Development of Antifouling Thin-Film Composite/Nanocomposite Membranes for Removal of Phosphate and Malachite Green Dye

Abstract

Nowadays polymer-based thin film nanocomposite (TFN) membrane technologies are showing key interest to improve the separation properties. TFN membranes are well known in diverse fields but developing highly improved TFN membranes for the removal of low concentration solutions is the main challenge for the researchers. Application of functional nanomaterials, incorporated in TFN membranes provides better performance as permeance and selectivity. The polymer membrane-based separation process plays an important role in the chemical industry for the isolation of products and recovery of different important types of reactants. Due to the reduction in investment, less operating costs and safety issues membrane methods are mainly used for the separation process. Membranes do good separation of dyes and ions, yet their separation efficiency is challenged when the impurity is in low concentration. Herewith, we have developed, UiO-66-NH₂ incorporated TFN membranes through interfacial polymerization between piperazine (PIP) and trimesoyl chloride (TMC) for separating malachite green dye and phosphate from water in their low concentration. A comparative study between thin-film composite (TFC) and TFN has been carried out to comprehend the benefit of loading nanoparticles. To provide mechanical strength to the polyamide layer ultra-porous polysulfone support was made through phase inversion. As a result, outstanding separation values of malachite green (MG) 91.90 ± 3% rejection with 13.32 ± 0.6 Lm^-2h^-1 flux and phosphate 78.36 ± 3% rejection with 22.22 ± 1.1 Lm^-2h^-1 flux by TFN membrane were obtained. The antifouling tendency of the membranes was examined by using bovine serum albumin (BSA)-mixed feed and deionized water, the study showed a good ~84% antifouling tendency of TFN membrane with a small ~14% irreversible fouling. Membrane's antibacterial test against E. coli. and S. aureus. also revealed that the TFN membrane possesses antibacterial activity as well. We believe that the present work is an approach to obtaining good results from the membranes under tricky conditions.

Keywords: UiO-66-NH2 nanoparticles; antibacterial test; antifouling study; interfacial polymerization; malachite green; phosphate removal; polysulfone.

Figure 1

Representation of preparation of TFN (thin-film nanocomposite) layer on the surface of PSf membrane (Polysulfone-membrane) via interfacial polymerization method.

Figure 2

The crossflow NF/RO (Nanofiltration/Reverse Osmosis) four-cell membrane testing unit.

Figure 3

The obtained (a) FE-SEM image at 200 nm scale, (b) FE-SEM image showing the shape of UiO-66-NH₂, (c) ATR-FTIR spectrum for UiO-66-NH₂ nanoparticles and (d) P-XRD pattern obtained for UiO-66-NH₂.

Figure 4

FE-SEM images of (a) surface view of M1 and (c) surface view of M2 membrane and the cross-section images of (b) M1 membrane and (d) M2 membrane.

Figure 5

ATR-FTIR spectra of prepared M1 and M2 membrane.

Figure 6

The high-resolution XPS plots of carbon, nitrogen and oxygen elements for M1 and M2 membranes.

Figure 7

TGA analysis graph of the prepared (a) M1 and (b) M2 membrane.

Figure 8

Zeta potential (ζ) observations of M1 and M2 membranes.

Figure 9

(a) M1 and M2 membrane’s permeation and rejection graphs against malachite green dye. (b) The images show the comparison of feed and obtained permeate per hour up to 7 h.

Figure 10

Permeability and rejection performance of M1 and M2 membrane at 15 bar pressure against phosphate.

Figure 11

Effect on the permeation of membranes after exposure to fouling materials (in mix feed) for 480 min.

Figure 12

Different fouling parameters were obtained for the prepared membranes (M1 and M2) showing (a) Total fouling (F_T), Flux recovery ratio (F_RR) and (b) reversible fouling (F_R) and irreversible fouling (F_IR).

Figure 13

The antibacterial results of the M1 and M2 membrane after being subjected to 24 h with E. coli and S. aureus.