Carboxylated Graphene Oxide (c-GO) Embedded ThermoPlastic Polyurethane (TPU) Mixed Matrix Membrane with Improved Physicochemical Characteristics.

Water is an important component of our life. However, the unavailability of fresh water and its contamination are emerging problems. The textile industries are the major suppliers of contamination of water, producing high concentrations of heavy metals and hazardous dyes posing serious health hazards. Several technologies for water purification are available in the market. Among them, the membrane technology is a highly advantageous and facile strategy to remediate wastewater. Herein, the distinguished combination of pore-forming agents, solvent, and nanoparticles has been used to achieve improved functioning of the polymeric composite membranes. To do so, graphene oxide (GO) was fabricated via Hummer's technique and GO functionalization using chloroacetic acid (c-GO) was performed. Thermoplastic polyurathane (TPU) membranes having different concentrations c-GO were made using the phase inversion technique. Scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) was used to examine surface morphology, chemical functionalities on membranes surfaces, and crystallinity of membranes, respectively. The temperature-dependent behavior of c-GO composite membranes has been analyzed using DSC technique. The water contact angle measurements were performed for the estimation of hydrophilicity of the c-GO based TPU membrane. The improved water permeability of the composite membrane was observed with increasing the c-GO concentration in polymeric membranes. c-GO was observed as a potential candidate that enhanced membrane physicochemical properties. The proposed membranes can behave as efficient candidates in multiple domains of environmental remediation. Furthermore, the improved dye rejection characteristics of proposed composite membranes suggest that the membranes can be best suited for wastewater treatment as well.

Optimization of carboxylated graphene oxide (C-GO) content in polymer matrix: Synthesis, characterization, and application study.

Carboxylated graphene oxide (C-GO) embedded in polysulfone (PSF) membrane composites were prepared with different wt. % (i.e., 0.2% M - 1, 0.3% M - 2, 0.4% M - 3, and 0.5% M - 4) using non-solvent induced phase separation (NIPS) method and ultrafiltration assembly was applied for the removal of dye effluents. The optimization of C-GO content into polymer matrix was found influencing factor in determining the composite membranes efficiency and application in various research fields. The membranes were characterized in terms of surface morphology (SEM), crystallinity (XRD), and functional groups identification (FTIR). The water permeability of the developed membranes was analyzed, and it is observed that increasing the content of C-GO in PSF membranes imposed a positive impact on permeation performance. M - 3 was found to be a potential candidate among all the membranes with a maximum water flux of about 183 LMH which is considerably higher as compared to the pristine PSF membrane's water flux (i.e., 27 LMH). Moreover, contact angle measurements of membranes were also checked to assess the hydrophilicity of PSF membranes. The results of contact angle also support the water permeability and efficient correlation was observed as contact angle decreases with increasing the content of C-GO. The minimum contact angle with excellent hydrophilicity was shown by the M - 3 membrane and it was found of about ±58.19° and this value is close to the M - 4 membrane having maximum C-GO content. The photocatalytic performance of the M - 3 membrane was checked under UV-254 nm using methylene blue dye and 97% dye removal was achieved within 220 min of reaction time under neutral pH conditions. The M - 3 membrane having C-GO content of 0.4% was found to be the best membrane with high pure water flux (183 LMH) and efficient dye rejection (82%) capability.

The Design of Ternary Composite Polyurethane Membranes with an Enhanced Photocatalytic Degradation Potential for the Removal of Anionic Dyes.

Photocatalysis is an efficient and an eco-friendly way to eliminate organic pollutants from wastewater and filtration media. The major dilemma coupled with conventional membrane technology in wastewater remediation is fouling. In this study, the photocatalytic degradation potential of novel thermoplastic polyurethane (TPU) based NiO on aminated graphene oxide (NH2-GO) nanocomposite membranes was explored. The fabrication of TPU-NiO/NH2-GO membranes was achieved by the phase inversion method and analyzed for their performances. The membranes were effectively characterized in terms of surface morphology, functional group, and crystalline phase identification, using scanning electron microscopy, Fourier transformed infrared spectroscopy, and X-ray diffraction analysis, respectively. The prepared materials were investigated in terms of photocatalytic degradation potential against selected pollutants. Approximately 94% dye removal efficiency was observed under optimized conditions (i.e., reaction time = 180 min, pH 3-4, photocatalyst dose = 80 mg/100 mL, and oxidant dose = 10 mM). The optimized membranes possessed effective pure water flux and excellent dye rejection (approximately 94%) under 4 bar pressure. The nickel leaching in the treated wastewater sample was determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). The obtained data was kinetically analyzed using first- and second-order reaction kinetic models. A first-order kinetic study was suited for the present study. Besides, the proposed membranes provided excellent photocatalytic ability up to six reusability cycles. The combination of TPU and NH2-GO provided effective strength to membranes and the immobilization of NiO nanoparticles improved the photocatalytic behavior.

Preparation of Polyvinylidene Fluoride Nano-Filtration Membranes Modified with Functionalized Graphene Oxide for Textile Dye Removal.

Water scarcity has become one of the most significant problems globally. Membrane technology has gained considerable attention in water treatment technologies. Polymeric nanocomposite membranes are based on several properties, with enhanced water flux, high hydrophilicity and anti-biofouling behavior, improving the membrane performance, flexibility, cost-effectiveness and excellent separation properties. In this study, aminated graphene oxide (NH2-GO)-based PVDF membranes were fabricated using a phase-inversion method for textile dye removal. These fabricated membranes showed the highest water flux at about 170.2 (J/L.h-1.m-2) and 98.2% BSA rejection. Moreover, these membranes removed about 96.6% and 88.5% of methylene blue and methyl orange, respectively. Aminated graphene oxide-based polyvinylidene fluoride (PVDF) membranes emerge as a good membrane material that enhances the membrane performance.

Preparation and Evaluation of Polymer-Based Ultrasound Gel and Its Application in Ultrasonography.

Ultrasound imaging is a widely used technique in every health care center and hospital. Ultrasound gel is used as a coupling medium in all ultrasound procedures to replace air between the transducer and the patient's skin, as ultrasound waves have trouble in traveling through air. This research was performed to formulate an inexpensive alternative to commercially available ultrasound gel as it is expensive and imported from other countries. Different formulations with different concentrations of carbopol 980 (CAR 980) and methylparaben were prepared with natural ingredients such as aloe vera gel and certain available chemicals that have no harmful effects on the skin. To justify the efficiency of the formulations; necessary physicochemical characteristics such as visual clarity, homogeneity, transparency, skin irritation, antibacterial activity, pH, stability, spreadability, conductivity, acoustic impedance, viscosity, and cost were evaluated. Moreover, a comparison study was also conducted with commercially available ultrasound gel that was utilized as a control. All samples showed excellent transparency and no microbial growth. S1 was the only formulation that met all of the requirements for commercial ultrasound gel and produced images that were similar to those produced by commercial ultrasound gel. So, this formulation could be used as an alternative to expensive commercial ultrasound gel for taking images in hospitals and medical centers.

Coal fly ash supported CoFe2O4 nanocomposites: Synergetic Fenton-like and photocatalytic degradation of methylene blue.

Rapid industrialization is causing a serious threat for the environment. Therefore, this research was aimed in developing ceramic cobalt ferrite (CoFe2O4) nanocomposite photocatalyst coated with coal fly ash (CFA-CoFe2O4) using facile hydrothermal synthesis route and their applications against methylene blue. The pristine cobalt ferrite photocatalyst was also prepared, characterized, and applied for efficiency comparison. Prepared photocatalyst were characterized by X-ray diffraction (XRD), fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). Optical response of catalysts was check using photoluminescence spectroscopy (PL). pH drift method was used for the surface charge characteristics of the material under acidic and basic conditions of solution pH. The photocatalytic degradation potential of all the materials were determined under ultra-violet irradiations. The influencing reaction parameters like pH, catalyst dose, oxidant dose, dye concentration, and irradiation time, were sequentially optimized to obtain best suited conditions. The 99% degradation of 10 ppm methylene blue was achieved within 60 min of reaction time under pH = 5 and 7, catalyst dose = 10 and 12 mg/100 mL, oxidant = 12 mM and 5 mM for cobalt ferrite and CFA-CoFe2O4 photocatalysts, respectively. Afterwards, the radical scavenging experiments were conducted to find out the effective radical scavengers (˙OH, h+, and e-) in photocatalytic degradation process. The kinetic study of the process was done by applying 1st order, 2nd order, and BMG models. Statistical assessment of interaction effect among experimental variables was achieved using response surface methodology (RSM).

Synthesis of Nickel Spinel Ferrites Nanoparticles Coated with Thermally Reduced Graphene Oxide for EMI Shielding in the Microwave, UV, and NIR Regions.

The co-precipitation and in situ modified Hummers' method was used to synthesize Nickel Spinal Ferrites (NiFe) nanoparticles and NiFe coated with Thermally Reduced Graphene Oxide (TRGO) (NiFe-TRGO) nanoparticles, respectively. By using polyvinyl chloride (PVC), tetrahydrofuran (THF), and NiFe-TRGO, the nanocomposite film was synthesized using the solution casting technique with a thickness of 0.12-0.13 mm. Improved electromagnetic interference shielding efficiency was obtained in the 0.1-20 GHz frequency range. The initial assessment was done through XRD for the confirmation of the successful fabrication of nanoparticles and DC conductivity. The microstructure was analyzed with scanning electron microscopy. The EMI shielding was observed by incorporating a filler amount varying from 5 wt.% to 40 wt.% in three different frequency regions: microwave region (0.1 to 20 GHz), near-infrared (NIR) (700-2500 nm), and ultraviolet (UV) (200-400 nm). A maximum attenuation of 65 dB was observed with a 40% concentration of NiFe-TRGO in nanocomposite film.

Fabrication and Characterization of Sulfonated Graphene Oxide (SGO) Doped PVDF Nanocomposite Membranes with Improved Anti-Biofouling Performance.

Emergence of membrane technology for effective performance is qualified due to its low energy consumption, no use of chemicals, high removal capacity and easy accessibility of membrane material. The hydrophobic nature of polymeric membranes limits their applications due to biofouling (assemblage of microorganisms on surface of membrane). Polymeric nanocomposite membranes emerge to alleviate this issue. The current research work was concerned with the fabrication of sulfonated graphene oxide doped polyvinylidene fluoride (PVDF) membrane and investigation of its anti-biofouling and anti-bacterial behavior. The membrane was fabricated through phase inversion method, and its structure and morphology were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-rays diffraction (XRD) and thermo gravimetric analysis (TGA) techniques. Performance of the membrane was evaluated via pure water flux; anti-biofouling behavior was determined through Bovine Serum albumin (BSA) rejection. Our results revealed that the highest water flux was shown by M7 membrane about 308.7 Lm-2h-1/bar having (0.5%) concentration of SGO with improved BSA rejection. Furthermore, these fabricated membranes showed high antibacterial activity, more hydrophilicity and mechanical strength as compared to pristine PVDF membranes. It was concluded that SGO addition within PVDF polymer matrix enhanced the properties and performance of membranes. Therefore, SGO was found to be a promising material for the fabrication of nanocomposite membranes.

Fabrication and Characterization of Sulfonated Graphene Oxide-Doped Polymeric Membranes with Improved Anti-Biofouling Behavior.

In this study, cellulose acetate (CA) was blended with sulfonated graphene oxide (SGO) nanomaterials to endow a nanocomposite membrane for wastewater treatment with improved hydrophilicity and anti-biofouling behavior. The phase inversion method was employed for membrane fabrication using tetrahydrofuran (THF) as the solvent. The characteristics of CA-SGO-doped membranes were investigated through thermal analysis, contact angle, SEM, FTIR, and anti-biofouling property. Results indicated that anti-biofouling property and hydrophilicity of CA-SGO nanocomposite membranes were enhanced with addition of hydrophilic SGO nanomaterials in comparison to pristine CA membrane. FTIR analysis confirmed the successful decoration of SGO groups on CA membrane surface while revealing its morphological properties through SEM analysis. Thermal analysis performed using DSC confirmed the increase in thermal stability of CA-SGO membranes with addition of SGO content than pure CA membrane.

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.

Development of Hydrogels with the Incorporation of Raphanus sativus L. Seed Extract in Sodium Alginate for Wound-Healing Application.

Hydrogels prepared from polymers have been proposed for tissue regeneration and the treatment of bruise wounds. In this research work, we synthesized a Raphanus sativus L.-based wound-healing hydrogel with recognized antimicrobial activity for the healing of cutaneous lesions, drawing on its healing potential. A structural analysis was performed by Fourier transform infrared spectroscopy, confirming the interaction between sodium alginate and Raphanus sativus L. The surface morphology was studied by scanning electron microscopy. A swelling test showed that the T-1 hydrogel capability of absorption of the solution was superior compared to other synthesized samples. It was evident that the swelling tendency decreased as the Raphanus sativus L. seed extract concentration was reduced. In a thermogravimetric analysis, T-1 shows high thermal stability over other prepared hydrogel samples, enjoying a high content of seed extract compared with all samples. The prepared hydrogels were placed on the chick chorioallantoic membrane of fertilized chick eggs, and their healing capability was examined. All seed extracts containing hydrogels showed clear curative performance as compared to the control hydrogel, whereas their healing magnitude lessened as the extract ratio decreased. It was concluded from the results of the current study that the Raphanus sativus L. plant has wound-healing characteristics.

Sustainable Development of Chitosan/Calotropis procera-Based Hydrogels to Stimulate Formation of Granulation Tissue and Angiogenesis in Wound Healing Applications.

The formation of new scaffolds to enhance healing magnitude is necessarily required in biomedical applications. Granulation tissue formation is a crucial stage of wound healing in which granulation tissue grows on the surface of a wound by the formation of connective tissue and blood vessels. In the present study, porous hydrogels were synthesized using chitosan incorporating latex of the Calotropis procera plant by using a freeze-thaw cycle to stimulate the formation of granulation tissue and angiogenesis in wound healing applications. Structural analysis through Fourier transform infrared (FTIR) spectroscopy confirmed the interaction between chitosan and Calotropis procera. Latex extract containing hydrogel showed slightly higher absorption than the control during water absorption analysis. Thermogravimetric analysis showed high thermal stability of the 60:40 combination of chitosan (CS) and Calotropis procera as compared to all other treatments and controls. A fabricated scaffold application on a chick chorioallantoic membrane (CAM) showed that all hydrogels containing latex extract resulted in a significant formation of blood vessels and regeneration of cells. Overall, the formation of connective tissues and blood capillaries and healing magnitude decreased in ascending order of concentration of extract.

Degradation of acetamiprid using graphene-oxide-based metal (Mn and Ni) ferrites as Fenton-like photocatalysts.

This study aims to explore the photocatalytic potential of graphene-oxide-based metal ferrites for the degradation of acetamiprid (an odorless neonicotinoid pesticide). Metal (Mn and Ni) ferrites (along with their graphene oxide composites) were prepared by the hydrothermal method while graphene oxide (GO) was synthesized using a modified Hummer's method. The composites were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The photocatalysts were studied for their Fenton-like advanced oxidation process to degrade acetamiprid. The composites showed excellent activity against acetamiprid degradation (>90%) in 60 min under UV irradiation. The detailed optimization study was carried out to investigate the influential variables (such as pH, catalyst dose, pollutant concentration, irradiation time, oxidant dose, etc.) to achieve enhanced degradation efficiency. Moreover, the findings were endorsed by central composite design (CCD). It was concluded that degradation was enhanced in an appropriate combination of photocatalyst and hydrogen peroxide. The magnetic character of the metal ferrites and their composites played an important role in the easy separation and reusability of these materials. The present findings result in highly effective, easy to handle and stable heterogeneous photo-Fenton materials for wastewater remediation.

A Highly Structured 1,10-Phenanthroline Arrayed Hydrophobic Sulfone Membrane Platform for the Rapid Determination and Speciation of Fe2+/Fe3+ Ions in Water.

An optical assay for the rapid determination and chemical speciation of Fe2+/Fe3+ species has been proposed for the first time on a polyether sulfone (PES) membrane platform. The small pore size and low wettability (θ ∼82°) of the membrane disallowed the dissipation of analyte droplets on the surface, thus localizing it onto nanoliter arrayed 1,10-phenanthroline spots. Under optimized conditions and within ∼5 min, an acceptable limit of detection (0.1 µg mL-1) and linear dynamic range (1 - 100 µg mL-1) were achieved. The proposed method was also successfully applied for indirect determination of Fe3+ ions in synthetic samples after reduction to Fe2+ using SO2. The performance of the proposed sensor was validated for its robustness and stability. Due to high selectivity and accuracy, the method was satisfactorily applied for the analysis of Fe2+/Fe3+ species in marine water samples. The proposed method is an easy and low-cost system coupled with good reproducibility and ruggedness, applicable for point-of-use testing.

Potent bactericidal activity of silver nanoparticles synthesized from Cassia fistula fruit.

We demonstrated one-step synthesis of silver nanoparticles (AgNPs) from Cassia fistula fruit extract and their antibacterial activity against E. coli and K. pneumoniae. Biogenic AgNPs were characterized by scanning electron microscopy, X-Ray diffraction and fourier transform infrared spectroscopy. Results confirmed spherical shaped AgNPs with an average crystallite size of ∼69 nm. Dose-dependent (0, 10, 20, 40 and 80 µg mL-1) growth kinetic studies showed 100% potency against E. coli (20 µg mL-1) and K. pneumoniae (80 µg mL-1) after 1 and 5 h, respectively. Surface morphology analysis revealed formation of groove/pits in the lysed cell membrane that eventually led to bacterial death.

Synthesis and Characterization of Silver Nanoparticles-Filled Polyethersulfone Membranes for Antibacterial and Anti-Biofouling Application.

BACKGROUND: The membrane processes are interesting and economical techniques for reuse of municipal and industrial wastewater as well as seawater desalination. However their drawbacks can be resumed in the fouling and biofouling due to the deposition and adsorption phenomenon of the components and the development of biofilm on membrane surface. Several studies have focused on the effect of the incorporation of nanoparticles in polymeric membrane matrix on the biofouling properties. Few relevant patents to the topic have been reviewed and cited. METHODS: Polyethersulfone (PES) membranes filled with silver nanoparticles (AgNPs) were prepared by non-solvent induced phase separation (NIPS) process using polyvinylpyrrolidone (PVP) as additive and N-Methyl-2-pyrrolidone (NMP) as solvent. Dope solution compositions, coagulation bath (CB) compositions, time before immersion in CB and casting speed were systematically studied. Membrane structure was characterized by scanning electron microscopy, contact angle, streaming potential measurement and X-ray diffraction (XRD). RESULTS: Membrane performance was assessed by pure water permeability, antifouling property, porosity and mechanical property. Silver nanoparticles (AgNPs) were prepared by the chemical reduction of silver nitrate solution with freshly prepared fructose solution, using PVP as capping agent and NaOH as accelerant and settled using acetone. The synthesized AgNPs were firstly characterized by Dynamic light scattering (DLS) technique, UV-visible spectrophotometer and X-ray diffraction spectroscopy (XRD). Then, we have selected a 15% PES mixed with 15% of PVP dope solution to prepare PESAgNPs blended membranes. CONCLUSION: All the nanocomposite membranes showed superb antibacterial and anti-biofouling performances, indicating that AgNPs in the PES membranes could be an effective approach to minimize membrane biofouling.