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A unique method for determining chlorophyll content in microalgae is devised employing a gold interdigitated electrode (G-IDE) with a 10-µm gap, augmented by a nano-molecularly imprinted polymer (nano-MIP) and a titanium dioxide/multiwalled carbon nanotube (TiO2/MWCNT) nanocomposite. The nano-MIP, produced using chlorophyll template voids, successfully trapped chlorophyll, while the TiO2/MWCNT nanocomposite, synthesized by the sol–gel technique, exhibited a consistent distribution and anatase crystalline structure. The rebinding of procured chlorophyll powder, which was used as a template for nano-MIP synthesis, was identified with a high determination coefficient (R2 = 0.9857). By combining the TiO2/MWCNT nanocomposite with nano-MIP, the G-IDE sensing method achieved a slightly better R2 value of 0.9892 for detecting chlorophyll in microalgae. The presented G-IDE sensor showed a significant threefold enhancement in chlorophyll detection compared with commercially available chlorophyll powder. It had a detection limit of 0.917 mL (v/v) and a linear range that spanned from 10-6 to 1 mL. The effectiveness of the sensor in detecting chlorophyll in microalgae was confirmed through validation of its repeatability and reusability. [ABSTRACT FROM AUTHOR]

Polymeric membranes have emerged as a competitive technology in gas separation processes due to their notable energy efficiency, environmentally friendly attributes and minimal system footprint. To enhance the performance of conventional polymeric membranes, significant research efforts have been dedicated to modifying their surface properties in the last decade. Among the various techniques explored, membrane surface modification using coating methods, such as dip-coating, spray-coating, grafting and interfacial polymerization stands out as one of the most popular and straightforward approaches. Scientists have utilized a diverse array of coating solutions comprising either polymeric materials or hybrid materials in these methods, yielding promising outcomes. This article aims to present a comprehensive review of the advancements made in surface coating approaches employed for modifying hollow fiber membrane surfaces over the past decade. The review encompasses an evaluation of how different coating approaches and solutions affect the surface's physicochemical properties and the gas separation performance of the membranes. Furthermore, the article delves into discussing technical challenges associated with these surface coating approaches, providing an insightful analysis. Lastly, the review concludes by outlining perspectives and recommending future research directions for this area of study, highlighting the potential avenues for innovation and advancement in surface-coated hollow fiber membranes for gas separation applications. [ABSTRACT FROM AUTHOR]

In response to the escalating global issue of microbial contamination, this study introduces a breakthrough photocatalyst: bismuth ferrite-activated carbon (BFO-AC) for visible light-driven disinfection, specifically targeting the Gram-positive bacterium Staphylococcus aureus (S. aureus). Employing an ultrasonication method, we synthesized various BFO-AC ratios and subjected them to comprehensive characterization. Remarkably, the bismuth ferrite-activated carbon 1:1.5 ratio (BA 1:1.5) nanocomposite exhibited the narrowest band gap of 1.86 eV. Notably, BA (1:1.5) demonstrated an exceptional BET surface area of 862.99 m2/g, a remarkable improvement compared to pristine BFO with only 27.61 m2/g. Further investigation through FE-SEM unveiled the presence of BFO nanoparticles on the activated carbon surface. Crucially, the photocatalytic efficacy of BA (1:1.5) towards S. aureus reached its zenith, achieving complete inactivation in just 60 min. TEM analysis revealed severe damage and rupture of bacterial cells, affirming the potent disinfection capabilities of BA (1:1.5). This exceptional disinfection efficiency underscores the promising potential of BA (1:1.5) for the treatment of contaminated water sources. Importantly, our results underscore the enhanced photocatalytic performance with an increased content of activated carbon, suggesting a promising avenue for more effective microorganism inactivation. [ABSTRACT FROM AUTHOR]

Nanocomposite membranes of average thickness 100 µm were successfully fabricated using a phase inversion method which involved use of sulfonated polyether ether ketone (SPEEK) incorporated with nanoclays of cloisite 30B and bentonite. The membranes were characterized for their organic functional groups, morphological structure, thermal and physical properties under the influences of cloisite 30B and bentonite addition in SPEEK matrix. The presence of nanoclays was confirmed by the changes observed in the membrane morphology and improved glass transition temperature in pristine SPEEK membrane. The fuel cell performance of the membranes was determined by their water uptake capacity, methanol permeability and proton conductivity. The 0.5 wt% addition of cloisite and bentonite in SPEEK showed 2.1% reduction of water uptake as compared to the pristine SPEEK membrane. The cloisite-added SPEEK membrane showed the average proton conductivity of 3.05 × 10–5 S cm−1 at 80 °C. Nevertheless, cloisite- and bentonite-incorporated SPEEK nanocomposite membranes demonstrated the reduced proton conductivity of 6.14% in the methanol permeability as compared to the pristine SPEEK membrane. Hence, the modified SPEEK nanocomposite membranes with cloisite and bentonite are being suggested to be a promising proton exchange membrane for direct methanol fuel cell. [ABSTRACT FROM AUTHOR]

Additive Manufacturing is noted for ease of product customization and short production run cost-effectiveness. As our global population approaches 8 billion, additive manufacturing has a future in maintaining and improving average human life expectancy for the same reasons that it has advantaged general manufacturing. In recent years, additive manufacturing has been applied to tissue engineering, regenerative medicine, and drug delivery. Additive Manufacturing combined with tissue engineering and biocompatibility studies offers future opportunities for various complex cardiovascular implants and surgeries. This paper is a comprehensive overview of current technological advancements in additive manufacturing with potential for cardiovascular application. The current limitations and prospects of the technology for cardiovascular applications are explored and evaluated. [ABSTRACT FROM AUTHOR]

Recently, frequent discharge of water-ladened emerging organic pollutants such as Bisphenol A has elicited serious concern due to its pernicious effects on public health and the ecological environment. In this study, hematite nanoparticles (Fe2O3) were synthesized via the sol–gel auto-combustion technique and incorporated as a nanofiller to fabricate a PVDF-PEG nanocomposite hollow fibre membrane with enhanced antifouling properties. A series of membranes comprising various loadings (1.0–2.0 wt%) of Fe2O3 NPs were fabricated through the phase inversion technique and thoroughly analyzed. The developed Fe2O3-membrane fibres were thoroughly characterized. The performance of the membrane fibres was investigated through permeation flux, BPA rejection, as well as antifouling characteristics. Based on the results obtained, the resultant nanocomposite membrane fibres exhibited superior performance in comparison with the pristine fibre. Also, the nanocomposite membrane with 1.5 wt%-Fe2O3 NPs exhibited remarkable performance with − 43.7 mV, 56.3º, 191.85 L/m2 h, 86.7%, and 12% of negatively charged zeta potential, least contact angle, water permeation flux, BPA rejection, and minimum weight loss, respectively. Besides, the 1.5 wt-Fe2O3 NPs nanocomposite membrane demonstrated superior antifouling performance after the third filtration, accomplishing a higher percent of FRR (77.35%) along with RFR of 21.29%, respectively. Hence, based on the performance of the fabricated hollow-fibre membranes loaded with Fe2O3 NPs, efficient antifouling membranes was achieved which can be suitably applied in the purification of industrial wastewater. [ABSTRACT FROM AUTHOR]

The innovative exploitation of diverse inorganic materials in environmental applications has received great scientific attention as a result of the rapid growth of nanotechnology and the expanding variety of nanomaterials currently being produced and developed. The idea of developing multifunctional nanocomposite membranes that can do more than just separate things has been made possible using inorganic nanoparticles as fillers in polymeric matrix. In this work, the nanocomposite was utilized to separate an oil/water emulsion. With the intention of enhancing the capabilities of PVDF-based membrane for oil/water emulsion filtration, synthesized hydrous manganese oxide (HMO) nanoparticles were mixed with poly(vinylidene fluoride) (PVDF) polymer to form mixed matrix membrane (MMM). With the addition of HMO nanoparticles, the MMM showed that the membrane wetting properties, hydrophilicity and oleophobicity, were greatly improved owing to the high amount of –OH functional groups. Subsequently, the improved surface hydrophilicity leads to greater water flux of PVDF/HMO MMM (402.0 ± 11.75 L/m2 h; oil rejection efficiency = 93.8%) in comparison to pristine PVDF membrane (42.4 ± 3.73 L/m2 h; oil rejection efficiency = 96.2%). Furthermore, compared to pristine PVDF membrane, the flux recovery rate (FRR) and reversible fouling (Rr) of the MMM were increased by two–three times, while the irreversible fouling (Rir) was reduced by half. This demonstrates that the HMO nanoparticles in the nanocomposite improved the water affinity and reduced low possibility of fouling problem. Hence, the modified nanocomposite membrane can be applied in oily wastewater treatment and competed with the current technologies. [ABSTRACT FROM AUTHOR]

The current study is focused on the facile synthesis of zeolitic imidazolate framework-8 (ZIF-8) at room temperature using three different solvents: ammonia solution (ZIF-8 (N)), aqueous solution (ZIF-8 (H)), and methanol (ZIF-8 (M)). The ZIF-8s produced have high crystallinity with different sizes and shapes. The morphology of ZIF-8 (H) resembled the mixture of cubic and the rhombic dodecahedron with truncated corners, whereas ZIF-8(M) occurred as the most stable rhombic dodecahedron, and ZIF-8(N) appeared as cubes with truncated corners. ZIF-8 (N) had the largest average particle size of 573 nm, followed by ZIF-8 (H) and ZIF-8 (M) with average sizes of 108 nm and 62 nm, respectively. ZIF-8 (N) showed a rapid Pb(II) and Cd(II) adsorption, within 15 min, while ZIF-8(H) achieved Pb(II) and Cd(II) equilibrium within 240 min, and 300 min for ZIF-8 (M). The adsorption of Pb(II) and Cd(II) is best fitted with the Langmuir isotherm and pseudo-second-order kinetic model. The maximum adsorption capacities for Pb(II) and Cd(II) sorption were 454.55 and 312.50 mg/g for ZIF-8 (H), 434.78 and 277.78 mg/g for ZIF-8 (M), respectively, and 476.19 and 263.16 mg/g for ZIF-8 (N), respectively. All of the prepared ZIF-8s showed a promising competency as adsorbents for the removal of Pb(II) and Cd(II) from an aqueous solution. [ABSTRACT FROM AUTHOR]

Various treatments of choice are available to overcome contamination of bisphenol A (BPA) in the environment including membrane technologies; however, the treatment still releases contaminants that threaten the human being. Therefore, the present study is conducted to investigate the degradation of BPA by recently developed visible-light-driven photocatalytic nitrogen-doping titanium dioxide (N-doped TiO2) dual-layer hollow fibre (DLHF) membrane and its efficiency in reducing the level of BPA in contaminated water. Fabricated with suitable polymer/photocatalyst (15/7.5 wt.%) via co-extrusion spinning method, the DLHF was characterized morphologically, evaluated for BPA degradation by using submerged photocatalytic membrane reactor under visible light irradiations followed by the investigation of intermediates formed. BPA exposure effects were accessed by immunohistochemistry staining of gastrointestinal sample obtained from animal model. BPA has been successfully degraded up to 72.5% with 2 intermediate products, B1 and B2, being identified followed by total degradation of BPA. BPA exposure leads to the high-intensity IHC staining of Claudin family which indicated the disruption of small intestinal barrier (SIB) integrity. Low IHC staining intensity of Claudin family in treated BPA group demonstrated that reducing the level of BPA by N-doped TiO2 DLHF is capable of protecting the important component of SIB. Altogether, the fabricated photocatalytic DLHF membrane is expected to have an outstanding potential in removing BPA and its health effect for household water treatment to fulfil the public focus on the safety of their household water and their need to consume clean water. [ABSTRACT FROM AUTHOR]

The current paper examines the effects of zinc oxide nanostructure configurations, as photo-anode formations of organic solar cells, on the performance of power conversion. To this end, some experiments were conducted during which a near band edge emission red shift of ~ 0.11 eV from nanoparticles to vertically oriented nano-rods was observed. This bandgap narrowing promotes transferring of photo-excited electrons towards the conduction band of photo-anode. A ~ 48% decrease in the deep level emission intensity revealed a smaller non-radiative waves emission due to lower level of crystal disorder. Using vertically oriented zinc oxide nanorods as photo-anodes, the photovoltaic efficiency of the organic solar cell improved considerably. The nano-rod-structured photo-anodes showed a 0.22 V rise in the open-circuit voltage, from 0.76 to 0.98 V, and a 2.08 times increment in the overall conversion performance, compared to the zinc oxide nanoparticle-structured photo-anodes. This superior performance is attributed to a greater chance of charge recombination and light-trapping in the cells, more efficient light absorption, and high level of crystallinity that grants easier electron mobility for vertically oriented zinc oxide nanorods. Moreover, a lower charge-transfer resistance (0.85 Ω) was achieved due to better electro-catalytic action for oxygen reduction for vertical nanorods compared to the other two zinc oxide configurations (1.62 Ω and 4.06 Ω). This boosted the cell performance by increasing the short-circuit current density (JSC). The fabricated solar cell may contribute to sustainable and environmentally friendly electricity generation process through reducing the consumption of non-renewable energy sources. [ABSTRACT FROM AUTHOR]

High toxicity of water resources by heavy metal ions is common and membrane filtration is one the solutions to this problem. Titanate nanotubes (TNT) are generally used due to their unique characteristics such as meso-porous structure, and high specific surface area. In this study, the internal surface of TNT was coated through a novel in-situ polymerization method with various polymers to alter the property and size of inner surface of the nanotubes, and then was embedded in the polyamide layer of the nanofiltration membrane. The modified nanotubes were supposed to act as the channels for water transport and reject the multivalent/monovalent ions; this phenomenon was more pronounced in the modified nanotubes because of the reduction in inner diameter. Fourier transform infrared spectroscopy, X-ray diffraction and Brunauer-Emmett-Teller analysis were used to characterize the unmodified/modified nanotubes. Furthermore, the membranes were synthesized by in-situ interfacial polymerization of trimesoyl chloride and m-phenylenediamine containing 0.05 wt% nanotubes; the performance of the fabricated membranes in terms of pure water flux (PWF), contact angle, feed flux and Na+ and Cu2+ rejections was studied. Generally, incorporation of the modified nanotubes improved the trade-off between the permeation and rejection. Among the fabricated membranes, the maximum PWF was 26.13 L m−2 h−1 for the membrane containing 0.05 wt% polystyrene modified TNT, 71.23% more than neat thin film membrane and without any significant change in the rejection; that can be related to the hydrophilicity of the nanotube and the formation of small cavities on the membrane surface. [ABSTRACT FROM AUTHOR]

Emerging technologies for the separation of proteins employ ultrafiltration membranes that incorporate hydrophilic zwitterionic nanoparticles for enhanced performances and efficacy. In this study, the zwitterionic nanoparticles were synthesized by the simple, facile distillation–precipitation polymerization (DPP) method. The monomers [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (DMAPDS) and 1-vinyl-2-pyrrolidone (VA), and the crosslinker N,N'-methylenebis(acrylamide) (MBAm) are utilized for the synthesis of P(MBAm-co-DMAPDS-co-VA) nanoparticle and the synthesized nanoparticle was incorporated into polyphenylsulfone (PPSU) flat sheet membrane for the effective protein rejection application. These nanoparticles greatly influence the membrane porosity and contact angle. The hydrophilic nature of the membrane samples was improved by the hydrophilic groups present in the nanoparticle. The modified membrane exhibited the highest pure water flux of the 249.4 L m−2 h−1 than the pristine of 70.6 L m−2 h−1 and enhanced flux recovery ratio and reversible fouling by 29.7 and 11.2%, respectively. The protein rejection of bovine serum albumin, pepsin, and egg albumin was found to be 92.1, 60.4, and 80.3%, respectively. Overall the fabricated membranes are highly effective in protein separation. [ABSTRACT FROM AUTHOR]

Polyamide thin film composite membranes have dominated current reverse osmosis market on account of their excellent separation performances compared to the integrally skinned counterparts. Despite their very promising separation performance, chlorine-induced degradation resulted from the susceptibility of polyamide toward chlorine attack has been regarded as the Achilles's heel of polyamide thin film composite. The free chlorine species present during chlorine treatment can impair membrane performance through chlorination and depolymerization of the polyamide selective layer. From material point of view, a chemically stable membrane is crucial for the sustainable application of membrane separation process as it warrants a longer membrane lifespan and reduces the cost involved in membrane replacement. Various strategies, particularly those involved membrane material optimization and surface modifications, have been established to address this issue. This review discusses membrane degradation by free chlorine attack and its correlation with the surface chemistry of polyamide. The advancement in the development of chlorine resistant polyamide thin film composite membranes is reviewed based on the state-of-the-art surface modifications and tailoring approaches which include the in situ and post-fabrication membrane modifications using a broad range of functional materials. The challenges and future directions in this field are also highlighted. [ABSTRACT FROM AUTHOR]

The presence of conventional and emerging pollutants infiltrating into our water bodies is a course of concern as they have seriously threatened water security. Established techniques such as photocatalysis and membrane technology have proven to be promising in removing various persistent organic pollutants (POP) from wastewaters. The emergence of hybrid photocatalytic membrane which incorporates both photocatalysis and membrane technology has shown greater potential in treating POP laden wastewater based on their synergistic effects. This article provides an in-depth review on the roles of both photocatalysis and membrane technology in hybrid photocatalytic membranes for the treatment of POP containing wastewaters. A concise introduction on POP's in terms of examples, their origins and their effect on a multitude of organisms are critically reviewed. The fundamentals of photocatalytic mechanism, current directions in photocatalyst design and their employment to treat POP's are also discussed. Finally, the challenges and future direction in this field are presented. [ABSTRACT FROM AUTHOR]

Phase inversion-based extrusion was employed in this study to fabricate porous cathode-supported micro-tubular solid oxide fuel cell (MT-SOFC). The fibers were developed from two different perovskite materials; lanthanum strontium manganate (LSM) and lanthanum strontium cobalt ferrite (LSCF), which mixed with yttria-stabilized zirconia (YSZ). The effect of high sintering temperature (1250–1450 °C) on both hollow fibers was examined. Both LSM/YSZ and LSCF/YSZ composites were composed of asymmetric structure that consists of sponge-like and finger-like voids. LSM/YSZ hollow fiber gave higher mechanical strength of 161 MPa with sufficient porosity of 22% compared to LSCF/YSZ which exhibited mechanical strength of 114 MPa at 1400 °C. Besides, the gas permeation for both composite cathode hollow fibers showed the same declining trends as the function of sintering temperature. Moreover, X-ray diffraction (XRD) result showed a formation of a resistive phase when the sintering temperature reached 1300 °C for LSCF/YSZ and destruction of cobalt phase occurred at 1400 °C. In contrary, LSM/YSZ showed a stable sign where only a small amount of pyrochlore phase was found. To sum, LSM/YSZ is more compatible and stable at high sintering temperature in term of its mechanical strength, gas permeability, desired crystal structure, and acceptable range of porosity. [ABSTRACT FROM AUTHOR]

New lanthanum orthoferrite (LaFeO3)/chitosan nanocomposites were synthesized with different chitosan loadings (15 and 35%). Their adsorptive photocatalytic activity in the removal of Reactive Black 5 (RB5) was studied by manipulating the pH of the RB5 solution (pH 3, pH 6, pH 9), the catalyst loading (1 g L−1, 2 g L−1, and 3 g L−1), and the initial concentration of RB5 (30 mg L−1, 50 mg L−1, and 70 mg L−1) under 100 W LED light. The nanocomposites have a nanocrystalline structure similar to LaFeO3 with a lower SBET and PV but a higher PR. The LaFeO3 was distributed well on chitosan matrices with variations in the elemental composition. The band gap was gradually decreased with increased chitosan loading. The nanocomposite with 15% chitosan loading (LC15) resulted as the most prominent photocatalyst with the highest removal of RB5 up to 98.5% under experimental conditions of pH 6, 2g L−1 of catalyst loading, and 30 mg L−1 of initial RB5 concentration. The LC15 showed good stability, wherein the degradation efficiency was more than 90% after the fifth cycle with no significant change in the chemical properties. This work provides a technique to improve the removal of recalcitrant dyes through the processing of adsorptive photocatalysis utilizing adsorbent and perovskite. [ABSTRACT FROM AUTHOR]

Heavy metals from industries and agricultural sectors have become a prominent source to cause the contamination of groundwater and water bodies. The toxicity of heavy metals is a significant concern as excessive exposure to these chemicals may cause severe harm to humans and other life beings. In this study, the effects of independent variables on the adsorption of copper(II) ions on ZIF-8 membrane were determined using a three-factor three-level central composite design (CCD) by a response surface methodology (RSM) approach. The adsorption process was investigated using batch experiments. The independent variables include the initial concentration of copper(II) ions, the mass of ZIF-8 membrane and volume of copper solution. A quadratic model was developed to correlate the variables with the adsorption yield of copper(II) on ZIF-8. The optimum condition for maximum copper(II)ions removal was found as follows: initial concentration of 100 mg/L, adsorbent dose 29.93 mg and the solution volume of 40 mL. The adsorption mechanism of copper(II) onto the ZIF-8 membrane was best fitted to the Freundlich isotherm. The kinetic study concluded that the adsorption was best fitted to the pseudo-second-order model with a higher correlation coefficient. ZIF-8 membrane showed the promising adsorbent for copper(II) ions with the advantage of easier isolation from reaction mixtures than other powder form adsorbents. [ABSTRACT FROM AUTHOR]

Metal organic framework (MOF) is a class of porous material that has been acknowledged for its high porosity, tunable pores and distinctive chemical functionalities. This paper reviewed some of the selected MOF applied in adsorption and membrane separation for wastewater treatment. As adsorbent, certain MOF demonstrated high solute rejection and adsorption capacity, much contributed by high surface area and more active sites to bind with solutes. In another way, MOF can be incorporated as nanofiller in thin-film nanocomposite or mixed-matrix membrane. This water stable MOF inclusion has tuned the membrane chemistry and morphology to be more selective toward solute while enhancing water permeability. The stability of MOF was governed by high number of positive charge per atom, high coordination number, presence of hydrophobic functional groups and also their ability to resist coordination with water molecules. Important issues regarding with MOF in membrane had been addressed, particularly MOF agglomeration that further deteriorated membrane performance. At the end of the review, a conclusion and future perspective is suggested as remarks. [ABSTRACT FROM AUTHOR]

A Composite proton exchange membrane consists of octaphenyl polyhedral silsesquioxane (POSS) has been incorporated into a highly sulfonated polyphenylsulfone (SPPSU) for potential use in fuel cell applications. The effect of modified POSS by functionalization with sulfonic acid groups (SPOSS) addition on physicochemical properties, mechanical strength, and proton conductivity of the SPPSU is examined. Results revealed that the incorporation of POSS and SPOSS has significantly improved the mechanical strength and conductivity of the SPPSU composite membranes. SPPSU-POSS composite membrane shows tough and ductile features. Meanwhile, the SPPSU-SPOSS composite membrane exhibits mechanically lower strength but greater in flexibility as compared to SPPSU-POSS composite membrane. As per expectation, the proton conductivity of the SPPSU-SPOSS composite membrane is significantly improved compared to SPPSU-POSS composite membrane according to its relatively higher water uptake value. Based on the obtained results, it has been suggested that POSS has enhanced the proton conductivity and mechanical strength of the highly sulfonated PPSU based membrane desirable to be served as a proton exchange membrane in fuel cell application. [ABSTRACT FROM AUTHOR]

Among numerous sustainable advanced nanomaterials, nanocellulose is receiving increasing attention for its utilization in water treatment technologies due to its various specific properties and functionalities. The term "nanocellulose" is used for cellulosic material having a nanoscopic scale (or nanoscale) for their dimensional characteristics. It can be obtained in three different forms, which are fibrous form, crystalline form, or bacterial form. One of the benefits of this natural polymer is that it can be found abundantly on Earth, as most plants or waste contains the cellulose. For decades, this material has been widely used in various applications, mainly in water purification, with current studies focusing on surface functionalization of nanocellulose to enhance its properties. This brief review aims to provide the readers with the recent studies (year 2015 to year 2021) of nanocellulose properties, alongside the application of the material for removal of heavy metals from water and its reusability efficiency. In this regard, the main limitations for the specific applications of nanocellulose-based materials and its future prospective are identified in an effort to make possible enhancements in the future. [ABSTRACT FROM AUTHOR]

The membrane contactor system is one of the most important technologies to trap CO2 from natural gas. To apply this technology, hollow fibre membranes with a superhydrophobic surface must be used, where membranes were prepared from kaolin clay through the phase inversion/sintering technique and modified by three types of fluoroalkylsilane (FAS) molecules (C6, C8, C10) at different immersion times (6, 24, 48,72 h) to capture CO2 from natural gas via contacting the gas-liquid system. The kaolin was chosen due to its abundant availability at an affordable price as well as the high amount of the hydroxyl (OH) group in the surface which easily reacts with FAS during the grafting process. Superhydrophobicity was distinguished by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), liquid entry pressure of water (LEPw) measurement, and contact angle (CA). The lowest pore size of the grafted membrane obtained for C8 was about 1.32 μm; it was considered the perfect target for high membrane resistance. The chosen superhydrophobic kaolin membrane was tested for carbon dioxide (CO2) capture via the membrane contactor system. With increasing time of immersion, the hydrophobicity phenomena rose gradually until superhydrophobicity property was obtained. Forty-eight hours was proven as sufficient time to obtain the desired superhydrophobicity property to avoid wetting pores of the membranes. Besides, the perfect type of FAS for separating CO2 was C8 based on the sufficient LEPw and contact angle. The reduction of pH was observed after testing the performance of using a membrane contactor to separate CO2 by using water as absorbent where pH value decreased from 6.6 to 4.3 within 1 h, which concludes the success of the gas-liquid system into removing CO2 from natural gas. [ABSTRACT FROM AUTHOR]

This work investigates the effectiveness of ammoniacal nitrogen (NH4+-N) removal from contaminated water by adsorptive hollow fiber ceramic membrane (HFCM) derived from naturally made clinoptilolite. The technological value of this work is the simple mechanism of the adsorptive HFCM in removing gaseous ammonia in water by combining adsorption and separation. To test the technical feasibility of this proposed technology, clinoptilolite HFCM was fabricated via phase inversion-based extrusion/sintering technique and characterized by SEM and water permeation flux. The produced HFCM corresponds to the desired morphology of the asymmetric structure (dense and void formations) with outstanding adsorption performance of NH4+-N. The effects of the HFCM's operational parameters on its removal are examined in terms of membrane dosage and isothermal studies. The adsorption isotherm behavior exhibited that the adsorption process fitted the Freundlich isotherm model with outstanding removal performance even at trace concentration of ammonia. The low amount used by HFCM (4.75×10−4m2) resulted in over 96% ammonia removal, indicating a low cost of adsorption process. The regeneration of saturated HFCM suggests an outstanding recovery of the HFCM for its subsequent use for NH4+-N removal. This study also reveals the potential of adsorptive HFCM as a simple and cost-effective technology for ammonia removal from wastewater. [ABSTRACT FROM AUTHOR]

In this study, nanostructured titania (TiO2; n-TO) and nanostructured alumina-titania (Al2O3-13 wt.%TiO2; n-ATO) coatings were successfully deposited on the 6061 aluminum alloy by applying the high-velocity oxy-fuel process. The n-TO coating showed limited pores or microcracks accompanied by both partially and fully melted areas within splats. The n-TO coating exhibited about 25% higher microhardness compared with the n-ATO coating. The agglomerated non-molten nanostructured TiO2 particles that are randomly dispersed and embedded within the n-TO coating microstructure act as arresters of cracks through either branching or blunting crack tips, resulting in about 17% higher bonding strength, as compared to the n-ATO coating with a looser microstructure. The n-TO coating demonstrated superior hardness, higher wear resistance, and smoother wear scar than the n-ATO and uncoated Al substrate. The electrochemical test indicated that the n-ATO coating had about a 50% higher corrosion rate than the n-TO coating because of its looser structure. The immersion test revealed that the n-ATO coating had been severely attacked by blistering and deep cracks corrosions, whereas limited attacks could be distinguished using the n-TO coating in the substrate interface. Based on the results, the n-TO coating can effectively protect the Al alloy substrate against 3.5 wt.% NaCl solution. [ABSTRACT FROM AUTHOR]

The CO2 gas separation performance of aminated reduced graphene oxide (A-rGO) incorporated PEBAX mixed matrix composite membranes, by means of amination heating time and A-rGO loading, is reported. The 5 h of heating time resulted in an essential molecular sieving property for CO2 separation, thus used in membrane fabrication. The selective PEBAX/A-rGO5 layers were fabricated on top of the polysulfone supporting layer by a dip-coating method. The A-rGO was well-dispersed, the selective and support layers were seamlessly attached. The CO2 permeability and CO2/N2 selectivity of the PEBAX/A-rGO5 was greater than that of pristine PEBAX. 3 wt% of A-rGO5 loading resulted as the optimum since the gas selectivity decreased at higher loading. The PEBAX/A-rGO5 performance, which was slightly above the Robeson 2008 upper bound of permeability-selectivity relation for CO2/N2 gas separation, shows a promising application for industrial CO2 gas separation process. [ABSTRACT FROM AUTHOR]

A simple, promising, environmentally friendly, and high yield technique to synthesize high specific surface area (SSA) and porous graphene-like materials from glucose precursor through carbonization and controlled chemical iron chloride (FeCl3) activation was demonstrated. Designing this nanoporous graphene-based adsorbent with high SSA, abundant micropore volume, tunable pore size distribution, and high adsorption capacity, is crucial in order to deal with the demands of large-scale reversible natural gas storage applications. Raman spectroscopy, BET method of analysis, and N2 adsorption/desorption measurements at 196 °C were adopted to evaluate the structural and textural properties of the resultant glucose derived-graphene (gluGr) samples. The effects of different carbonization conditions, such as the inert environments (argon, helium, and argon) and temperatures (700, 800, 900, and 1,000 °C), have been studied. A glucose-derived graphene carbonized under nitrogen environment at 700 °C (NGr700) with highly interconnected network of micropores and mesopores and large SSA (767 m2/g) exhibited excellent methane (CH4) storage property with exceptionally high adsorption capacity, superior to other glucose-derived graphene (gluGr) samples. A maximum volumetric capacity up to 42.08 cm3/g was obtained from CH4 adsorption isotherm at 25 °C and 35 bar. Note that the adsorption performance of the CH4 is highly associated with the SSA and microporosity of the gluGr samples, especially NGr700 that was successfully synthesized by FeCl3 activation under N2 environment. [ABSTRACT FROM AUTHOR]

Advanced filtration requires a cost-effective, highly efficient and environmentally friendly membrane fabrication to achieve excellent and extreme oleophobic and hydrophilic states with an appropriate surface functionalization approach. For an efficient oil-water separation, surface material and structure have been categorized as superoleophobic (high oil repellency) and superhydrophilic (strong affinity to water). This can be attributed to their selective mechanisms. In addition, it is very important to consider these key factors as they will imperatively provide a unique capability to exhibit surface roughness, stimulate low and high surface energy, and improve surface chemistry, which makes membranes function efficiently for the oil and water separation system. In this review article, the application of ceramic membrane for oily water treatment and the principle of superhydrophilic and superoleophobic ceramic membrane for oil-water separation are elaborated and, in addition, the current progress for the use of inorganic material to functionalize ceramic membrane surface based on physical and chemical methods is appraised. Finally, the challenges and outlook on the membrane for oily-water treatment are briefly examined. [ABSTRACT FROM AUTHOR]

The oil concentration as a petroleum quality parameter is an eternal mystery that determines the oil value. We report detection of crude oil refractive index (RI) changes by modified polymer optical fiber (POF) sensor which is prepared via removing the majority of cladding part until ~ 100 nm thickness remains followed by the deposition of discontinuous silver (Ag) nanofilm as an inner layer (~ 20 nm thicknesses) and coating with different shapes of zinc oxide (ZnO) nanostructures including nanoparticles and horizontally and vertically oriented nanorods as an outer layer. Upon conversion from ZnO nanoparticles to vertically oriented ZnO nanorods, the rms roughness, optical band gap, and light transmittance are varied from ~ 23 to ~ 346 nm, ~ 3.45 to ~ 3.20 eV, and 31 to 27%, respectively. The higher sensing performance is obtained for the probe coated with vertically aligned ZnO nanorods at near-infrared wavelength and the value for intensity and wavelength sensitivity are 38 dB/RIU and 78 nm/RIU, respectively. This superior performance is originated from deep penetration of evanescent wave, high surface volume ratio, good crystallinity, adhesive interaction with crude oil molecules, large surface roughness, and high-order dispersion. [ABSTRACT FROM AUTHOR]

Membrane technology for industrial gas separation was begun in the 1980s and has shown significant advantages over conventional techniques such as cryogenic distillation and solvent absorption in terms of energy consumption and operational cost. The main objective of this work is to develop a simple yet effective coating technique to modify the surface properties of polysulfone (PSF) hollow fiber membranes for enhanced separation of CO2/CH4 and O2/N2. The hollow fiber membranes made of different polymer concentration (15–35 wt%) were coated with different materials (polydimethylsiloxane (PDMS) or polyether-block-amide (Pebax) or PDMS followed by Pebax) through a simple dip-coating method before subjecting to pure gases testing and instrumental characterization. Results showed that the multilayer coated membranes exhibited better performance compared to the single-layer PDMS-coated and single-layer Pebax-coated membranes. It is also found that the Pebax concentration could affect the performance of the multilayer coated membranes in which the gas permeance decreased while its selectivity decreased with increasing Pebax concentration from 1 to 3 wt.%. Further increase in Pebax concentration from 3 to 9 wt% however negatively affected selectivities as high Pebax concentration tended to cover the membrane surface with tighter polymer chain packing which led to lower free volume. Experimental results also showed that the optimized multilayer coated membrane (3 wt.% Pebax) could achieve the highest gas pair selectivity, recording 34.28 and 6.65 for CO2/CH4 and O2/N2 separation, respectively. As a comparison, the membrane coated with 1 wt% Pebax only showed selectivity of 29.47 and 6.07, respectively. The findings of this work demonstrated that multilayered coating could be performed on the outer layer of hollow fiber membranes and is not limited to the flat sheet membranes as previously reported in the literature, provided a good combination of two coating solutions were used. [ABSTRACT FROM AUTHOR]

Water pollution is becoming a crucial problem posing a serious threat for living organisms. Recently, photocatalytic membranes are used to purify drinking water and have shown a great potential in efficient for water and wastewater treatment. This study was conducted to remove bisphenol A (BPA) from water. Ag-doped TiO2 nanoparticles were deposited onto ceramic hollow fiber support by facile dip coating method to produce photocatalytic Ag-doped TiO2 ceramic membrane. The nanoparticles were firstly synthesized via liquid impregnation method, while kaolin support was fabricated using phase inversion and sintering method. BPA was used to evaluate the photocatalytic performance of the coated ceramic membrane. The effect of deposition time (0–120 s) of Ag-doped TiO2 photocatalyst over the ceramic membrane on the photocatalytic efficiency of the ceramic membrane was investigated. The structural analysis of Ag-doped TiO2 ceramic membranes was performed through X-ray diffraction (XRD), which confirmed the anatase crystal phase of Ag/TiO2 nanoparticles over the ceramic membrane. The surface morphology was explored via field-emission electron scanning electron microscope (FESEM), and a significant change was observed in the surface morphology of the coated membrane over deposition time. The energy-dispersive X-ray analysis (EDX) was used to find the elemental composition. UV–visible absorption spectra indicate that the Ag/TiO2 nanoparticles were extended to the visible region. The photocatalytic BPA removal efficiency of 88% was exhibited by Ag/TiO2-coated TM-120 ceramic membrane (the membrane coated for 120 s) in 270 min under visible light. This research is useful for purification of drinking water through nanoparticle-coated ceramic membrane. [ABSTRACT FROM AUTHOR]

In this present study, adsorptive membranes for Cr(VI) ion removal were prepared by blending polyethersulfone (PES) with hydrous ferric oxide (HFO) nanoparticles (NPs). The effects of HFO NPs to PES weight ratio (0–1.5) on the physicochemical properties of the resultant HFO/PES adsorptive membranes were investigated with respect to the surface chemistry and roughness as well as structural morphologies using different analytical instruments. The adsorptive performance of the HFO NPs/PES membranes was studied via batch adsorption experiments under various conditions by varying solution pH, initial concentration of Cr(VI), and contact time. The results showed that the membrane made of HFO/PES at a weight ratio of 1.0 exhibited the highest adsorption capacity which is 13.5 mg/g. Isotherm and kinetic studies revealed that the mechanism is best fitted to the Langmuir model and pseudo-second-order model. For filtration of Cr(VI), the best promising membranes showed improved water flux (629.3 L/m2 h) with Cr(VI) ion removal of 75%. More importantly, the newly developed membrane maintained the Cr(VI) concentration below the maximum contamination level (MCL) for up to 9 h. [ABSTRACT FROM AUTHOR]

In this study, the effects of two fuel types, i.e., hydrogen and methane on the electrochemical performance of the co-extruded triple layer hollow fiber, were systemically studied. The triple layer hollow fiber consisted of electrolyte/active functional layer (AFL)/anode was fabricated by single-step phase-inversion-based co-extrusion technique prior to the sintering process at temperature range of 1400 to 1500 °C. The hollow fibers were characterized by three-point bending test, gas tightness test, and scanning electron microscope (SEM). The electrochemical performance test was carried out at temperatures of 700–800 °C by flowing fuel at 20 ml/min. Based on the results attained, the gas tightness and bending test are improved by the increase of sintering temperature. SEM results show that the finger-like morphology length around 100 μm is obtained. In addition, the AFL layer located in the middle layer of the hollow fiber has its own finger like which forms sandwich-like structure with the anode layer. The open circuit voltage is recorded at 1.05 V with the highest power density obtained at 0.6 W cm−2 by using hydrogen. By changing the fuel into methane gas, the highest power density is achieved at 0.8 W cm−2. This is due to the methane that carries more hydrogen molecule. This indicates that the methane fuel can be utilized in hollow fiber SOFC systems. [ABSTRACT FROM AUTHOR]

Water desalination and recycling of wastewater is a key challenge to meet water shortage issues. Thin film composite polyamide membranes are widely used for desalination; however, their low permeability due to a poor hydrophilicity is a major drawback. Here, we designed novel thin film composite membranes having good hydrophilicity, permeability, and stability without compromising solute rejection. We improved the membrane hydrophilicity by incorporation of hydrophilic additives, such as glycine and l-glutamine, into the polyamide layer. Hence polyamide-based flat sheet membranes were fabricated via interfacial polymerization of m-phenylenediamine and trimesoyl chloride and then were coated over a polysulfone/sulfonated polyphenylsulfone (85:15) support. Polyamide membranes were then characterized and tested for desalination. Results show that the ridge and valley structure observed by scanning electron microscopy confirms the formation of the polyamide layer on membrane surface. The performance reached the highest pure water flux of 36.23 Lm−2 h−1 and flux recovery ratio of 89.18% for membranes with 2 wt% of l-glutamine. Incorporation of 2 wt% l-glutamine induced a high permeate flux and a maximum rejection of 87.87% for MgSO4, 83.50% for Na2SO4 and 60.77% for NaCl solutions. Overall, the polyamide nanofiltration membrane with hydrophilic groups displayed superior antifouling property and can be used as a potential candidate for desalination. [ABSTRACT FROM AUTHOR]

This work describes the development of photocatalytic mesoporous aluminum oxide (alumina) membranes for oil emulsion separation. The mesoporous alumina membrane was deposited on alumina hollow fiber using hydrothermal synthesis. Aluminum nitrate nonahydrate, Al(NO3)3.9H2O, cetyltrimethylammonium bromide (CTAB), and urea were used in the preparation of the mesoporous alumina membranes. The successfully prepared mesoporous alumina membranes on ceramic support were then deposited with copper-doped ceria, which acted as photocatalyts, using the sol-gel Pechini method. The results showed that the membranes had an excellent separation performance in separating 1000 ppm polyethylene glycol and 1000 ppm bovine serum albumin when the samples were calcined at 800 °C. Under UV irradiation, there was a remarkable increase in the permeability of water through the membrane. The photocatalytic mesoporous alumina membrane showed a permeability of 1422 L/h m2 bar with 92% oil emulsion rejection. An excellent increase in the performance can be associated with the production of superoxide radical and hydroxyl radicals by the photocatalytic membrane once exposed to UV light. [ABSTRACT FROM AUTHOR]

The removal of toxic dyes from the wastewater and industrial effluents is a major environmental challenge. Various techniques have been employed for the removal of dyes, including the application of nano-sized adsorbents, nanocomposite membranes and photodegradation. Membrane filtration is an alterntive but suffers from drawbacks such as fouling. Here we present a simple approach  for the development of antibiofouling membranes based on chitosan. The application of chitosan-based nanoparticles as additives for wastewater treatment is poorly explored. The chitosan and silver-loaded chitosan nanoparticles were synthesized by ionic gelation method and incorporated to fabricate hollow-fiber membranes by dry-wet spinning technique. The prepared membranes were characterized by morphological study, permeability test, antibiofouling study and dye rejection study. The nanocomposite hollow-fiber membranes displayed superior performance than their pristine form. The incorporation of 0.30 weight percent of the chitosan and silver-loaded chitosan nanoparticles into the hollow-fiber membranes enhanced the antifouling property with flux recovery ratio of 81.21 and 86.13%, respectively. The dye rejection results showed maximum rejection of 89.27 and 86.04% for Reactive Black 5 and Reactive Orange 16, respectively. Hence, it can be concluded that hollow-fiber membranes with silver-loaded chitosan nanoparticles are pertinent in developing antibiofouling membranes for the treatment of industrial dye effluents. [ABSTRACT FROM AUTHOR]

This work describes the development of zeolitic imidazolate framework-8 (ZIF-8) membranes on modified alumina hollow fiber for desalination by forward osmosis. Effects of different seeds (ZnO, NiO and PDA) and sodium formate on in-situ deposition of ZIF-8 were studied in relation to the membrane's morphology and performance. XRD result shows that ZIF-8 was successfully synthesized in the presence of sodium formate. FESEM images showed PDA modified support was unsuccessful in producing well defined and dense ZIF-8 membrane layer even after another ZIF-8 re-deposition due to its minimal amount. The NiO modified support was also found unsuccessful, as ZIF-8 crystals were formed in clusters. On the contrary, dense ZIF-8 membrane was successfully prepared on ZnO modified support with SF-1 synthesis solution producing bigger ZIF-8 crystal and thinner ZIF-8 membrane than as of SF-2. Water flux performance in forward osmosis showed that NiO/ZIF-8, PDA/ZIF-8 and PDA/ZIF-8 (re-deposition) membranes gave negative water fluxes of -50 kg/m2·h, -5.2 kg/m2·h and -1.7 kg/m2·h with reverse solutes of 42.66 mol/m2·h, 27.42mol/m2·h and 3.22 mol/m2·h, respectively, indicating the solute from draw solution diffused into the feed solution. However, ZIF-8 membrane prepared using SF with molar ratio of 1, on the ZnO modified support had a water flux of 13.3 kg/m2·h, reverse solute of 0.95 kg/m2·h and salt rejection of 52.1%. When the SF ratio was increased to 2, the ZIF-8 membranes showed a water flux of 12.5 kg/m2·h, reverse solute of 1.64 kg/m2·h and salt rejection of 54.9%. The moderate salt rejection could be associated with defects in the ZIF-8 membranes due to poor grain boundaries. [ABSTRACT FROM AUTHOR]

Graphene was discovered in 2004 and has attracted intensive interests because of its unique mechanical, electric, thermal, optical, and structural properties, which makes graphene a potential candidate for various applications. Graphene is being used as a composite or filler material with metals, metal oxides, and polymers for potential advanced applications in solar cells, lithium-ion batteries, photocatalysis and sensing. These applications depend upon the distinctive properties of graphene, which in turn depend on the adopted synthetic approach. This article reviews the recent developments in synthesis of graphene and related composite materials. The synthesis of graphene through exfoliation, epitaxial growth and direct growth via carbon source, and modification approaches by covalent and noncovalent methodologies are discussed. Graphene-based metal and metal oxide composites for the purification of wastewater using photolytic process are also presented. [ABSTRACT FROM AUTHOR]

Palm oil fuel ash (POFA) is an agricultural waste which was employed in this study to produce novel adsorptive ceramic hollow fibre membranes. The membranes were fabricated using phase inversion-based extrusion technique and sintered at 1150 °C. The membranes were then evaluated on their ability to adsorb cadmium (Cd(II)). These membranes were characterised using (nitrogen) N2 adsorption-desorption analysis, field emission scanning electron microscopy-energy-dispersive X-ray spectroscopy (FESEM-EDX) mapping, X-ray fluorescence (XRF), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analyses while adsorptivity activity was examined by batch adsorption studies. The adsorption test results show that the quantity of hollow fibre used and water pH level significantly affected the adsorption performance with the 3-fibre membrane yielding 96.4% Cd(II) removal in 30 min equilibrium time at pH 7. These results are comparable to those reported by other studies, and hence demonstrate a promising alternative of low-cost hollow fibre adsorbent membrane.Figure of FESEM image of the hollow fibre, proposed mechanism and the graph of percentage removal of Cd(II) using POFA [ABSTRACT FROM AUTHOR]

This work describes the development of supported zeolite-Y membranes, prepared using the hydrothermal method, for the removal of nickel from an aqueous solution. Alumina hollow fibers prepared using the phase inversion and sintering technique were used as an inert support. The supported zeolite-Y membranes were characterized using the field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and the water permeation and rejection test. The performance of the supported zeolite-Y membranes for heavy metal removal using batch adsorption and filtration test was studied using the atomic absorption spectroscopy (AAS). The adsorption study shows that the removal of nickel was pH-dependent but affected by the presence of α-alumina. The seeded zeolite-Y membrane gave the highest adsorption capacity which was 126.2 mg g−1. This enabled the membrane to remove 63% of nickel ions from the aqueous solution within 180 min of contact time. The adsorption mechanism of nickel onto the zeolite-Y membrane was best fitted to the Freundlich isotherm. The kinetic study concluded that the adsorption was best fitted to pseudo-second-order model with higher correlation coefficient (R2 = 0.9996). The filtration study proved that the zeolite-Y membrane enabled to reduce the concentration of heavy metal at parts per billion level. [ABSTRACT FROM AUTHOR]

A simple, promising, environmentally friendly, and high yield technique to synthesize high specific surface area (SSA) and porous graphene-like materials from glucose precursor through carbonization and controlled chemical iron chloride (FeCl3) activation was demonstrated. Designing this nanoporous graphene-based adsorbent with high SSA, abundant micropore volume, tunable pore size distribution, and high adsorption capacity, is crucial in order to deal with the demands of large-scale reversible natural gas storage applications. Raman spectroscopy, BET method of analysis, and N2 adsorption/desorption measurements at 196 °C were adopted to evaluate the structural and textural properties of the resultant glucose derived-graphene (gluGr) samples. The effects of different carbonization conditions, such as the inert environments (argon, helium, and argon) and temperatures (700, 800, 900, and 1,000 °C), have been studied. A glucose-derived graphene carbonized under nitrogen environment at 700 °C (NGr700) with highly interconnected network of micropores and mesopores and large SSA (767 m2/g) exhibited excellent methane (CH4) storage property with exceptionally high adsorption capacity, superior to other glucose-derived graphene (gluGr) samples. A maximum volumetric capacity up to 42.08 cm3/g was obtained from CH4 adsorption isotherm at 25 °C and 35 bar. Note that the adsorption performance of the CH4 is highly associated with the SSA and microporosity of the gluGr samples, especially NGr700 that was successfully synthesized by FeCl3 activation under N2 environment. [ABSTRACT FROM AUTHOR]