Strong Basic Solution Research Articles

An unmodified recycled polyethylene terephthalate (PET) nanofibrous membrane for water-in-oil and oil-in-water emulsions separation

A nanofibrous membrane made of unmodified recycled polyethylene terephthalate (rPET) was fabricated by electrospinning using plastic water bottle as raw materials. Using rPET polymer to fabricate membranes may help limit the discharge of plastic bottle waste into the environment and can treat oily wastewater simultaneously, especially emulsions. The variation in the concentration of rPET polymer and the properties of electrospun nanofibers, such as surface morphology and fiber diameter, had a significant impact on both the efficiency of oil droplet capturing and the surface wettability of the membrane. Water-in-oil emulsions and oil-in-water emulsions were separated using the nanofibrous membranes of different concentrations of rPET polymer, and the separation efficiencies at different concentrations of oil, and oil types were measured. The rPET nanofibrous membrane exhibited a water contact angle of 140.1° and was superoleophilic in air and underwater. The membranes exhibited excellent separation performances: >98% separation efficiency and a flux of more than 6500 L m-2 h-1 for water in hexadecane and octane emulsions; >95 % efficiency and a flux of 1509.70 L m-2 h-1 after three separation cycles of water-in-oil emulsions. For oil-in-water emulsions, the separation efficiencies were higher than 95 %, and flux was more than 3525.22 L m-2 h-1 for hexadecane octane and heptane in water emulsions, with an efficiency of >87.9 % and flux of 4186.20 L m-2 h-1 after three separation cycles. Moreover, the as-prepared membrane exhibited high performance of oil-water separation in harsh conditions, including strong acidic, strong basic, and strong salt solutions, with separation efficiencies of more than 98 % and flux of more than 12,700 L m-2 h-1. However, as water accumulated on the membrane surface, absorption and separation efficiency and flux were lowered significantly. This suggests the need to enhance the efficiency of the membrane and reduce the chance of water accumulation on the membrane surface.

Enhancing biomethane quality via the activation of natural zeolite from Lombok Island

<p>This study presents the results of the biogas purification test using the fixed-bed column method. As an adsorbent, natural zeolite from the Lombok island Indonesia was used. Zeolite is used for the purpose of purifying biogas produced from the anaerobic digestion (AD) process. To enhance the adsorption capacity, the zeolite underwent activation using distinct strong base and acid solutions—potassium hydroxide (KOH) and hydrochloric acid (HCl)—with concentrations of 10%, 15%, and 20%, individually. The experiment was carried out until the adsorbent reached saturation, at which point the methane (CH4) concentration began to decline. It was revealed that the typical Lombok zeolite showed good performance in increasing the concentration of CH4 in biogas. Furthermore, zeolites work better when activated with strong base solutions and at high concentrations. This is indicated by the achievement of higher CH4 concentrations and a longer saturation time. The results from analyzing zeolite features and pore characteristics indicate that acidic and base compounds yield distinct outcomes in terms of the surface structure of zeolite pores.</p>

Engineering of robust conjugated polymer-based aerogels via surface-initiated polycondensation towards sunlight-driven seawater desalination and uranium extraction.

The aerogels with low thermal conductivity and cross-linked 3D networks can be easily integrated with functional materials to maximize their functionalities, realizing diverse applications such as photothermal seawater desalination and photocatalytic uranium extraction. Sp2C-conjugated porous polymers (sp2C-CPPs) with robust and conjugated CC linkages are ideal photosensitizers for these applications, owing to their exceptional semiconducting properties as well as chemical stability. However, the limited processability and collectability of as-synthesized sp2C-CPP powders impede their extended applications. Herein, we report the preparation of robust sp2C-CPP (DHA-TMT and DBD-TMT) based aerogels via surface-initiated aldol polycondensation (SI-AP). The fully conjugated CC skeletons and electron-donating groups (-OH) endow the sp2C-CPP aerogels with excellent photothermal conversion efficiency (95.6%) and strong affinity for uranium adsorption. In particular, the DHA-TMT aerogel with hydrophilic porous channel exhibits a superb evaporation performance achieving ∼1.55 kg m-2 h-1 under AM 1.5 G while the fast mass transfer caused by photothermal conversion increases the uranium extraction capacity up to 1200 mg m-2 in simulated seawater. Moreover, the sp2C-CPP aerogels demonstrate high stability under strong acid, base and brine solutions. This work shows a strategy for the preparation of uniform and high stability sp2C-CPP-based aerogels to simultaneously enhance their photothermal and photocatalytic performance.

Solid-state mechanochemical synthesis of chitosan from mud crab (Scylla serrata) chitin

This study presents a method for solvent-free mechanochemical synthesis of chitosan from chitin, sourced from the shells of mud crabs (Scylla serrata). The procedure involves a sequence of demineralization and deproteinization to extract chitin from the crab shells, followed by mechanochemical deacetylation. The chitin was deacetylated by grinding it as a solid blend with sodium hydroxide (NaOH) using a stainless steel mortar and pestle. After grinding, chitosan is isolated from the blend by repetitive washing and centrifugation. The chitosan product is then characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction analysis. These characterization techniques confirm the successful deacetylation of chitin to form chitosan. A high degree of deacetylation (DD) is achieved when the weight ratio of NaOH to chitin is 1:1 or higher, implying that the DD value can be enhanced by increasing this weight ratio. The mechanochemical reaction mechanism involves the hydroxyl groups on the NaOH particles reacting with the acetamide groups of the chitin strands, yielding solid chitosan and sodium acetate. This mechanochemical deacetylation approach is more practical than the conventional heterogeneous deacetylation in strong basic solutions, since it could suppress depolymerization of the resulting chitosan and requires significantly less base. This makes it a promising method for large-scale industrial applications.

Enhancing adsorption performance of alkali activated kaolinite in the removal of antibiotic rifampicin from aqueous solution

In this study, raw kaolin clay was activated with a strong base solution in order to improve its surface characteristics and adsorption performance. The alkali activation evidently caused etching process and ion exchanges of both Al3+ and Si4+ with Na+ on the silica and gibbsite basal surfaces, enhancing the surface area of the kaolinite particles. Adsorption of rifampicin (RIF) on the raw and alkali-activated kaolin was well described by the Langmuir isotherm and the pseudo-second-order kinetics models. The maximum adsorption capacity of RIF on the alkali-activated kaolin was 8.295 mg g−1, enhanced compared with the raw kaolin (5.931 mg g−1). The adsorption was due to weak electrostatic and hydrogen bonding interactions between RIF and the kaolinite surfaces. Adsorption mechanism, kinetics, rate limiting-step, and thermodynamics were described in detail by fitting mathematical functions of the established semiempirical models to the experimental data. The recyclability of the kaolin-based adsorbents was demonstrated by their effective regeneration. Overall, the alkali activation improves the adsorption performance of kaolin to be practically applicable as environmentally friendly and sustainable absorbents for the removal of RIF and probably other pharmaceutical compounds from hospital wastewater.

A fluorescent enhancement method for footwear impressions in ice melt products

There are limited options reported for the detection of footwear impressions in ice melt products. Enhancement of footwear impressions in ice melt products using a fluorescent metal-organic complex was identified in this work. The deprotonation of 8-hydroxyquinoline with a solution of strong base led to the formation of a complex between calcium and magnesium ions commonly found in winter ice melt products. Three ice melt products containing 0.01–99% calcium were compared for enhancement with 8-hydroxyquinoline reagent. With 254 nm light, footwear impressions enhanced with this method fluoresced on a semi-porous tile surface. This application of 8-hydroxyquinoline is a simple, efficient method to enhance footwear impressions, and offers a stable alternative reagent compared to the acetone solution used in previous work.

A novel robust phosphate-functionalized metal–organic framework for deep desulfurization at wide temperature

The need to decrease environmental pollution, reduce energy consumption and produce high-purity chemicals has become an increasingly important driving force for sulfur dioxide (SO2) capture. The efficient capture of low concentrations of SO2, a highly corrosive acid gas that is not typically present in high concentrations in industrial settings, is a major challenge. Herein, a novel phosphate-functionalized metal–organic framework, ZU-801, is designed with precisely controlled pore sizes and chemical environment to achieve excellent adsorption capacity for SO2 (1.44 mmol g−1 at 0.002 bar, 2.00 mmol g−1 at 0.01 bar) and high IAST selectivities for SO2/CO2 (145), which provides great potential for selective capture of SO2. ZU-801 shows excellent stability to air, water, SO2, strong acid and strong base solutions, and it is thermally stable up to 733 K. Additionally, ZU-801 exhibits outstanding separation ability in removing SO2 from SO2/CO2 mixtures at temperature as high as 383 K or in humid environments. This work demonstrates the potential of designing ion-functionalized ultramicroporous materials with tailored pore sizes and porous chemical environments for efficient capture and separation of SO2 and sheds light on designing stable high-performance materials that operate at high temperatures.

Achieving anti-corrosion and anti-biofouling dual-function self-healing coating by natural carrier attapulgite loading with 2-Undecylimidazoline

In the marine environment, the protective coatings face serious corrosion and biofouling problem, limitations, and challenges that made self-healing coatings unable to perform both anti-corrosion and anti-biofouling dual-function at the same time. Here we constructed the corrosion resistance and anti-biofouling self-healing coating by integrating nano-containers into the coating matrix, the 2-Undecylimidazoline (ULM) acted as a corrosion inhibitor and anti-biofouling dual-functional agent which was loaded on the natural container attapulgite (ATP). To obtain high healing efficiency, a fluidity-driven self-healing silicone oil coating was thickened by fibrous ATP to enhance its stability, which played a key role in the self-healing and long-term corrosion resistance. The self-healing time of ULM@ATP reinforced oil coating was 4 s at least in the air and up to 30 s in the 1 M HCl solution. Meanwhile, the ULM@ATP can significantly enhance the corrosion resistance of the self-healing coating, with the best effect achieved when the content of ULM@ATP was 5 wt.%. The impedance modulus of ULM@ATP-2 still reached 1.62 × 108 Ω cm2 after 480 immersion in 3.5 wt.% NaCl solution, which is 3 orders of magnitude high than pure Oil coating (2.17 × 105 Ω cm2). The restructure of the ATP network and the release of ULM could largely inhibit the corrosion of metal. The continuous open circuit potential of the composite coating performed the potentially infinite self-healing capacity. The self-healing performances of the composite coating in strong acid and base solutions exhibited high environmental suitability. This anti-corrosion and anti-biofouling (the surface coverage of adhered chlorella decreased 96.88%) dual-function strategy of self-healing coatings could be also realized by many other porous nano-materials or function modifications. The self-healing performances of the composite coating in strong acid and base solutions exhibited high environmental suitability. This anti-corrosion and anti-biofouling dual-function strategy of self-healing coatings could be also realized by many other porous nano-materials or function modifications. The rapid response self-healing coating possessed anti-biofouling and active self-healing functions and showed wide application under more service environments.

Chemical resistant silver nanowire/cellulose nanofibril flexible transparent conductive coatings

In this research, a coating method is developed to produce chemical resistant transparent conductive films (TCFs). First, cellulose nanofibers are ultrasonicated to physically untangled into thinner units. Silver nanowires (AgNWs) are then mixed with the ultrasonicated cellulose nanofibers (uCNF), which serve as a dispersion agent for stable coating fluids. After coating on a flexible substrate by a blade coating procedure, the uCNFs wrap over AgNWs to form a thin protecting layer, and the embedded AgNWs exhibit a highly percolating conductive network. As a result, the coating shows not only a low sheet resistance of 7.5 Ω/square with a great transparency of 91.5 % transmittance, but also an excellent adhesion under bending conditions. Additionally, the chemical and mechanical stability of the TCF can be further improved by cross-linking with citric acid. The ester bonding between the crosslinked uCNF rods provides a continuous hydrophobic network with a more compact structures for great mechanical stability under bending or ultrasonication conditions. Moreover, the crosslinked TCF shows high chemical tolerance and remain conductive after submerged in strong acid or basic solutions. The crosslinked TCF exhibits a high transparency and conductivity with a high figure of merit factor of 515, much better than many AgNW-based TCF, and can be used for various optoelectronic applications.

Relationship between morphological and physical properties in nanostructured CuMnO2

In this study, crednerite CuMnO 2 nanostructures were prepared using a hydrothermal method at 100 °C with various amounts of NaOH mineralizator. Obtained nanostructured crednerite CuMnO 2 with monoclinic structure (space group C 2/ m ) exhibits two morphologies: nanobelts with lengths of 1–1.5 nm and thickness of 15–25 nm, and nanoplates with diameters of 50–70 nm. Comparative analyses of the prepared samples reveal a close relationship between morphological and physical properties of nanostructured CuMnO 2 . A low NaOH concentration promotes elongated crystal growth along the c-axis, resulting in nanobelt-shaped morphology. A strong base solution, on the other hand, promotes the formation of nanoplates. The different morphologies of nanostructured CuMnO 2 have different spectroscopic and magnetic properties. The Raman active A 1g mode at 637 cm −1 and a modified Curie-Weiss behavior characterize the nanobelt-shaped sample. This phase has two magnetic phase transitions: ferromagnetic at 9.2 K and antiferromagnetic at 42 K. The nanoplate-shaped sample, on the other hand, exhibits typical behavior as reported in the literature, namely the Raman active A 1g mode at 688 cm −1 and low-dimensional magnetism with antiferromagnetic ordering below 62 K. The variation in magnetic properties is presumably due to partial oxidation of Cu 1+ /Cu 2+ and Mn 3+ /Mn 4+ , as well as a change in Mn 3+ spin states from low-spin in nanobelt-shaped samples to high-spin in nanoplate-shaped samples. Both morphological and preferred crystal growth of nanostructured CuMnO2 can be tuned utilizing suitable amounts of NaOH mineralizator in the growth solution. A pure CuMnO2 phase of monoclinic structure has been prepared in the form of nanobelts with lengths up to 1.5 mm or nanoplates possessing 50–70 nm in diameter. The physical properties measurements imply distinct behaviour amongst these samples.The CuMnO2 nano-belts exhibit a Raman peak at a lower Raman number compared to that of the nanoplates. The nanobelt sample has been shown to be undergone two successive magnetic phase transitions: antiferromagnetically at 42 K and ferromagnetically at 9.2 K. The nanoplate samples have exhibited low-dimensional magnetic behaviour. The variation in the magnetic properties can be ascribed to the partial oxidation of Cu1+/Cu2+ and Mn3+/Mn4+. The variation of spin states of the Mn ions can be correlated with the change in the morphologies, i.e., from a low-spin state in the belt-shaped sample to a high-spin state in the plate-shaped samples. • Both morphological and preferred crystal growth of nanostructured CuMnO2 and then their physical properties can be tuned utilizing suitable amounts of NaOH mineralizator in the growth solution. Remarkably, a nanobelt CuMnO2 has been obtained for the first time. • Our experiments divulge that a pure CuMnO2 phase of monoclinic structure can been prepared in the form of nano-belts with lengths up to 1.5 mm or nanoplates possessing 50–70 nm in diameter. • The physical properties measurements imply distinct behaviour amongst these samples. The CuMnO2 nano-belts exhibits Raman peak at a lower Raman number compared to that of the nanoplates. • Regarding to the magnetic characteristics, the nanobelt samples have shown to be undergone into two successive magnetic phase transitions: antiferromagnetically at 42 K and ferromagnetically at 9.2 K. • The variation in the magnetic properties can be ascribed to the partial oxidation of Cu 1+ /Cu2+ and Mn 3+ /Mn4+. Remarkably, the variation of spin states of the Mn ions can be correlated with the change in the morphologies, i.e., from low-spin state in the belt-shaped sample to high-spin state in the plate-shaped samples.

Germanium silicon oxide achieves multi-coloured ultra-long phosphorescence and delayed fluorescence at high temperature

Colour-tuned phosphors are promising for advanced security applications such as multi-modal anti-counterfeiting and data encryption. The practical adoption of colour-tuned phosphors requires these materials to be responsive to multiple stimuli (e.g., excitation wavelength, excitation waveform, and temperature) and exhibit excellent materials stability simultaneously. Here we report germanium silicon oxide (GSO) – a heavy-metal-free inorganic phosphor – that exhibits colour-tuned ultra-long phosphorescence and delayed fluorescence across a broad temperature range (300 – 500 K) in air. We developed a sol-gel processing strategy to prepare amorphous oxides containing homogeneously dispersed Si and Ge atoms. The co-existence of Ge and Si luminescent centres (LC) leads to an excitation-dependent luminescence change across the UV-to-visible region. GSO exhibits Si LC-related ultra-long phosphorescence at room-temperature and thermally activated delayed fluorescence at temperatures as high as 573 K. This long-lived PL is sensitized via the energy transfer from Ge defects to Si LCs, which provides PL lifetime tunability for GSO phosphors. The oxide scaffold of GSO offers 500-day materials stability in air; and 1-week stability in strong acidic and basic solutions. Using GSO/polymer hybrids, we demonstrated colour-tuned security tags whose emission wavelength and lifetime can be controlled via the excitation wavelength, and temperature, indicating promise in security applications.

Three-dimensional acanthosphere-like hierarchical Co@graphitic carbon for dispersive magnetic solid-phase extraction of nitroimidazole

Herein, a magnetic three-dimensional acanthosphere-like hierarchical Co@graphitic carbon (3D Co@GC) is introduced as an efficient adsorbent for extraction of three nitroimidazoles (NMZs: metronidazole (MNZ), ornidazole (ONZ) and tinidazole (TNZ)) from environmental water and food samples. The proposed 3D Co@GC was synthesized by a simple template-free method, which consisted of plentiful freely arranged one-dimensional nanowires. The adsorption properties of 3D Co@GC for three NMZs were investigated systematically by adsorption kinetic and isotherm studies. 3D Co@GC exhibits good adsorption capacity and fast adsorption kinetics toward three NMZs by virtue of its unique hierarchical structure. In addition, it was also found that a bit of methanol can effectively elute the adsorbed NMZs, eliminating the need for other dangerous strong acid or base solutions. Thus, 3D Co@GC as adsorbent to extraction three trace NMZs followed by direct quantification detection of targets with high-performance liquid chromatography with ultraviolet–visible detector (HPLC-UV) was developed. The parameters of dispersed magnetic solid-phase extraction (d-MSPE) were optimized by univariate and multivariate methods (Box-Behnken design). This established method revealed wide linear range and low limits of detection. Furthermore, the satisfactory recoveries of NMZs (86.7–106.7%) were acquired in spiked river water, honey, milk, and muscle samples. This study might provide a potential strategy for the efficient extraction and sensitive analysis of trace NMZs in river water, honey, milk, and muscle samples.

Novel process design of desalination wastewater recovery for CO2 and SOX utilization

Desalination is one of the most effective methods of supplying industrial water. Desalination has evolved into a feasible water supply alternative that allows the use of ocean water, and desalination plants operate in many countries, including in arid areas. Therefore, a large amount of desalination wastewater is generated, which is discharged into the sea. Since highly concentrated mineral ions in desalination wastewater are useful substitutes for carbon dioxide (CO2) and sulfur oxide (SOx) utilization compared with limited feedstock, such as high-grade limestone, it is crucial to improve the utilization of metal ions by recovering desalination wastewater. This study presents a novel process of desalination wastewater recovery CO2 and SOx utilization. The proposed process model comprises the following four systems based on validated experimental data: electrolysis, metal ion separation, SOx capture and utilization (SCU), and CO2 capture and utilization (CCU). First, desalination wastewater was electrolyzed to obtain a strong basic solution through electrolysis. Second, during metal ion separation, magnesium and calcium ions in the wastewater were precipitated in the form of a metal hydroxide and separated by the basic solution. Third, the separated Ca(OH)2 was used for desulfurization and produced gypsum in the SCU system. Finally, CO2 in the desulfurized flue gas was captured by the strong basic solution and utilized as CaCO3 and MgCO3 in the CCU procedures. Consequently, about 91% CO2 is captured and utilized from flue gas, and the desulfurization efficiency is 99%. In addition, the maximum net profit of the proposed process is $ 73.23 per tonne of CO2, and it is profitable and suitable for large-capacity processes, compared with other alternative CCU processes.

Design and synthesis of novel pyridine-rich cationic covalent triazine framework for CO2 capture and conversion

The covalent triazine frameworks (CTFs) have great application prospects in gas adsorption and separation, pollutant adsorption and heterogeneous catalysis due to their high specific surface area, rich nitrogen content and high physicochemical stability. Moreover, the simultaneous introduction of Lewis acid active sites (cation part) and Lewis base active sites (halogen anion) into the structure of CTFs will not only increase the adsorption capacity of CO 2 , but also greatly improve the catalytic performance of the CO 2 cycloaddition reaction. Herein, two novel cationic CTFs (CCTFs) based on 1,3,5-Tris(4-cyanopyridinium-1-ylmethyl)-benzene tribromide (TPM) were successfully synthesized by using anhydrous ZnCl 2 as a catalyst and reaction medium to force the cyanide group into trimerization. The obtained CTF-TPMs with ample pyridine cationic sites have outstanding chemical and thermal stability even in strong acid and strong base solutions, high specific surface area (up to 1206 m 2 g −1 ) and high CO 2 adsorption capacity (up to 61.4 cc g −1 , at 1 bar and 273 K). In addition, in the absence of co-catalyst and noble metal, CTF-TPMs can synergistically catalyze the cycloaddition of CO 2 with epoxy compounds to form corresponding cyclic carbonates with the synergy effect of the pyridinium salts and halide ions. More importantly, the catalytic performance of CTF-TPMs and their structural framework basically remain unchanged after 5 times recycles, which makes them excellent practical application prospect. • Two novel cationic CTF-TPMs with pyridine-rich were successfully prepared. • The CTF-TPMs have outstanding chemical stability in strong acid and base solutions. • CTF-TPMs show high affinity and high adsorption capacity for CO 2 . • CTF-TPM-400 can effectively catalyze the CO 2 cycloaddition reaction. • CTF-TPM-400 exhibits excellent recycle stability for CO 2 cycloaddition reaction.

Effect of CTAB Ratio to the Characters of Mesoporous Silica Prepared from Rice Husk Ash in the Pyrolysis of a–cellulose

Due to its wide application, synthesizing silica through a cost-effective process becomes an attractive subject to be studied today. In this work, mesoporous silica (MS) was prepared from the highly available agricultural waste, rice husk ash (RHA), to be used as catalyst in the pyrolysis of a-cellulose. Silica was extracted from RHA through a reflux process in a strong base solution and arranged into a mesoporous structure by using cetyltrimethylammonium bromide (CTAB). To find a condition that produces a mesoporous support with the highest surface area and catalytic activity, the mole ratios of CTAB:SiO2 used during the preparation of MS were varied; 0.05:1; 0.1:1; 0.2:1. Afterwards, all prepared MS were characterized using Fourier Transform Infra Red (FTIR), Scanning Electron Microscope (SEM), and Surface Area Analyzer (SAA). Through he surface area analysis, it was found that MS materials possessed surface area, pore diameter, and pore volume that range from 600–970 m2.g−1, 3.5–4.7 nm, 0.7–1 cm3.g−1, respectively. The highest surface area, with over 970.80 m2.g−1, was obtained in MS support prepared by using CTAB:SiO2 mole ratio of 0.1:1. SEM images showed a coral reef-like surface morphology for all MS. In the pyrolysis of a-cellulose evaluated by Py-GCMS, aside from producing biofuel compounds, the use of MS was able to generate two-fold furan production, which is considered as a valuable compound in many chemical syntheses. This result highlights the potential of MS prepared from RHA to be used as a catalysis support material that is more economical for biofuel and other chemical production. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Gate Alignment of Liquid Water Molecules in Electric Double Layer.

The behavior of liquid water molecules near an electrified interface is important to many disciplines of science and engineering. In this study, we applied an external gate potential to the silica/water interface via an electrolyte-insulator-semiconductor (EIS) junction to control the surface charging state. Without varying the ionic composition in water, the electrical gating allowed an efficient tuning of the interfacial charge density and field. Using the sum-frequency vibrational spectroscopy, we found a drastic enhancement of interfacial OH vibrational signals at high potential in weakly acidic water, which exceeded that from conventional bulk-silica/water interfaces even in strong basic solutions. Analysis of the spectra indicated that it was due to the alignment of liquid water molecules through the electric double layer, where the screening was weak because of the low ion density. Such a combination of strong field and weak screening demonstrates the unique tuning capability of the EIS scheme, and would allow us to investigate a wealth of phenomena at charged oxide/water interfaces.

Using a simple method to prepare UiO‐66‐NH2/chitosan composite membranes for oil–water separation

AbstractChitosan (CS) was used as a cross‐linking agent to modify UiO‐66‐NH2, and the modified UiO‐66‐NH2 was fixed on the mixed cellulose membrane (MCE) through vacuum filtration technology to prepare a new type of membrane. The membrane exhibited excellent hydrophilicity in the air and excellent super‐oleophobic performance underwater, and effectively separated various oil–water emulsions. When separating petroleum ether‐water emulsion, the filtration flux of the modified membrane was 2000 L m−2 h−1 higher than that of MCE, and the separation efficiency can reach more than 95%. After 10 cycles, the flux of the modified membrane was about four times of that MCE, which was 500 L m−2 h−1. Most importantly, the membrane still maintained underwater superoleophobicity in the environment of strong acid, strong base, and salt solution.

Poly(ionic liquid)-crosslinked graphene oxide/carbon nanotube membranes as efficient solar steam generators

Graphene oxide (GO) is regarded as a promising candidate to construct solar absorbers for addressing freshwater crisis, but the easy delamination of GO in water poses a critical challenge for practical solar desalination. Herein, we improve the stability of GO membranes by a self-crosslinking poly (ionic liquid) (PIL) in a mild condition, which crosslinks neighbouring GO nanosheets without blemishing the hydrophilic structure of GO. By further adding carbon nanotubes (CNTs), the sandwiched GO/CNT@PIL (GCP) membrane displays a good stability in pH = 1 or 13 solution even for 270 days. The molecular dynamics simulation results indicate that the generation of water nanofluidics in nanochannels of GO nanosheets remarkably reduces the water evaporation enthalpy in GCP membrane, compared to bulk water. Consequently, the GCP membrane exhibits a high evaporation rate (1.87 kg m−2 h−1) and displays stable evaporation rates for 14 h under 1 kW m−2 irradiation. The GCP membrane additionally works very well when using different water sources (e.g., dye-polluted water) or even strong acidic solution (pH = 1) or basic solution (pH = 13). More importantly, through bundling pluralities of GCP membrane, an efficient solar desalination device is developed to produce drinkable water from seawater. The average daily drinkable water amount in sunny day is 10.1 kg m−2, which meets with the daily drinkable water needs of five adults. The high evaporation rate, long-time durability and good scalability make the GCP membrane an outstanding candidate for practical solar seawater desalination.

Simple and scalable synthesis of super-repellent multilayer nanocomposite coating on Mg alloy with mechanochemical robustness, high-temperature endurance and electric protection

Multi-functionalization is the future development direction for protective coatings on metal surface, but has not yet been explored a lot. The effective integration of multiple functions into one material remains a huge challenge. Herein, a superhydrophobic multilayer coating integrated with multidimensional organic-inorganic components is designed on magnesium alloy via one-step plasma-induced thermal field assisted crosslinking deposition (PTCD) processing followed by after-thermal modification. Hard porous MgO ceramic layer and polytetrafluoroethylene (PTFE) nano-particles work as the bottom layer skeleton and filler components separately, forming an organic-inorganic multilayer structure, in which organic nano-particles can be crosslinked and cured to form a compact polymer-like outer layer with hierarchical surface textures. Remarkably, the chemical robustness after prolonged exposure to aqua regia, strong base and simulated seawater solution profits from polymer-like nanocomposite layer uniformly and compactly across the film bulk. Moreover, the self-similar multilayer structure coating endows it attractive functions of strong mechanical robustness (>100th cyclic rotary abrasion), stable and ultra-low friction coefficient (about 0.084), high-temperature endurance, and robust self-cleaning. The organic-inorganic multilayer coating also exhibits high insulating property with breakdown voltage of 1351.8 ± 42.4 V, dielectric strength of 21.4 ± 0.7 V/µm and resistivity of 3.2 × 1010 Ω·cm. The excellent multifunction benefits from ceramic bottom skeleton, the assembly and deposition of multidimensional nano-particles, and the synergistic effect of organic inorganic components. This study paves the way for designing next generation protective coating on magnesium alloy with great potential for multifunctional applications.

The effect of ion exchange membranes on the bipolar membrane electrodialysis of ammonium chloride wastewater

The different bipolar membranes and their configurations with monopolar ion exchange membranes from different manufacturers such as FAB-FBM-FKB, AHA-(BP-1E)- CMB, and JAM-(BMP-1)-JCM are used in the bipolar membrane electrodialysis (BMED) of simulated NH4Cl wastewater to examine the effect of membrane properties on the generation of HCl and NH3∙H2O. The results indicated that the configuration of AHA-(BP-1E)-CMB presented the promising performance among all the ion exchange membranes according to the generated acid and base concentration. And the configuration of FAB-FBM-FKB presented the expected performance on the membrane stack voltage, energy consumption, current efficiency of the BMED system. The stability of different ion exchange membranes in strong acid and base solution were investigated further by the analyses of SEM, contact angle and membrane resistance. It was found that the membranes AHA and FKB had better chemical stability than other membranes.