Novel synergistic hydrous iron-nickel-manganese (HINM) trimetal oxide for hazardous arsenite removal

A novel hydrous iron-nickel-manganese (HINM) trimetal oxide was successfully fabricated using oxidation and coprecipitation method for metalloid arsenite removal. The atomic ratio of Fe:Ni:Mn for this adsorbent is 3:2:1. HINM adsorbent was identified as an amorphous nanosized adsorbent with particle size ranged from 30 nm to 60 nm meanwhile the total active surface area and pore diameter of HINM area of 195.78 m²/g and 2.43 nm, respectively. Experimental data of arsenite adsorption is best fitted into pseudo-second order and Freundlich isotherm model. The maximum adsorption capacity of arsenite onto HINM was 81.9 mg/g. Thermodynamic study showed that the adsorption of arsenite was a spontaneous and endothermic reaction with enthalpy change of 14.04 kJ/mol and Gibbs energy of -12 to -14 kJ/mol. Zeta potential, thermal gravimetric (TGA) and Fourier transform infrared (FTIR) analysis were applied to elucidate the mechanism of arsenite adsorption by HINM. Mechanism of arsenite adsorption by HINM involved both chemisorption and physisorption based on the electrostatic attraction between arsenite ions and surface charge of HINM. It also involved the hydroxyl substitution by arsenite ions through the formation of inner-sphere complex. Reusability of HINM trimetal oxide was up to 89% after three cycles of testing implied that HINM trimetal oxide is a promising and practical adsorbent for arsenite.

A low cost, superhydrophobic and superoleophilic hybrid kaolin-based hollow fibre membrane (KHFM) for efficient adsorption–separation of oil removal from water

Inspired by the lotus leaf surface structure, which possesses a hydrophobicity behaviour, a low cost, high performance superhydrophobic and superoleophilic kaolin hollow fibre membrane (KHFM) was obtained by a simple sol–gel grafted method using tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) for oil removal from water. The KHFM was grafted at various grafting times ranging from 1 to 5 coating cycles. Prior to the calcination process at 400 °C, the grafted KHFM was dried in an oven at 100 °C for 1 hour for each grafting coating cycle. The grafting process efficiency was measured by the contact angle of water and hexane. Scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM) were used to study the morphology and surface roughness, respectively, of the grafted KHFM. The oil removal was conducted by using the homogeneous mixture of hexane and water. The highest hydrophobicity and oleophilicity was obtained for the KHFM grafted at 2 coating cycles with a contact angle value equal to 157° and 0°, respectively. In fact, the mechanical strength of KHFM was also improved from 16.21 MPa to 72.33 MPa after grafting. In terms of performance, KHFM grafted for 2 coating cycles obtained an almost 99.9% absorption of oil. Thereby, KHFMs were assembled into a module for a filtration study. A high oil flux of 102 L m⁻² h⁻¹ was obtained for superhydrophobic and superoleophilic KHFM with 2 grafting coating cycles of 2, and this result is in agreement with the trend of the adsorption result.

This paper outlines a low cost, high performance superhydrophobic/superoleophilic KHFM through a simple sol–gel grafted method using TEOS and MTES for efficient adsorption–separation of oil removal from water.

Polyetherimide hollow fiber membranes for CO2 absorption and stripping in membrane contactor application

Porous asymmetric polyetherimide (PEI) hollow fiber membranes with various non-solvent additives, e.g. lithium chloride, methanol and phosphoric acid (PA) were prepared for CO₂ absorption and stripping process in a membrane contractor. The PEI membranes were characterized via gas permeation, liquid entry pressure of water (LEPw), contact angle and field emission scanning electronic microscopy analysis. The CO₂ absorption and stripping performance was evaluated via the membrane contactor system. Addition of non-solvent additives increased the LEPw and membrane porosity of the PEI membrane with the formation of various membrane microstructures and contact angles. Absorption test was performed at 40 °C showed that the PEI–PA membrane produced the highest absorption flux of 2.7 × 10⁻² mol m⁻² s⁻¹ at 0.85 m s⁻¹ of liquid velocity. Further testing on PEI–PA membrane was conducted on CO₂ stripping at 60 °C, 70 °C to 80 °C and the results indicated that the stripping flux was lower compared to the absorption flux. Stripping tests at 80 °C produced the highest stripping flux which might due to the increase in equilibrium partial pressure of CO₂ in the liquid absorbent. Modification of PEI membrane via incorporation of additive can enhanced the performance of a membrane contactor via increasing the absorption and stripping flux.

Porous asymmetric polyetherimide (PEI) hollow fiber membranes with various non-solvent additives, e.g. lithium chloride, methanol and phosphoric acid (PA) were prepared for a CO₂ absorption and stripping process in a membrane contractor.

Effect of organic ligand-decorated ZnO nanoparticles as a cathode buffer layer on electricity conversion efficiency of an inverted solar cell

Efficiency improvement of the industrial scale solar cells to capture sunlight as an important renewable energy source is attracting significant attention to prevent the consumption of a finite supply of unsustainable fossil fuels. ZnO nanoparticles decorated with an imine-linked receptor have been used in the fabrication of a photocathode based on dye-sensitized solar cells for the purpose of photovoltaic efficiency enhancement. Various characterization techniques have been employed to investigate the structural, morphological, and optical behaviors of the solar cell having ZnO nanoparticles and ZnO nanoparticles decorated with an organic ligand as a photocathode layer. The decorated nanoparticles have a stable wurtzite structure and an average grain size of ∼45 nm, confirmed by the TEM image and XRD through the Scherrer equation. The ZnO sample emits wide peaks in the visible range, and the emission intensity of the ZnO-DOL sample increases along with a red-shift (0.38 eV) in the band gap. This shift can be explained using deep level transition, surface plasmon energy of a surfactant, and coupling of ZnO with local surface plasmon energy. UV-vis absorption spectra together with photoluminescence spectra confirm the higher absorption rate due to organic ligand decoration on ZnO nanoparticles. The greatest solar power-to-electricity conversion efficiency (η) of 3.48% is achieved for the ZnO-DOL sample. It is enhanced by 3.13% as compared to that of the ZnO-based solar cell. The ZnO-DOL device exhibits a higher external quantum efficiency (EQE), responsivity (R_λ), and photocurrent-to-dark current ratio; this confirms the improvement in the solar cell performance.

Efficiency improvement of the industrial scale solar cells to capture sunlight as an important renewable energy source is attracting significant attention to prevent the consumption of a finite supply of unsustainable fossil fuels.

Fabrication of a novel hollow fiber membrane decorated with functionalized Fe2O3 nanoparticles: towards sustainable water treatment and biofouling control

We explored a new strategy using well dispersed functionalized Fe₂O₃ nanoparticles to fabricate a polyetherimide nanocomposite hollow fiber membrane with enhanced surface and anti-biofouling properties.

Structural, optical and electrical evolution of Al and Ga co-doped ZnO/SiO2/glass thin film: role of laser power density

This study investigates the characteristics of laser annealed thin films of Al–Ga co-doped zinc oxide (ZnO:Al–Ga) nanoparticles on top of SiO₂/glass.

Efficient rejection of organic compounds using functionalized ZSM-5 incorporated PPSU mixed matrix membrane

Zeolite (ZSM-5) and functionalised zeolite blended polyphenylsulfone (PPSU) mixed matrix membranes (MMMs) were fabricated for comparing their performance with virgin PPSU.

Physicochemical characterization of cellulose nanocrystal and nanoporous self-assembled CNC membrane derived from Ceiba pentandra

This research involves the rare utilisation of the kapok fibre (Ceiba pentandra) as a raw material for the fabrication of cellulose nanocrystal (CNC) and self-assembled CNC membranes. The isolation of CNC from Ceiba pentandra began with the extraction of cellulose via the chemical alkali extraction by using 5wt% NaOH, followed by the typical acidified bleaching method and, finally, the CNC production through acid hydrolysis with 60wt% H₂SO₄ at the optimum time of 60min. The prepared CNC was then employed for the preparation of self-assembled membrane through the water suspension casting evaporation technique. The obtained CNC membrane was characterised in terms of its composition, crystallinity, thermal stability, as well as, structural and morphological features with the use of several techniques including FTIR, XRD, AFM, TEM, FESEM, and TGA. The FESEM and AFM analyses had illustrated the achievement of a self-assembled CNC membrane with a smooth surface and a well-distributed nano-porous structure, with the porosity of 52.82±7.79%. In addition, the findings proved that the self-assembled CNC membrane displayed good adsorption capability indicated by the recorded efficiency of 79% and 85% for 10mg/L and 5mg/L of methylene blue in an aqueous solution, respectively.

Preparation and characterization of a novel highly hydrophilic and antifouling polysulfone/nanoporous TiO2 nanocomposite membrane

In this research, novel ultrafiltration nanocomposite membranes were prepared by incorporating self-synthesized nanoporous titanium dioxide (NTiO2) nanoparticles into polysulfone. The surface of the nanoparticle was treated with a silane-based modifier to improve its distribution in the host polymer. Atomic-force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller, transmission electron microscopy, energy-dispersive x-ray spectroscopy, porosity and contact angle tests were conducted to characterize the properties of the particles as well as the fabricated nanocomposite membranes. The effects of the nanoparticle incorporation were evaluated by conducting ultrafiltration experiments. It was reported that the membrane pure water flux was increased with increasing NTiO2 loading owing to the high porosity of the nanoparticles embedded and/or formation of enlarged pores upon addition of them. The antifouling capacity of the membranes was also tested by ultrafiltration of bovine serum albumin fouling solution. It was found that both water flux and antifouling capacity tended to reach desired level if the NTiO2 added was at optimized loading.

Solvothermal synthesis of nanoporous TiO2: the impact on thin-film composite membranes for engineered osmosis application

In the current study, the impact of self-synthesized nanoporous titanium oxide (NT) on the morphology, performance and fouling of a polyamide (PA) thin-film composite (TFC) membrane was investigated when the membrane was applied for engineering osmosis (EO). The nanoporous structure and the spindle-like shape of NT were revealed through transmission electron microscopy (TEM), while the AATPS modification of NT was verified by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The results of x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) confirmed the presence of modified NT (mNT) in the PA dense active layer of the TFC membrane. The outgrowth of the 'leaf-like' structure, upon mNT loading, at the surface of the PA layer was observed by field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The TFC membrane prepared with 0.05 wt% mNT loading in the organic phase showed the water flux of 26.4 l m(-2) h(-1) when tested in the forward osmosis (FO) mode using 0.5M and 10 mM NaCl solution as the draw and feed solution, respectively. Moreover, the TFC-mNT membrane also demonstrated an intensified antifouling property against organic foulant during FO application and it was possible to retrieve the initial water flux almost completely with a simple water-rinsing process.

Electrospinning applications from diagnosis to treatment of diabetes

Modern applications of electrospinning.

Biopolymer-based electrolyte membranes from chitosan incorporated with montmorillonite-crosslinked GPTMS for direct methanol fuel cells

A composite membrane was fabricated from biopolymer chitosan and montmorillonite (MMT) filler as an alternative membrane electrolyte for direct methanol fuel cell (DMFC) application.

Graphene oxide/polysulfone hollow fiber mixed matrix membranes for gas separation

The application of graphene oxide as a nano-filler in polysulfone asymmetric hollow fiber mixed matrix membranes for CO₂ removal.

Preparation of polysulfone-based PANI–TiO2 nanocomposite hollow fiber membranes for industrial dye rejection applications

Polysulfone-based nano-polyaniline–TiO₂ containing hollow fiber membranes were prepared via a dry wet spinning method. The membranes were used for rejection of Reactive Black-5 and Reactive Orange-16 dyes.

Recent development on the effect of water/moisture on the performance of zeolite membrane and MMMs containing zeolite for gas separation; review

Understanding the effects of water vapour on gas permeation and separation properties of zeolite membranes especially at lower temperatures is important for the applications of these zeolite membranes for gas separations involving water vapour.

Treatment of laundry wastewater using polyethersulfone/polyvinylpyrollidone ultrafiltration membranes

In this study, laundry wastewater filtration was studied using hydrophilic polyvinylpyrollidone (PVP) modified polyethersulfone (PES) ultrafiltration membranes. The performances of PES/PVP membranes were assessed using commercial PES membrane with 10kDa in ultrafiltration. Operating parameters The influence of transmembrane pressure (TMP) and stirring speed on laundry wastewater flux was investigated. A higher permeate flux of 55.2L/m(2)h was obtained for modified PES membrane with high concentration of PVP at TMP of 500kPa and 750rpm of stirring speed. The separation efficiencies of membranes were also studied with respect to chemical oxygen demand (COD), total dissolved solids (TDS), turbidity and conductivity. Results showed that PES membrane with 10% of PVP had higher permeate flux, flux recovery and less fouling when compared with other membranes. Higher COD and TDS rejection of 88% and 82% were also observed for modified membranes due to the improved surface property of membranes. This indicated that modified PES membranes are suitable for the treatment of surfactant, detergent and oil from laundry wastewater.

Influence of bentonite in polymer membranes for effective treatment of car wash effluent to protect the ecosystem

In this study, modified polyethersulfone (PES) and cellulose acetate (CA) membranes were used in the treatment of car wash effluent using ultrafiltration. Hydrophilic sulfonated poly ether ether ketone (SPEEK) and bentonite as nanoclay were used as additives for the PES and CA membrane modification. Performances of modified membranes were compared with commercial PES membrane with 10kDa molecular weight cut off (MWCO). The influencing parameters like stirrer speed (250-750rpm) and transmembrane pressure (100-600kPa) (TMP) were varied and their effects were studied as a function of flux. In the treatment of car wash effluent, a higher permeate flux of 52.3L/m(2)h was obtained for modified CA membrane at TMP of 400kPa and stirrer speed of 750rpm. In comparison with modified PES membrane and commercial PES membrane, modified CA membranes showed better performance in terms of flux and flux recovery ratio. The highest COD removal (60%) was obtained for modified CA membrane and a lowest COD removal (47%) was observed for commercial PES membrane. The modified membranes were better at removing COD, turbidity and maintained more stable flux than commercial PES membrane, suggesting they will provide better economic performance in car wash effluent reclamation.