In the current study, the impact of self-synthesized nanoporous titanium oxide (NT) on the morphology, performance and fouling of a polyamide (PA) thin-film composite (TFC) membrane was investigated when the membrane was applied for engineering osmosis (EO). The nanoporous structure and the spindle-like shape of NT were revealed through transmission electron microscopy (TEM), while the AATPS modification of NT was verified by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The results of x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) confirmed the presence of modified NT (mNT) in the PA dense active layer of the TFC membrane. The outgrowth of the ‘leaf-like’ structure, upon mNT loading, at the surface of the PA layer was observed by field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The TFC membrane prepared with 0.05 wt% mNT loading in the organic phase showed the water flux of 26.4 l m ⁻² h ⁻¹ when tested in the forward osmosis (FO) mode using 0.5M and 10 mM NaCl solution as the draw and feed solution, respectively. Moreover, the TFC-mNT membrane also demonstrated an intensified antifouling property against organic foulant during FO application and it was possible to retrieve the initial water flux almost completely with a simple water-rinsing process.

Many studies indicated that phthalates, a common plasticizer, lurk silently in water bodies and can potentially harm living organisms. Therefore, removing phthalates from water sources prior to consumption is crucial. This study aims to evaluate the performance of several commercial nanofiltrations (NF) (i.e., NF3 and Duracid) and reverse osmosis (RO) membranes (i.e., SW30XLE and BW30) in removing phthalates from simulated solutions and further correlate the intrinsic properties of membranes (e.g., surface chemistry, morphology, and hydrophilicity) with the phthalates removal. Two types of phthalates, i.e., dibutyl phthalate (DBP) and butyl benzyl phthalate (BBP), were used in this work, and the effects of pH (ranging from 3 to 10) on the membrane performance were studied. The experimental findings showed that the NF3 membrane could yield the best DBP (92.5–98.8%) and BBP rejection (88.7–91.7%) regardless of pH, and these excellent results are in good agreement with the surface properties of the membrane, i.e., low water contact angle (hydrophilicity) and appropriate pore size. Moreover, the NF3 membrane with a lower polyamide cross-linking degree also exhibited significantly higher water flux compared to the RO membranes. Further investigation indicated that the surface of the NF3 membrane was severely covered by foulants after 4-h filtration of DBP solution compared to the BBP solution. This could be attributed to the high concentration of DBP presented in the feed solution owing to its high-water solubility (13 ppm) compared to BBP (2.69 ppm). Further research is still needed to study the effect of other compounds (e.g., dissolved ions and organic/inorganic matters that might be present in water) on the performance of membranes in removing phthalates.

Incorporating nanoparticles (NPs) into the selective layer of thin-film composite (TFC) membranes is a common approach to improve the performance of the resulting thin-film nanocomposite (TFN) membranes. The main challenge in this approach is the leaching out of NPs during membrane operation. Halloysite nanotubes (HNTs) modified with the first generation of poly(amidoamine) (PAMAM) dendrimers (G1) have shown excellent stability in the PA layer of TFN reverse-osmosis (RO) membranes. This study explores, for the first time, using these NPs to improve the properties of TFN nanofiltration (NF) membranes. Membrane performance was evaluated in a cross-flow nanofiltration (NF) system using 3000 ppm aqueous solutions of MgCl₂, Na₂SO₄ and NaCl, respectively, as feed at 10 bar and ambient temperature. All membranes showed high rejection of Na₂SO₄ (around 97–98%) and low NaCl rejection, with the corresponding water fluxes greater than 100 L m⁻² h⁻¹. The rejection of MgCl₂ (ranging from 82 to 90%) was less than that for Na₂SO₄. However, our values are much greater than those reported in the literature for other TFN membranes. The remarkable rejection of MgCl₂ is attributed to positively charged HNT-G1 nanoparticles incorporated in the selective polyamide (PA) layer of the TFN membranes.

The application of nanofiltration (NF) membranes in the forward osmosis (FO) process to remove heavy metal ions from wastewater is an emerging concept. Unlike NF, FO does not require an external driving force. Although the product, a dilute draw solution, must further be processed by NF to produce pure water and reconcentrate a draw solution, the feed to that NF process is “clean”, which minimizes membrane fouling. This paper examines the role of Cu²⁺ and Pb²⁺ in the feed solution on the water and the reverse solute fluxes in FO process using novel thin film nanocomposite (TFN) NF membranes. The TFN membranes were fabricated by in situ interfacial polymerization of piperazine (PIP) and 1,3,5-benzenetricarbonyl trichloride (TMC) containing different amounts of dispersed halloysite nanotubes (HNTs) nanoparticles functionalized with the first generation of poly(amidoamine) (PAMAM) dendrimers. The presence of Cu²⁺ and Pb²⁺ in the feed solution decreased the reverse flux of MgCl₂ by at least 2.5 times compared to the experiments with pure water as a feed. Simultaneously, the water flux also increased. The corresponding rejections of Cu²⁺ and Pb²⁺ in the FO process ranged from 94.5% to 98.1%.

This study explored the use of a combination of hydrothermal and sol–gel methods to produce porous titanium dioxide (PTi) powder with a high specific surface area of 112.84 m²/g. The PTi powder was utilized as a filler in the fabrication of ultrafiltration nanocomposite membranes using polysulfone (PSf) as the polymer. The synthesized nanoparticles and membranes were analyzed using various techniques, including BET, TEM, XRD, AFM, FESEM, FTIR, and contact angle measurements. The membrane’s performance and antifouling properties were also assessed using bovine serum albumin (BSA) as a simulated wastewater feed solution. Furthermore, the ultrafiltration membranes were tested in the forward osmosis (FO) system using a 0.6-weight-percent solution of poly (sodium 4-styrene sulfonate) as the osmosis solution to evaluate the osmosis membrane bioreactor (OsMBR) process. The results revealed that the incorporation of PTi nanoparticles into the polymer matrix enhanced the hydrophilicity and surface energy of the membrane, resulting in better performance. The optimized membrane containing 1% PTi displayed a water flux of 31.5 L/m²h, compared to the neat membrane water value of 13.7 L/m²h. The membrane also demonstrated excellent antifouling properties, with a flux recovery of 96%. These results highlight the potential of the PTi-infused membrane as a simulated osmosis membrane bioreactor (OsMBR) for wastewater treatment applications.