an initial concentration of 200 ppm, as determined through a series of experiments. Various isotherms, including Langmuir, Freundlich, Temkin, and Dubinin, were analyzed, with Langmuir emerging as the most suitable model. The kitchen waste-based adsorbent, in conjunction with the Langmuir isotherm, indicated a monolayer adsorption mechanism that is non-spontaneous and endothermic. The calculated sorption capacity of the kitchen waste-based adsorbent is 19 mgg-1, providing a quantitative measure of its efficacy in Cd(II) removal. This research signifies a significant step toward sustainable and effective water treatment methodologies for heavy metal contamination.