Search

OBJECTIVE: In this article, monomers (tannic acid (TA) and m- phenylenediamine (MPD)) were used in the fabrication of a novel PES based thin-film composite nanofiltration (TFC-NF) membrane for the treatment of a common effluent treatment plant (CETP) of textile industrial wastewater. MEMBRANE SYNTHESIS: PES support sheets and TFC layers were fabricated via non-solvent induced phase inversion and in-situ interfacial polymerization (IP) process. The ultra-thin active layer was synthesized via the IP process with monomers such as tannic acid (TA) and m- phenylenediamine (MPD). T and M series membranes correspond to (PES/x wt% TA, x = 2, 4, 6) as T1, T2, T3 -TA and (PES/x wt% MPD, x = 2, 4, 6) as M1, M2, M3–MPD respectively. M0 corresponds to PES which is the virgin membrane. RESULTS: The chemical structure, surface morphology, surface roughness and surface properties were explored using fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and contact angle, respectively. The filtration performance of the thin-film composite nanofiltration (TFC-NF) membranes was investigated by various properties like pure water flux, salt rejection, porosity, mean pore radius and antifouling analysis. CONCLUSION: T1-TA membrane showed better water permeability, high salt rejection and better industrial effluent rejection with 94.4% of TDS that are suitable for industrial reuse and agricultural irrigation. Moreover, for T1-TA membrane, the water flux, porosity, mean pore radius, salt rejection, surface roughness and contact angle of 43.5lm(− 2)h(− 1), 47.1%, 16.7nm, 72.7%, 11.7nm and 41.48°was achieved respectively that was found to be higher than that of all the other fabricated membranes. Further, the rejection efficiency rate of textile effluent characteristics such as pH, turbidity, TDS, alkalinity, total hardness, BOD and COD were also achieved with maximum deduction in the T1-TA TFC-NF membrane compared to the M0-Virgin PES membrane. From the results, it can be confirmed that the T1-TA membrane significantly reduced the alkalinity, total hardness, BOD and COD rejections of 78%, 77.3%, 58.5% and 67.5% respectively, present in the effluent. Water flux recovery ratio (FRR) was improved from 74.6% for M0-Virgin PES membrane to 94.8% for T1-TA membrane. The modified TFC-NF membranes especially T1-TA, had better anti-fouling property and excellent hydrophilicity than the unmodified M0-Virgin PES membrane. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40201-021-00624-x.

Electrospun (CNFs/TiO2-PAN) hybrid membrane was synthesized using the base polyacrylonitrile (PAN) polymer with carbon nanofibers (CNF)/TiO2 nanoparticles at different weight percentage (%). SEM images confirmed the formation of PAN nanofiber membrane with diameter ranging from 200 nm to 260 nm after incorporation of CNFs/TiO2 nanoparticles. Fourier transform infrared (FTIR) spectra showed the presence of functional groups confirming the successful incorporation of CNFs/TiO2 in PAN nanofiber membranes. The water contact angle (WCA) of CNFs/TiO2-PAN hybrid membrane decreased from 38° to 18° by addition of different concentration CNFs/TiO2 (0.5 wt% to 6 wt %). The rejection performance of hybrid CNFs/TiO2-PAN membrane was evaluated with different metal ions (such as Pb2+, Cu2+, Cd2+) and cationic dye (such as methylene blue (MB)) from wastewater. The adsorption studies of the heavy metal ions were performed at different pH (3–7), metal ion concentrations (50 ppm to 300 ppm) and time (48 h). CNFs/TiO2 –PAN hybrid membranes exhibited a maximum rejection around 87%, 73%, 66%, for Pb2+, Cu2+, Cd2+ metal ions and 84% for methylene blue dye, respectively. The developed electrospun CNFs/TiO2-PAN hybrid membranes could be adopted for the removal of metal ions and dyes from polluted drinking water source.

We report the facile and low temperature synthesis of one dimensional graphitic fibers with hollow structured morphology (VO-CF) by modified chemical vapor deposition using vegetable oil as a carbon source. Graphitization of the prepared phase is validated with various analytical tools. Prior to the fabrication of charge storage devices like Li-ion battery (LIB) and Li-ion capacitor (LIC), Li-insertion properties of VO-CF is studied in half-cell assembly. Mass adjustment between the electrodes are very crucial and adjusted for aforesaid energy storage devices. Pre-treatment or pre-lithiation is carried out using an electrochemical approach in Swagelok fittings with Li. LIB assembly with LiFePO4 delivered a maximum energy density of ∼233 Wh kg−1 whereas the LIC displayed the energy density of ∼112 Wh kg−1 when paired with activated carbon electrode. Both LIB and LIC assemblies rendered very decent cycling profiles for extended 500 and 10000 cycles, respectively. NRF (Natl Research Foundation, S’pore)

Co–intercalation process using glyme-based solvents has brought new prospects for the reversible Na-intercalation into the graphitic materials. We report a high-energy Na-ion capacitor (SIC) with graphitic carbon nanofibers (GCNF) as a battery-type component obtained from the depolymerization of waste rubber. The kinetic study reveals that ~ 51% contribution is originated from the diffusion-controlled Faradaic mechanism for GCNF compared to the ~ 61% for commercial graphite powder. The synthesis procedure and less crystalline nature of the GCNF lead to the lowered intercalation potential, and extended Na-ion storage capacity in the lower potential region (vs. Na+/Na) which is significant compared to the graphite powder. Further, the half-cell delivered a discharge capacity of ~ 118 mAh g−1 irrespective of the applied current rate, which signifies the importance of this concept. In a SIC configuration with activated carbon, the SIC renders an energy density of 55.58 Wh kg−1 at 25 °C. In addition, exceptional low-temperature performance ( 97% capacity retention after 5000 cycles. This low-temperature performance, high energy density, and exceptional cyclability certainly offer a unique hybrid charge storage system that eventually explores the possibility of using graphitic carbon fibers towards balanced energy and power capabilities. On a lighter note, this study also provides the opportunity to handle the waste materials effectively for sustained charge storage applications.

Coconut shell derived mesoporous carbon (CS-AC) is explored as prospective supercapacitor component in Li-ion and Na-ion capacitors (LIC and NIC) along with pre-lithiated/sodiated natural plant derived hard carbon (HC) as battery element. Though, there is no obvious variation from the capacitive properties of CS-AC, but an obvious difference is evident for battery component in single electrode configuration. Based on such performance, the mass loading has been adjusted during the fabrication of LIC and NIC. Prior to this, HC is pre-lithiated/sodiated for LIC/NIC assembly. The CS-AC and pre-treated HC based materials registered the maximum energy density of ∼121 and ∼82 Wh kg−1 for LIC and NIC assemblies, respectively. An excellent long-term cycleability of ∼83% retention is noted for LIC after 8000 cycles, whereas NIC showed inferior performance (∼60%) under similar testing conditions. Multilayer surface film is the main reason for such performance which has been clearly revealed from the impedance measurements. First, the CS-AC is prepared by hydrothermal carbonization and subsequent chemical activation with ZnCl2 to yield high specific surface area and pore volume of 1795 m2 g−1 and 2.2 cm3 g−1, respectively, in which 71% originated from mesoporous region.

We report the fabrication of high energy Li-ion capacitor (LIC) using teak wood sawdust derived mesoporous activated carbon (AC-HBP) with electrochemically pre-lithiated graphite (LiC6). Three interesting supercapacitor assemblies are constructed using AC-HBP to realize the high energy density. Amongst, AC-HBP paired with LiC6 delivered a maximum energy density of ∼111 Wh kg−1 compared to Li4Ti5O12 in LIC (∼53 Wh kg−1) and AC-HBP (∼37 Wh kg−1) in symmetric configurations. This excellent energy density is mainly ascribed to the tailored mesoporous nature (∼67%) of the high surface area activated carbon (2108 m2 g−1) obtained via hydrothermal carbonization process in the presence of processing agent, benzene tetracarboxylic acid followed by physico-chemical activation.

Patchouli oil is a high‐value essential oil used in cosmetic, food, and pharmaceutical industries. In this work, supercritical fluid extraction of patchouli oil with various operating process parameters (pressure, temperature, flow rate, and particle size) were studied and the results were modeled using the broken and intact cell model (BICM). From the experimental studies, it was found that the extraction rate was improved at higher pressures and flow rates, where the mass transfer resistances in the liquid and solid phase were decreased; however, the increase in temperature had an inverse effect on extraction rate and mass transfer. In the case of particle size, a moderate size of 0.3 to 0.6 mm gave the optimal extraction rate. The BICM predictions showed good agreements with experimental data and gave valuable insights regarding the mass transfer mechanism of the extraction process, including mass transfer coefficients and extraction periods governed by convection and diffusion.

Patchouli oil is a commercially important essential oil in the flavor and fragrance industry. In this study, a technoeconomic feasibility assessment was conducted to commission a supercritical fluid extraction plant for the extraction of patchouli oil in Singapore. The study revealed that the manufacturing cost for patchouli oil is 53.87 USD/kg for a plant processing capacity of 400,000 kg of raw material/year with the cost of utilities being a major contributing factor to the manufacturing cost. In addition, financial indicators such as net present value, discount cash flow rate of return, return on investment and payback period have been applied to evaluate the profitability of the supercritical fluid extraction plant. The total investment cost for the plant is around 4.77 million USD. Calculation of the discounted cash flow rate of return shows that a maximum interest rate of 26.3% can be loaned from investors and the project would still breakeven. At an interest rate of 5.25%, the return on investment for the project is calculated to be 27.4% and the payback time is estimated to be 5.4 years with a total profit of 5.27 million USD after 10 years.

Extraction of peroxidase from raw vegetables using supercritical carbon dioxide (scCO 2 ) and its simultaneous application for oxidation of organics in wastewater in the presence of hydrogen peroxide has been demonstrated. Ethanol and phenol were used as the model organic contaminants and potato and cabbage were employed as the sources of peroxidase. The extractions were carried out at 10 MPa for 2 h over a temperature range of 25 °C to 60 °C. Oxidation of ethanol increased by 330% when the treatment was carried out in the scCO 2 medium compared to conventional aqueous medium when cabbage was employed, while use of potato as the enzyme source resulted in an increase of 85%. In the case of phenol, scCO 2 exhibited a huge increase of 400% in presence of cabbage and 140% in presence of potato. Comparison of vegetable extracts with commercial horseradish peroxidase indicated the feasibility, importance and advantage of employing vegetables as a peroxidase source. This work presents the simultaneous extraction of enzymes and its application for oxidation of organics and opens up new opportunities for recovery of resources from unwanted/discarded plant materials and their use for environmental remediation in a single step.

Oxide-free silicon chemistry has been widely studied using wet-chemistry methods, but for emerging applications such as molecular electronics on silicon, nanowire-based sensors, and biochips, these methods may not be suitable as they can give rise to defects due to surface contamination, residual solvents, which in turn can affect the grafted monolayer devices for practical applications. Therefore, there is a need for a cleaner, reproducible, scalable, and environmentally benign monolayer grafting process. In this work, monolayers of alkylthiols were deposited on oxide-free semiconductor surfaces using supercritical carbon dioxide (SCCO2) as a carrier fluid owing to its favorable physical properties. The identity of grafted monolayers was monitored with Fourier transform infrared (FTIR) spectroscopy, high-resolution X-ray photoelectron spectroscopy (HRXPS), XPS, atomic force microscopy (AFM), contact angle measurements, and ellipsometry. Monolayers on oxide-free silicon were able to passivate the surface for more than 50 days (10 times than the conventional methods) without any oxide formation in ambient atmosphere. Application of the SCCO2 process was further extended by depositing alkylthiol monolayers on fragile and brittle 1D silicon nanowires (SiNWs) and 2D germanium substrates. With the recent interest in SiNWs for biological applications, the thiol-passivated oxide-free silicon nanowire surfaces were also studied for their biological response. Alkylthiol-functionalized SiNWs showed a significant decrease in cell proliferation owing to their superhydrophobicity combined with the rough surface morphology. Furthermore, tribological studies showed a sharp decrease in the coefficient of friction, which was found to be dependent on the alkyl chain length and surface bond. These studies can be used for the development of cost-effective and highly stable monolayers for practical applications such as solar cells, biosensors, molecular electronics, micro- and nano- electromechanical systems, antifouling agents, and drug delivery.

Poor tribological properties of SU-8, a promising MEMS structural material, have been recently addressed by developing a perflouropolyether (Z-dol) lubricant droplet-filled SU-8 composite. The composite shows wear durability four orders of magnitude greater than that of SU-8. The chemical reaction between the SU-8 and PFPE molecules and the physical self-lubrication mechanism were found responsible for this dramatic improvement. In this work, the self-lubrication mechanism at the ball–composite interface of SU-8+5 wt% Z-dol composite was further investigated by varying sliding speed. Effects of normal load on the tribological responses of SU-8+5 wt% Z-dol composite was also investigated independently and various possible wear mechanisms are proposed.

Immobilization of enzymes on solid supports is crucial in enzymatic reactions and catalysis as it allows reutilization of soluble enzymes and reduces cost. Covalent immobilization of horseradish peroxidise (HRP) on surface-modified mesoporous activated carbon (SMAC) in combination with supercritical carbon dioxide (scCO2) has been investigated in this study. The supercritical medium achieved higher enzyme loading of 83.5% within 3 h compared to 54% when incubated in aqueous phosphate buffer for 30 h. HRP loading in the scCO2 environment was consistently higher for different HRP: SMAC ratios. The significant increase in the rate and quantity of HRP immobilization is attributed to the favourable transport properties of solutes in scCO2 coupled with greater affinity of HRP for the non-polar supercritical solvent which enhances the diffusivity of enzymes into the porous matrix. Immobilized HRP retained enzymatic activity after being reutilized 11 times which indicated that immobilization did not detract from HRP's activity. The immobilized HRP was successfully employed in removing phenol from water via polymerization of dissolved phenol in the presence of hydrogen peroxide (H2O2). The study shows the advantage of using a mesoporous substrate as the immobilization platform for enzymes in combination with scCO2 as the transport medium. It resulted in significant enhancement in the capacity as well as the uptake rate of HRP and resulting in the enhanced phenol removal.

Polymers capable of forming hydration layers have gained increasing attention due to their ability to form environmentally friendly antifouling surfaces. Zwitterionic polymers are an important class of materials under this category. However, the effectiveness of many zwitterionic polymers for long-term applications is compromised because of their solubility in sea water, poor hydrolytic stability and deteriorating mechanical integrity upon wetting. This study reports on the preparation and characterization of electrospun fibers derived from novel polysulfobetaine and polysulfabetaines (PSBs) composed of polyvinylbenzyl backbones. The morphology of the electrospun nanofibers was elucidated with the help of a scanning electron microscope. Hydration studies were conducted in deionized water and artificial sea water. Antifouling performance of the electrospun nanofibers was evaluated by studying the adhesion and growth of bacteria in natural, and filtered sea water. Terminal restriction fragment length polymorphism (TRFLP) fingerprinting was performed to determine the nature of the bacterial community attached to the electrospun fibers. Some of the PSBs prevented bacterial growth without showing any biocidal nature. Thus the findings of this study are potentially relevant for current trends seeking environmentally friendly antifouling solutions.

In this work, supercritical fluid extraction (SFE) was employed to fully utilize patchouli plant including the stems to extract patchouli oil. In the conventional extraction by steam distillation, patchouli stems are often underutilized and discarded as waste. Using Taguchi’s orthogonal array method, the effect of pressure (10–20 MPa), temperature (35–45 °C) and CO2 flowrate (40–80 g/min) on SFE yield, antioxidant activity and patchoulol concentration from patchouli plant were evaluated. The SFE process conditions were optimized based on the selective yield of patchoulol as patchoulol is generally considered as an indicator of the patchouli oil quality. SFE with the optimized pressure of 15 MPa, temperature of 45 °C and CO2 flow rate of 60 g/min obtained yield, antioxidant activity and patchoulol concentration of 3.51 %, IC50:1.21 mg/mL and 0.2953 g patchoulol/g oil respectively. The results were compared with steam distillation where SFE shown significantly improved yield and antioxidant activity over the distillation process.

We report a new electrochemical procedure to suppress the irreversible capacity loss (ICL) from high capacity anodes, specifically for high capacity anodes that undergo either alloying or conversio...

We report a facile low-temperature synthesis of graphitic carbons with a spherically shaped morphology (CO-CS) and high purity by the modified catalytic chemical vapour deposition using vegetable cooking oil as a carbon source. The excellent Li-insertion properties are noted with high reversibility (∼369 mA h g−1) in the half-cell assembly, which is very close to the theoretical capacity of graphite. Further explored the suitability to be used as an anode in the practical configurations, the intercalation type LiFePO4 and double layer forming activated carbon (AC) have been used as the cathodes toward the fabrication of Li-ion battery (LIB) and Li-ion capacitor (LIC), respectively. Prior to the LIC assembly, CO-CS has been pre-lithiated electrochemically. Both LiFePO4/CO-CS and AC/CO-CS assemblies display a maximum energy density of ∼337 and ∼108 W h kg−1 (based on an active material loading), respectively. The obtained values are better than those of the state-of-the-art LIB and LIC based on a graphitic anode. A decent cycle-ability is also registered for both cases. NRF (Natl Research Foundation, S’pore)

We report the possibility of recycling carbonaceous materials (GC) from used/spent Li‐ion batteries (LIBs) and re‐using the material again as a negative electrode. In addition to LIB, the possibility of using them in Li‐ion capacitor (LIC) configuration with activated carbon is also explored. First, the carbonaceous materials are recovered from the mechanical treatment and subsequent leaching process. After the successful recovery, the Li‐insertion properties are studied in half‐cell assembly and it exhibits very decent electrochemical activity. While re‐using GC as an anode, large irreversibility is noted compared to fresh usage. Therefore, the elimination of such irreversible capacity is desperately required prior to the fabrication of either LIBs or LICs. Full‐cell LIB is assembled with olivine phase LiFePO4 cathode and the configuration delivers a maximum energy density of ∼313 Wh kg−1. Similarly, the GC is used as an anode in LIC assembly with commercial activated carbon. The LIC displays an energy density of ∼112 Wh kg−1 with decent cycling profiles. National Environmental Agency (NEA) Submitted/Accepted version VA thank the financial support from Science & Engineering Research Board (SERB), a statutory body of the Department of Science & Technology, Govt. of India through Ramanujan Fellowship (SB/S2/RJN-088/2016). SM would like to thank the grant award from NEA (National Environmental agency) on Singapore – CEA Alliance for Research in Circular Economy (SCARCE), award number USS-IF-2018-4.

A significant improvement of up to 94% in mesopore area of hydrochar-derived activated carbons (ACs) has been achieved using optimal concentrations of biomass (coconut shell) and chemical activating agent (ZnCl2) during hydrothermal pre-treatment. For the first time, we have demonstrated that stoichiometry can influence hydrochar properties and availability of ZnCl2 for activation which has significant impact on the textural properties of mesoporous activated carbons. Tuning of key process parameters and hydrothermal treatment conditions (ZnCl2:biomass ratios and biomass & ZnCl2 concentrations), together with hydrothermal pre-treatment with H2O2, resulted in BET and mesopore areas up to 2440 m2 g−1 and 1121 m2 g−1, respectively. When the mesoporous carbon was employed as an electrode material in supercapacitors, stable energy density at 7.6 W h kg−1 was observed (90% of 8.5 W h kg−1 @ 0.22 kW kg−1) at a high power density of ∼4.5 kW kg−1, which is one the best performance observed thus far in biomass-derived activated carbons.

We demonstrated the functionalization of one dimensional (1-D) zinc oxide nanorods (ZnO NRs) using bi-functional organic molecules to create hybrid structures with surface functionalities and tuneable organic/inorganic interface. Bi-functional molecules with carboxylic acid, thiol and silane end groups and amine termination had been employed to functionalize the NRs by forming carboxylate, thiolate and hydroxylation bonds, respectively, with ZnO. The surface textures of NRs were preserved even after functionalization. The functionalized NRs were decorated with gold nanoparticles (AuNPs) and the hybrid structures exhibited a quenched blue shift ultraviolet emission which depended on the distance between the ZnO surface and the AuNPs. The NR functionalization with bi-functional molecules and decoration of NPs, and surface morphologies were analyzed using x-ray photoelectron spectroscopy, field emission scanning electron microscopy and transmission electron spectroscopy. These hybrid structures can play a vital role in tuning the interface properties and have potential applications in future photovoltaics, chemical sensors, biomarkers, and wavelength based biosensors. Refereed/Peer-reviewed

We first report the possibility of using spinel LiNi0.5Mn1.5O4 (LNM) nanofibers as cathode for constructing high (∼3.2 V) and low (∼1.2 V) voltage “rocking-chair” type Li-ion cells with spinel Li4Ti5O12 (LTO) by utilizing Li-insertion into tetrahedral (Ni2+/4+) and octahedral (Mn4+/3+) sites of LNM. We also explored the possibility of constructing symmetric cells (LNM/LNM) with a working potential of ∼1.8 V. Among the three configurations investigated, LNM/LTO (electrochemically prelithiated) is found superior in terms of high rate capability, cyclability, and good capacity retention characteristics. High performance spinel LNM nanofibers are prepared via a scalable electrospinning technique and their Li-insertion properties are evaluated in half-cell assembly. The half-cell studies are used for adjusting the mass balance while fabricating “rocking-chair” Li-ion cells.

Formation of dense monolayers with proven atmospheric stability using simple fabrication conditions remains a major challenge for potential applications such as (bio)sensors, solar cells, surfaces for growth of biological cells, and molecular, organic, and plastic electronics. Here, we demonstrate a single-step modification of organophosphonic acids (OPA) on 1D and 2D structures using supercritical carbon dioxide (SCCO2) as a processing medium, with high stability and significantly shorter processing times than those obtained by the conventional physisorption-chemisorption method (2.5 h vs 48-60 h).The advantages of this approach in terms of stability and atmospheric resistivity are demonstrated on various 2D materials, such as indium-tin-oxide (ITO) and 2D Si surfaces. The advantage of the reported approach on electronic and sensing devices is demonstrated by Si nanowire field effect transistors (SiNW FETs), which have shown a few orders of magnitude higher electrical and sensing performances, compared with devices obtained by conventional approaches. The compatibility of the reported approach with various materials and its simple implementation with a single reactor makes it easily scalable for various applications.

We first report the multi-couple reaction in all vanadium redox flow batteries (VRFB) while using biomass (coconut shell) derived mesoporous carbon as electrode. The presence of V 3þ /V 4þ redox couple certainly supplies the additional electrons for the electrochemical reaction and subsequently provides improved electrochemical performance of VRFB system. The efficient electro-catalytic activity of such coconut shell derived high surface area mesoporous carbon is believed for the improved cell performance. Extensive power and electrochemical studies are performed for VRFB application point of view and described in detail.

Prelithiated, electrospun α‐Fe2O3 nanofibers display an exceptional cycleability when it is paired with commercial LiMn2O4 cathode in full‐cell assembly. The performance of such α‐Fe2O3 nanofibers is mainly due to the presence of unique morphology with porous structure, appropriate mass balance, and working potential. Also, synthesis technique cannot be ruled out for the performance.

Poly(sulfobetaine methacrylate) (PSBMA) films known for their resistance to nonspecific protein adsorption, cell/bacterial adhesion and biofilm formation were produced by surface initiated polymerization on a silicon surface via a batch reaction system in CO2 expanded liquid (CO2-EL) medium. Atom transfer radical polymerization (ATRP) was carried out using 2,2'-bipyridyl as ligand and CuBr as a catalyst in water/methanol mixture with trichloro[4-(chloromethyl)phenyl]silane (CMPS) used as the initiating species. The films were grown in the CO2-EL environment at a range of conditions and thickness up to 10nm. In contrast to films produced by conventional solvent systems at atmospheric pressure, the polymer films grown by the CO2-EL process showed uniform thickness and pin-hole free topography. Most importantly, the CO2-EL processed PSBMA films showed no trace of copper (used as the catalyst), thus obviating the need for post-deposition processing and avoiding adverse effects of the metal leaching during service. Finally, PSBMA films from both the conventional and CO2-EL processes were exposed to Human mesenchymal stem cells (hMSCs) and the results showed that, while in both the cases the cell proliferation rate was inhibited by the charged polymeric brush surface, the CO2-EL-processed brush exhibited inhibition to a larger extent due to the reduced occurrence of pinholes. The process can be easily exploited effectively when carrying out surface initiated polymerization on non-flat topographies, such as in trenches and nanostructured features with high aspect ratios.

Temperature-triggered switchable nanofibrous membranes are successfully fabricated from a mixture of cellulose acetate (CA) and poly(N-isopropylacrylamide) (PNIPAM) by employing a single-step direct electrospinning process. These hybrid CA-PNIPAM membranes demonstrate the ability to switch between two wetting states viz. superhydrophilic to highly hydrophobic states upon increasing the temperature. At room temperature (23 °C) CA-PNIPAM nanofibrous membranes exhibit superhydrophilicity, while at elevated temperature (40 °C) the membranes demonstrate hydrophobicity with a static water contact angle greater than 130°. Furthermore, the results here demonstrate that the degree of hydrophobicity of the membranes can be controlled by adjusting the ratio of PNIPAM in the CA-PNIPAM mixture.

Prelithiated, electrospun α-Fe2O3 nanofibers display an exceptional cycleability when it is paired with commercial LiMn2O4 cathode in full-cell assembly. The performance of such α-Fe2O3 nanofibers is mainly due to the presence of unique morphology with porous structure, appropriate mass balance, and working potential. Also, synthesis technique cannot be ruled out for the performance. NRF (Natl Research Foundation, S’pore) Published version

Clay minerals can act as a uniform dispersion medium for nano-sized carbon particles. However, literature on the preparation and characteristics of palygorskite-carbon nanocomposites is scant. Using a hydrothermal carbonisation technique this study developed two nanocomposites on fibrous palygorskite from starch: the first without a post-synthesis treatment (Composite 1); and the second with an activation at 550°C for 3h (ramp at 10°Cmin-1) under CO2 environment (200mLmin-1) (Composite 2). A uniform dispersion of nano-scale carbon spheres was formed on partially destroyed palygorskite structures. Composite 2, which indicated the formation of graphitised carbon nanoparticles, generated a 17-fold greater specific surface area than Composite 1 and also created micro- and mesopores in its structure. The nanocomposites, especially in Composite 1, contained organic surface functional groups (CH, CC, CO) and indicated variable affinity to cationic and anionic dye compounds. While Composite 2 adsorbed a larger amount of anionic orange II dye (23mgg-1), Composite 1 adsorbed more cationic methylene blue (46.3mgg-1). Isothermal and kinetic modelling of the adsorption data indicated that in addition to electrostatic attraction for methylene blue adsorption on both nanocomposites, a pore diffusion mechanism was involved and the boundary resistance was greater for orange II than methylene blue adsorption. Being a material developed from green biomass (starch) and an abundant natural resource (palygorskite), these nanocomposites have immense potential for application in environmental remediation including in situ immobilisation of contaminants in soil. Refereed/Peer-reviewed