Preparation of mixed matrix PES-based nanofiltration membrane filled with PANI-co-MWCNT composite nanoparticles

Recovery of Oleuropein from Olive Leaf Extract Using Zinc Oxide Coated by Polyaniline Nanoparticle Mixed Matrix Membranes

This study explores the integration of zinc oxide coated with polyaniline (ZnO-PANI) nanoparticles into a poly(ether sulfone) (PES) matrix to concurrently enhance permeate flux and oleuropein (OLP) rejection during the filtration of olive leaf extract (OLE). The effect of ZnO-PANI content on porosity, pore size, surface hydrophilicity, and pure water flux (PWF) was studied. The results indicate that an increase in ZnO-PANI content (0-0.2%) leads to a 3-fold increase in mean pore size, permeability (1.29-7.18 L/m2 h bar), porosity (72.2-77.8%), and improved surface hydrophilicity of the prepared membranes. Membrane performance was tested for OLE permeate flux of the OLE and total phenolic compounds (TPC) rejection at various pressures (10-30 bar), the performance of the OLP rejection at 30 bar, and fouling resistance. The 0.2 wt % ZnO-PANI membrane exhibits the highest permeate flux, while the 0.4 wt % ZnO-PANI membrane offers the highest rejection values (90-97% for TPC and 100% for OLP). Bare PES demonstrated the best fouling resistance. Strategic ZnO-PANI incorporation achieves a balance, enhancing both the flux and rejection efficiency. The 0.2 wt % ZnO-PANI membrane emerges as particularly favorable, striking a beneficial equilibrium between permeate flux and OLP rejection. Intriguingly, the use of these membranes for OLE filtration, postpretreatment with ultrafiltration (UF), results in a remarkable 100% rejection of OLP. This discovery underscores the significant and specific separation of OLP from OLE facilitated by a ZnO-PANI-based mixed matrix membrane (MMM). The study contributes valuable insights into the development of advanced membranes with enhanced filtration capabilities for high-added value phenolic compound separation.

Improvement of salt rejection efficiency of cellulose acetate membrane through modification by poly(amidoamine) dendrimer-functionalized graphene oxide

In this work, the grafting method using graphene oxide (GO) - poly(amidoamine) dendrimer (PAMAM) nanocomposite as filler for the functionalization of cellulose acetate membrane is reported. Here, cellulose acetate membrane incorporated by nanocomposite in the polymer solution was prepared through the phase inversion technique. The effect of embedding GO-PAMAM on the characterization properties and rejection performance was studied. The results of zeta potential, thermogravimetric analysis (TGA), contact angle measurements, Fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FE-SEM) established successful modification. Based on the data found, adding the filler improves membrane properties. Loading of 1.00 wt% of GO/PAMAM was found to be the optimized amount of the filler in the membrane processing with the highest porosity (74%), antifouling behavior (88%), reversible fouling ratio (45.71%), and the least contact angle (∼40°). Hence, the rejection and permeability tests of the prepared membrane were examined by Na2SO4 (98.40%), NaCl (52%), and MgCl2 (57%) solutions through a lab dead-end cell. According to the results, the value of salt rejection established more permeability and rejection than neat cellulose acetate membrane.

Impact of Silver-Decorated Graphene Oxide (Ag-GO) towards Improving the Characteristics of Nanohybrid Polysulfone Membranes

The utilization of membranes has been extensively employed in the treatment of water and wastewater. Membrane fouling, attributed to the hydrophobic nature of membranes, constitutes a noteworthy concern in the realm of membrane separation. The mitigation of fouling can be achieved through the modification of membrane characteristics, including but not limited to hydrophilicity, morphology, and selectivity. In this study, a nanohybrid polysulfone (PSf) membrane embedded with silver-graphene oxide (Ag-GO) was fabricated to overcome problems related to biofouling. The embedment of Ag-GO nanoparticles (NPs) is the aim towards producing membranes with antimicrobial properties. The fabricated membranes at different compositions of NPs (0 wt%, 0.3 wt%, 0.5 wt%, and 0.8 wt%) are denoted as M0, M1, M2, and M3, respectively. These PSf/Ag-GO membranes were characterized using FTIR, water contact angle (WCA) goniometer, FESEM, and salt rejection. The additions of GO significantly improved the hydrophilicity of PSf membranes. An additional OH peak at 3380.84 cm^-1 of the nanohybrid membrane from FTIR spectra may be related to hydroxyl (-OH) groups of GO. The WCA of the fabricated membranes decreased from 69.92° to 54.71°, which confirmed the improvement in its hydrophilicity. In comparison to the pure PSf membrane, the morphology of the finger-like structure of the fabricated nanohybrid membrane slightly bent with a larger bottom part. Among the fabricated membranes, M2 achieved the highest iron (Fe) removal, up to 93%. This finding proved that the addition of 0.5 wt% Ag-GO NPs enhanced the membrane water permeability together with its performance of ionic solute removal (Fe²⁺) from synthetic groundwater. In conclusion, embedding a small amount of Ag-GO NPs successfully improved the hydrophilicity of PSf membranes and was able to achieve high removal of Fe at 10-100 mg L^-1 towards purification of groundwater for safe drinking water.

Cellulose nanofiber-poly(ethylene terephthalate) nanocomposite membrane from waste materials for treatment of petroleum industry wastewater

Petroleum industry wastewater contains high level of crude oil and other types of organic substances that can cause immense harm to the agriculture, aquatic as well as terrestrial organisms. Organic solvent resistance of membranes is very important to treat such wastewater that contains high level of organic pollutants. This work reports the designing of a superhydrophilic and organic solvent resistant nanocomposite membrane using waste bottles made of poly(ethylene terephthalate) (PET) and cellulosic papers. Using in-situ synthesized cellulose nanofibers we could successfully fabricate porous membranes which is not possible for bare PET matrix using water as nonsolvent. Thus, we could successfully replace methanol which was used as a suitable non-solvent in earlier reports by distilled water. We successfully used the membrane for separation of synthetic crude oil-water emulsion. The membrane showed permeability up to 98 Lm^-2h^-1 applying pressure of 1.5 bar. The membrane also achieved removal of more than 97 % of organic substances from a crude oil-water emulsion system. The optimum membrane also showed good thermal stability with initial degradation temperature ∼350 °C and tensile strength of 0.86 MPa. The antimicrobial property of the nanocomposite membranes could be achieved by coating its surface with carbon dots rooted graphene oxide.