Doxycycline (DOX) contamination in water has posed a serious threat to mankind health and environmental safety. Herein, a novel goethite modified phosphogypsum (GPG) composite was developed by impregnating synthesized goethite on phosphogypsum (PG) surface. The results obtained by pH gradient experiments indicate that GPG has superior adsorption efficiency and exhibits stable removal of DOX over a wide pH range of 4–11. The pseudo-second-order kinetic model and Langmuir isotherm model can better describe the adsorption process of DOX on GPG, indicating that the adsorption of DOX is a process characterized by the presence of chemical adsorption and monolayer coverage. Without adjusting the pH value of DOX solution, the maximum adsorption capacities of PG, goethite and GPG for DOX were 20.79 mg/G, 172.12 mg/g and 722.91 mg/g, respectively, according to Langmuir equation. The negative values of the thermodynamic parameters ΔH and ΔG in the studied range indicate the exothermic and spontaneous characterization of the DOX adsorption process. GPG exhibits good environmental resistance and reusability stability to DOX in electrolyte ion interference, real water samples and cyclicity experiments. The mechanism analysis shows that the adsorption of DOX on GPG is mainly controlled by the interaction of hydrogen bond, complexation and hydrophobic interactions. This study develops a convenient technique to synthesize effective adsorbents that can be used for DOX removal from real wastewater and provides new perspective on resourceful utilization of industrial wastes.

中文翻译：

---

以废止废：针铁矿改性磷石膏去除水中强力霉素


水中强力霉素（DOX）污染已对人类健康和环境安全构成严重威胁。在此，通过在磷石膏（PG）表面浸渍合成针铁矿，开发了一种新型针铁矿改性磷石膏（GPG）复合材料。 pH梯度实验结果表明，GPG具有优异的吸附效率，并在4-11的较宽pH范围内稳定去除DOX。准二级动力学模型和Langmuir等温线模型可以更好地描述DOX在GPG上的吸附过程，表明DOX的吸附是一个以化学吸附和单分子层覆盖为特征的过程。在不调节DOX溶液pH值的情况下，根据Langmuir方程，PG、针铁矿和GPG对DOX的最大吸附量分别为20.79 mg/G、172.12 mg/g和722.91 mg/g。研究范围内热力学参数 ΔH 和 ΔG 的负值表明 DOX 吸附过程的放热和自发特征。 GPG在电解质离子干扰、真实水样和循环实验中表现出良好的耐环境性和对DOX的重复使用稳定性。机理分析表明，DOX在GPG上的吸附主要受氢键、络合和疏水相互作用的控制。这项研究开发了一种便捷的技术来合成有效的吸附剂，可用于从实际废水中去除DOX，并为工业废物的资源化利用提供了新的视角。