Development of thin film nanocomposite membrane incorporated with mesoporous synthetic hectorite and MSH@UiO-66-NH2 nanoparticles for efficient targeted feeds separation, and antibacterial performance

Abstract

Functionalized metal-organic frameworks (MOFs) and their composites are found one of the best material to develop the thin-film nanocomposite (TFN) membranes and concern water purification technologies with boosted water flux and targeted feeds rejection performance. MOFs with suitable functionalities are found more stable and efficient due to strong interfacial polymerization with free functional groups which consequently resulted in a thin selective nanocomposite layer on the surface of polysulfone flat sheet membranes. Similarly, mesoporous synthetic hectorite (MSH), due to negative surface charge acts as the best support material to avoid high agglomeration of positively charged MOF crystals. Additionally, surface hydroxyl functionalities with high dispersion capability in a polymer monomer solution makes MSH as a promising material for MOF support and development of novel membranes. Herein considering all these advantageous aspects of both material, we have established a novel approach for developing of TFN membranes by incorporating MSH, and composite of MSH and MOF (UiO-66-NH2) nanoparticles in piperazine (PIP) aqueous monomer solution, which were further interfacially polymerized with trimesoyl chloride (TMC) organic phase monomer. The developed nanoparticles (MSH and MSH@UiO-66-NH2) formulation were confirmed by ideal characterization techniques such as, PXRD, FTIR, TGA and SEM. Whereas, alteration impact of MSH and MSH@UiO-66-NH2 nanoparticles on prepared membranes were physicochemically evaluated with original TFC membrane by ATR-FTIR, FE-SEM, HR-TEM, AFM, XPS, TGA, zeta potential and contact angle analysing techniques. The efficacy performance of the developed TFN membranes were compared with thin-film composite (TFC) membrane and found that TFN membranes showed excellent water flux and rejection performances against different synthetic feed solutions including most common salts (i. e. NaCl, Na2SO4, CuSO4, MgSO4, MnSO4), toxic boron in the seawater and bulky humic substances. Interestingly upon incorporation of a small amount of (0.01%) MSH and MSH@UiO-66-NH2 nanoparticles into the developed membrane dramatically improved rejection performance against applied feed solutions in the trend of TFC < MSH-TFN < MSH@UiO-66-NH2-TFN. The highest rejection 94.42% for MgSO4 was obtained along with the flux 34.78 L/m2.h at 1.5 MPa. Likewise, 69.56 L/m2.h flux with 71.23% rejection for boron at pH 8 (close to sea water) at 1.5 MPa. Due to hydrophilic and notable antifouling nature of TFN membranes the tested membrane shows excellent humic acid permeate flux of 80.68 L/m2.h and rejection of 98.96%. Besides, MSH@UiO-66-NH2-TFN membrane showed noteworthy antibacterial properties with efficient reduction in the bacterial colony growth. We believed that the present novel membrane modification approach has high potential in the development of high efficient water purification technologies in future.