Singh Hari Om, Murugesan Gokulakrishnan, Selvaraj Raja, Varadavenkatesan Thivaharan, Vinayagam Ramesh
Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India.
Department of Biotechnology, M.S.Ramaiah Institute of Technology, Bengaluru, 560054, Karnataka, India.
Sci Rep. 2025 May 19;15(1):17312. doi: 10.1038/s41598-025-02213-6.
The persistence of tetracycline (TC) in water poses environmental risks, including antibiotic resistance, necessitating effective removal. This study explores the synthesis and application of activated carbon from copper pod tree leaves for TC adsorption. The adsorbent was produced through orthophosphoric acid activation at low temperature and characterized using multiple techniques. FESEM revealed a porous structure favorable for adsorption, while EDS confirmed the presence of carbon, oxygen, and phosphorus. FTIR identified hydroxyl and carbonyl groups facilitating hydrogen bonding with TC, enhancing adsorption. XRD confirmed the adsorbent's amorphous nature, while BET revealed a high surface area (865.06 m²/g). XPS further identified C-O and C = O bonds, further supporting adsorption. Kinetic experiments showed that the adsorption fitted to pseudo-second-order kinetics (R² = 0.9765), indicating chemisorption as the dominant mechanism. The isotherm modeling results indicated that the Langmuir model provided an excellent fit to the experimental data (R² = 0.9952), demonstrating a high monolayer adsorption capacity of 103.32 mg/g. Thermodynamics confirmed spontaneity and endothermicity with a ΔH° of 50.75 kJ/mol. The prepared adsorbent effectively removed TC across natural water matrices, retaining high performance after five regeneration cycles.
四环素（TC）在水中的持久性带来了包括抗生素耐药性在内的环境风险，因此需要有效去除。本研究探索了用铜荚树叶制备活性炭用于吸附TC的合成方法及应用。该吸附剂通过低温下的正磷酸活化制备，并采用多种技术进行表征。场发射扫描电子显微镜（FESEM）显示出有利于吸附的多孔结构，而能谱仪（EDS）证实了碳、氧和磷的存在。傅里叶变换红外光谱（FTIR）确定了有助于与TC形成氢键从而增强吸附的羟基和羰基。X射线衍射（XRD）证实了吸附剂的无定形性质，而比表面积分析仪（BET）显示其具有较高的比表面积（865.06 m²/g）。X射线光电子能谱（XPS）进一步确定了C-O键和C=O键，进一步支持了吸附作用。动力学实验表明，吸附符合准二级动力学（R² = 0.9765），表明化学吸附是主要机制。等温线模型结果表明，朗缪尔模型与实验数据拟合良好（R² = 0.9952），显示出103.32 mg/g的高单层吸附容量。热力学证实吸附过程具有自发性和吸热性，ΔH°为50.75 kJ/mol。制备的吸附剂能有效去除天然水体中的TC，经过五次再生循环后仍保持高性能。
