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In the study, the reduced graphene oxide/graphitic Bi12O17Cl2–TiO2 heterojunctions sheet membrane(RGO/PDA/Bi12O17Cl2–TiO2) was fabricated by the dopamine modification and assembling the RGO/PDA/Bi12O17Cl2–TiO2 composites on the surface of commercial CA(cellulose acetate) membrane to degrade methylene blue (MB) and p-chlorophenol (4-CP) to harmless products. These membrane materials were comprehensively characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectra (DRS). The results showed that RGO/PDA/Bi12O17Cl2–TiO2 nanofiber membrane exhibited extremely high degradation performance with a good distribution of RGO/PDA/Bi12O17Cl2–TiO2 on the CA nanofiber membrane surface. Besides, the complete photodegradation of 100 mL MB (15 mg L−1) solution and 100 mL 4-CP (15 mg L−1) solution with artificial visible-light was achieved after 100 min and 160 min, respectively. The RGO/PDA/Bi12O17Cl2–TiO2-CA composite membrane revealed the ability of continuous and simultaneous flow-through separation of oil/water emulsion and degradation of soluble organic dye under visible-light irradiation in a short time. Moreover, the nanofiber membranes exhibited excellent stability and reusability for MB-containing oil–water mixed emulsion separation has great potential to be applied in industrial application.

In order to effectively solve the two major problems of photocatalyst recovery and membrane fouling, this research combines photocatalyst and membrane separation technology. In this study, the NH2-MIL-88B(Fe)/CDs@GO material with good photocatalytic properties was synthesized by hydrothermal method and mechanical stirring, and the photocatalytic membrane was obtained by vacuum filtration. The results show that the NH2-MIL-88B(Fe)/CDs@GO membrane can effectively intercept and degrade methylene blue (MB). After 10 cycles, the rejection rate of MB can still reach 99.5%, which is about 2.5 times of pure GO membrane (40%). After 15 min of visible light irradiation, the Flux recovery rate (FRR) of NH2-MIL-88B(Fe)/CDs@GO membrane can reach 95%, and the antifouling performance is excellent. In this study, the composite photocatalytic membrane shows excellent stability, photocatalytic performance and self-cleaning property, which is conducive to widening the application prospect of wastewater treatment.

A novel strategy to construct a visible-light-driven Z-scheme heterojunction catalyst was employed by crosslinking ZnAl-layered double hydroxide (ZnAl-LDH) nanosheets with the active phase on carbon nitride (g-C

In this work, the layered double hydroxide @ graphitic nitrogen carbide (LDH@g-C3N4@PDA) composite photocatalysts were fabricated by dopamine modification method. Then, the LDH@g-C3N4@PDA and graphene oxide (GO) composites were assembled on PVDF membrane to construct the photocatalytic self-cleaning composite membrane. The prepared PVDF/LDH@g-C3N4@PDA/GO composite membrane has excellent performance in contaminant separation and photocatalytic degradation. The rejection rates of methylene blue (MB), rhodamine b (RhB), gasoline, diesel, and petroleum ether were 100%, 94.61%, 96.74%, 93.22%, and 92.35%,respectively. More importantly, under visible-light irradiation, the membrane could achieve continuous and simultaneous flow-through separation and degradation of dye in short time. The rejection rate and the flux of organic dye were 99.28% and 397.14 L•m−2h−1bar−1. The photocatalytic cycle experiment, which has been repeated 10 times, have also revealed the stability and high efficiency of PVDF/LDH@g-C3N4@PDA/GO membrane on account of its superior photocatalytic self-cleaning function. Therefore, this self-cleaning composite membrane would have a range of applications in wastewater treatment.

A composite membrane based on a novel strategy was prepared which using graphene oxide (GO), UiO-66-NH2 and polyacrylic acid (PAA) as basic materials on the surface of nylon membrane by vacuum filtration self-assembly. The structure of the composite membrane was made of graphene oxide as vertical separation layer, the PAA@UiO-66-NH2 (PAA@UiO) embedding between GO as horizontal capture material. The PAA@UiO-66-NH2/GO (PAA@UiO/GO) membrane was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Compared with the GO membrane, PAA@UiO/GO membrane combined the effects of GO, UiO-66-NH2 and PAA, which significantly enhances the separation performance of dye wastewater. In particular, the PAA@UiO/GO membrane can achieve complete removal of MB, RB and CR while the fluxes during filtration process can reach about 100 L ∙ m - 2 ∙ h - 1 . At the same time, PAA@UiO/GO membrane almost retained stable removal rate on all dyes under extreme pH and ionic strength conditions. In addition, after 10 cycles of experiments, PAA@UiO/GO membrane retained a removal rate and a flux more than 95% and 85 L ∙ m - 2 ∙ h - 1 for all dyes, respectively. Compared to a composite membrane based on intercalation, the unique structure of PAA@UiO/GO membrane with a large number of adsorption sites and screening structures, resulting a better removal rate for dyes. Furthermore, PAA@UiO/GO membrane has a great potential in practical applications and a solution to balance trade-off effect.

The application of two-dimensional metal carbides (MXenes) in heavy metal processing has attracted more and more attention. In this experiment, using titanium carbide as a 2D platform, an atomic-scale 2D/2D adsorbent alk-MXene/LDH was constructed by in situ mechanical self-assembly and alkali-level intercalation to remove Ni2+. Due to its unique layered structure, the oxidized functional groups and available active binding sites of MXene nanoplatelets constitute a unique adsorbent for removing heavy metals in water. The adsorption capacity of alk-MXene/LDH adsorbent for Ni2+ was 222.717 mg/g. The efficiency of Ni2+ was 97.35%, and the synthesized material could efficiently remove Ni2+ under a wide range of pH conditions (pH = 5–13). The adsorption behavior was studied using Redlich-Peterson adsorption isotherms, pseudo-second-order kinetics and thermodynamic models. In this study, the adsorbent exhibited excellent reproducibility after 8 adsorption-desorption cycles. According to the experimental results and various characterizations, the mechanism of the adsorbent was revealed. This study indicates that the atomic scale 2D/2D large basal plane has great potential in adsorbents.

A novel photocatalytic membrane was prepared by using graphene oxide (GO), UiO-66-NH2 and Ag2CO3 as basic materials on the surface of PVDF membrane by vacuum filtration self-assembly. The prepared Ag2CO3@UiO-66-NH2/GO (AgCO@UiO/GO) membrane was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The AgCO@UiO/GO membrane possessed the photocatalytic effects, which significantly enhanced the separation effect of dyes and Cr(VI) wastewater. In particular, the AgCO@UiO/GO membrane can achieve complete removal of MB, RB,MR and Cr(VI) under light conditions maintaining the fluxes during filtration process reach about 50 L · m−2 · h−1. In addition, after long-time experiments, the AgCO@UiO/GO membrane retained a higher removal rate and maintained a high flux under light conditions than without light for all dyes and Cr(VI). The unique structure of AgCO@UiO/GO membrane with a large number of screening structures and photocatalytic activity resulting a better removal rate for pollutants and reducing membrane fouling. Furthermore, the AgCO@UiO/GO membrane shows a great potential in improving membrane removal performance and a solution to balance trade-off effect.

The graphene-based film is an interlayer separation film having a special mass transfer property. In this study, a novel TiO2 nanorod inserted graphene-based membrane on a CA (Cellulose Acetate) mat was fabricated by a vacuum filtration method for water treatment application. The intercalated TiO2 nanorods expanded the interlamellar spacing among the graphene sheets and thus advanced the separation efficiency of graphene-based membrane, which exhibited a flux several times higher than some commercial nanofiltration membranes and an extremely high rejection especially for dyes, for MB (99.3%), Rhb (99.4%), MO (99.3%), CR (99.6%).

One of the major challenges in the removal of organic pollutants is to design a material with high efficiency and high flux that can remove both cationic and anionic dyes, oil-in-water (O/W) emulsion and heavy metal ions. Herein, we constructed novel chemically stabilized MgAl-layered-double-hydroxide/sepiolite (MgAl-LDH/Sep) composite membranes via 3D hierarchical architecture construction methods. These membranes were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD), etc. Benefiting from the presence of hydrophilic functional groups on the surface of the film, the membranes show an enhanced water flux (~1200 L&middot, m&minus, 2 h&minus, 1), while keeping a high dyes rejection (above 99.8% for anionic and cationic dyes). Moreover, the CA membrane coupled with MgAl-LDH/Sep exhibits a multifunctional characteristic for the efficient removal of mesitylene (99.2%), petroleum ether (99.03%), decane (99.07%), kerosene (99.4%) and heavy metal ion in water due to the layer-by-layer sieving. This hierarchical architecture is proved to have excellent environmental and chemical stability. Therefore, the membrane has potential in the treatment of sewage wastewater.

A one-pot strategy for the preparation of NH2-MIL-88B(Fe)/CDs composite was successfully developed via a simple solvothermal synthesis method. NH2-MIL-88B(Fe)/CDs composites were characterized by XRD, FT-IR, SEM, TEM, XPS, UV–vis DRS, PL, transient photocurrent response and Mott-Schottky plots. The synthesized NH2-MIL-88B(Fe)/CDs composites exhibit stronger photocatalytic activity than the original NH2-MIL-88B(Fe) in both photoreduction of Cr(VI) and photodegradation of MB. This is mainly because on the one hand, there is an interaction at the interface between CDs and NH2-MIL-88B(Fe), and on the other hand, CDs in the composite as local electron acceptors can effectively enhance charge transfer and inhibit electron-hole recombination. The experimental results show that the pH value greatly affects the reduction efficiency of Cr(VI) over photocatalyst, and the addition of hole trapping agent is beneficial to photocatalytic reduction. Moreover, we have proposed the possible photocatalytic mechanism on composites through trapping experiments of active species. Importantly, cycling experiments have also revealed that NH2-MIL-88B(Fe)/CDs photocatalysts have good chemical stability and reusability, and have broad industrial application prospects.

A novel strategy to construct a visible-light-driven Z-scheme heterojunction catalyst was employed by crosslinking ZnAl-layered double hydroxide (ZnAl-LDH) nanosheets with the active phase on carbon nitride (g-C3N4) substrates via a polydopamine bridge (a similar "bridge" structure). In this paper, multiple optical and electrochemical detection methods indicated that the 0.5P-LDH_500CN photocatalyst demonstrated excellent visible-light absorption properties, photo-generated electron-hole separation ability and photocatalytic activity for p-nitrophenol under visible-light (> 420 nm), etc. A Z-scheme charge transfer mechanism via PDA bridge was proposed to achieve heterojunction charge separation. This mechanism involved the recombination of photo-induced electrons directly on the ZnAl-LDH_500 valence band through the PDA channel and the holes were captured at the conduction band energy level of the g-C3N4. The detection of active species, including O2-, h+ and OH, further proofed the Z-scheme charge transfer mechanism, which could be speculated that all active species affected the photocatalytic reaction with the order of h+ > OH > O2-. Meanwhile, this work also exposed that the formation of active phase in ZnAl-LDH could synergize with PDA to promote the application of visible-light-active photocatalysts based on g-C3N4 materials in high-efficiency energy.

Herein, by vacuum-filtered an aqueous sepiolite/graphene oxide (Sep/GO) dispersion on polyvinylidene fluoride (PVDF) microfiltration membrane, and embedded the Sep nanofibers between adjacent GO nanosheets to expand the mass transfer channel and create hierarchical nanostructures on the membrane surface. Accordingly, the pure water flux increased from 7.2 L m−2 h−1 bar−1 of the GO membrane to 531.75 L m−2 h−1 bar−1 of the Sep/GO membrane, which was greatly improved. Sep/GO membranes are effective in separating oil-in-water emulsions because of their good oil/water selectivity and low oil adhesion, with high separation efficiency and relatively high flux. In addition, the membrane maintains underwater superoleophobicity and superior stability in harsh environments. It is worth mentioning that Sep/GO membrane can also separate dyes (methylene blue, Congo red) and some heavy metal ions (Fe3+, Cu2+) from aqueous solution to achieve multifunctional water treatment. Sep/GO membrane is not difficult to fabricate and has broad prospects for multifunctional wastewater treatment.

In this work, a multi-site adsorption inhibitor (DBI) was synthesized and characterized. The corrosion inhibition performance of symmetric benzyl lauric acid imidazoline quaternary ammonium salt under 1 M hydrochloric acid (HCl) condition was studied by weight loss test, potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS), SEM and XRD techniques. The experiment results have shown that the inhibition efficiency increases with an increase in an inhibitor concentration. Potentiodynamic polarization showed that this inhibitor is an anodic-type inhibitor. It is proved that the corrosion inhibitor has high surface properties and good adsorption performance on the surface of P110 steel through the contact angle and surface tension test. Furthermore, the adsorption of the corrosion inhibitor conforms to the Langmuir's adsorption isotherm on the surface of P110 steel.