Membrane M4 Research Articles

Effect of Crosslinking on the Properties of Membrane Formulated from Quaternized Chitosan

Heavy metals are easily absorbed by living things because of their high-water solubility. Adsorption is a popular separation technique that is used to remove heavy metals from water since it is inexpensive, widely available, and ecologically benign. Chitosan's structure includes hydroxyl and amino groups, which make it a popular adsorbent for heavy metals. In this study, quaternization was used to change chitosan and improve its adsorption capacity. As the quaternizing agent, hexadecyltrimethylammonium bromide (TMAB) was employed. After blending the quaternized chitosan with polyvinyl alcohol and polysulfone, a membrane was created, and tetraethyl orthosilicate (TEOS) was used to crosslink it. Tetraethyl orthosilicate loadings of 1, 2, and 4 weight percent were added to the membrane formulation as a crosslinker. The surface morphology and surface charge of the prepared membranes were then described. Antifouling analysis and water permeation were used to test the performances. According to the results, membrane M4 with 4 weight percent TEOS exhibited the best characteristics, especially in terms of surface charge and surface morphology with strong antifouling capabilities. Furthermore, it has the highest water flux attributed to good surface hydrophilicity. The developed membranes may find application in the heavy metal removal phase of water treatment.

Effect of chitosan-zinc oxide coated in PVDF membrane; morphology and performance testing

PVDF membrane modification has been done by coating it using chitosan which is mixed with zinc oxide. This study was conducted to determine the effect of chitosan-zinc oxide hybrid on PVDF membrane’s hydrophobicity and performance. The coating has been processed by immersing PVDF membrane into a chitosan-zinc oxide hybrid solution with a ratio chitosan : zinc oxide of 1: 0 (M1), 6: 1 (M2), 4: 1 (M3), and 2: 1 (M4). Membrane morphology characterization was carried out by FE-SEM and FTIR. Water contact angle analysis and performance test was conducted to determine the effect of chitosan and zinc oxide on the hydrophobicity, permeability, percent rejection, and antifouling performance of PVDF membrane. The result of water contact angle analysis shows that the more zinc oxide was added to chitosan-zinc oxide hybrid, the hydrophobicity of membrane was decreased. Membrane performance test shows that the most stable membrane permeability to time is membrane M4, while the membrane with the most stable permeability to pressure is PVDF membrane without coating (membrane M). The best rejection performance ad flux recovery ratio of membranes is shown by membrane M4.

Synthesizing Ag/PDA/PES Antibacterial Membrane for Natural Organic Molecules Removal

Silver nanoparticles (NP) was successfully immobilized on polydopamine (PDA) supported polyethersulfone (PES) membrane via a redox reaction. Polyvinylpyrrolidone (PVP) was added into membrane dope solution as a pore-forming agent. Four pieces of membranes (M1, M2, M3 and M4) were fabricated with different active layer coatings to compare their morphological and performance properties. The differences between each sample were highlighted as follow: M1 (pristine PES), M2 (PES+PVP), M3 (PDA/PES+PVP) and M4 (Ag/PDA/PES+PVP). All membranes were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction and contact angle analysis. The membrane performance was examined using pure water permeability (PWP) test, antibacterial test and humic acid (HA) rejection test. Pristine M1 membrane showed that PWP of 27.16 LMH/bar and HA rejection of 84 %. In this study, it was found that the addition of PVP as a pore agent into the membrane M2 increased water flux but slightly deteriorated HA rejection. Coating of PDA on M3 and immobilizing silver NP on M4 membrane surface have improved HA rejection but compromised PWP. The results showed that membrane M4 carried excellent antibacterial property and highest HA rejection among all fabricated membranes.