Adsorptive Membranes for The Removal of Antibiotics from Pharmaceutical Wastewater

Abstract

Adsorptive membranes are considered among the promising technologies that have shown competence in removing different pollutants from wastewater. They possess the dual advantage of adsorption and filtration. Pharmaceutical compounds including antibiotics are emerging contaminants of major concern because they cannot be fully removed via conventional wastewater treatment methods. Therefore, there is a crucial need for an effective technology such as the adsorptive membrane technology. In this work, an adsorptive membrane composed of Polyethersulfone (PES) with Zirconium Phosphate (ZrP) adsorbent was synthesized for the removal of Ciprofloxacin antibiotic from synthetic water solutions. Batch adsorption experiments using zirconium phosphate were conducted first to determine the optimum conditions for the antibiotic removal. Several factors were studied including the initial concentration of the antibiotic, the adsorbent dosage, contact time, pH, and temperature. The experimental data were best fit by the Temkin isotherm. Based on the adsorption batch results, the PES/ZrP membrane was synthesized by solution spin coating and tested with various adsorbent loadings to investigate the optimum ZrP loading in the membrane. The composite membrane showed a high ciprofloxacin removal reaching up to 99.7% which indicated an enhancement compared to the use of PES membrane alone (68%). Moreover, a significant improvement in the membrane's water flux (100.84 L/m².h) and permeability (97.62 L/m².hr.bar) were noticed as opposed to pure PES membrane's flux and permeability. Several characterization analyses were conducted including SEM, EDS, FTIR, XRD, and BET, which demonstrated the successful ZrP deposition in the membrane’s pores with enhanced hydrophilicity properties and effective surface area. Lastly, the membrane was successfully regenerated and reused up to 5 times which indicates the potential of PES/ZrP adsorptive membrane for the removal of ciprofloxacin and at a high efficiency.