Cellulose Membrane Research Articles

Beyond waste: Transforming wheat straw into oxygen and UV‐resistant cellulose films

AbstractRegenerated cellulose membrane is a biomaterial obtained by activating, dissolving, solidifying, and regenerating cellulose powder using solvents of different polarities. It has the characteristics of high oxygen resistance and high strength. However, its low water vapor barrier and single function limit its application. In order to improve the water resistance of regenerated cellulose membranes and endow them with UV resistance, lignin was extracted from waste wheat straw using formic acid method. The extracted formic acid lignin (FAL) was added to the cellulose solution to prepare a series of regenerated lignocellulosic membranes (RC‐FAL) with different lignin contents. The results indicate that lignin can not only improve the water vapor barrier, tensile strength, and water resistance of the film, but also enhance the oxygen barrier and UV absorption of the film. Compared with pure cellulose film, the contact angle of lignocellulose film can be increased by 66.2%, the UV absorption rate can reach 100%, and the oxygen transmission coefficient has no significant effect. In this paper, a new kind of biological packaging material with high oxygen resistance, strong ultraviolet absorption, and water resistance was prepared by recycling waste wheat straw, it has a broad application prospect in the industrial production of packaging materials.

Mechanistic Insight in Permeability through Different Membranes in the Presence of Pharmaceutical Excipients: A Case of Model Hydrophobic Carbamazepine.

The present study reports the effects of two pharmaceutical excipients of differing natures-non-ionic surfactant pluronic F127 (F127) and anionic sulfobutylether-β-cyclodextrin (SBE-β-CD)-on the permeation of the model compound, carbamazepine (CBZ). The permeability coefficients of CBZ at three concentrations of the excipients were measured through two different artificial barriers: hydrophilic cellulose membrane (RC) and lipophilic polydimethylsiloxane-polycarbonate membrane (PDS). The equilibrium solubility of CBZ in F127 and SBE-β-CD solutions was determined. The micellization, complexation, and aggregation tendencies were investigated. Systemically increasing the solubility and the reduction of permeation upon the excipients' concentration growth was revealed. The quantitative evaluation of the permeability tendencies was carried out using a Pratio parameter, a quasi-equilibrium mathematical mass transport model, and a correction of permeability coefficients for the free drug concentration ("true" permeability values). The results revealed the mutual influence of the excipient properties and the membrane nature on the permeability variations.

The Performance of Cellulose Composite Membranes and Their Application in Drinking Water Treatment.

Water scarcity and water pollution have become increasingly severe, and therefore, the purification of water resources has recently garnered increasing attention. Given its position as a major water resource, the efficient purification of drinking water is of crucial importance. In this study, we adopted a phase transition method to prepare ZrO2/BCM (bamboo cellulose membranes), after which we developed IP-ZrO2/BC-NFM (bamboo cellulose nanofiltration membranes) through interfacial polymerization using piperazine (PIP) and tricarbonyl chloride (TMC). Subsequently, we integrated these two membranes to create a combined "ultrafiltration + nanofiltration" membrane process for the treatment of drinking water. The membrane combination process was conducted at 25 °C, with ultrafiltration at 0.1 MPa and nanofiltration at 0.5 MPa. This membrane combination, featuring "ultrafiltration + nanofiltration," had a significant impact on reducing turbidity, consistently maintaining the post-filtration turbidity of drinking water at or below 0.1 NTU. Furthermore, the removal rates for CODMN and ammonia nitrogen reached 75% and 88.6%, respectively, aligning with the standards for high-quality drinking water. In a continuous 3 h experiment, the nanofiltration unit exhibited consistent retention rates for Na2SO4 and bovine serum protein (BSA), with variations of less than 5%, indicating exceptional separation performance. After 9 h of operation, the water flux of the nanofiltration unit began to stabilize, with a decrease rate of approximately 25%, demonstrating that the "ultrafiltration + nanofiltration" membrane combination can maintain consistent performance during extended use. In conclusion, the "ultrafiltration + nanofiltration" membrane combination exhibited remarkable performance in the treatment of drinking water, offering a viable solution to address issues related to water scarcity and water pollution.

Water resistant, biodegradable and flexible corn starch/carboxymethyl cellulose composite film for slow-release fertilizer coating materials

The inherent limitations of Cornstarch (CS) and Carboxymethyl Cellulose (CMC) membranes, such as brittleness, fragility, and water solubility, limit their use in controlled-release fertilizers. This study reports on the synthesis of crosslinked CMC/CS-20-E composite membranes using the casting technique, with epichlorohydrin (ECH) as the crosslinking agent in an acidic environment to crosslink CS and CMC. The synthesized composite film demonstrates remarkable water resistance, as evidenced by the insignificant alteration in its morphology and structure post 72 h of water immersion. Its flexibility is reflected in its capacity to endure knotting and bending, with an elongation at break reaching 78.1 %. Moreover, the degradation rate surpasses 90 % within a span of seven days. The CMC/CS-20-E-x-urea controlled-release fertilizer was subsequently produced using a layer-by-layer self-assembly technique, where urea particles were incorporated into the crosslinked composite solution. This CMC/CS-20-E-x-urea controlled-release fertilizer displayed superior controlled-release performance over a duration of seven days when juxtaposed with pure urea. In particular, the CMC/CS-20-E-3 %-urea controlled-release fertilizer showed a cumulative release rate of 84 % by the seventh day. The controlled-release fertilizers developed in this study offer a promising strategy for creating eco-friendly options that are crucial for fertilizing crops with short growth cycles.

Emulsified oil fouling resistant cellulose acetate-MoS2-nanocomposite membrane for oily wastewater remediation

This study evaluated the performance stability of amphiphilic cellulose acetate-MoS2-nanocomposite membranes (CMN) on oil removal and flux, oil fouling trends, as well as MoS2's catalytic peroxidase-like efficiency for oily wastewater treatment. When H2O2 was present in the feed, the membrane consistently achieved oil removal rates as high as 83.12 %, with only <10 % flux decline over an 80-minute filtration. During longer-term filtration of 4–6 h, the CMN membrane also exhibited significantly lower overall flux decline rates compared to the neat membrane with flux decline rates of 16.27 %, which was half of the cellulose membrane flux of 39.38 %. The fouling resistant performance was underpinned by the generation of reactive oxygen species (ROS) via catalytic reactions of MoS2 and H2O2. Coumarin was use as ROS scavenging agent and confirmed that the ROS amount was affected by the MoS2 and H2O2 dosages. The CMN membrane achieved the oil removal to the permissible discharge limit for low concentration wastewater. As a low-pressure membrane, it offered advantages of less energy consumption and continuously operating mode without frequent chemical cleaning and desorption. These findings support the CMN membrane's potential as a promising solution for treating industrial oily wastewater.

Effect of Sucrose Amounts on the Bacterial Cellulose Membrane's Breathability Properties

This study aims to produce a bacteria cellulose (BC) membrane. The critical parameter controlled in this study was the amount of carbon source during the production. The effects of carbon source concentrations on BC membrane properties, such as yield, thickness, and breathability, were evaluated. The BCs' yields and thicknesses were increased with the higher concentration of sucrose utilised during the production process. By weighing and observing the BC membranes, sample BCS10.0 possessed the highest yield and thickness. Nonetheless, the lowest yield and thickness of BC membrane (1.374%, 0.07mm) produced a high mean pore diameter (16.909Å) and increased permeability of water vapour (4242.23g/m2/day).

Silver nanoparticles coated cellulose-based flexible membrane with excellent UV resistance, high infrared reflection and water resistance for personal thermal management

Designing of a green and multifunctionally integrated cellulose-based flexible wearable material with personal thermoregulation, water and ultraviolet (UV) resistance is essential for the development of personal thermal management and smart textiles. Herein, a hydrophobic silver nanoparticles cellulose-based membrane (H-AgNPs/CEPCM) was prepared through simple solution blending, spin-coating process and chemical vapor modification. The prepared membrane exhibited excellent UV resistance due to the synergistic effect of carbon quantum dots (CQDs) as well as UV-absorbing functional groups. The spin-coated AgNPs layer with high infrared reflectivity has great radiant insulation, and temperature was reduced by 3.4 °C compared with H-CEPCM in indoor environment. Furthermore, the mechanical properties of H-AgNPs/CEPCM were significantly improved by the introduction of amide and ether bonds, as well as a large number of hydrogen bonds. This led to a tensile strength of 23.21 MPa and an elongation at break of 16.57 %, while also providing water resistance. Additionally, the H-AgNPs/CEPCM exhibited outstanding thermal stability and hydrophobicity. This work may provide a feasible and promising strategy for the construction of multifunctional integrated cellulose membrane materials for radiant insulation, outdoor textiles and novel UV protection applications.

Different physicochemical interactions between varietal wines and human saliva: Correspondence with astringency

Astringency corresponds to the sensation of dryness and roughness that is experienced in the oral cavity in association with the interaction between salivary proteins and food polyphenols. In this study, the phenolic composition of seven varietal wines, the intensity of astringency they evoke and the physicochemical reactivity of these wines with whole human saliva were evaluated.Phenolic composition of wines was characterized by spectrophotometry and HPLC chromatography. Intensity of astringency was evaluated by trained sensory panels. Saliva from a single volunteer subject was used to assess wine-saliva interactions. To this end, binary mixtures were produced at different v/v wine/saliva ratios and each of them assayed for the ability of the salivary protein to diffuse on a cellulose membrane (diffusion test) and to remain in solution (precipitation test). Physicochemical reactivities between wine components and the protein fraction of saliva were contrasted against the astringency and the phenolic profile of each varietal wine. The study supports the view that astringency depends on physicochemical interactions between two complex matrices -wine and saliva- and not between some of their particular components.

Joule Heating-Assisted Crude Oil Purification by a Poly(pyrrole)-Modified Microfibril Cellulose Membrane.

Using membrane materials to purify viscous watery oil from industrial production processes and accidental oil spills is of great importance but still challenging. Based on the excellent electrical conductivity and electric-thermal conversion of poly(pyrrole) (PPy), a hydrophobic PPy-modified micro-fibrillated cellulose membrane (P-CP) was successfully prepared. The size of the P-CP membrane can be customized to meet specific requirements. In this research, the membrane diameter is capable of reaching 24 cm. By applying a voltage ranging from 0 to 12 V, the surface temperature of the P-CP membrane can be elevated to roughly 120 °C. After 10 cycles of heating and cooling under 12 V voltage, the electric-thermal curves, surface hydrophobicity, and pore structure of P-CP membrane can remain stable, which suggests remarkable electric-thermal stability and reliability despite prolonged operation. The P-CP membrane shows good linearity between voltage and current (R2 = 0.997) and easy temperature control from room temperature to ∼120 °C at low supply voltage (0-12 V). Under the condition of 12 V power supply and self-gravity, the separation flux of the P-CP membrane for water-in-oil (W/O) emulsions (kerosene, diesel) is 2-3 times higher than that at room temperature, and the separation efficiency is also improved. Importantly, the P-CP membrane shows excellent separation performance for high viscosity water-in-crude oil emulsions, with a separation flux of 40 L m-2 h-1 by gravity. Compared to the situation without electricity, the separation flux of water-in-crude oil emulsion has increased four-fold. The joule heating of the P-CP membrane expands its service time and application scenarios, demonstrating its great application prospects in actual viscous oil-water emulsion separation.

Influence of the coagulation bath on the nanostructure of cellulose films regenerated from an ionic liquid solution.

Cellulose membranes were prepared from an EMIMAc ionic liquid solution by nonsolvent-induced phase separation (NIPS) in coagulation baths of water-acetone mixtures, ethanol-water mixtures and water at different temperatures. High water volume fractions in the coagulation bath result in a highly reproducible gel-like structure with inhomogeneities observed by small-angle neutron scattering (SANS). A structural transition of cellulose takes place in water-acetone baths at very low water volume fractions, while a higher water bath temperature increases the size of inhomogeneities in the gel-like structure. These findings demonstrate the value of SANS for characterising and understanding the structure of regenerated cellulose films in their wet state. Such insights can improve the engineering and structural tuning of cellulose membranes, either for direct use or as precursors for carbon molecular sieve membranes.

Immobilization of L-asparaginase on Oxidized Bacterial Cellulose to Improve the Thermal Stability of the Enzyme

Bacterial cellulose (BC) membranes can be modified for covalent immobilization of macromolecules. One type of modification is oxidation, after which the oxidized BC membrane (OBC) could be used as a matrix for covalent immobilization of enzymes. In this work, the BC membrane was chemically oxidized with sodium periodate (NaIO4) to increase the stability of immobilized mesophilic L-asparaginase (L-ASNase) from Erwinia carotovora (EwA). IR spectroscopy confirmed the immobilization of L-ASNase EwA on OBC membranes. Immobilization of the enzyme increased its temperature optimum for its activity by 15°C and raised the inactivation temperature to 60°C. The OBC membrane could be used as a potential carrier for covalent immobilization of enzymes to improve their pharmacological properties by increasing their thermostability.

Enhanced ion transport in ultrathin regenerated cellulose supercapacitor separators

This work reports the fabrication of regenerated cellulose-based separators with efficient ion transport properties, high porosity, and excellent electrolyte wettability using vacuum freeze-dried cellulose membranes.

Study of the incorporation of propolis into kombucha bacterial cellulose membrane and its release kinetics

Study of the incorporation of propolis into kombucha bacterial cellulose membrane and its release kinetics

A lignin-derived carbon dot-upgraded bacterial cellulose membrane as an all-in-one interfacial evaporator for solar-driven water purification.

Solar-driven interfacial evaporation has emerged as an efficient approach for wastewater treatment and seawater desalination. New trends demand adaptive technology to develop photothermal membranes with multifunctional features. Herein, we report a robust multi-purpose near-infrared (NIR)-active hydrogel composite (c-BC@N-LCD) from broad-spectrum active nitrogen-doped lignin-derived carbon dots (N-LCDs) covalently cross-linked with a bacterial cellulose (BC) matrix. BC provides adequate porosity and hydrophilicity required for easy water transport while managing heat loss. A commendable evaporation rate (ER) of 2.2 kg m-2 h-1 under one sun (1 kW m-2) is achieved by c-BC@N-LCD. The developed hydrogel system is also found to be efficient for desalination (∼2.1 kg m-2 h-1) and for remediating various pollutants (heavy metal ions, dyes, and pharmaceuticals) from feed water. The efficacy of the membrane remains unaltered by different grades of water, and hence can be adoptable for economically stressed communities living in water-polluted regions as well as those residing in coastal areas.

Evaluation of drug release, mucoadhesive and viscoelastic performances of Netildex gel versus an antibiotic‐steroid combination system

Purpose: The poor bioavailability and therapeutic response exhibited by conventional antibiotic‐steroid ophthalmic solutions due to rapid precorneal elimination of the drug may be overcome using a gel systems. Netildex gel is a preservative‐free product based on netilmicin and dexamethasone indicated for the treatment of inflammatory ocular conditions of the anterior segment and ocular adnexa including post‐cataract surgery. The current investigation evaluated the in vitro drug release, viscosity and mucoadhesion profile of Netildex gel in comparison to a gel matrix with regard to steroid and antibiotic delivery.Methods: In vitro drug release was assessed using Franz‐type diffusion cells, under sink condition, exploiting a simulated tear solution (STS) as dissolution medium and a regenerated cellulose membrane. Evaluation of mucoadhesive and viscoelastic properties were performed by texture analyzer TA‐XT2 and rheometer.Results: The dexamethasone and netilmicin release curves in Netildex gel exhibited a better sustained and controlled pattern over an extended time period (48 h) with respect to another gel system containing anti‐inflammatory and antibiotic drugs. The results were expressed as cumulative percentage of drug release and the antibiotics‐release kinetics from the polymeric matrix, evaluated by different mathematical models. The determination of detachment force demonstrated a significant mucoadhesive strength of Netildex gel compared to mucin. Moreover, rheological analysis of Netildex gel highlighted a strong pseudo‐plastic behaviour under shear strain due to its formulation features.Conclusions: Overall, Netildex gel exhibits a sustained and controlled drug release of both dexamethasone and netilmicin from polymeric matrix thanks to its viscoelastic and mucoadhesive properties allowing to prolong drug residence time on the ocular surface. These data support the reduced administration frequency while maintaining the same efficacy and simultaneously favouring patients' compliance [1].Reference1. Mencucci R. et al. Adv Ther (2022) 39: 5474–5486.

Mono-component bacterial cellulose heterogeneous membrane mediated by ionic liquids for osmotic energy harvesting

The massive reserves of osmotic energy existing in estuary will be highly desired as promising energy source that avails to solve the problem of energy shortage and environment deterioration. The ion transport membrane is core component optimized through composite membrane heterostructure to maximize the osmotic energy harvesting but suffer from gaps and resistance increase, which limit their practical applications. Here we demonstrate mono-component heterogeneous regenerated bacterial cellulose (RBC) membranes fabricated by subtle regenerated technique through Ionic Liquids (ILs). Such membranes obtain heterogeneous nature by the difference in fiber intertwining states due to the different treatment conditions on both sides. It achieves osmotic energy conversion with maximum power density of 0.70 W·m−2at 100-fold, which provides ingenious strategy for excellent performance and low-cost osmotic energy harvesting. By minimizing pores and maximizing the surface charges, energy barriers can be lowered, ion permeable and selective transport channels for energy harvesting device can be increased, as supported by the numerical simulation. This is the first time the construction strategy for mono-component heterogeneous membrane mediated by ILs for osmotic energy harvesting is proposed, which averts gaps between the layers of different materials effectively and provides theoretical guidance for subsequent in-depth research on mono-component ion-selective heterogeneous membrane.

Impact of Formulation and Microneedle Length on Transdermal Metronidazole Permeation through Microneedle-Treated Skin.

This study aimed to determine the impact of formulation (gel vs cream) and microneedle characteristics (length, number) on permeation of metronidazole through excised microneedle-treated skin. The long-term goal is to apply these results towards a pharmacokinetic study in human subjects with diverse skin types, using in vitro flux data to determine dosing conditions and ultimately establish in vitro-in vivo correlations. Metronidazole release from 0.75% gel and cream was quantified with flow-through diffusion cells, using a cellulose membrane. Excised porcine skin was treated with stainless steel microneedles (500 or 800μm length), to create 50 or 100 micropores. Metronidazole gel or cream was applied to microneedle-treated skin and replaced every 48h for up to 7days. Metronidazole permeation was quantified using HPLC. Intact skin (no microneedle treatment) served as controls. Metronidazole release was faster from the gel vs cream. At 7days there was no difference between gel vs cream in total metronidazole permeated through intact skin. For both formulations, metronidazole permeation was significantly higher (vs intact skin) following microneedle application, regardless of microneedle length or micropore number. Increasing microneedle length and micropore number enhanced MTZ permeation multiple fold for both gel and cream. The greatest enhancement in total permeation for both formulations was achieved with the 800μm MN, 100 micropore condition. Formulation and microneedle conditions both impacted metronidazole permeation. These data will be used to estimate in vivo serum concentrations after applying metronidazole to microneedle-treated skin in humans.

The photocatalytic extraction of U(VI) by CdS/g-C3N4 cellulose film

Photocatalysis is considered as a promising way for separating and extracting uranium. However, powder catalysts used in most studies are hard to be recovered and reused in practical application. Herein, a CdS/g-C3N4 cellulose membrane (CCM) was successfully fabricated for the photocatalytic extraction of uranium. It was revealed that the incorporation of catalyst in membrane remarkably enhanced the separation and transfer of charge carriers. CCM showed outstanding performance of uranium extraction under air conditions without sacrificial reagent. Under light irradiation, ∼95 % of 15 mL 0.1 mM uranyl could be removed within 140 min and a high extraction capacity of 1599.72 mg/g could be achieved. After four cycles, CCM still remained high reactivity and could remove ∼ 85 % uranyl from aqueous solution. During the photocatalytic reactions, U(VI) was mainly reduced by •O2– radicals, and •OH also contributed to the removal of uranium. Owing to the generation of reactive oxygen species, CCM exhibited excellent antifouling property. The results suggest CCM can be a good candidate for separating and extracting uranium from solutions.

Membrane process and adsorption on pine nut shell for removal of dye from synthetic wastewater

ABSTRACT Purification methods such as membrane technology and adsorption have been studied for the purification of textile effluents. This article aimed to evaluate the membrane separation process and adsorption on pine nut shell, separately and sequentially, for reactive dye blue 5G removal from a synthetic effluent. The membrane separation process was carried out in a front filtration module using polymeric membranes. The maximum dye retention was 35.9% using a regenerated cellulose membrane, with agitation and a pressure of 0.5 bar. The permeate flux was fully restored after cleaning the membrane. In the adsorption using pine nut shell, the best results were at pH 2, 50°C, and 50 ppm, with 85% dye removal. The Freundlich isotherm showed the best fit to the data, as did the pseudo-second-order kinetic model. The thermodynamic parameters indicated that the adsorption is of the physical type, with the process being endothermic and spontaneous. In the combined process, the permeate from the membrane separation process was subjected to adsorption on pine nut shell, achieving a removal rate of 98.7 for the initial concentration of 50 ppm. Therefore, this work shows the potential of pine nut shell as an adsorbent, not only to purify textile effluents but also to add value to a waste product, indicating that the combination of membrane technology and adsorption on pine nut shell could be an alternative for the treatment of textile effluents containing the reactive dye 5G blue.

In situ generated CdS on mixed cellulose membrane matrix as an easily recyclable photocatalyst for mineral flotation wastewater treatment

In situ generated CdS on mixed cellulose membrane matrix as an easily recyclable photocatalyst for mineral flotation wastewater treatment