Removal of Emerging Contaminants from Water by Using Carbon Materials Derived from Tingui Shells

Abstract

This study explored the adsorption of acetaminophen and caffeine using CO2-activated biochar (BT-CO2) and hydrochar (HT-CO2) derived from Tingui shell biomass. The experimental data from kinetic and equilibrium adsorption tests were employed in batch and fixed-bed systems. In the batch system, a specific amount of the adsorbent was added to a known volume of the solution, and the mixture was agitated for a set period to allow adsorption to occur. In the fixed-bed system, the solution was passed through a column packed with the adsorbent, allowing for continuous adsorption. These systems pave the way for future research. The findings revealed that HT-CO2 exhibited a greater surface area and a higher presence of oxygen-containing functional groups than BT-CO2. These functional oxygen groups had a notable impact on the adsorption capacity of the adsorbents for pharmaceutical substances. In the batch systems, BT-CO2 demonstrated a maximum adsorption capacity of 221.4 mg g−1 for acetaminophen and 162.7 mg g−1 for caffeine, while HT-CO2 exhibited higher capacities of 383.2 mg g−1 for acetaminophen and 189.7 mg g−1 for caffeine. In the fixed bed configuration, HT-CO2 displayed a maximum adsorption capacity of 82.2 mg g−1 for acetaminophen and 45.60 mg g−1 for caffeine. The predominant mechanisms involved in the removal of acetaminophen and caffeine were identified as H-bonding and π-π bonds. These results underscore the promising potential of these carbons as effective adsorbents for treating water contaminated with pharmaceutical residues, inspiring further exploration in this field and offering hope for the future of water treatment by providing a solid foundation for future research and development.