Facile removal of caffeine in 30 seconds using tea waste-derived porous carbon: Effect of surface area and adsorption technique

Abstract

Background: The release of contaminants from various pharmaceutical sources into water bodies has severely polluted the resources, making them unfit for utilization. Among the pharmaceutical wastes, caffeine has been identified as a serious pollutant due to its widespread consumption by the general public. Biomass-derived porous materials have been considered a suitable adsorbent material for wastewater treatment, owing to their low cost, reusability, and eco-friendly nature. However, the main drawback of adsorbents has been the low maximum adsorption capacity, which has not been given enough attention. Methods: In this work, we have synthesized porous carbon from tea waste with high specific surface area (2260.82 m2/g) by activating with KOH in nitrogen atmosphere. Further, adsorption studies were performed using shaker and spin column technique. Significance: The material was used to remove caffeine in 30 s, using the spin column technique. The material can be recycled with the same spin column and can be reused up to three cycles without a decrease in performance. The maximum adsorption capacity of caffeine at room temperature was found to be 491.4 mg/g, outperforming many reported adsorbents. When considered together, this group of materials has the potential to be used as a cost-effective remedy for environmental-related concerns, especially for large-scale wastewater treatment applications. © 2023 Taiwan Institute of Chemical Engineers