Plentiful Hydroxyl Groups Research Articles

Fabrication of ultra-permeable membranes with antibiofouling capability by incorporating bifunctionalized zeolite

Poor water permeance and biofouling significantly limit the application of nanofiltration (NF) membranes in wastewater treatment and seawater desalination. Herein, bifunctionalized FAU-Ag-OH zeolites, featuring abundant hydroxyl groups and silver ions on their surface, were designed and incorporated into polyamide (PA) layer of a thin-film nanocomposite (TFN) membrane, effectively enhancing the antibiofouling properties and water permeance of membrane. The plentiful hydroxyl groups and well-dispersed silver ions on the bifunctionalized FAU-Ag-OH zeolites impart the membrane with more negative surface charge, increased hydrophilicity, and superior antibiofouling property. Additionally, the doped FAU-Ag-OH zeolites can retard the diffusion of piperazine during interfacial polymerization (IP) process and have improved chemical compatibility with polymers, which results in desirable membrane structure. Consequently, the optimal M–0.05 membrane containing FAU-Ag-OH zeolites exhibited a 2.3-fold increase in water permeance (18.8 ± 2.0 L m−2 h−1 bar−1) and enhanced antibiofouling ability (with antibacterial efficiency up to 95.4 % and flux recovery ratio up to 85 %) compared with the TFC membrane. The successful fabrication of such membrane with enhanced antibiofouling properties and improved water permeance is expected to promote the application of NF membranes in water treatment.

A transparent hydrophilic coating for long-lasting anti-fogging with self-cleaning and antibacterial properties

Transparent substrates with anti-fogging properties endowed by surface hydrophilic modification have been proved to applied in various fields. In this study, a superhydrophilic coating (PAT coating) was generated on glass substrate via dip coating technique using a solution comprising polyvinyl alcohol (PVA), alkyl polyglycoside (APG1214), and tetraethoxysilane (TEOS). The plentiful hydroxyl groups present in PVA and APG1214 endow the PAT coating with high hydrophilicity for excellent anti-fogging and self-cleaning properties, and facilitate to form a stable homogeneous hydrogen-bonded crosslinked network. Meanwhile, the in situ generated tetraethoxysilane hydrolysate (TEOH) from hydrolysis of TEOS acts as a crosslinker, which can covalently connect the organic components to the glass substrate. As a result, the resulting PAT coating displays excellent stability during various mechanical and chemical durability tests. In addition, the coating exhibits antibacterial adhesion properties owing to the broad-spectrum antibacterial property of APG1214. Importantly, the PAT coating can be easily prepared with readily available and economical raw materials through a simple method under mild conditions that does not require complicated separation and purification, thereby enabling its potential industrial application.

Designing ionophilic MXene-based organohydrogel electrolytes for high performance supercapacitor with wide-potential-window and anti-freezing properties

Supercapacitors based on organohydrogel electrolytes can function at subzero temperatures and demonstrate a large potential range. However, for the development of next-generation energy-storage technologies, improvements in the ionic conductivity, mechanical strength, and flexibility of organohydrogel electrolytes are required. We employed Ti3C2Tx, an ionophilic MXene, as a nanofiller in this study to improve the ionic conductivity of organohydrogel electrolytes. Strong affinity for Li+ ions and good dispersibility in water/glycerol were obtained by the hydroxyl group's abundance on the surface of the ionophilic MXene. Due to the enhanced Li-ion hopping through the plentiful hydroxyl groups, an antifreezing supercapacitor based on the MXene/poly(vinyl alcohol) organohydrogel electrolyte (MXPVA-OHE) displayed a gravimetric capacitance as high as 19.84 F g−1 at room temperature and 3.49 F g−1 at -20 °C. Due to their high ionic conductivity, wide potential window, and favorable post-freezing recyclability, MXPVA-OHE-based supercapacitors are thus excellent energy-storage devices.

Rapid electron transfer-promoted tetracycline hydrochloride degradation: Enhanced activity in visible light-coupled peroxymonosulfate with PdO/g-C3N4/kaolinite catalyst

In this work, a novel highly dispersed PdO/g-C3N4/kaolinite (P/CNK) composite was synthesized to activate peroxymonosulfate (PMS) under visible light for tetracycline hydrochloride (TCH) degradation. The 4 %P/CNK catalyst showed the best catalytic ability for TCH degradation within 20 min (94.5 %) over the vis/PMS system. The favorable specific surface area and pore volume of CNK allowed for the high dispersion of PdO and the adsorption of PMS, while PdO anchoring on CNK endowed the catalyst with channels and acceptors that could accommodate a large number of electrons to achieve rapid transfer between electrons. Furthermore, kaolinite is inexpensive, and the plentiful hydroxyl groups on the kaolinite surface can accelerate the self-decomposition of PMS. The 4 %P/CNK system also showed excellent degradation efficiency under different pH conditions and maintained its catalytic activity (87.1 %) after five cycles. The intermediates produced during the degradation of TCH and the corresponding differences in aquatic toxicity were identified. The results of electron paramagnetic resonance and reactive oxygen species quenching experiments showed that 1O2 was the key reaction species, while O2− and h+ were secondary species during the degradation process. In addition to TCH, 4 %P/CNK also had good degradation and mineralization effects on sulfamethoxazole, chlortetracycline, and carbamazepine. This work provides a deep foresight into the efficient degradation of antibiotic pollutants by kaolinite-based catalytic materials in a photocatalytic coupled PMS system.

Enhanced heat resistance and compression strength of microcellular poly (lactic acid) foam by promoted stereocomplex crystallization with added D-Mannitol

Owing to low melt strength and slow crystallization rate, poly (lactic acid) (PLA) foams are usually obtained by adding micro-/nano-particles, which inevitably sacrifices its green nature. Stereocomplex (SC) crystallites formed between poly (L-lactic acid) (PLLA) and poly (D-lactic acid) (PDLA) are appealing to endow PLA with promoted crystallization and superior heat resistance. Herein, microcellular PLA foams with high heat resistance and compression property were obtained using asymmetric PLLA/PDLA blends by a supercritical carbon dioxide (sc-CO2) foaming technology. To facilitate the formation of SC, D-Mannitol (DM) with plentiful hydroxyl groups was applied, which notably promoted the formation of SC and subsequently the crystallization of homocrystallites (HC). The PLLA/PDLA/DM blends foams revealed much smaller cell sizes and higher cell densities compared with the neat PLLA. Furthermore, the PLA foam with 0.7 wt% DM exhibited good heat resistance under a loading of 1200 times, which displayed no changes after treating at 150 °C for 10 min, while the PLLA was obviously deformed. Additionally, the specific compressive modulus of PLLA/PDLA/DM blend foam was enhanced by 330% compared with the pure PLLA. Such fully-biobased PLA foams with superior heat resistance and high mechanical performance could be potentially applied into thermoformed food packaging.

Rice straw derived adsorbent for fast and efficient phosphate elimination from aqueous solution

Rice straw (RS) is an abundant agricultural residue with plentiful hydroxyl groups. In this study, a low-cost and effective RS-based phosphate adsorbent (RS-PA) was prepared through a three-step reaction process, successively with epichlorohydrin (ECH), ethylenediamine (EDA), and triethylamine (TEA). The elimination process of phosphate was optimized by considering altered adsorption conditions. The successful production of RS-PA was confirmed by FTIR, organic element, and zeta potential analyses. The key factors influencing the phosphate adsorption were the temperature in the second reaction step and EDA dosage. Langmuir isotherm and pseudo-second-order kinetic models predicted the phosphate adsorption on the RS-PA very well. A complete phosphate removal was achieved at 50 mg/L phosphate concentration, 10 g/L adsorbent dosage and 25 ℃ in 10 min. The exothermic nature of phosphate adsorption on RS-PA was confirmed since the temperature rise reduced the adsorption of phosphate on the adsorbent. These results demonstrate that full component rice straw-based phosphate adsorbent was successfully prepared for the removal of phosphorus compounds from waste water.

Eco-friendly self-crosslinking cellulose membrane with high mechanical properties from renewable resources for oil/water emulsion separation

As for many reported polymer-crosslinked membranes, challenges remain in terms of membrane fouling, complex processing, high cost and poor degradability. Herein, all-natural multiply self-crosslinking cellulose membrane (SC membrane) was fabricated by blending long and short cellulose micro/nanofibers in a simple crosslinker-free manner. The forming of abundant and compact hydrogen bonding among cellulose fibers enables SC membrane with strong network structure, showing excellent mechanical performance without any extra additives. Due to the plentiful hydroxyl groups, SC membrane possesses underwater superoleophobicity and low oil adhesion. As a proof-of-concept, separation of oil-in-water emulsions using the SC membrane was demonstrated, exhibiting fine separation performance, outstanding reusability and anti-fouling performance. Importantly, SC membrane with admirable thermal stability and corrosion resistance, holds great promise in harsh conditions. Therefore, from perspective of environment sustainability and preparation technology, the SC membrane with supreme properties is expected to open up new avenues for the development of functional cellulose-based membranes.

NIR-responsive multi-healing HMPAM/dextran/AgNWs hydrogel sensor with recoverable mechanics and conductivity for human-machine interaction

Conductive and self-healing hydrogel sensor is perspective in human-machine interaction applications. However, the design of ideal self-healing hydrogels are always challenging. Herein, by introducing disulfide modified Ag nanowires (AgNWs), we show a novel self-healing hydrogel strain sensor with superior mechanics, conductivity, antibacterial property, and firstly realizing of self-healing with both recovery of mechanics and sensing properties. We demonstrate that the covalent and reversible non-covalent hydrophobic blocks in hydrophobic modified polyacrylamide (HMPAM) achieves the basic self-healing network; dextran with plentiful hydroxyl groups synergistic helps the self-healing by hydrogen bonds; disulfide on the AgNWs surface forms a NIR-responsive and dynamic Ag-S coordination bridge between HMPAM and AgNWs. The resulted hydrogel sensor exhibits comprehensive electromechanical properties, and precisely monitors human motion and subtle electromyography (EMG) signals. Importantly, we firstly achieved the recovery of sensing properties on human motion detection and EMG signal detection after self-healing. This work provides a promising exploration to manufacture bionic strain sensors for potential applications in wearable electronics.

Synthesis and characterization of a new hydrophilic boehmite-PVB/PVDF blended membrane supported nano zero-valent iron for removal of Cr(VI)

Abstract A novel composite based on hydrophilic boehmite-PVB/PVDF blended membrane- immobilized nanoscale zero-valent iron (nZVI) (BPPN) was synthesized. When the initial concentration of Cr(VI) was 20 mg/L, 100% Cr(VI) was removed by BPPN at an initial pH of 4.08 under room temperature of 25 °C within 90 min. In addition, the reactivity of the regenerated BPPN composites toward Cr(VI) removal were not obviously declined after 6 cycles. The resultant BPPN demonstrated high reactivity, preeminent stability and reusability in the reaction course. Meanwhile, the BPPN composites showed a higher removal efficiency toward the removal of Cr(VI) compared with alumina-PVB/PVDF-nZVI (APPN) composites. The plentiful hydroxyl groups of boehmit on the BPPN surface resulted in the enhancement in hydrophilicity and improved Fe0 loading of the BPPN composites. For environmental parameters, results indicated that there was a negative effect of increasing the initial concentration or decreasing reaction temperature toward the removal of Cr(VI) by BPPN, and that the acidic and neutral conditions showed more favorable effect on Cr(VI) removal than the alkaline ones. The generated ferrous ions on the surface of BPPN were certified to play an important role in removal of Cr(VI). XPS analysis suggested that the reduction reaction of Cr(VI) occurred on the surface of the composite and produced precipitation of Cr(III). The Cr(VI) removal by BPPN composite was found to follow a revised kinetics well. This study suggests that the novel BPPN composite possessing excellent performance may be a promising functional material of heavy metal wastewater treatment.

PGMA-Based Star-Like Polycations with Plentiful Hydroxyl Groups Act as Highly Efficient miRNA Delivery Nanovectors for Effective Applications in Heart Diseases.

Poly(glycidyl methacrylate)-based star-like polycations with rich hydrophilic hydroxyl groups can efficiently transfer miRNA into primary cardiac fibroblasts for effective applications in cardiac diseases, such as inhibition of cardiac fibrosis and hypertrophy.

A Facile Strategy to Prepare Hyperbranched Hydroxyl-Rich Polycations for Effective Gene Therapy.

For effective gene therapy, nonviral gene carriers with low toxicity and high transfection efficiency are of much importance. In this work, we developed a facile strategy to prepare hyperbranched hydroxyl-rich polycations (denoted by TE) by the one-pot method involving ring-opening reactions between two commonly used reagents, ethylenediamine (ED) with two amino groups and 1,3,5-triglycidyl isocyanurate (TGIC) with three epoxy groups. The hyperbranched TEs with different molecular weights were investigated on their DNA condensation ability, protein absorption property, biocompatibility, transfection efficiency, and in vivo cancer therapy and toxicity. TE exhibited low cytotoxicity and protein absorption property due to the plentiful hydroxyl groups. The optimal transfection efficiency of TE was significantly higher than that of the gold standard polycationic gene carrier branched polyethylenimine (PEI, 25 kDa). Furthermore, TE was applied for in vivo tumor inhibition by the delivery of antioncogene p53, which showed good antitumor efficiency with low adverse effects. The present work provides a new concept for the facile preparation of hyperbranched hydroxyl-rich polycationic carriers with good transfection performances.

PGMA-Based Star-Like Polycations with Plentiful Hydroxyl Groups Act as Highly Efficient miRNA Delivery Nanovectors for Effective Applications in Heart Diseases.

Poly(glycidyl methacrylate)-based star-like polycations with rich hydrophilic hydroxyl groups can efficiently transfer miRNA into primary cardiac fibroblasts for effective applications in cardiac diseases, such as inhibition of cardiac fibrosis and hypertrophy.

Fabrication of mesoporous lignin-based biosorbent from rice straw and its application for heavy-metal-ion removal

Lignocellulosic biomass offers the most abundant renewable resource in replacing traditional fossil resources. However, it is still a major challenge to directly convert the lignin component into value-added materials. The availability of plentiful hydroxyl groups in lignin macromolecules and its unique three-dimensional structure make it an ideal precursor for mesoporous biosorbents. In this work, we reported an environmentally friendly and economically feasible method for the fabrication of mesoporous lignin-based biosorbent (MLBB) from lignocellulosic biomass through a SO3 micro-thermal-explosion process, as a byproduct of microcrystalline cellulose. BET analysis reveal the average pore-size distribution of 5.50nm, the average pore value of 0.35cm3/g, and the specific surface area of 186m2/g. The physicochemical properties of MLBB were studied by fourier transform infrared spectroscopy (FTIR), attenuated-total-reflection fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and element analysis. These results showed that there are large amounts of sulfonic functional groups existing on the surface of this biosorbent. Pb(II) was used as a model heavy-metal-ion to demonstrate the technical feasibility for heavy-metal-ion removal. Considering that lignocellulosic biomass is a naturally abundant and renewable resource and SO3 micro-thermal-explosion is a proven technique, this biosorbent can be easily produced at large scale and become a sustainable and reliable resource for wastewater treatment.

Porous Pr(OH)3 Nanostructures as High-Efficiency Adsorbents for Dye Removal

Herein we report the electrochemical synthesis of porous Pr(OH)(3) nanobelt arrays (NBAs), nanowire arrays (NWAs), nanowire bundles (NWBs), and nanowires (NWs) and their applications as dye absorbents in water treatment. These Pr(OH)(3) nanostructures exhibit high efficient and selective adsorption of the dyes with amine (-NH(2)) functional groups such as Congo red, reactive yellow, and reactive blue. The high efficiency and selectivity is attributed to the large effective surface area of the porous structure, plentiful hydroxyl groups, and basic sites on the Pr(OH)(3) surface. Furthermore, the toxicity studies of these porous Pr(OH)(3) nanostructure show a negligible effect on seed germination, indicating that they hold great potential as environmentally friendly absorbents in water treatment.