Sustainable and Rapid Water Purification at the Confined Hydrogel Interface.

Emerging organic contaminants in water matrices have challenged ecosystems and human health safety. Persulfate-based advanced oxidation processes (PS-AOPs) have attracted much attention as they address potential water purification challenges. However, overcoming the mass transfer constraint and the catalyst's inherent site agglomeration in the heterogeneous system remains urgent. Herein, the abundant metal-anchored loading (≈6-8 g m-2) of alginate hydrogel membranes coupled with cross-flow mode as an efficient strategy for water purification applications is proposed. The organic flux of the confined hydrogel interfaces sharply enlarges with the reduction of the thickness of the boundary layer via the pressure field. The normalized property of the system displays a remarkable organic (sulfonamides) elimination rate of 4.87 × 104 mg min-1 mol-1. Furthermore, due to the fast reaction time (<1 min), cross-flow mode only reaches a meager energy cost (≈2.21 Wh m-3) under the pressure drive field. It is anticipated that this finding provides insight into the novel design with ultrafast organic removal performance and low techno-economic cost (i.e., energy operation cost, material, and reagent cost) for the field of water purification under various PS-AOPs challenging scenarios.

Characterization of a chlorine resistant and hydrophilic TiO2/calcium alginate hydrogel filtration membrane used for protein purification maintaining protein structure.

The development of membranes for protein purification has stringent requirement of disinfection resistance, low protein adsorption and anti-fouling, without changing protein structure. In this study, hydrophilic titanium dioxide (TiO2)/calcium alginate (TiO2/CaAlg) hydrogel membranes were prepared by a simple ionic cross-linking method. The effects of the porogenic agent polyethylene glycol (PEG) concentration, the molecular weight of PEG, and the concentration of TiO2 on the filtration properties were systematically investigated. The TiO2/CaAlg membrane exhibited excellent bovine serum albumin (BSA) rejection and anti-fouling properties. The mechanical properties and surface energy of the TiO2/CaAlg membrane were significantly improved. The chemical bonding mechanism of TiO2 and NaAlg was investigated by molecular dynamic simulation. The TiO2/CaAlg membrane had good chlorine resistance and could be disinfected or cleaned with sodium hypochlorite. The TiO2/CaAlg hydrogel membrane loaded with polyhydroxybutyrate (PHB) nanofibers maintained high flux (136.7 L/m2h) and high BSA rejection (98.0 %) at 0.1 MPa. The results of circular dichroism and synchronous fluorescence indicated that the secondary structure of BSA was maintained after membrane separation. This study provides one method for the preparation of green and environmentally friendly membrane for protein purification.

Mussel- and nacre-inspired dual-bionic alginate-based hydrogel coating with multi-matrix applicability, high separation stability and antifouling performance for oil/water separation.

Natural hydrogel-modified porous matrices with superwetting interfaces are ideal for oil/water separation. In this study, inspired by two marine organisms, a novel hydrogel coating with multi-matrix suitability, high oil/water separation capability and antifouling properties was developed. Specifically, inspired by mussel byssus, hydrogel coating was successfully deposited on porous matrix surface based on the introduction of tannic acid (TA). Moreover, inspired by the "brick and mortar" microstructure of Pinctada nacre, silica particles were in-situ synthesized in the sodium alginate (SA)/Ca2+ hydrogel to provide the filling effect and to increase strength. Furthermore, Sodium alginate-tannic acid-tetraethyl orthosilicate (SA-TA-TEOS) hydrogel coating-modified membrane exhibited super-hydrophilic and underwater super-oleophobic performance (underwater oil contact angle >150°), and achieved efficient oil/water separation for four oil/water emulsions (flux = 493-584 L·m-2·h-1 and rejection = 97.3-99.5 %). The modified membrane also demonstrated good anti-fouling performance and flux recovery. Notably, hydrogel coating-modified non-woven fabric also had high oil/water separation capacity (rejection >98 %) and cyclic stability, which proved the universal applicability of this hydrogel coating. In short, this work provides new insights into the fabrication of hydrogel coating-modified porous materials based upon a marine organism biomimetic strategy, which has potential applications in separating oil/water emulsions in industrial scenarios.

LncRNA HOXA-AS2 Promotes Temozolomide Resistance in Glioblastoma by Regulated miR-302a-3p/IGF1 Axis.

Background: Glioblastoma (GBM) is a highly prevalent brain tumor characterized by high rates of morbidity, recurrence, and mortality. While temozolomide (TMZ) is commonly used as a first-line treatment for this cancer, the emergence of TMZ resistance limits its utility. The long noncoding RNA HOXA-AS2 reportedly drives GBM progression, but whether it can influence therapeutic resistance to TMZ has yet to be established. Methods: HOXA-AS2 expression was analyzed in TMZ-resistant and sensitive GBM tissue samples and cell lines by qPCR. A siRNA-based approach was used to knock down HOXA-AS2 in GBM cells, after which TMZ resistance was tested. Bioinformatics approaches were used to predict miRNA binding targets of HOXA-AS2, after which a series of luciferase reporter assay and rescue experiments with appropriate miRNA inhibitor/mimic constructs were performed to validate these predictions and to clarify the ability of HOXA-AS2 to regulate chemoresistant activity. Results: TMZ-resistant GBM patients and cell lines exhibited increased HOXA-AS2 expression that was correlated with worse overall survival. Knocking down HOXA-AS2 increased the sensitivity of resistant GBM cells to TMZ. miR-302a-3p was identified as a HOXA-AS2 target confirmed through luciferase reporter assays and rescue experiments, and IGF1 was further identified as a confirmed miR-302a-3p target. In addition, HOXA-AS2 knockdown resulted in a corresponding drop in IGF1 expression consistent with indirect regulation mediated by miR-302a-3p. Conclusion: In summary, these results highlight the role of HOXA-AS2 as a driver of TMZ resistance in GBM through its ability to regulate the miR-302a-3p/IGF1 signaling axis, highlighting this pathway as a promising target for the diagnosis, therapeutic sensitization, and/or treatment of affected patients.

The Electrical Conductivity and Mechanical Properties of Monolayer and Multilayer Nanofibre Membranes from Different Fillers: Calculated Based on Parallel Circuit.

Advanced research on improving the performance of conductive polymer composites is essential to exploring their potential in various applications. Thus, in this study, the electrical conductivity of multilayer nanofibre membranes composed of polyvinyl alcohol (PVA) with different electroconductive fillers content including zinc oxide (ZnO), multiwalled carbon nanotubes (MWNTs), and Ferro ferric oxide (Fe3O4), were produced via electrospinning. The tensile property and electrical conductivity of monolayer membranes were explored. The results showed that PVA with 2 wt.% MWNTs nanofibre membrane has the best conductivity (1.0 × 10-5 S/cm) and tensile strength (29.36 MPa) compared with other fillers. Meanwhile, the combination of multilayer membrane ZnO/Fe3O4/Fe3O4/MWNTs/ZnO showed the highest conductivity (1.39 × 10-5 S/cm). The parallel circuit and calculation of parallel resistance were attempted to demonstrate the conductive mechanism of multilayer membranes, which can predict the conductivity of other multilayer films. The production of multilayer composites that enhance electrical conductivity and improve conductive predictions was successfully explored.

Engineering a superwetting membrane with spider-web structured carboxymethyl cellulose gel layer for efficient oil-water separation based on biomimetic concept.

Superhydrophilic and underwater superoleophobic membranes have recently attracted significant interest as materials for effective oil-water emulsion separation. In this work, a superwetting membrane with a spider web structured gel layer was designed for efficient oil-water separation. Biomaterial, carboxymethyl cellulose (CMC), was used as the raw material, a spider web structured gel layer was constructed on the PVDF membrane surface by heat-treatment and chemical cross-linking. The hydrophilic gel layer imparted excellent superhydrophilic and underwater superoleophobic properties to the membrane, while the special spider web structure improved the membrane mechanical stability. The fabricated membrane exhibited superhydrophilicity and underwater superoleophobicity. Among different CMC concentration-modified membranes, the M-0.5 membrane containing 0.5 wt% CMC exhibited a flux of 612 L·m-2 h-1 during dichloromethane oil-water emulsion separation, which was 4.2-fold higher than that of the pristine PVDF membrane, while the membrane showed efficient oil-water separation capacity. Additionally, the water flux recovery reached as high as 93.3 %, and oil rejection attained 99.1 %. Meanwhile, the spiderweb-structured gel layer on the membrane surface displayed good mechanical stability. In summary, this novel membrane-modification method, inspired by the spider web structure, was simple, cost effective and environmentally friendly, thereby making it promising for future preparation of highly efficient oil-water emulsion separation membranes.

High-strength and anti-bacterial BSA/carboxymethyl chitosan/silver nanoparticles/calcium alginate composite hydrogel membrane for efficient dye/salt separation.

In order to solve the problems of poor mechanical property, non-antibacterial and low flux of calcium alginate (CaAlg) membrane, silver nanoparticles (AgNPs) were synthesized with bovine serum albumin (BSA) and carboxymethyl chitosan (CMCS) for improving CaAlg membrane in this paper. Meanwhile, the dispersion property of silver nanoparticles and the mechanical property, thermal stability, antibacterial property and filtration efficiency of the composite membrane were explored. The results illustrated CMCS observably strengthened the mechanical property and thermal stability of the composite membrane, and AgNPs endowed the composite membrane with excellent antibacterial property. The flux of the BSA/CMCS/AgNPs/CaAlg composite membrane was raised compared to CaAlg membrane. Finally, the viscose fiber/polyethylene terephthalate fiber (VF-PET) nonwoven fabric was introduced as the support layer to further improve the filtration flux and mechanical property of the composite membrane. VF-PET/BSA/CMCS/AgNPs/CaAlg membrane had a rejection rate of over 99.0 % for dye molecules and <9.0 % for salt ions, while the flux maintained 38.5 L·m-2·h-1. Furthermore, VF-PET/BSA/CMCS/AgNPs/CaAlg membrane also had excellent separation effect on actual dye wastewater. The separation of dye and salt by the membrane mainly depended on the screening mechanism of membrane pore size, rather than adsorption. The composite membrane had an outstanding performance on the separation of dye molecules and inorganic salt ions.

Rapid determination of hemoglobin concentration by a novel ensemble extreme learning machine method combined with near-infrared spectroscopy.

A novel ensemble extreme learning machine (ELM) approach that combines Monte Carlo (MC) sampling and least absolute shrinkage and selection operator (LASSO), named as MC-LASSO-ELM, is proposed to determine hemoglobin concentration of blood. It employs MC sampling to randomly select samples from the training set and LASSO further to choose variables from selected samples to establish plenty of ELM sub-models. The final prediction is obtained by combining the predictions of these sub-models. Combined with near-infrared spectroscopy, MC-LASSO-ELM is used to determine the hemoglobin concentration of blood. Compared with ELM, MC-ELM and LASSO-ELM, MC-LASSO-ELM can obtain the best stability and highest accuracy.

Superhydrophobic Surface-Constructed Membrane Contactor with Hierarchical Lotus-Leaf-Like Interfaces for Efficient SO2 Capture.

An organic-inorganic polyvinylidene fluoride/polyvinylidene fluoride-silica (PVDF/PVDF-SiO2) mixed matrix membrane contactor is fabricated via a facile and efficient hydrophobic modification method. The solubility parameters of the PVDF particle are precisely regulated, the PVDF particles are blended with SiO2 nanoparticles to form PVDF-SiO2 suspension, and then the suspension is introduced onto the surface of the PVDF substrate by an in situ spin coating strategy. The PVDF particles are partly etched and incorporated to construct the adhesive PVDF-SiO2 core-shell layer on the PVDF substrate, which results in a more stable PVDF-SiO2 coating layer on the substrate. The surface structure is precisely regulated by changing the etching morphology of PVDF particles and amount of doped PVDF and SiO2 particles, forming an integrated porous PVDF-SiO2 layer and constructing hierarchical lotus-leaf-like interfaces. The resultant PVDF/PVDF-SiO2 membrane contactors display the relatively regular distribution of pore size with ∼420 nm and excellent hydrophobic property with a water contact angle of ∼158°, which noticeably lightens wetting phenomena of membrane contactors. The SO2 absorption fluxes can reach as high as 1.26 × 10-3 mol·m-2·s-1 using 0.625 M of ethanolamine (EA) as liquid absorbent. The high stability of the SO2 absorption flux test indicates the excellent interface compatibility between the PVDF-SiO2 coating layer and the PVDF substrate. The versatile organic-inorganic layer exhibits super hydrophobic property, which prevents wetting of membrane pores. In addition, the membrane mass transfer resistance (H/Km) and membrane phase transfer coefficient (Km) are explored.

Fabrication of pH-Sensitive Superhydrophilic/Underwater Superoleophobic Poly(vinylidene fluoride)-graft-(SiO2 Nanoparticles and PAMAM Dendrimers) Membranes for Oil-Water Separation.

The efficient treatment of oil-water emulsions under acidic condition remains a widespread concern. Poly(amidoamine) (PAMAM) dendrimer with hyperbranched structures and a large amount of primary and tertiary amino groups has exhibited advantages to solve this issue. Here, a novel poly(vinylidene fluoride)-graft-(SiO2 nanoparticles and PAMAM dendrimers) (PVDF-g-SiO2 NPs/PAMAM) membrane was fabricated using a surface-grafting strategy. SiO2 NPs were immobilized on PVDF-g-poly(acrylic acid) (PAA) membranes for improving the surface roughness, and PAMAM dendrimers were further immobilized on the membrane surface by interfacial polymerization (IP) for improving the surface energy. The obtained membrane demonstrated a water contact angle and a stable underwater-oil contact angle of 0° and >150°, respectively. These characteristics endowed the membrane with excellent water permeability [>3100 L/(m2·h) at 0.9 bar] and separation efficiency (>99%) during oil-water separation. Furthermore, the PAMAM chain will extend from a collapsed state into a fully extension state because of the protonation of amine groups under acidic condition, thus achieving a low underwater oil-adhesion property, fouling resistance, desirable stability, and recyclability (over 12 cycles) during usage. This work shows a promising prospect for the treatment of corrosive emulsions under acidic condition.

Modification of Supramolecular Membranes with 3D Hydrophilic Slide-Rings for the Improvement of Antifouling Properties and Effective Separation.

A three-dimensional (3D) strategy for the fabrication of ethylene vinyl alcohol (EVAL) membranes with a dynamic surface was developed based on sliding supramolecular polymer brushes (SSPBs). The SSPBs with a 3D hydrophilic structure were introduced into the alkyne-EVAL membrane matrix via an azide-alkyne click coupling reaction. The self-mobile hydrophilic slide-rings in the SSPB provided a proactive exclusion system. This resulted in reduced direct contact of the membrane surface with multiple pollutants such as bovine serum albumin (BSA) and oil droplets. The EVAL-SSPB membrane demonstrated increased surface hydrophilicity, underwater oleophobicity, and antifouling properties. More importantly, the abundant hydrophilic rings in the membrane matrix result in supramolecular assembly and efficient hydrophilic sliding channels. This resulted in a dramatic increase in the water flux [2000 L/(m2 h)] while retaining a 96% rejection of BSA and oil/water emulsions. The results of the study indicate that three effects of the cyclodextrins rings, i.e., the hydrophilic effect, the exclusion effect, and the sliding effect, enabled the improved membrane performance. The demonstrated 3D fabrication strategy is versatile, facile, and scalable, which allows for its application to various other membranes. The fabricated materials possess excellent permeability and separation efficiencies, which make them attractive candidates for use as separation membranes with novel functions.

Bioinspired EVAL membrane modified with cilia-like structures showing simultaneously enhanced permeability and antifouling properties.

A simple and effective strategy to simultaneously enhance the permeability and antifouling properties of ethylene vinyl alcohol (EVAL) membrane was developed based on the bioinspired natural cleaner, cilia. Taking clue from the self-cleaning effect of cilia, supramolecular polyrotaxanes (PRs) with sliding and rotating cyclic molecules along linear chains were synthesized using azide-alkyne click chemistry. Cilia-like PRs were incorporated into EVAL matrix in the fabrication of modified EVAL membranes. Cilia-like structures protruding from the membrane surface have been observed by SEM, TEM and AFM. By imitating natural ciliary movements, these structures provided a proactive self-cleaning system to remove the foulants. The introduction of cilia-like PRs enhanced the surface roughness and hydrophilicity, and significantly enhanced permeability by 55.3% compared to raw EVAL membrane. Moreover, the membrane modified with cilia-like PRs showed an excellent antifouling property with a lower water flux decline (12.6%) and higher water flux recovery (94%) in dynamic fouling tests. Furthermore, this modified membrane develops the scope of bioinspired membranes, inspiring more attractive potential applications in self-cleaning materials, dynamic membranes and supramolecular machines.

MicroRNA-193a-5p exerts a tumor suppressor role in glioblastoma via modulating NOVA1.

BACKGROUND AND OBJECTIVES: Glioblastoma (GBM) is the most common and lethal of intracranial tumors, which is characterized by extensive proliferation and the diffused invasion of tumor cells. MicroRNA-193a-5p (miR-193a-5p) have been demonstrated previously as a functional suppressor in the development and progression of various cancers. The current study aimed to investigate whether miR-193a-5p influences cell proliferation and migration through the mitogen-activated protein kinase/extracellular signal-regulated kinase signaling pathway by targeting neuro-oncological ventral antigen 1 (NOVA1) in glioblastoma. MATERIALS AND METHODS: The miR-193a-5p expression was detected by quantitative real-time polymerase chain reaction assay in GBM tissues and cell lines. Cell Counting Kit-8 assay, colony formation analysis, wound-healing, and transwell invasion assays were performed to evaluate cell proliferation, colony formation, migration, and invasion, respectively. Western blot analysis and luciferase reporter gene assay were performed to verify the downstream target gene of miR-193a-5p. RESULTS: The expression of miR-193a-5p was significantly downregulated in GBM tissues and cell lines. Kaplan-Meier analysis showed that patients with low miR-193a-5p expression had a shorter disease-free survival (P < 0.05). Functionally, miR-193a-5p overexpression dramatically suppressed the proliferation, colony formation, migration, and invasion in glioma cells. Bioinformatics prediction and a luciferase assay confirmed that NOVA1 was a direct functional target of miR-193a-5p. Moreover, ectopic expression of NOVA1 could partially reverse the inhibitory effects of miR-193a-5p on glioma cell proliferation, colony formation, migration, and invasion. NOVA1 overexpression abrogated the inhibitory effect of miR-193a-5p on the PTEN/PI3k/AKT pathway. CONCLUSION: Taken together, our findings suggested that miR-193a-5p functions as a tumor suppressor in glioma cells by directly targeting NOVA1.

Robust boosting neural networks with random weights for multivariate calibration of complex samples.

Neural networks with random weights (NNRW) has been used for regression due to its excellent performance. However, NNRW is sensitive to outliers and unstable to some extent in dealing with the real-world complex samples. To overcome these drawbacks, a new method called robust boosting NNRW (RBNNRW) is proposed by integrating a robust version of boosting with NNRW. The method builds a large number of NNRW sub-models sequentially by robustly reweighted sampling from the original training set and then aggregates these predictions by weighted median. The performance of RBNNRW is tested with three spectral datasets of wheat, light gas oil and diesel fuel samples. As comparisons to RBNNRW, the conventional PLS, NNRW and boosting NNRW (BNNRW) have also been investigated. The results demonstrate that the introduction of robust boosting greatly enhances the stability and accuracy of NNRW. Moreover, RBNNRW is superior to BNNRW particularly when outliers exist.

Synergistic effects of zeolite imidazole framework@graphene oxide composites in humidified mixed matrix membranes on CO2 separation.

In this study, composite nanosheets (ZIF-8@GO) were prepared via an in situ growth method and then incorporated into a polyimide (PI) matrix to fabricate mixed matrix membranes (MMMs) for CO2 separation. The as-prepared MMMs were characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analyses (TGA) and water uptake measurements. Water uptake measurements establish the relationship between the gas permeability and water uptake of membranes and an increase in the water uptake contributes to the CO2 permeability owing to an increase in the CO2 transport channels. The MMMs exhibit excellent CO2 permeability in when compared with an unfilled PI membrane in a humidified state. The ZIF-8@GO filled membranes can separate CO2 efficiently due to the ZIF-8@GO nanocomposite materials combining the favorable attributes of GO and ZIF-8. First, the high-aspect ratio of the GO nanosheets enhances the diffusivity selectivity. Second, ZIF-8 with a high surface area and microporous structure is beneficial to the improvement of the CO2 permeability. Third, ZIF-8@GO possesses synergistic effects for efficient CO2 separation. The MMM with 20 wt% ZIF-8@GO exhibits the optimum gas separation performance with a CO2 permeability of 238 barrer, CO2/N2 selectivity of 65, thus surpassing the 2008 Robeson upper bound line.

Novel affinity membranes with macrocyclic spacer arms synthesized via click chemistry for lysozyme binding.

Affinity membrane has great potential for applications in bioseparation and purification. Disclosed herein is the design of a novel affinity membrane with macrocyclic spacer arms for lysozyme binding. The clickable azide-cyclodextrin (CD) arms and clickable alkyne ethylene-vinyl alcohol (EVAL) chains are designed and prepared. By the azide-alkyne click reaction, the EVAL-CD-ligands affinity membranes with CD spacer arms in three-dimensional micro channels have been successfully fabricated. The FT-IR, XPS, NMR, SEM and SEM-EDS results give detailed information of structure evolution. The abundant pores in membrane matrix provide efficient working channels, and the introduced CD arms with ligands (affinity sites) provide supramolecular atmosphere. Compared with that of raw EVAL membrane, the adsorption capacity of EVAL-CD-ligands membrane (26.24mg/g) show a triple increase. The study indicates that three effects (inducing effect, arm effect, site effect) from CD arms render the enhanced performance. The click reaction happened in membrane matrix in bulk. The effective lysozyme binding and higher adsorption performance of affinity membranes described herein compared with other reported membranes are markedly related with the proposed strategy involving macrocyclic spacer arms and supramolecular working channels.

High and low frequency unfolded partial least squares regression based on empirical mode decomposition for quantitative analysis of fuel oil samples.

Accurate prediction of the model is fundamental to the successful analysis of complex samples. To utilize abundant information embedded over frequency and time domains, a novel regression model is presented for quantitative analysis of hydrocarbon contents in the fuel oil samples. The proposed method named as high and low frequency unfolded PLSR (HLUPLSR), which integrates empirical mode decomposition (EMD) and unfolded strategy with partial least squares regression (PLSR). In the proposed method, the original signals are firstly decomposed into a finite number of intrinsic mode functions (IMFs) and a residue by EMD. Secondly, the former high frequency IMFs are summed as a high frequency matrix and the latter IMFs and residue are summed as a low frequency matrix. Finally, the two matrices are unfolded to an extended matrix in variable dimension, and then the PLSR model is built between the extended matrix and the target values. Coupled with Ultraviolet (UV) spectroscopy, HLUPLSR has been applied to determine hydrocarbon contents of light gas oil and diesel fuels samples. Comparing with single PLSR and other signal processing techniques, the proposed method shows superiority in prediction ability and better model interpretation. Therefore, HLUPLSR method provides a promising tool for quantitative analysis of complex samples.

A supramolecular strategy for self-mobile adsorption sites in affinity membrane.

Disclosed here is the design of a novel supramolecular membrane with self-mobile adsorption sites for biomolecules purification. In the 3D micropore channels of membrane matrix, the ligands are conjugated onto the cyclic compounds in polyrotaxanes for protein adsorption. During membrane filtration, the adsorption sites can rotate and/or slide along the axial chain, which results in the enhanced adsorption capacity. The excellent performance of supra-molecular membrane is related with the dynamic working manner of adsorption sites, which plays a crucial role on avoiding spatial mismatching and short-circuit effect. The supra-molecular strategy described here has general suggestions for the "sites" involved technologies such as catalysis, adsorption, and sensors, which is of broad interest.

Biodiesel production from waste chicken fat with low free fatty acids by an integrated catalytic process of composite membrane and sodium methoxide.

An integrated process of catalytic composite membranes (CCMs) and sodium methoxide was developed to produce biodiesel from waste chicken fat. The free fatty acids (FFAs) in the chicken oil were converted to methyl esters by esterification with methanol using a novel sulfonated polyethersulfone (SPES)/PES/non-woven fabric (NWF) CCMs in a flow-through catalytic membrane reactor. The CCM is that the NWF fibers were fully embedded in SPES/PES with a homogeneous and microporous structure. The oil obtained after esterification was carried out by transesterification of sodium methoxide. The results showed that the FFAs conversion obtained by CCMs with the acid capacity of 25.28 mmol (H(+)) was 92.8% at the residence time 258s. The CCMs present a good stability during the continuous running of 500 h. The conversion of transesterification was 98.1% under the optimum conditions. The quality of the biodiesel met the international standards.

Sulfur removal from fuel using zeolites/polyimide mixed matrix membrane adsorbents.

A novel membrane adsorption process was proposed for the sulfur removal from fuels. The mixed matrix membranes (MMMs) adsorbents composed of polyimide (PI) and various Y zeolites were prepared. By the detailed characterization of FT-IR, morphology, thermal and mechanical properties of MMMs adsorbents, combining the adsorption and desorption behavior research, the process-structure-function relationship was discussed. Field-emission scanning electron microscope (FESEM) images show that the functional particles are incorporated into the three-dimensional network structure. MMMs adsorbents with 40% of zeolites content possess better physical properties, which was confirmed by mechanical strength and thermo stability analysis. Influence factors including post-treatment, content of incorporated zeolites, adsorption time, temperature, initial sulfur concentration as well as sulfur species on the adsorption performance of MMMs adsorbents have been evaluated. At 4 wt.% zeolites content, adsorption capacity for NaY/PI, AgY/PI and CeY/PI MMMs adsorbents come to 2.0, 7.5 and 7.9 mg S/g, respectively. And the regeneration results suggest that the corresponding spent membranes can recover about 98%, 90% and 70% of the desulfurization capacity, respectively. The distinct adsorption and desorption behavior of MMMs adsorbents with various functional zeolites was markedly related with their various binding force and binding mode with sulfur compounds.