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Membrane distillation (MD) purifies water by transporting its vapor through a hydrophobic membrane. An ideal MD membrane poses high water flux and high fouling, scaling, and wetting resistances. In this study, we develop polyvinylidene fluoride (PVDF) membranes for MD by focusing on reduction of PVDF degree of crystallinity. We explore the roles of dope solution temperature in dictating the phase separation mechanisms as well as the structure and the performance of semicrystalline PVDF membranes. DSC spectra show that higher dope solution temperature depresses crystallinity via formation of imperfect crystal. Such findings were also supported by FTIR and XRD results. The SEM images reveal formation of spherulite-like morphology in the membrane matrices for membranes prepared from high temperature dope solutions. A good balance between solid-liquid and liquid-liquid phase separations that offers low degree of crystallinity was found at a dope solution temperature of 60°C (PVDF-60), which showed the MD flux of 18 l/m2 h (vs. 6 l/m2 h for temperature of 25°C, as a benchmark) and nearly complete salt rejection when run at hot and cold temperatures of 65°C and 25°C, respectively. The PVDF-60 shows a high wetting resistance and stable MD flux of 10.5 l/m2 h over a 50 h test for treating brine solution as the feed (70 g NaCl/l). [ABSTRACT FROM AUTHOR]

A surprisingly simple, yet effective blending method for ionic liquids (ILs) and polysulfone (PSf) is presented in this paper. Not only is the IL properly immobilised in the polymer matrix, which is crucial in high-pressure gas separation applications, but this method also produces tunable porous surfaced membranes that can be useful in several other applications. The size and distribution of the pores are dependent on the type and amount of IL incorporated into the PSf. A membrane formation mechanism is proposed to explain the presence of such a regular surface pore structure. Several commercially available ILs were tested to examine their compatibility with the polymer, and the CO 2 /N 2 gas separation performance of the resulting membrane was screened. ATR-FTIR spectroscopy, FTIR microscopy, and SEM imaging were also employed to shed light on the observed membrane structures. [ABSTRACT FROM AUTHOR]

An improved method for mass production of good-quality tungsten disulfide (WS 2) nanosheets via ball milling of commercial powder of WS 2 with different ball sizes is reported in this paper. Bulk/Commercial WS 2 (W c) powder was milled in a high energy planetary ball milling machine using two different ball sizes with diameter 0.5 mm and 7 mm in two separate milling jars. The as-prepared WS 2 nanosheets (W 0.5 and W 7) corresponding to 0.5 mm and 7 mm ball size respectively, were investigated in detail using several characterization techniques, such as Scanning electron microscopy (SEM) for morphological analysis, X-ray diffractometry (XRD) for crystal structure analysis, Fourier transform infrared spectroscopy (FTIR) for functional group analysis and Brunauer-Emmett-Teller (BET) characterization for surface area and pore size/distribution analysis. Ultraviolet–Visible diffuse reflectance spectroscopy (UV–Vis DRS) was performed for bandgap analysis, Time resolved photoluminescence (TRPL) was done for exciton decay studies and Mott-Schottky (MSK) characterization for flat band positions. W 7 , as a photocatalyst showed enhanced performance of ∼95% in degrading both Methylene blue (MB) and Methyl orange (MO) dyes while as W 0.5 showed enhanced surface area. Highly efficient adsorbents were obtained in this whole process of wet ball milling optimized for the degradation of MB and MO dyes. So, the prepared material is potential candidate for wastewater treatment. • Mass production of WS 2 nanosheets from commercially available powder for wastewater treatment is reported. • Physical route of synthesis makes the whole process ecofriendly. • Electrochemical study has been done for flat band positions which shows both n-type and p-type. • Reusability of the photocatalyst has been studied up to five times. • Scavenger study has been done for degradation mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • Preparation of highly selective Choline Chloride based Deep Eutectic Solvent. • High CO 2 permeability for a supported DES based liquid membrane. • Supported liquid membranes showed excellent stability under different operating conditions. This study focuses on a forward looking approach in which deep eutectic solvents (DESs), a new class of designer solvents, were impregnated into micro porous polyvinylidene fluoride (PVDF) membrane for the separation of CO 2 from CH 4. Three types of DESs were prepared by mixing and heating of hydrogen bond acceptor (choline chloride) with either malic acid, tartaric acid or oxalic acid as hydrogen bond donor. The Fourier transform infrared spectroscopy confirmed the hydrogen bond interactions in the resulting DES. Thermal gravimetric analysis (TGA) was used to evaluate the thermal stability of the prepared membranes. The DES based supported liquid membranes were investigated systematically to determine the permeability and selectivity for the mixture of gases at both ambient and elevated temperatures. The results showed that Choline Chloride-Malic acid, Choline Chloride-Tartaric acid and Choline Chloride-Oxalic acid DES-SLMs exhibited CO 2 permeability of 30.32 Barrer, 34.00 Barrer and 37.30 Barrer, respectively while ideal selectivity of these membranes was found 51.39, 55.74 and 60.16 for CO 2 /CH 4 , respectively. The fabricated membranes were compared with some of the imidazolium supported ionic liquid membranes (SILMs) on the Robeson upper bound plot. The current study on DES-SLMs is expected to open new pathways for the exploitation of DESs for CO 2 capture. [ABSTRACT FROM AUTHOR]

This study focuses on the effect of modified silica fillers by [EMIN][Tf2N] via physical adsorption on the CO2 separation performance of a mixed matrix membrane (MMM). The IL-modified silica was successfully synthesized as the presence of fluorine element was observed in both Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometer (XPS) analyses. The prepared MMMs with different loadings of the IL-modified silica were then compared with an unmodified silica counterpart and neat membrane. The morphology of IL-modified MMMs was observed to have insignificant changes, while polymer chains of were found to be slightly more flexible compared to their counterpart. At 2 bar of operating pressure, a significant increase in performance was observed with the incorporation of 3 wt% Sil-IL fillers compared to that of pure polycarbonate (PC). The permeability increased from 353 to 1151 Barrer while the CO2/CH4 selectivity increased from 20 to 76. The aforementioned increment also exceeded the Robeson upper bound. This indicates that the incorporation of fillers surface-modified with ionic liquid in an organic membrane is worth exploring for CO2 separation. [ABSTRACT FROM AUTHOR]

A photocatalytic system for decolorization of double azo reactive black 5 (RB5) dye and water disinfection of E. coli was developed. Sol gel method was employed for the synthesis of Fe-TiO2 photocatalysts and were characterized using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS) and Brunauer–Emmett–Teller (BET) analysis. Results showed that photocatalytic efficiency was greatly influenced by 0.1 weight percent iron loading and 300 °C calcination temperature. The optimized reaction parameters were found to be the ambient temperature, working solution pH 6.2 and 1 mg g−1 dose to completely decolorize RB5. The isotherm studies showed that RB5 adsorption by Fe-TiO2 followed the Langmuir isotherm with maximum adsorption capacity of 42.7 mg g−1 and Kads 0.0079 L mg−1. Under illumination, the modified photocatalytic material had higher decolorization efficiency as compared to unmodified photocatalyst. Kinetic studies of the modified material under visible light irradiation indicated the reaction followed the pseudo-first-order kinetics. The illumination reaction followed the Langmuir-Hinshelwood (L-H) model as the rate of dye decolorization increased with an incremental increase in dye concentration. The L-H constant Kc was 1.5542 mg L–1∙h–1 while Kads was found 0.1317 L mg–1. The best photocatalyst showed prominent percent reduction of E. coli in 120 min. Finally, 0.1Fe-TiO2-300 could be an efficient photocatalyst and can provide a composite solution for RB5 decolorization and bacterial strain inhibition. [ABSTRACT FROM AUTHOR]

Textile dyes and microbial contamination of surface water bodies have been recognized as emerging quality concerns around the globe. The simultaneous resolve of such impurities can pave the route for an amicable technological solution. This study reports the photocatalytic performance and the biocidal potential of nitrogen-doped TiO2 against reactive black 5 (RB5), a double azo dye and E. coli. Molecular docking was performed to identify and quantify the interactions of the TiO2 with β-lactamase enzyme and to predict the biocidal mechanism. The sol-gel technique was employed for the synthesis of different mol% nitrogen-doped TiO2. The synthesized photocatalysts were characterized using thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) and diffuse reflectance spectroscopy (DRS). The effects of different synthesis and reaction parameters were studied. RB5 dye degradation was monitored by tracking shifts in the absorption spectrum and percent chemical oxygen demand (COD) removal. The best nanomaterial depicted 5.57 nm crystallite size, 49.54 m2 g−1 specific surface area, 11–40 nm particle size with spherical morphologies, and uniform distribution. The RB5 decolorization data fits well with the pseudo-first-order kinetic model, and the maximum monolayer coverage capacity for the Langmuir adsorption model was found to be 40 mg g−1 with Kads of 0.113 mg−1. The LH model yielded a higher coefficient KC (1.15 mg L−1 h−1) compared to the adsorption constant KLH (0.3084 L mg−1). 90% COD removal was achieved in 60 min of irradiation, confirmed by the disappearance of spectral peaks. The best-optimized photocatalysts showed a noticeable biocidal potential against human pathogenic strain E. coli in 150 min. The biocidal mechanism of best-optimized photocatalyst was predicted by molecular docking simulation against E. coli β-lactamase enzyme. The docking score (−7.6 kcal mol−1) and the binding interaction with the active site residues (Lys315, Thr316, and Glu272) of β-lactamase further confirmed that inhibition of β-lactamase could be a most probable mechanism of biocidal activity. [ABSTRACT FROM AUTHOR]

• Preparation of highly selective 3-(trimethoxysilyl)propan-1-aminium acetate and PIM-1 based membrane. • Up to 58.62% and 40.11% increase in CO 2 /CH 4 and CO 2 /N 2 selectivity respectively compared to the pristine membrane. • The selectivity increases attributed to the strong interaction and high solubility of CO 2 in the RTIL. Blend membranes were fabricated by incorporating an ionic liquid, 3-(trimethoxysilyl) propan-1-aminium acetate ([APTMS][Ac]), as a filler into the polymer of intrinsic microporosity PIM-1. The analyses using FTIR spectroscopy, AFM, and SEM confirmed a uniform dispersion and excellent polymer-filler compatibility, even at higher loadings. Gas transport properties were assessed with filler loadings up to 10 wt% of IL, revealing a slight reduction in permeability but an enhancement in selectivity. CO 2 permeability of the blend membrane decreased by 37% at 10% filler loading, while the ideal selectivity increased from 19.6 to 29.0 for CO 2 /CH 4 and from 20.9 to 31.7 for CO 2 /N 2 upon increasing [APTMS][Ac] content (0 wt% − 10 wt%). The CO 2 /CH 4 gas mixture selectivity rose by 58.62% and the CO 2 permeability dropped by 40.44% compared to the pristine PIM-1 membrane. For the CO 2 /N 2 gas mixture, the selectivity and CO 2 permeability were enhanced by 40.11% and reduced by 39.07%, respectively. The permeability reduction can be ascribed to the filling of free volume voids in the PIM-1 polymer matrix by the IL [APTMS][Ac], while the selectivity improvement can be attributed to the strong interaction and high solubility of CO2 in the ionic liquid. The CO 2 solubility coefficient increased with the rising IL concentration, indicating the high solubility of the IL in the polymer matrix. [ABSTRACT FROM AUTHOR]

The ability to tailor ionic liquids can result in very high separation efficiency for CO 2 /CH 4 and CO 2 /N 2 . In this study, a new protic ionic liquid was synthesized with high CO 2 absorption capacity employing (3-aminopropyl) trimethoxysilane and acetic acid, both of these have been reported to exhibit high affinity for CO 2 . The synthesized ionic liquid was characterized by FTIR and the supported ionic liquid membrane was tested to determine the separation of CO 2 from CH 4 . Experiments were conducted at different temperatures and feed conditions, and pure and mixed gas permeability/selectivity data were reported. This combination of silyl ether functionalized cation and acetate ion dramatically improved the membrane separation performance as the SILM displayed CO 2 permeance of 23 GPU combined with CO 2 /CH 4 selectivity of 41. The synthesized SILM was stable upto 10 bar as no leaching of ionic liquid was observed and the permeance increased from 23 to 31 GPU as the temperature was raised from 25 °C to 65 °C, while the selectivity slightly decreased from 41 to 35 over the same temperature range. The exceptionally high selectivity of CO 2 /CH 4 makes [APTMS][Ac] a promising room temperature ionic liquid for CO 2 separation without facilitated transport. A synergistic effect of methoxy groups from [APTMS] part of the ionic liquid caused the enhanced permeability of CO 2 as supported by theoretical calculations. [ABSTRACT FROM AUTHOR]

The intensification of biochar into fluidized bed membrane bioreactor was investigated to mitigate membrane fouling. Different biochars from algal biomass were produced and used as biomaterials for wastewater treatment. In this study, different macroalgal biochar was synthesized at different pyrolysis temperatures and characterized using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Brunauer Emmett-Teller (BET) and Fourier transform infrared spectroscopy (FTIR) techniques to implicate their effect on membrane fouling reduction in fluidized bed membrane bioreactor. The combined effect of macroalgal biochars and biocarriers with gas sparging was evaluated for fouling mitigation. Macroalgal biochar curtailed membrane fouling effectively at low gas sparging rate. Transmembrane pressure (TMP) was reduced to 0.053 bar; under the fluidization of biochar-650 and biocarriers with gas sparging; from 0.27 bar (gas sparging only). Combined effect of gas sparging, biocarriers and biochar-650 instigated 92.1% fouling reduction in comparative to gas sparging alone. Mechanical scouring driven by biocarriers could reduce fouling due to removing surface deposit of foulants from membrane surface effectively and biochar can efficiently adsorb foulants because of its active functional groups resulting in reduction of colloidal fouling. The addition of divalent ions (Ca2+) further enhanced the fouling reduction in fluidized bed membrane bioreactor. [Display omitted] • Different microalgal biochars were synthesized and characterized using various techniques. • Implications of biochars for fouling mitigation in fluidized bed membrane reactor were evaluated. • Membrane fouling was examined by fluidizing biocarriers, different biochars with gas sparging. • Combined effects of biochar, biocarriers, gas sparging and calcium ions were critically investigated. • Fouling control by integrating hybrid approach at reduced gas rates leading to low energy need. [ABSTRACT FROM AUTHOR]