Carrier-conducted membranes (CCMs) have emerged as a promising class of functional membranes for selective ion separation because carrier-mediated transport enables precise regulation of membrane selectivity through tailored carrier-ion interactions. However, extending CCMs from single-ion systems to competitive multicomponent separations remains challenging owing to continuously evolving metal speciation and competitive carrier interactions. Herein, a chloride-regulated carrier-conducted membrane electrodialysis strategy is proposed to regulate competitive ion transport by controlling metal speciation within the membrane transport process. By systematically optimizing chloride concentrations in the feed and stripping solutions, competitive transport among Zn(II), Cr(VI), and Ni(II) was quantitatively regulated, establishing an operating window for selective multimetal separation. Under the optimized conditions, complete retention of Ni(II), 92.2% recovery of Zn(II), and 86.1% recovery of Cr(VI) were achieved, with corresponding product purities of 96.7%, 87.3%, and 96.5%, respectively. Mechanistic analyses demonstrated that chloride primarily regulates membrane transport through Zn(II) chloro-complex formation and competitive carrier-mediated transport, whereas Cr(VI) transport remains comparatively insensitive to chloride concentration within the investigated operating window. Furthermore, integrating CCMs with a selectrodialysis configuration transforms membrane transport into a synergistic ion-screening process, enabling cascade separation of multiple metal ions within a single electrodialysis operation. This work provides new mechanistic insights into chloride-regulated competitive ion transport in carrier-conducted membranes and establishes a membrane-based strategy for selective multimetal separation.

The feasibility of an analogous reverse electrodialysis (RED) process for power generation and acid recovery from acidic waste streams in the steel industry is investigated in this study. A comprehensive model was established to simulate the transport phenomena and power generation, which was validated through experimental data. The simulated operation time was 3 h, during which an acid recovery rate of 41.7% was achieved, and the maximum output power density reached 30.37 μW·cm−2. The results demonstrated a strong dependence of output power density on the acid concentration, with a linear relationship within the tested range of 1.0–3.0 mol·L−1 HCl. An optimal flow rate range was identified that maximized power output, with the best value of 90 mL∙min−1. The differences in energy harvesting between the traditional acid diffusion dialysis process and our analogous RED process were demonstrated via simulation. The importance of system electroneutrality in driving ion migration and forming ionic currents was crucial for effective power generation. The analogous RED process is a promising solution for efficient acid recovery and power generation from industrial acid waste, offering a sustainable treatment approach.

This study presents a comprehensive electrochemical characterization and simulation of anion exchange membranes (AEMs) for water treatment applications, focusing on ion transport behavior. Experimental techniques, including chronopotentiometry, current–voltage (I–V) curve measurements, and electrochemical impedance spectroscopy (EIS), were employed to investigate the kinetics and dynamics of ion transport at the membrane interface. The results were validated and further explored through finite element method (FEM) simulations using COMSOL Multiphysics. The study revealed key insights into the role of membrane resistance, ion diffusion, and capacitive effects on overall membrane performance. Parametric analyses of electrolyte layer thickness, bulk solution concentration, and membrane porosity provided guidelines for optimizing membrane design. The findings highlight the importance of considering these factors in enhancing the efficiency and applicability of AEMs in water treatment processes. Future work will focus on refining simulation models and exploring advanced materials to further improve membrane performance.

A thermodynamic analysis of a compact hydrogen generation system for mobile fuel cell applications is presented. The system consists of a miniature autothermal steam reformer (ATR) and a water–gas shift (WGS) reactor, designed to produce hydrogen from hydrocarbon fuels for a 1 kW proton exchange membrane (PEM) fuel cell. Methane is used as the model fuel, and the study focuses on optimizing feed compositions and operational conditions to maximize hydrogen yield and purity. Feed compositions and operational conditions are optimized. In total, 0.7 Nm3 h−1 H2 is generated from 0.25 Nm3 h−1 CH4 with properly adjusted steam and air feeding. Issues with product purity and start-up procedures have been identified and discussed, along with feasible solutions. The system is suitable for remote and mobile applications.

Cu/ZnO nanoparticles embedded in zeolites possess smaller particle sizes than those in the conventional Cu/ZnO/Al2O3 catalyst. Therefore, they exhibit a distinctive manner of interaction with the reactants in the catalytic hydrogenation of CO2 to methanol. The present paper uses in situ FTIR spectroscopy to recognize the introduction and removal of various carbonates, carbonyl, formates and water species adsorbed on the surface of a Cu/ZnO/SPP-zeolite catalyst in reactive flows. Together with other characterization results, such as quasi-in situ XPS, it was revealed that the Cu surfaces have an uneven electronic distribution and that constant carbonate coverage, low water adsorption, and fast consumption of carbonyls and formates are associated with the high conversion frequency of CO2 over the Cu/ZnO/zeolite material.

Zeolites, are characterized by their microporous, crystalline structures with a four-connected framework with variable compositions, predominantly aluminosilicates. They are extensively utilized as adsorbents, catalysts, and ion exchangers across domestic and industrial sectors. With the ongoing energy transition from fossil fuels to renewable sources and the pursuit of environmentally sustainable development, zeolites are increasingly being explored beyond their traditional application fields. They are investigated for their adsorption and catalytic capabilities in the protection and restoration of air, water, and soil quality, as well as in the environmentally friendly “green” production of chemicals. This review article details these novel and potential applications of zeolites, emphasizing the unique properties that render them suitable for each specific use case and discussing how these properties can be fine-tuned through material selection or purpose-driven synthesis methods.

This study aimed to improve Cu-based catalysts for CO2 hydrogenation to methanol by embedding Cu/ZnO nanoparticles in the mesopores of the self-pillared pentasil (SPP) zeolite at optimized particle-size distribution and metal loading amounts. Ethylenediamine was found to be a proper agent aiding the metal dispersion. A composite of Cu/ZnO-SPP with 2-8 nm Cu particles, 25.6 wt% CuO and 11.2 wt% ZnO loadings was obtained, which performs better than Cu/ZnO/Al2O3 catalyst in terms of CO2 turnover frequency and MeOH formation rates per unit Cu. Quasi-in-situ XPS and in-situ FTIR experiments discovered that the Cu/ZnO-SPP composite has electronic deficient spots on Cu surfaces during reactions, and can maintain a constant CO2 coverage and very low water adsorption.

The synthesis of zeolites in a strongly acidic medium is a new and nearly unexplored chemistry field. In addition to the previously reported silicalite-1 and the several clathrasils, this paper elaborates that one more material of unique properties could be successfully crystallized in the strongly acidic fluoride medium. A pure-silica zeolite ZSM-8 has been obtained using tetraethylammonium ion as a structure-directing agent. Rietveld refinement proves that ZSM-8 is of the MFI topology, i.e., it is another silicalite-1 but different in framework distortions. Moreover, the discrete and uniform crystals of the acidic-medium synthesized pure-silica ZSM-8 possess a substantially perfect framework structure and thus hydrophobic surfaces. This remarkable character renders the material an ideal adsorbent for discriminating molecules on the polarity basis, which is desired in developing green separation processes. C3H8, CH4, and CO2 are chosen as examples respecting their different polarities and tested for the adsorptive parameters.

Zeolites are crystalline microporous materials constructed by corner-sharing tetrahedra (SiO4 and AlO4), with many industrial applications as ion exchangers, adsorbents and heterogeneous catalysts(1-4). However, the presence of micropores impedes the use of zeolites in areas dealing with bulky substrates. Introducing extrinsic mesopores, that is, intercrystal/intracrystal mesopores, in zeolites is a solution to overcome the diffusion barrier(5-8). Still, those extrinsic mesopores are generally disordered and non-uniform; moreover, acidity and crystallinity are always, to some extent, impaired(9). Thus, synthesizing thermally stable zeolites with intrinsic mesopores that are of uniform size and crystallographically connected with micropores, denoted here as intrinsic mesoporous zeolite, is highly desired but still not achieved. Here we report ZMQ-1 (Zeolitic Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, no. 1), an aluminosilicate zeolite with an intersecting intrinsic meso-microporous channel system delimited by 28x10x 10-rings, in which the 28-ring has a free diameter of 22.76 angstrom x11.83 angstrom, which reaches the mesopore domain. ZMQ-1 has high thermal and hydrothermal stability with tunable framework Si/Al molar ratios. ZMQ-1 is the first aluminosilicate zeolite with an intrinsic meso-microporous channel system. The BrOnsted acidity of ZMQ-1 imparts high activity and unique selectivity in the catalytic cracking of heavy oil. The position of the organic structure-directing agent (OSDA) used for ZMQ-1 synthesis was determined from three-dimensional electron diffraction (3DED) data, which shows the unique structure-directing role of the OSDA in the formation of the intrinsic meso-microporous zeolite. This provides an incentive for preparing other stable mesopore-containing zeolites.

The fluoride medium synthesis of zeolites, especially in the strongly acidic regions, yields products with unique characteristics such as ultra-hydrophobic surfaces and defect-free lattices. However, it is often difficult to incorporate aluminum into the framework of zeolites in this medium, limiting the acquisition and development of catalytic materials. The present paper shows that inter-zeolite transformation is efficient for obtaining ZSM-5 zeolites with lower Si/Al ratios in a strongly acidic fluoride medium. The critical point is that the parent zeolites can retain some locally ordered fragments during their dissolution, including framework Al atoms, and incorporate them into the ZSM-5 product. The acidic properties of the trans-crystallization products obtained in an acidic medium display significant differences from the traditional ZSM-5 with a similar Si/Al ratio in the amounts, strength, and types of the acid sites; thus, they behave differently in typical acid-catalysed reactions, such as dehydration of alcohols.

Zeolites are typically synthesized in alkaline or fluoride-containing near-neutral media. Sophisticated organic structure-directing agents have been investigated for such systems with the aim of discovering materials with unprecedented structures and properties for novel technical applications. In contrast, zeolite crystallization in strongly acidic media has yet to be explored. This study demonstrates that a zeolitic silicate phase crystallizes from acidic gels using trimethylamine as an organic additive with the composition 1 SiO2:0.3 TMA:0.3 HCl: 0.15 HF:55 H2O:(0.1-0.4) GeO2. This phase has an interrupted four-connected framework analog to the octahedron/ tetrahedron-mixed framework of the mineral family pharmacosiderite. In comparison to the pharmacosideritetype HK3(Ge7O16)(H2O)4, the four GeO6-octahedra forming the central [HGe4O4O12]-cluster are replaced by four SiO4-tetrahedra in a [Si4O6(OH)2.89]-unit in the new phase. However, the structure is distorted and may contain connectivity and point defects; thus, healing by the occasional incorporation of GeO6-units is necessary. The refined unit cell has a cubic symmetry, space group P-43m (#215), with a = 7.7005(1) & Aring;. Acidic-medium synthesis is a useful way to find new zeolites that move in a fundamentally different direction from sophisticated organic structure-directing agents.

Narrowly dispersed ultrafine Cu clusters of sizes smaller than 2.0 nm have been encapsulated in nanosized silicalite-1 zeolite through direct crystallization in the presence of Cu(en)(2)(2+) complex ions as the metal precursor. The growing silicalite-1 crystals are rich in vacancy defects and connectivity defects on the grain boundaries, where the terminating silanols promote the decomposition of Cu(en)(2)(2+), thus the deposition of ultrafine Cu species. The obtained composite material as a model catalyst is active for CO2 activation and hydrogenation to methanol. The preliminary in situ FTIR study recognizes a series of surface-adsorbed carbonyl, formyl, carbonate, and formate species when the material is exposed to CO2 and H-2. Among others, the adsorbed formate decays most rapidly upon cofeeding CO2 and H-2, implying that the most probable pathway toward methanol formation over this material is via the formate-mediated mechanism.

The sequential enzyme biosensors hold significant importance in measuring species which are usually hard to process with single-enzyme-based biosensors. However, sequential enzyme electrodes experience critical issues such as low catalytic efficiency, insensitivity and poor reproducibility. In this work, yeast surface co-displaying sequential enzymes of glucoamylase (GA) and glucose oxidase (GOx) with controllable ratios through the specific cohesion-dockerin protein interaction was explored, by which starch hydrolyzing by GA into glucose is the rate-limiting step. The modified electrodes were prepared by immobilizing yeast-GA&GOx whole-cell and reduced graphene oxide (RGO) on glassy carbon electrode (GCE), for which the direct electron transfer between the electrode and recombinant GOx was arrived. Interestingly, the current responses of sensors to starch and glucose are dependent on the displayed enzyme composition, of which the yeast-GA&GOx (2:1) exhibited the highest current. Thereafter, sequential enzyme sensor of yeast-GA&GOx (2:1)/RGO/GCE was developed. Based on reduction detection at negative potential without interference, the sensor is stable and capable of assaying glucose (linear range: 2.0-100 mg/L) or starch (linear range, 50-3500 mg/L), separately. Coupled with yeast-GOx/RGO/GCE glucose sensor, both glucose and starch in real samples can be detected satisfactorily. This work provides new ideas for the development of other sequential enzyme electrodes for potential applications.

This paper deals with the extension of the synthesis field of microporous zeolite-type materials and types of organic structure-directing agents (OSDA) that can be used to promote their crystallization. The highly hydrophilic hexamethylenetetramine (urotropine), with its C/N ratio = 1.5, which is unusual to act as a structure-directing agent in the crystallization of open-framework silica polymorphs, is used to exemplify the novelty of the employed approach. Namely, the protonation of urotropine in an acidic fluorine-containing medium transforms it into a very efficient OSDA that yields dodecasil 3C (MTN-type). This novel synthesis also allows gaining insights into OSDA-framework interactions in the MTN-type structure. The comprehensive 29Si and 19F MAS NMR indicate a small number of point defects of the framework T sites and the multiple bonding of F- ions to Si in a disordered manner. Based on this finding, a unit cell model has been generated using Monte Carlo simulation and validated with Rietveld refinement using experimental powder X-ray diffraction data. In the model, protonated urotropine cations are located in the center of the big hexakaidecahedral [51264] cages at full occupancy with random orientations. The charge balance is provided by the disordered F- ions.

Zeolites are the catalytic materials that are widly applied in the processing of conventional and renewable fuels and chemicals. The present study provides a comprehensive analysis of the factors controlling the acidic medium synthesis of high silica silicalite-1 zeolite. The effect of various silica sources (TEOS, fumed and colloidal silica) and alkali metal cations (Na and K) on the silicalite-1 formation is studied. The efficiency of different types of seeds (micron-sized, nanosized, and silicalite-1 amorphous colloidal precursor) on the silicalite-1 crystal growth kinetics and crystal size formed under acidic conditions is also investigated. Further, the zeolite crystallization kinetics under acidic, neutral, and basic conditions is compared. The obtained highly crystalline samples are used to compare the physicochemical properties of zeolites synthesized in acidic, neutral, and basic medium. Thus, the crystallinity, thermal stability, and local order in silicalite-1 samples synthesized in the (2–12) pH range are evaluated.

A series of clathrasils, including AST, DOH, MTN, and DDR topologies, was synthesized in an acidic medium. The general composition of the initial system was 1 SiO2: 0.3-0.5 SDA: 0.1-0.5 HF/NH4F: 0-0.3 HBr: 10-50H(2)O in the pH range of 2-6, where SDA stands for organic amines or ammonium ions as the structure-directing agents. And the hydrothermal syntheses were performed in the 150-200 degrees C temperature range. Besides elaborating the synthesis recipes and product characterizations, the study also attempted to elucidate the origins of slow crystallization kinetics. It was found that the thermodynamic stabilities of the SDA@Framewrok-SiO2 compounds play an overwhelming role in the crystalline phase selection. The finding of this study can be used as a guidance of silica-based porous materials synthesis under acidic conditions.

Extending the chemistry filed of zeolite crystallization from the basic and near-neutral conditions to strongly acidic region generates a series of new features to the zeolite materials, such as substantially perfect lattices, hydrophobic surfaces, extremely high thermal stability, and predictable diffusivity. The present paper elaborates using both previously published and newly acquired data, that the acidic-medium crystallization method is generally applicable to a number of zeolites with various framework topologies, and that an unprecedentedly ordered lattice structure can be achieved for the products of such syntheses.

Screening of the dominant or core oil resistant bacteria in Aged Oil Sludge (AOS) contaminated soil in Daqing and Shengli oilfields (DQ and SL) in China was investigated through High-Throughput Sequencing method. Enhanced total organic carbon (TOC, 12.53 to 28.35 g/kg in DQ and 3.07 to 4.97 g/kg in SL) and total petroleum hydrocarbons (TPHs, 21 to 2837 mg/mg in DQ and 13 to 1558 mg/kg in SL) were observed. The internal transcribed spacer (ITS) sequencing by Illumine Miseq platform at each taxonomic level revealed the notable toxicological effect of AOS on the diversity and community structure of bacteria. In this study, sequence analyses showed 77–89% and 92–98% reduction of Firmicutes at phylum level in DQ and SL respectively after treated with AOS. Enhanced universal gene location was observed in Proteobacteria, Actinobacteria, Gemmatimonadetes and Bacteroidetes in DQ and SL. The universal dominant family in the two oilfields was anaerolineaceae. At the genus level, Algiphilus in DQ and Pseudomonas in SL were the majority respectively. In total, 3 negligible genera (Perlucidibaca, Alcanivorax and Algiphilus) in DQ and 13 negligible genera (Salinisphaera, Microbulbifer and Idiomarina, et al.,) in SL were significantly enriched after oil treatment indicating their possible role in the attenuation of petroleum hydrocarbons.

Electric field intensification has been demonstrated as an effective strategy for facilitating ion transfer and separation in polymer inclusion membrane (PIM) involved processes. However, it is still a challenge to develop compatible PIMs with high performance and to reveal the underlying mechanisms. Herein, crosslinked PIMs with different base polymers have been employed in PIM-electrodialysis processes. Cross-linked cellulose triacetate (CTA) based PIMs exhibited significant improvement in Cr(VI) transport, which permeability coefficient was 5.9 times larger than the non-cross-linked counterpart. The characterizations of cross-linked PIMs showed higher hydrophilicity and lower membrane area resistance. Furthermore, cross-linked polymeric network inside CTA based PIMs structure increased their crystallinity, thus supporting the fixed-site jumping mechanism, thereby enabling ions to be transported directly in a manner of continuous pathway at low current density. This study shed light on further improvement of efficient ion transport and gave insights into the mechanism understanding in PIM-ED systems.

Three amino acids, namely proline, histidine, and lysine, are used as organic additives in the hydrothermal synthesis of the zeotype material AlPO4 center dot 1.5H(2)O-H-3 (framework topology code APC). A detailed analysis of the factors controlling the formation of AlPO4 center dot 1.5H(2)O-H3 is performed. The role of amino acids in the formation process of the frameworks is addressed based on comparisons of the crystal phase selection of different synthetic recipes and the insights provided by the Fourier transform infrared analysis of the synthetic gels and the crystalline products. The phase transition of AlPO4 center dot 1.5H(2)O-H3 to AlPO4-C (APC) and subsequently to AlPO4-D (APD) upon heating to 1000 degrees C was followed by in situ X-ray diffraction analysis. The present work has been the first progress in understanding the role of these bioactive molecules in the crystallization of inorganic open-framework microporous materials. An active, nonclassical structure-directing role that amino acids play during the zeotype crystallization is proposed, that is, positively charged amino acids cap the growing surface of microporous AlPO4 and attract aluminate and phosphate anions from the solution phase for further growth.