Publication: Graphene oxide doped polyvinyl chloride- polysulfone self-plasticized polymer inclusion membrane for ibuprofen and tetracycline removal
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Date
2023-07-01
Authors
Oluwasola Ebenezer Idowu
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Abstract
Polymer inclusion membrane (PIM) is an effective and economical alternative to advanced treatment techniques (ATTs) for separating pharmaceutical residues of emerging concerns. However, the relative chemical instability of PVC -based PIM, particularly in alkaline media, is a major drawback to its industrial prospect. Similarly, the toxicity and biodegradability concerns of the usually incorporated liquid plasticizer in PIM fabrication are concerning. Therefore, this study fabricated and characterized a flexible, chemically stable, and efficient self-plasticized PIM embedded with (tri-capryl methylammonium chloride (Aliquat 336) or Bis (2-ethylhexyl)phosphoric acid (HDEHP) as extractants /carriers. The PIM was effectively applied to treat low concentrations (5 -15 mg/L) of aqueous Tetracycline (TC) and Ibuprofen (IBU) drugs. A comparative performance study at varied process parameters (pH, stirring speed, receiver phase, feed phase) showed that the self-plasticized PVC-Aliquat 336 carrier at 60 % concentration has better transportability than the 50 % HDEHP carrier PIM at a stirring speed of 700 rpm, pH of 9, using 2 M NaCl as the receiver phase. Moreover, doping with 2 % hydrophilic graphene oxide (GO) improved the flexibility and performance of the PVC-PIM embedded with a minimum concentration of the effective Aliquat 336 carrier (33 %). Furthermore, a partial substitution of PSF polymer at 10 % to fabricate GO-doped PSF -PVC PIM as a bi-polymer PIM synergistically modified the physicochemical and morphological structure of the self-plasticized PIM. The GO-doped PSF-PVC PIM at 33 % carrier concentration shows significantly improved physicochemical properties and transportation efficiencies. Its mass loss in the alkaline and deionized water after 24 h was only 5.85 ± 0.90 % and 8.53 ± 0.46 %, respectively. The nanoindentation plot and mathematical data obtained confirmed the better flexibility of the GO-doped-PSF-PVC PIM. Furthermore, ~ 100 and 80 % 10 mg /L aqueous TC and IBU were successfully transported to the receiving phase. The GO-doped-PSF-PVC PIM was successfully applied for a prolonged transportation process of 10 cycles with 5 and 10 mg/L TC at 45 h per cycle (450 h). The dynamic kinetic study has a correlation coefficient of 0.9156 and a permeability coefficient k value of 0.09472 s−1. The current study is a potentially greener approach to obtaining chemically stable and efficient PIM.