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

Highly Efficient Biosorption of Cationic Dyes via Biopolymeric Adsorbent-Material-Based Pectin Extract Polysaccharide and Carrageenan Grafted to Cellulosic Nonwoven Textile

Water scarcity and contamination have emerged as critical global challenges, requiring the development of effective and sustainable solutions for the treatment of contaminated water. Recently, functionalized polymer biomaterials have garnered significant interest because of their potential for a wide range of water treatment applications. Accordingly, this paper highlights the design of a new adsorbent material based on a cellulosic nonwoven textile grafted with two extracted biopolymers. The layer-by-layer grafting technique was used for the polyelectrolyte multi-layer (PEM) biosorbent production. Firstly, we extracted a Suaeda fruticosa polysaccharide (SFP) and confirmed its pectin-like polysaccharide structure via SEC, NMR spectroscopy, and chemical composition analyses. Afterward, the grafting was designed via an alternating multi-deposition of layers of SFP polymer and carrageenan crosslinked with 1,2,3,4-butanetetracarboxylic acid (BTCA). FT-IR and SEM were used to characterize the chemical and morphological characteristics of the designed material. Chemical grafting via polyesterification reactions of the PEM biosorbent was confirmed through FT-IR analysis. SEM revealed the total filling of material microspaces with layers of grafted biopolymers and a rougher surface morphology. The assessment of the swelling behavior revealed a significant increase in the hydrophilicity of the produced adsorbent system, a required property for efficient sorption potential. The evaluation of the adsorption capabilities using the methylene blue (MB) as cationic dye was conducted in various experimental settings, changing factors such as the pH, time, temperature, and initial concentration of dye. For the untreated and grafted materials, the greatest adsorbed amounts of MB were 130.6 mg/g and 802.6 mg/g, respectively (pH = 4, T = 22 C, duration = 120 min, and dye concentration = 600 mg/L). The high adsorption performance, compared to other reported materials, was due to the presence of a large number of hydroxyl, sulfonate, and carboxylic functional groups in the biosorbent polymeric system. The adsorption process fitted well with the pseudo-first-order kinetic model and Langmuir/Temkin adsorption isotherms. This newly developed multi-layered biosorbent shows promise as an excellent adsorption resultant and cheap-cost/easy preparation alternative for treating industrial wastewater.

Synthesizing pectin-crosslinked gum ghatti hydrogel for efficient adsorptive removal of malachite green

Pectin-crosslinked gum ghatti hydrogel (PGH) has been synthesized utilizing pectin and gum ghatti through an uncomplicated and inexpensive copolymerization method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM-elemental mapping), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS) characterization techniques have been employed to determine various structural, chemical and compositional characteristics of fabricated PGH. Three different weight ratios (1:1, 2:1, or 1:2 for pectin and gum ghatti, respectively) were employed to synthesize three distinct types of PGH. Swelling studies has been done to determine the best ratios for PGH fabrication. PGH has been assessed as an adsorbent for the removal of malachite green dye from aqueous solutions. The effects of PGH dosage (100-400 mg/L), dye concentration (10-160 mg/L), pH (2-9 pH), adsorption time (0-480 min), and temperature (25-55 °C) has been examined through batch solutions. According to Langmuir isotherm analysis, the maximum adsorption capacity is 658.1 mg/g. By using pseudo-second-order kinetics and the Freundlich adsorption isotherm, the adsorption process could be well explained. After five consecutive cycles, PGH had an adsorption percentage of 86.917 % for the malachite green dye. It is safe for the environment and may be used to remove malachite green (MG) dye from aqueous solutions.

Integration of Porous Nanomaterial-Infused Membrane in UF/FO Membrane Hybrid for Simulated Osmosis Membrane Bioreactor (OsMBR) Process

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.

Thin-Film Nanocomposite (TFN) Membranes for Water Treatment Applications: Characterization and Performance

Thin-film nanocomposite (TFN) membranes have been widely investigated for water treatment applications due to their promising performance in terms of flux, salt rejection, and their antifouling properties. This review article provides an overview of the TFN membrane characterization and performance. It presents different characterization techniques that have been used to analyze these membranes and the nanofillers within them. The techniques comprise structural and elemental analysis, surface and morphology analysis, compositional analysis, and mechanical properties. Additionally, the fundamentals of membrane preparation are also presented, together with a classification of nanofillers that have been used so far. The potential of TFN membranes to address water scarcity and pollution challenges is significant. This review also lists examples of effective TFN membrane applications for water treatment. These include enhanced flux, enhanced salt rejection, antifouling, chlorine resistance, antimicrobial properties, thermal stability, and dye removal. The article concludes with a synopsis of the current status of TFN membranes and future perspectives.

Performance Enhancement of Kaolin/Chitosan Composite-Based Membranes by Cross-Linking with Sodium Tripolyphosphate: Preparation and Characterization

A new family of environmentally friendly and low-cost membranes based on readily available mineral and polymeric materials has been developed from cast suspensions of kaolin and chitosan using aqueous phase separation and polyethylene glycol as a pore-forming agent. The as-fabricated membranes were further cross-linked with sodium tripolyphosphate (STPP) in order to strengthen the properties of the obtained samples. The functional groups determined by FTIR and EDX confirmed that the reaction occurred. A detailed study of the effects of cross-linking time on the physicochemical, surface and permeation properties showed that a 30-minute reaction enabled the composite membrane to be stable in acidic media (up to pH 2) and increased the mechanical strength twofold compared to the non-cross-linked membrane. A similar morphology to that generally observed in polymeric membranes was obtained, with a sponge-like surface overlaying a finger-like through structure. The top layer and cross-section thicknesses of the membranes increased during STPP post-treatment, while the pore size decreased from 160 to 15 nm. At the same time, the molecular weight cut-off and permeance decreased due to the increase in cross-linking density. These results observed in a series of kaolin/chitosan composite membranes showed that STPP reaction can provide control over the separation capability range, from microfiltration to ultrafiltration.

Research Progress and Application of Polyimide-Based Nanocomposites

Polyimide (PI) is one of the most dominant engineering plastics with excellent thermal, mechanical, chemical stability and dielectric performance. Further improving the versatility of PIs is of great significance, broadening their application prospects. Thus, integrating functional nanofillers can finely tune the individual characteristic to a certain extent as required by the function. Integrating the two complementary benefits, PI-based composites strongly expand applications, such as aerospace, microelectronic devices, separation membranes, catalysis, and sensors. Here, from the perspective of system science, the recent studies of PI-based composites for molecular design, manufacturing process, combination methods, and the relevant applications are reviewed, more relevantly on the mechanism underlying the phenomena. Additionally, a systematic summary of the current challenges and further directions for PI nanocomposites is presented. Hence, the review will pave the way for future studies.

Animal Cellulose with Hierarchical Structure Isolated from Halocynthia aurantium Tunic as the Basis for High-Performance Pressure-Resistant Nanofiltration Membrane

The structure and transport properties of the new Cellokon-AKH membrane based on animal cellulose obtained from tunic of ascidian Halocynthia aurantium were studied. The results of scanning electron microscopy (SEM), FTIR spectroscopy, and the X-ray diffraction data revealed significant differences in the structure and morphology of upper and lower surfaces of this layered film membrane based on animal cellulose. It was shown that the membrane surface is a network of intertwined cellulose fibers, with both denser and looser areas present on the lower surface compared to the completely uniform morphology of the main part of the upper surface. The hierarchical structure of tunicin-based outgrowths evenly distributed over the upper surface was determined and analyzed. The 3D visual representation of the surface structure was performed with the surface reconstruction technique using scanning electron microscope images. A surface model was calculated from the aligned images based on the photogrammetric approach. The transport properties of samples with different prehistory with respect to ethanol, water, and their mixtures of different compositions were studied depending on the pressure. Representing an alcohol-containing gel film in its original state, as solvents are removed, the membrane transforms into a low-permeability fibrillary organized selective film. The obtained results confirmed the possibility of using Cellokon-AKH (dried form) for the filtration of substances with a molecular weight of more than 600 Da in various media. Further study of this new material will allow to get closer to understanding the structure of the studied seabed inhabitants and to use these natural resources more efficiently.

Lyophilization of Curcumin–Albumin Nanoplex with Sucrose as Cryoprotectant: Aqueous Reconstitution, Dissolution, Kinetic Solubility, and Physicochemical Stability

An amorphous curcumin (CUR) and bovine serum albumin (BSA) nanoparticle complex (nanoplex) was previously developed as a promising anticancer nanotherapy. The CUR-BSA nanoplex had been characterized in its aqueous suspension form. The present work developed a dry-powder form of the CUR-BSA nanoplex by lyophilization using sucrose as a cryoprotectant. The cryoprotective activity of sucrose was examined at sucrose mass fractions of 33.33, 50.00, and 66.66% by evaluating the lyophilized nanoplex’s (1) aqueous reconstitution and (2) CUR dissolution and kinetic solubility. The physicochemical stabilizing effects of sucrose upon the nanoplex’s 30-day exposures to 40 °C and 75% relative humidity were examined from (i) aqueous reconstitution, (ii) CUR dissolution, (iii) CUR and BSA payloads, (iv) amorphous form stability, and (v) BSA’s structural integrity. The good cryoprotective activity of sucrose was evidenced by the preserved BSA’s integrity and good aqueous reconstitution, resulting in a fast CUR dissolution rate and a high kinetic solubility (≈5–9× thermodynamic solubility), similar to the nanoplex suspension. While the aqueous reconstitution, CUR dissolution, and amorphous form were minimally affected by the elevated heat and humidity exposures, the treated nanoplex exhibited a lower BSA payload (≈7–26% loss) and increased protein aggregation postexposure. The adverse effects on the BSA payload and aggregation were minimized at higher sucrose mass fractions.