Removal of Tetracycline from Aqueous Solutions Using Avocado Peel-Based Biochar

Abstract

Tetracycline (TC), a widely used antibiotic, is increasingly found in aquatic environments, posing significant risks to ecosystems and human health. Therefore, this study aimed to evaluate TC removal using alkaline-modified biochar (BioCH-M) derived from avocado peels. The methodology involved pyrolysis of avocado peels, alkaline hydrothermal treatment, comprehensive characterization using techniques such as Scanning Electron Microscopy (SEM) and Fourier- Transform Infrared Spectroscopy (FTIR), batch adsorption experiments for kinetic and equilibrium studies, and data fitting to kinetic and isotherm empirical models. The results showed that BioCH-M exhibited a high adsorption capacity (45.05 mg/g at 25°C) for tetracycline, with optimal adsorption occurring at slightly acidic to neutral pH. The adsorption process was rapid and reached equilibrium quickly (300 min). The Langmuir isotherm model suggested that TC molecules occupy specific sites on the biochar surface, and the temperature effect indicates that the adsorption process is endothermic. This study demonstrates that BioCH-M is an effective and sustainable adsorbent for removing tetracycline from aqueous solutions, highlighting the potential of waste biomass to produce biochar as a viable solution to treat pharmaceutical pollution in water bodies.