School of Chemistry and Environmental Science, Shaanxi University of Technology, Hanzhong 723001, China.
Shaanxi Reconnaissance Design & Research Institute of Water Environmental Engineering, Xi'an 710021, China.
Molecules. 2024 Jun 20;29(12):2928. doi: 10.3390/molecules29122928.
In this study, RM (red mud) was acidified with sulfuric acid, and the acidified ARM (acidified red mud) was utilized as an innovative adsorption material for treating antibiotic-containing wastewater. The adsorption conditions, kinetics, isotherms, thermodynamics, and mechanism of ARM for CIP (ciprofloxacin) were investigated. The characterization of the ARM involved techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), X-ray fluorescence (XRF), thermogravimetric analysis (TGA), and NH-TPD analysis. Adsorption studies employed a response surface methodology (RSM) for the experimental design. The results showed that ARM can absorb CIP effectively. The RSM optimal experiment indicated that the most significant model terms influencing adsorption capacity were solution pH, CIP initial concentration, and ARM dosage, under which the predicted maximum adsorption capacity achieved 7.30 mg/g. The adsorption kinetics adhered to a pseudo-second-order model, while equilibrium data fitted the Langmuir-Freundlich isotherm, yielding maximum capacity values of 7.35 mg/g. The adsorption process occurred spontaneously and absorbed heat, evidenced by Δ values between -83.05 and -91.50 kJ/mol, Δ at 281.6 J/mol/K, and Δ at 0.86 kJ/mol. Analysis using attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) indicated a complex reaction between the Al-O in the ARM and the ester group -COO in CIP. The C=O bond in CIP was likely to undergo a slight electrostatic interaction or be bound to the internal spherical surface of the ARM. The findings indicate that ARM is a promising and efficient adsorbent for CIP removal from wastewater.
在这项研究中，使用硫酸对赤泥（RM）进行酸化，然后将酸化后的赤泥（ARM）用作处理含抗生素废水的创新吸附材料。研究了 ARM 对 CIP（环丙沙星）的吸附条件、动力学、等温线、热力学和机制。采用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、BET、X 射线衍射（XRD）、X 射线荧光（XRF）、热重分析（TGA）和 NH-TPD 分析等技术对 ARM 进行了表征。吸附研究采用响应面法（RSM）进行实验设计。结果表明，ARM 可以有效地吸附 CIP。RSM 优化实验表明，影响吸附容量的最显著模型项是溶液 pH、CIP 初始浓度和 ARM 用量，在此条件下，预测的最大吸附容量达到 7.30mg/g。吸附动力学符合准二级模型，而平衡数据符合 Langmuir-Freundlich 等温线，最大容量值为 7.35mg/g。吸附过程是自发进行的，并且是吸热的，Δ 值在-83.05 到-91.50kJ/mol 之间，Δ 在 281.6J/mol/K 之间，Δ 在 0.86kJ/mol 之间。衰减全反射傅里叶变换红外光谱（ATR-FTIR）分析表明，ARM 中的 Al-O 与 CIP 中的酯基-COO 之间发生了复杂的反应。CIP 中的 C=O 键可能会发生轻微的静电相互作用或与 ARM 的内球面结合。研究结果表明，ARM 是一种很有前途且高效的吸附剂，可用于从废水中去除 CIP。
