Separation Efficiency Research Articles

Hybridizing engineering strategy of decatungstate III: Transition metal modified carbon quantum dot-regulated photo-catalytic oxidation performance of decatungstate

The selective oxidation of hydrocarbons (RH) by dioxygen (O2) is a very important method for industrial production of bulk oxygen-containing compounds, However, due to the high chemical inertness of RH and O2, achieving this reaction under mild conditions still faces significant challenges. This paper discloses an efficient hybridizing engineering (HE) strategy of decatungstate (DT) with 3d transition metal ions (Mn+=Ni2+, Co2+ or Cu2+)-modified carbon quantum dots (Mn+/CQD) as the dopants. Compared to pure CQD, The Mn+/CQD can more efficiently combine with DT anion to fabricate a high-quality hybrid via electrostatic interactions, thereby bestowing the hybrid with an enhanced visible light response especially the separation efficiency of photo-generated charge pairs. Furthermore, the above hybridization effects of Mn+/CQD on DT anion can be fine-tuned and gradually improved with a change of the metal ion from Cu2+, Co2+ to Ni2+, along with a continuous enhancement of the hybrid's photo-catalytic efficiency in the visible light- triggered selective oxidation of ethylbenzene with O2 in acetonitrile. The best Ni2+/CQD-doped TBADT can achieve ca. 48% ethylbenzene conversion and 87.6% acetophenone selectivity in the presence of 2 M HCl, and it also shows a much higher photo-catalytic activity for the photo-oxidation of toluene, cyclohexane and benzyl alcohol compared to pure TBADT. The HE strategy with Mn+/CQDs as the cationized hybridizers is much superior to that with pure CQD or Ni2+ as the hybridizer in hoisting the photo-catalytic performance of DT.

Synthesis of CdS QDs/NH2-Nb2O5 via electrostatic self-assembly method for highly efficient photocatalytic removal of NO and synchronous inhibition of NO2

A two-step electrostatic self-assembly method was used to first graft –NH2 groups onto the Nb2O5 followed by loading of CdS QDs onto the NH2-Nb2O5 to obtain CdS/NH2-Nb2O5. The performance of the samples under visible light was evaluated under simulated conditions of 25 °C and varying relative humidity (RHs). The results showed that with the increase of RH, the NO removal efficiency by CdS/NH2-Nb2O5 increased first and then decreased, reaching the maximum NO removal efficiency when RH = 50 %. The selectivity of NO2 on CdS/NH2-Nb2O5 (9.01 %) was significantly lower compared to that of Nb2O5 (24.44 %) and NH2-Nb2O5 (19.72 %). The introduction of –NH2 groups and CdS QDs significantly enhanced visible light absorption and improved the separation efficiency of photogenerated charge carriers. In-situ DRIFTS analysis revealed that Cd2+ served as an additional active site for NO adsorption. Furthermore, CdS had a relatively negative conduction band position, which was conducive to the generation of O2–, further inhibiting the generation of NO2. This work provides a new approach to the design and preparation of catalysts for photocatalytic oxidation of NO.

A Ni-Based Metal Hydroxide-Organic Framework Mesh Membrane with Ultra-Durable Underwater Superoleophobicity for High-Efficient Oil/Water Separation

Recently, MOF-based oil/water separation membranes with superwettability have attracted great attention in the treatment of oily wastewater due to their uniform chemical composition and intrinsic porosity. However, the real separation performance is still limited by broking the metal-ligand bonds of conventional MOF materials in extreme chemical and mechanical environments, such as acidic, alkaline, saline, organic, and abrasion. Herein, we provide a metal hydroxide-organic framework (MHOF) composite mesh membrane for high-efficient oil/water separation by simply growing Ni2(OH)2 clusters onto a polydopamine (PDA)-modified stainless-steel mesh (SSM). Compared with conventional MOF materials, our membrane possesses ultra-durable underwater superoleophobicity by taking advantages of its strong chemical bridging, rich hydrophilic groups, and rough surface morphology, which enables a 1 μL water droplet to spread to 0° contact angle within <100 ms and also obtains an ultra-low underwater oil adhesion force ∼1.9 μN. Separation of both oil/water mixtures and oil-in-water emulsions can be achieved by this Ni-based MHOF mesh membrane with high separation efficiency >99.7% and large permeate flux >57,000 L·m-2·h-1. Furthermore, the Ni2(OH)2@PDA-SSM mesh membrane exhibits excellent anti-oil-fouling, chemical stability and abrasion resistance, which shows a promising candidate for practical applications. This study provides a rational strategy to construct high-performance MHOF membranes for oil/water separation.

Na-doped nitride-rich carbon nitride for efficient photocatalytic NO abatement

Nitride-rich carbon nitride (C3N5) is gaining prominence as a substantial catalyst for photocatalytic reaction because of its narrow bandgap, extensive light responsiveness, and photocatalytic stability. To enhance the efficiency of photogenerated carrier separation in C3N5, we propose a strategy for Na-doped modification. Photocatalytic NO removal efficiency of C3N5/Na achieved 73.9 % under 15 % relative humidity, which is 3.5 times higher than that of C3N5. Besides, the NO removal efficiency of C3N5/Na maintained above 70 % even after six cycles under different relative humidities. Detailed analytical characterization revealed that Na doping of C3N5 not only increased its specific surface area by 5.5-fold but also modulated its energy band structure and molecular structure, leading to improved hole-carrier separation efficiency and enhancing the photocatalytic performance of C3N5/Na. ESR and reactive species trapping experiments confirmed that electrons and superoxide are the main reactive species, and modulation of the energy band structure accelerates the reaction. This work explains the effect of Na doping on C3N5 and provides a new strategy for designing efficient for photocatalytic treatment of air pollution.

A stability-indicating method development and validation for the determination of related substances in novel synthetic decapeptide by HPLC.

In the present scenario, peptide is an emerging field of research having vast therapeutic applications. Diverse impurities may rise from various stages of the synthesis process and storage of the peptides. Because these contaminants may have an impact on the therapeutic safety and effectiveness of peptides in their approaching applications, they must be identified and carefully monitored. Considering the pharmaceutical importance of the extent of peptides, we were motivated to synthesize a decapeptide and establish a novel gradient reversed-phase high-performance liquid chromatography (RP-HPLC) method for its analysis along with efficient separation of its six related impurities. Different buffers, organic modifiers, and columns were used in the tests for good separation of these impurities. To establish a stability-indicating method, a stress study was also conducted. The International Conference on Harmonization (ICH) guidelines have been followed for validation of the developed analytical method. The validated method revealed sufficient accuracy, specificity, linearity, robustness, precision, and high sensitivity for its intended use. The proposed method could be appropriate for routine analysis and stability assessment of the decapeptide, which might be useful for further scientific investigation.

Multifunctional aluminum 12-hydroxystearate/lignin polyurethane foam for selective gelation and efficient separation of oil and organic solvents

During frequent transportation, the marine environment is continuously exposed to significant threats from crude oil and organic solvent leakage. Non-covalent self-assembly of organogelator on the adsorbent matrix to fix non-polar solvents is an efficient and sustainable remediation method. This contribution proposes an organogelator-adsorbent composite by blending aluminum 12-hydroxystearate (Al HSA) and expanded graphite (EG) during lignin-based polyurethane foaming. Al HSA molecule synergizes with EG to modulate the shape (hexagonal), oil retention, mechanical property, and hydrophobicity (water contact angle = 151.3°) of the lignin-based polyurethane foam (LPUF) skeleton. Al HSA-LPUF (OTS-LPUF/EAH) superhydrophobic foam exhibits sorption capacity up to 13.2–53.0 g g−1 in various oils and organic solvents. From the microscopic morphology, the Al HSA on the skeleton self-assembles into spherical nanoclusters driven by hydrogen bonding, realizing the capturing of oils and organic solvents. Even after 20 cycles, the foam still has a high oil/water separation capacity and mechanical performance. OTS-LPUF/EAH also shows improved flame retardancy and a 61 % reduction in total smoke release (TSR) compared to pristine LPUF.

Vacancy defect and piezoelectric field assisted photocatalytic performance of BiO(Cl1/3Br1/3I1/3)x for the degradation of organic pollutants

Semiconductor photocatalysts have been widely researched in wastewater treatment of organic dyes, among which bismuth halide semiconductors have shown great application prospects due to their unique layered structure and diverse micromorphology. As for photocatalysis, high concentration of photo-generated carriers and their effective separation are considered to be the key to obtain excellent photocatalytic performance. In view of the common issues of high bandgap energy and low carrier separation rate in bismuth halide, in this paper, the BiO(Cl1/3Br1/3I1/3)x catalysts with different proportions of Bi3+ and (Cl1/3Br1/3I1/3)- were designed and synthesized by hydrothermal method, through constructing hybrid energy levels and thus accomplishing by multi-halogen doping to widen the light absorption range. For another, the efficient separation of electrons and holes was achieved in BiO(Cl1/3Br1/3I1/3)x in virtue of a built-in field stemmed from the intrinsic piezoelectric effect, and band tilting. Meanwhile, more active sites were induced by Vo•• and VBiʹʹʹ due to the directional impact of the built-in field. Ultimately, BiO(Cl1/3Br1/3I1/3)5/7 demonstrated the optimum catalytic performance under the combined light irradiation and ultrasonic vibration, with the degradation efficiency of MB reaching 91.28% in 60 min and the k of 0.0360 min-1, and 97.44% degradation efficiency of Rh B within 18 min and the k of 0.1565 min-1 together with excellent cycling stability. The prepared BiO(Cl1/3Br1/3I1/3)5/7 catalyst has a huge application potential for the degradation of wastewater, taking full advantage of environmental vibration energy and light energy.

Synergistic effects of advanced MoSe2/MnO2 nanocomposite for direct yellow dye degradation for enhanced photocatalytic applications

MoSe2, a significant component within the class of two-dimensional transition metal dichalcogenides (TMDCs), boasts diverse photocatalysis characteristics. Herein, this research focuses on the hydrothermal approach to fabricate and thoroughly characterize Molybdenum diselenide (MoSe2) nanoparticles and Manganese dioxide (MnO2) nanoflakes as their co-catalyst with controllable morphologies size and enhanced photocatalytic activity. The samples were advanced characterizations such as SEM and HR-TEM to examine morphology, Powder X-ray diffraction (PXRD) to validate phase and crystal structure, Fourier transform infrared (FTIR) spectroscopy for analysing functional groups and bonds, and XPS for insights into elemental composition and chemical state of the nanocomposite. Due to the efficient separation of photogenerated electron-hole pairs facilitated by the rapid transfer of electrons by the addition of MnO2 and MoSe2/MnO2 nanocomposite demonstrates significantly enhanced photocatalytic performance and excellent stability in Direct Yellow (DY), a common pollutant found in industrial effluents. The MoSe2/MnO2 nanocomposite photocatalytic activity was 1.2 to 1.6 times higher than that of its individual components of MoSe2 and MnO2, indicating synergistic effects leading to enhanced performance. Consequently, this study illustrates that the MoSe2/MnO2 nanocomposite effectively degrades direct yellow dye under base conditions through photocatalysis.

A microporous fluorinated MOF for efficient separation of C2H2 from C2H2/CO2 and C2H2/C2H4 mixtures

Acetylene (C2H2)-adsorbed physisorbents are promising in addressing significant yet challenging industrial separation processes, such as the purification of C2H2 from carbon dioxide (CO2) and ethylene (C2H4) from C2H2. Herein, we report a fluorinated metal–organic framework (MOF), QDU-MOF-1, featuring micropores full of fluorinated anions, which enables preferential C2H2 adsorption over CO2 and C2H4. QDU-MOF-1 exhibits a high C2H2 adsorption capacity of 141.03 cm3/g at 298 K and 1 bar. Dynamic breakthrough experiments demonstrate a C2H2 capture capacity of 127.76 cm3/g for equimolar C2H2/CO2 mixtures. Strong affinity was revealed by density functional theory calculations between C2H2 and SiF62- in pores through hydrogen bonding, contributing to high C2H2 adsorption capacity. QDU-MOF-1 also shows good air stability and recyclability, making it potential for the C2H2/CO2 and C2H2/C2H4 separation applications. This study underscores the strength of discovering advanced physisorbents for challenging gas separations with low energy footprints.

Efficient Li+/Mg2+ separation by two-dimensional montmorillonite membrane with stable channel structure through ion exchange and metal–organic coordination strategy

Two-dimensional (2D) nanochannel membranes stacked by nanosheets are promising membrane separation materials. However, intrinsic swelling properties of 2D membrane have emerged as a significant challenge to establish stable nanochannels and achieve high separation performance. Inspired by the natural ion exchange property of montmorillonite (MMT), we constructed a two-dimensional MMT membrane with robust nanochannels by exchanging Fe3+ into interlayer of the membrane, and further achieved efficient separation of Li+/Mg2+ through coordination manipulation of tannic acid (TA) and Fe3+. Swelling was dramatically prevented by strong interlayer interaction between exchanged Fe3+ and nanosheets resulting in a 32-fold increase in anti-swelling properties. Furthermore, experiments and simulations revealed that TA could rapidly chelate with Fe3+ to form a dense hydrophilic functional layer on the membrane interface, which endowed MMT membranes with enhanced mechanical strength, cation transport and recognition, as well as anti-fouling properties. Consequently, the resulting MMT membranes showed the Li+/Mg2+ selectivity as high as 9.98 with a fast Li+ permeation rate (0.108 mol m-2h−1), which exceeded most of the previously reported membranes. This study proposed a novel strategy to diminish the trade-off effect among stability, ion flux, and selectivity of membranes, and inspired the development of next-generation ion selective separation membranes.

Controllable H2S supply via membrane contactors for safe and efficient arsenic precipitation from acidic wastewater

Sulfide precipitation is a popular technique for the treatment and resource recovery of arsenic-containing dirty acid wastewater. However, this approach frequently suffers from toxic hydrogen sulfide (H2S) escape and agent wastage issues. Herein, a safe and efficient technique is proposed based on a polytetrafluoroethylene membrane contactor wherein the mass transfer resistance of the gas, membrane, and liquid phases can be easily and independently regulated to control the H2S supply. Additionally, H2S is transferred in bubble-free form, fundamentally avoiding the issue of gas escape, and uniform membrane distribution contributes to evenly distributed H2S delivery. The results demonstrated that 99.3% arsenic precipitation could be achieved and the H2S emission ratio was limited to <0.12%, which was significantly better than traditional methods. Thus, highly efficient separation and resource recovery of heavy metals in wastewater can be achieved using this unique and controllable low-dose H2S supply method. The separation factor between copper and arsenic was as high as 7490.9. This study provides a safe, reliable, and promising new approach for the treatment of arsenic-containing acidic wastewater.

Efficient Photocatalytic Degradation of Humic Acid in Water Using N‐Doped Ti3AlC2 MAX

AbstractHumic acid (HA) is the main precursor of carcinogenic compounds such as trichloromethane, which form during the disinfection of drinking water. Therefore, removing HA from water sources is crucial for producing safe drinking water. This study introduces a novel approach using dilute nitric acid as a nitrogen source to dope pristine Ti3AlC2 (TAC) to varying degrees, enhancing the material‘s photocatalytic degradation performance for HA. Characterisations through X‐ray diffraction, Fourier transform infrared, scanning electron microscopy, UV–vis and X‐ray photoelectron spectroscopy revealed that the surface morphology of the modified catalyst changed from an original blocky lamellar structure to a rod‐like cluster structure, which is advantageous for light trapping. In addition, the incorporation of nitrogen reduced the band gap of the material from 1.25 to 1.15 eV, considerably enhancing its overall light responsiveness and thereby improving its photocatalytic performance. The results demonstrated that the photocatalytic degradation efficiency of HA by TAC under optimal conditions reached 93.8 %, which is 4.3 times higher than the 21.8 % efficiency achieved using the undoped TAC material. The enhanced photocatalytic activity is attributed to N doping, which not only reduces the TiO2 band gap at the TAC surface but also improves the electrochemical behaviour of TAC. This results in enhanced light response and more efficient separation of photogenerated electron–hole pairs. The mechanism for CTAC–Nx photocatalytic degradation of HA was investigated using trapping agent experiments, revealing that the primary active substance responsible for the degradation is O2−.

Flotation separation of ilmenite and titanaugite modified by Fe2+-assisted peroxymonosulfate oxidation: Performance and activation mechanism

Efficient separation of ilmenite and titanaugite has always been recognized challenge in modern mineral processing. The use of a heterogeneous Fenton-like oxidation process composed of peroxymonosulfate (PMS) and Fe2+ is promising to address this issue. Flotation findings indicated that effective recovery of ilmenite could be achieved under weak acidic conditions, and a TiO2 recovery of 81.56 % and a grade of 32.16 % concentrate was collected. A series of characterization analyses confirmed that the PMS-Fe2+-mediated Fenton-like reaction in the ilmenite system generated more •OH and SO4•- radicals, which oxidized Fe2+ to Fe3+ on its surface, thus improving the active sites on ilmenite surface. Moreover, PMS-Fe2+ promoted the positive shift of surface charge on ilmenite, facilitating NaOL adsorption and making the surface more hydrophobic. NaOL primarily interacted with Fe active sites on the ilmenite surface and Mg2+ and Ca2+ active sites on the titanaugite surface in the formation as chemisorption. Thus, PMS-Fe2+ activated ilmenite mainly via augmenting the quantity and reactivity of Fe active sites on the surface. In summary, these findings provide the innovative pathways to implement the advanced oxidation processes in mineral flotation.

Photocatalytic H2 production over CoxNi0.85-xSe decorated TiO2 S-scheme heterojunction

The construction of an S-scheme heterojunction facilitates the efficient separation of charges and preserves its high REDOX potential. In this study, a series of CoxNi0.85-xSe(x=0.05,0.1,0.2,0.3and0.4) and TiO2 nanoparticles were both prepared using solvothermal method, and then Co0.3Ni0.55Se was combined with TiO2 to form Co0.3Ni0.55Se/TiO2 heterojunction through a solvent evaporation strategy for efficient photocatalytic H2 production. It found that the H2 production rate of 10 wt%-Co0.3Ni0.55Se/TiO2 composite can reach 10,070.9 µmol∙g−1∙h−1 with TEOA as a sacrificial agent under a simulated sunlight irradiation, which is 307.9, 33.5and 3.3 times higher than those of pure Co0.3Ni0.55Se,TiO2 and 10 wt%-Ni0.85Se/TiO2, respectively. This enhanced performance is primarily attributed to the formation of an S-scheme heterojunction between TiO2 and Co0.3Ni0.55Se, which effectively enhances light absorption capacity and facilitates charge separation and migration during light irradiation processes. Especially, the S-scheme charge separation can retain the active REDOX capacity of electrons in the conduction band of CoxNi0.85-xSe and the holes in the valance band of TiO2, thereby promoting H2 generation. This study demonstrates that CoxNi0.85-xSe serves as a reducing photocatalyst that offers a viable approach for achieving ideal S-scheme heterojunctions.

Enhanced catalytic activity of modified g-C3N4 heterojunction for photocatalytic degradation of methylene blue from wastewater

Rapid recombination of photoinduced charge carriers and poor photocatalytic degradation performance greatly hinder the large-scale application of g-C3N4 photocatalysis. Therefore, the g-C3N4 is modified by BiPO4 to overcome its poor photocatalytic performance, which is investigated by methylene blue (MB) removal. The S scheme heterojunction is constructed by modifying g-C3N4 with BiPO4, which can effectively preserve the redox activities of holes and electrons on VB and CB, exhibiting good photocatalytic activity. Therefore, the modified g-C3N4 exhibits excellent photocatalytic activity with efficient separation of the photoelectron-hole, compared to pure g-C3N4 and BiPO4. The modified g-C3N4 exhibits large MB degradation removal of 96.7 %, which is significantly larger than the pure g-C3N4 (46.3 %) and BiPO4 (3.3 %) owe to synergy, respectively. The photodegradation rate constant of the modified g-C3N4 is 4.8 and 43 times larger than that of the pure g-C3N4 and BiPO4, respectively. The modified g-C3N4 still has large MB removal of 92.9 % after 5 cycles, indicating excellent stability and recyclability. The fractal density calculation of the modified g-C3N4 is investigated combined with LUMO and HOMO analysis. The MB photocatalytic degradation process follows the S scheme charge transfer mechanism, based on degradation mechanism analysis combined with semiconductor energy band and density functional theory calculation analysis. The MB photocatalytic degradation path is systemically analyzed based on MS-UPLC result analysis, which indicates that MB is finally decomposed into CO2 and H2O, achieving the degradation of MB.

Enhanced selective photocatalytic reduction and oxidation of perfluorooctanoic acid on Bi/Bi5O7I decorated with poly (triazine imide)

Perfluorooctanoic acid (PFOA) is detected widely in surface and groundwater globally. Its removal poses a significant challenge due to its high chemical stability. This study demonstrates efficient PFOA degradation using poly-triazine-imides-tailored defective Bi5O7I (PTI/BB). Under 300W Xe irradiation, 1µg·L-1 PFOA could be degraded to 9.86ng·L-1 after 3hours in the presence of 0.5g·L-1 25% PTI/BB. The mechanism investigation reveals that the oxygen vacancy (OV) in partially reduced Bi/Bi5O7I (BB) generates impurity states, enhancing the light-harvesting capacity. Furthermore, forming a type Ⅱ heterojunction between conjugated PTI and BB facilitates the efficient separation of photogenerated carriers. The resulting photogenerated electrons (reduction) and holes (oxidation) drive hydrogenation reduction and oxidative decarboxylation of PFOA, respectively. This synergistic effect consequently achieves significant defluorination of PFOA. The proposed PFOA degradation pathway via the PTI/BB catalyst offers new insights into the catalyst design for photocatalytic degradation of per- and polyfluoroalkyl substances (PFAS).

Investigating Dual Inlet Cyclone Separator Performance: Effects of Vortex Finder Diameter, Shape, and Particle Diameter on Separation Efficiency and Pressure Drop

The diameter and shape of the vortex finder of cyclone separator plays a significant role in separation efficiency and pressure drop. Currently, there have been many studies conducted on the shape and ratio of vortex finder of cyclone separator. This paper aims to compare numerical results of Raynold stress turbulence model RSM with K-ε RNG numerical analysis results and analyse the effect of further variation of the vortex finder diameter and shape of dual inlet cyclone separators. Five variation of vortex finder diameters namely 291mm, 310mm, 330mm, 348mm, and 366mm, four types of vortex finder shapes namely normal (cylindrical), spiral, divergent and spiral-divergent have been studied with different particle diameter and constant inlet velocity. The result obtained from this study suggests that increasing the vortex finder diameter have negative effect on separation efficiency. It also shows that increasing the vortex finder diameter consistently decrease the pressure drop. From the result, it is been found that the 291mm vortex finder has higher separation efficiency than the rest. Analysis with different vortex shapes, the spiral-divergent shape proved to be best in terms of separation efficiency.

Numerical study of influencing geometry of separator elements for cleaning dust of food production on its efficiency

At modern food enterprises, the task of providing high-quality air cleaning from dust is relevant. The paper proposes an original dust separator, the peculiarity of which is the presence of structural elements of different shapes, arranged in a chess order. This design solution ensures the formation of a wave-like structure of the gas-dust flow within the device. The separation of solids from air is due to inertial and centrifugal forces. The aim of the work is to evaluate the fractional efficiency of this separator with structural elements of different geometric shape during the dust capture process. The paper considers I-shaped, P-shaped, arc-shaped and V-shaped structural elements. The study is carried out by numerical simulation at a gas dust flow rate of 0.5 to 3 m/s and a particle size of 10 to 200 ?m. During the work it has been found that the shape of the structural elements largely determines the efficiency of separation of dust material from the gas stream. The V-shaped design elements have shown the highest average separation efficiency compared to other shapes under other equal conditions. This is due to the fact that in such a separator the particles are directed to their apex, where the velocity of the particles decreases contributing to their subsequent settling into the bunker. The maximum efficiency for V-shaped elements is on average 80.1 % at a gas dust inlet velocity of 0.5 m/s. The lowest efficiency is observed for I-shaped elements, as particles return to the air stream after rebounding from the walls.

In-situ construction of 3D/2D ZnIn2S4/Ni-MOLs: Highly efficient visible-light-driven photocatalytic heterojunction in hydrogen evolution

Photocatalytic water splitting for hydrogen production is a sustainable and environmentally friendly technology. However, the rapid recombination of photo-induced electrons and holes results in low hydrogen production activity of photocatalysts. Constructing low-cost and high-efficiency heterojunctions is an imperative strategy to address the current challenges in photocatalytic hydrogen production. This study presents a novel binary heterojunction photocatalyst constructed of ZnIn2S4 nanoflowers and Ni-MOLs nanosheets, which was successfully synthesized via an in-situ hydrothermal method. Furthermore, the ZnIn2S4/Ni-MOLs heterojunction exhibited an excellent visible light absorption performance, which was conducive to hydrogen production under visible light irradiation. Specifically, the optimized ZnIn2S4/Ni-MOLs exhibited a remarkable hydrogen evolution rate of 4.75 mmol·g−1·h−1 under visible light irradiation, which was about 95 times and 8 times higher than that of pure Ni-MOLs and ZnIn2S4, respectively. Additionally, the catalyst exhibited excellent stability in five recycling cycles test, and the apparent quantum efficiency (AQE) of the optimized ZnIn2S4/Ni-MOLs had reached 23.3 %. The formation of the ZnIn2S4/Ni-MOLs heterojunction significantly enhanced photocatalytic activity by promoting efficient charge carrier separation, exposing more active sites and enhancing absorption of visible light. The experimental characterization and density functional theory (DFT) calculations revealed that the synergistic effect within the ZnIn2S4/Ni-MOLs heterojunction significantly facilitated the directional transfer of electrons from ZnIn2S4 to Ni-MOLs, achieving efficient charge carrier separation. This study not only synthesized an efficient photocatalyst for hydrogen production under visible light but also provided a novel strategy for constructing effective and stable ZnIn2S4-based or MOLs-based heterojunction photocatalysts.

3D Covalent Organic Framework Membranes for Molecular Separations.

Membrane separation has become an indispensable separation technology in social production, playing an important role in drug production, water purification, etc. The key core of membranes lies in achieving efficient and precise sieving between substances. As a result, a typical trade-off arises: highly permeable membranes usually sacrifice selectivity and vice versa. To address this dilemma, long-term research has focused on comprehensive understanding and modelling of synthetic membranes at various scales. A significant advancement in this arena is the advent of three-dimensional covalent organic framework (3D COF) membranes, a novel category of long-range ordered porous organic polymer materials. Characterized by an abundance of interconnected channels, diverse pore wall properties, tunable structures, and robust thermal and chemical resilience, 3D COF membranes offer a promising approach for efficient substance separation. This review undertakes a meticulous investigation of the synthesis and physicochemical properties of 3D COF membranes, accentuating the underlying design principles, fabrication methods, and application attempts. A comprehensive assessment of their research trajectory and current standing in the field of membrane processes is provided. The review culminates in a forward-looking outlook, summarizing future research directions and highlighting the substantial potential of this innovative work to shape the future of efficient membrane separation processes.