TiO2@碳纳米管吸附去除盐酸四环素

采用静电组装法制备了TiO2@碳纳米管复合吸附剂,用以除去水中的盐酸四环素。通过FE-SEM、EDS和XRD进行表征,考察了pH、初始浓度和吸附剂用量对吸附过程的影响,研究了吸附动力学、等温模型和热力学,并对吸附剂的再生进行了评价。结果表明,复合吸附剂对盐酸四环素的最大饱和吸附量为52.33 mg/g;最佳吸附pH值为6,强酸不利于吸附;当初始浓度在15~60 mg/L范围内时,吸附量随着初始浓度的增大而增加;当吸附剂投加量为0.50 g/L时,吸附效率最高。吸附过程符合准二级动力学模型和Langmuir等温模型。热力学参数ΔG H >0,表明该吸附过程是自发、吸热过程。H2O2-TiO2光催化协同效应可有效完成吸附剂的再生。

Removal of tetracycline hydrochloride by TiO2@carbon nanotubes composite adsorbent

TiO2@carbon nanotubes composite adsorbents were fabricated by electrostatic assembly. The obtained composites were used as adsorbents for the removal of tetracycline hydrochloride in aqueous solutions. The products were characterized by field emission scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. The adsorption performance was investigated by analyzing the influence of factors such as pH, initial concentration of tetracycline hydrochloride and dosage of composite adsorbents. The results indicated that the maximum saturated adsorption capacity of tetracycline hydrochloride was 53.23 mg/g, strong acidity was not good for the adsorption of tetracycline hydrochloride onto the TiO2@carbon nanotubes composite adsorbent, and the optimal pH value was about 6. The maximum adsorption of tetracycline hydrochloride by TiO2@ carbon nanotubes was achieved at a dosage of 0.50 g/L, and the adsorption capacity was enhanced with the increasing of initial concentration of tetracycline hydrochloride. The pseudo-second-order model was more suitable than the pseudo-first-order model for the simulation of adsorption processes. Equilibrium data were best represented by the Langmuir isotherm model. Moreover, the spontaneous and endothermic nature could be verified by the negative values of the standard free energy change ΔG and the positive values of ΔH, respectively. Regeneration experiments showed that the synergistic effect between H2O2 and TiO2 photo-catalysis could efficiently promote the regeneration of TiO2@MWCNTS adsorbent under UV irradiation.