| Abstract: | Porous surface-modified microspheres can have widespread applications in the removal of wastewater pollutants. In this study, using a nonionic surfactant (Span80) as the pore-forming agent and Zr4+ as the cross-linking agent, polyethyleneimine (PEI)-modified porous CYCTS/Span80 microspheres ((CYCTS/Span80)-@-PEI) were successfully prepared for the adsorptive removal of diclofenac sodium (DS) from wastewater. The adsorbent was characterized using Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectrometry, scanning electron microscopy, and X-ray diffractometry. The activity of the porous (CYCTS/Span80)-@-PEI microspheres as adsorbents of DS was investigated by varying the experimental parameters (i.e., adsorbent dosage, adsorbent ratio, pH, contact time, temperature, and pollutant concentration). A possible adsorption mechanism was also discussed. The experimental results showed that the adsorption process followed a pseudo-second order kinetic model and the Langmuir adsorption isotherm model, in addition to the Freundlich isotherm model, indicating that the porous structure allowed multi-layer adsorption. Adsorption equilibrium was reached after 240 min at pH 5 and 303 K, yielding a maximum adsorption capacity of 572.67 mg/g. After five adsorption cycles, the removal rate of DS remained >80%, and the recovery rate was high. Therefore, we concluded that the porous (CYCTS/Span80)-@-PEI microspheres are efficient and inexpensive candidates for the removal of DS from wastewater. |
