Humic Acid Modified Jeanbandyite for Tetracycline Removal: Synthesis, Characterization, and Adsorption Studies

Abstract

Mass-scale therapeutic use of tetracycline (TC) is substantially increasing its prevalence in the aquatic environments, posing potential ecological and health concerns. In this study, humic acid-modified Jeanbandyite (HAJB) was synthesized via a simple co-precipitation method, and its efficacy as an adsorbent was tested for TC removal from wastewater. Characterization studies successfully confirmed the formation of crystalline HAJB with spherical morphology, thermal stability, and superparamagnetism. Batch adsorption studies revealed that TC removal efficiency was strongly influenced by contact time, adsorbent dose, initial TC concentration, solution pH, and temperature. HAJB exhibited rapid adsorption, reached equilibrium within 6 h, and followed a pseudo-second-order kinetic model. The adsorption data fitted well to the Langmuir isotherm model, indicating monolayer adsorption with a maximum monolayer adsorption capacity (qm) of 129.8 mg g−1. The adsorption was highly efficient under acidic conditions (pH 4), where electrostatic attraction dominated. Thermodynamic parameters confirmed that the process was spontaneous and exothermic. Recyclability tests demonstrated that HAJB maintained a significant TC removal efficiency after five adsorption–desorption cycles, and real water studies showed moderate performance in the presence of competing ions. Overall, HAJB combines high efficiency, magnetic recoverability, and reusability, offering a promising, cost-effective strategy for the removal of TC from contaminated water.