Fabrication of cellulose acetate nanocomposite membranes using 2D layered nanomaterials for macromolecular separation

Cellulose-Acetate-Based Films Modified with Ag2O and ZnS as Nanocomposites for Highly Controlling Biological Behavior for Wound Healing Applications

For wound healing, functional films with certain physicochemical and biological properties are needed. Thus, the current work aimed to fabricate multifunctional materials comprising metal oxide nanoparticles loaded with an efficient polymer to be used as dressing material. A composite containing polymeric phases of cellulose acetate (CA) blended with zinc sulfide (ZnS), silver oxide (Ag₂O), and graphene oxide (GO) was successfully synthesized. The prepared composite crystallinity was studied using the X-ray diffraction technique (XRD). Further, the functional groups and the elemental analysis were investigated using Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDX). Furthermore, the surface morphology was studied using scanning electron microscopy (SEM) to obtain the shape and size of particles. SEM showed that the particles were formed in wide distribution in the range of 18-915 nm with an average size of 235 nm for Ag₂O/ZnS/GO/CA. The particle size of Ag₂O in the CA film was in the range between 19 and 648 nm with an average size of 216 nm, while the particle size of ZnS in CA was in the range of 12-991 nm with an average age particle size of 158 mm. In addition, EDX, based on SEM investigation, detected high carbon and oxygen quantities at around 94.21% of the composite. The contact angle decreased and reached 26.28° ± 2.12° in Ag₂O/ZnS/CA. Furthermore, thermogravimetric analysis (TGA) was used to investigate the thermal stability, and the composition was thermally stable until 300 °C. Moreover, the cell viability of "normal lung cells" reached 102.66% in vitro at a concentration of 1250 µg/mL. The antibacterial activity of Ag₂O/ZnS/GO/CA was also detected against E. coli with a zone of inhibition reaching 17.7 ± 0.5 mm. Therefore, the composite can be used in biomedical applications due to its biocompatibility and antibacterial activity.

Recent Development in Laminar Transition Metal Dichalcogenides-based Membranes Towards Water Desalination: A Review

Transition metal dichalcogenides (TMDCs)-based laminar membranes have gained significant interest in energy storage, fuel cell, gas separation, wastewater treatment, and desalination applications due to single layer structure, good functionality, high mechanical strength, and chemical resistivity. Herein, we review the recent efforts and development on TMDCs-based laminar membranes, and focus is given on their fabrication strategies. Further, TMDCs-based laminar membranes for water purification and seawater desalination are discussed in detail. Finally, present their merits, limits and future challenges needed in this area.

Investigating the Antibacterial Activity of Polymeric Membranes Fabricated with Aminated Graphene Oxide

A novel, functionalized graphene oxide-based cellulose acetate membrane was fabricated using the phase inversion method to improve the membrane characteristics and performance. We studied the effect of aminated graphene oxide (NH2-GO) composite on the CA membrane characteristics and performance in terms of membrane chemistry, hydrophilicity, thermal and mechanical stability, permeation flux, and antibacterial activity. The results of contact angle and water flux indicate the improved hydrophilic behavior of composite membranes in comparison to that of the pure CA membrane. The AGO-3 membrane showed the highest water flux of about 153 Lm-2h-1. The addition of hydrophilic AGO additive in CA membranes enhanced the antibacterial activity of AGO-CA membranes, and the thermal stability of the resulting membrane also improved since it increases the Tg value in comparison to that of a pristine CA membrane. The aminated graphene oxide (NH2-GO) was, therefore, found to be a promising additive for the fabrication of composite membranes with potent applications in wastewater treatment.

Cellulose acetate based Complexation-NF membranes for the removal of Pb(II) from waste water

This study investigates the removal of Pb(II) using polymer matrix membranes, cellulose acetate/vinyl triethoxysilane modified graphene oxide and gum Arabic (GuA) membranes. These complexation-NF membranes were successfully synthesized via dissolution casting method for better transport phenomenon. The varied concentrations of GuA were induced in the polymer matrix membrane. The prepared membranes M-GuA2–M-GuA10 were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, atomic force microscope and bio-fouling studies. Thermal stability of the membranes was determined by thermogravimetric analysis under nitrogen atmosphere. Dead end nanofiltration was carried out to study the perm- selectivity of all the membranes under varied pressure and concentration of Pb(NO₃)₂. The complexation-NF membrane performances were significantly improved after the addition of GuA in the polymer matrix membrane system. M-GuA8 membrane showed optimum result of permeation flux 8.6 l m⁻² h⁻¹. Rejection of Pb(II) ions was observed to be around 97.6% at pH 9 for all the membranes due to electrostatic interaction between CA and Gum Arabic. Moreover, with the passage of time, the rate of adsorption was also increased up to 15.7 mg g⁻¹ until steady state was attained. Gum Arabic modified CA membranes can open up new possibilities in enhancing the permeability, hydrophilicity and anti-fouling properties.

Development and investigation of novel antifouling cellulose acetate ultrafiltration membrane based on dopamine modification

In this contribution, a novel cellulose acetate modified with dopamine (CA-DA) membrane material was designed and prepared by a two-step route consist of chlorination and further substitution reactions. The chemical structure of the prepared CA-DA material was determined by FTIR and ¹H NMR, respectively. The CA-DA ultrafiltration membrane was subsequently fabricated by the scalable phase inversion process. Compared with cellulose acetate membrane as the control sample, the introduction of dopamine improved the porosity, pore size and hydrophilicity of the CA-DA membrane, which was helpful to the water permeability (181.2 L/m²h) without obviously affecting the protein rejection (93.5%). According to the static protein adsorption and dynamic cycle ultrafiltration experiments, the CA-DA membrane displayed persistent antifouling performance, which was verified by flux recovery ratio, flux decline ratio and filtration resistance. Moreover, the water flux recovery ratio of the CA-DA membrane was retained at 97.3% after three-cycles of BSA solution filtration, which was much higher than that of the reference CA membrane. This new approach provided a long life and excellent ultrafiltration performance for polymer-based membranes, which has potential application prospects in the field of separation process.

Synthesis, characterization of cellulose acetate membrane and application for the treatment of oily wastewater

This study reports the synthesis of cellulose acetate (CA) membranes of different weight percentages of the polymer ranging from 5 to 17.5 wt% with 2.5% increment and their behaviour towards oil removal from water. The membrane showed decreased water content and porosity and also increased hydraulic resistance upto 3.38 kPa/(l m^-2 h^-1) as the concentration of polymer increases. The Atomic Force Microscopic studies reveal that the membrane shows decreased arithmetic mean roughness from 36.291 to 5.935 nm as the concentration of the polymer increases from 5% to 17.5%. Field Emission Scanning Electron Microscopy shows the surface morphology of the CA membrane. X-ray diffraction studies indicate that in the membrane having above 15% polymer concentration, the polymer chains orient to regularity showing higher crystallinity. The thermal studies indicate their stability upto 280°C, and exothermic decompositions from 338°C to 380°C implying the compactness of chains as polymer concentration increases. From Total Organic Carbon studies, the oil rejection was found to be maximum (96.4%) for the highest concentration of polymer in the membrane.

Applications of Nanocellulose/Nanocarbon Composites: Focus on Biotechnology and Medicine

Nanocellulose/nanocarbon composites are newly emerging smart hybrid materials containing cellulose nanoparticles, such as nanofibrils and nanocrystals, and carbon nanoparticles, such as "classical" carbon allotropes (fullerenes, graphene, nanotubes and nanodiamonds), or other carbon nanostructures (carbon nanofibers, carbon quantum dots, activated carbon and carbon black). The nanocellulose component acts as a dispersing agent and homogeneously distributes the carbon nanoparticles in an aqueous environment. Nanocellulose/nanocarbon composites can be prepared with many advantageous properties, such as high mechanical strength, flexibility, stretchability, tunable thermal and electrical conductivity, tunable optical transparency, photodynamic and photothermal activity, nanoporous character and high adsorption capacity. They are therefore promising for a wide range of industrial applications, such as energy generation, storage and conversion, water purification, food packaging, construction of fire retardants and shape memory devices. They also hold great promise for biomedical applications, such as radical scavenging, photodynamic and photothermal therapy of tumors and microbial infections, drug delivery, biosensorics, isolation of various biomolecules, electrical stimulation of damaged tissues (e.g., cardiac, neural), neural and bone tissue engineering, engineering of blood vessels and advanced wound dressing, e.g., with antimicrobial and antitumor activity. However, the potential cytotoxicity and immunogenicity of the composites and their components must also be taken into account.

Impact of graphene/graphene oxide on the mechanical properties of cellulose acetate membrane and promising natural seawater desalination

New formulations of cellulose acetate (CA) membrane with graphene (G)/graphene oxide (GO) are suggested and investigated in the present work. This study is intended to find a wide range of conditions for fabricating CA membranes in the presence of some additions of graphene (G), and graphene oxide (GO). The membrane is prepared by phase inversion process. Microscopic investigations for graphene (G), graphene oxide (GO), and prepared membrane were performed by high-resolution transmission electron microscope (HRTEM) and scanning electron microscopy (SEM). The mechanical properties of prepared membranes are determined and evaluated. Permeation tests were performed using natural seawater and simulated seawater to check the prepared membrane performance. The results presented that the permeate flux of M25% CA membranes containing 0.01 wt.% G is the highest flux (57–74 l/m2 h) compared with the neat CA membrane, and the 0.01 wt.% GO-based membranes, while the GO-based membranes were comparable as the neat CA membrane at operating pressures (30–35 bar) and with a feed of 35 g/l NaCl solution. The results showed a remarkable salt rejection of simulated seawater of 95%, and natural seawater with a feed from the Mediterranean Sea displayed 90% salt rejection and accepted pure water flux as well.

Cellulose acetate ultrafiltration membranes customized with bio-inspired polydopamine coating and in situ immobilization of silver nanoparticles

Schematic representation of the surface modification of cellulose acetate membranes with self-polymerized dopamine and in situ immobilization of AgNPs.

Fabrication of anti-fouling PVDF nanocomposite membranes using manganese dioxide nanospheres with tailored morphology, hydrophilicity and permeation

Manganese dioxide (MnO₂) nanospheres were prepared by a facile hydrothermal technique and their influence on the permeation and antifouling properties of poly(vinylidene fluoride) (PVDF) ultrafiltration (UF) membranes was investigated.