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Advanced oxidation processes (AOPs) as an efficient oxidation technology, have been extensively applied for degrading recalcitrant organic contaminants viathe generated reactive oxygen species from the activation reaction of catalysts. However, the leaching of metal ions and the consumption of catalysts have brought the incomplete degradation of target contaminants, the generation of wastewater containing toxicity, and the increase in costs. Here, dual metal Fe and Co co-doped g-C3N4composite (N/CoFeX) was successfully synthesized and used as an efficient peroxymonosulfate (PMS) activator for oxytetracycline (OTC) degradation with a slight leaching of metal ions and superb degradation performance. In addition, the specific insertion structure and the formation of the Fe–O–Co bond into N/CoFeX can bring remarkable catalytic ability and stability, which further prevents the leaching of Co (0.004 mg L−1) and Fe ions (0.005 mg L−1) and achieves an efficient OTC removal rate (100%) within 60 min. Further calculations show that the lowest adsorption energy of PMS on N/CoFeX aids in PMS activation and can boost the electron transfer from organic pollutants to PMS, further enhancing the generation of radicals and the decomposition of OTC. The relatively slight toxicity of the degradation intermediates examined by proteomics analysis strongly as well as minor leaching of metal ions exhibit great potential for large-scale applications of AOPs in the field of wastewater purification and remediation.

A unique 1D nanostructure of Pt@CeO2–BDC was prepared from Pt@CeBDC MOF. The Pt@CeO2–BDC was rich in oxygen vacancies (i.e., XPS Oβ/(Oα+ Oβ) = 39.4%), and on the catalyst, the 2 nm Pt clusters were uniformly deposited on the 1D mesoporous polycrystalline CeO2. Toluene oxidation was conducted in a spectroscopic operandoRaman–online FTIR reactor to elucidate the reaction mechanism and establish the structure–activity relationship. The reaction proceeds as follows: (I) adsorption of toluene as benzoate intermediates on Pt@CeO2–BDC at low temperature by reaction with surface peroxide species; (II) reaction activation and ring-opening involving lattice oxygen with a concomitant change in defect densities indicative of surface rearrangement; (III) complete oxidation to CO2and H2O by lattice oxygen and reoxidation of the reduced ceria with consumption of adsorbed oxygen species. The Pt clusters, which mainly exist as Pt2+with minor amounts of Pt0and Pt4+on the surface, facilitated the adsorption and reaction activation. The Pt-CeO2interface generates reduced ceria sites forming nearby adsorbed peroxide at low temperature that oxidize toluene into benzoate species by a Langmuir–Hinshelwood mechanism. As the reaction temperature increases, the role of lattice oxygen becomes important, producing CO2and H2O mainly by the Mars-van Krevelen mechanism.

Superacid-catalyzed polymers of intrinsic microporosity have attracted increasing attention in membrane-mediated gas separation due to their good processability, facile polymerization procedure, and tunable microporosity and gas separation performance. In this study, we synthesized a series of new superacid-catalyzed polymers with fully ladder backbones and well-defined micropores using a one-pot condensation polymerization. The incorporation of a contorted spirobisindane building block facilitated the formation of highly microporous structures in the resulting polymers, enhancing their intrinsic microporosity and gas separation properties. Among the three SACPs, SACP-PhMe exhibited the largest d-spacing value, specific surface area, and pore volume due to its bulkiest side group. The gas separation performance of the SACP membranes surpassed several benchmark polymer membranes, with the SACP-PhMe membrane demonstrating excellent performance in separating CO2/CH4, H2/CH4, O2/N2, and H2/N2. The SACP-Me membrane exhibited the lowest porosity, making it less susceptible to CO2absorption and showing superior plasticization resistance. The results highlight the promising gas separation properties of the SACPs and their potential for various gas separation applications, offering new opportunities for advanced polymer membrane design.

The adsorption selectivity of NH2-MCM-41 follows the Irving-William order observed in transition metal complexes (i.e., Cu2+> Zn2+> Co2+> Ni2+) that is consistent with X-ray photoelectron spectroscopy (XPS) and adsorption thermodynamics data. The interplays between surface aminopropyl ligands and the transition metals are adequately explained by the Pearson HSAB principle, but a multicomponent Freundlich adsorption model based on the single component adsorption data gives a more accurate prediction and description of the metal adsorptions from binary, ternary and quaternary solutions at different pHs and from complex water sources (i.e., tap water, runoff water, and seawater) that contained myriad humic substances, dissolved minerals, and various anions.

Magnetic MCM-41 of large surface area (ca. 800 m2g−1) and high magnetization (ca. 8.3 emu g−1) was prepared at a reasonable iron oxide nanoparticles loading of 10 wt % by a two-step synthesis process. The 8 nm iron oxide nanoparticles (i.e., 30 m2g−1) were embedded in the MCM-41 with no observable effects on the particle morphology and pore symmetry, but a slight change (i.e., <20%) in the textural properties and surface chemistry was detected. Aminopropyls (2.7 mmol g−1) were grafted on the mesopore channels followed by the adsorption of 1.2 mmol g−1Fe3+to prepare selective adsorbents for arsenic(V) and chromium(VI) oxyanions. Detailed analyses indicated that the surface modifications of the magnetic and nonmagnetic MCM-41 by aminopropyls and Fe3+yield similar site chemistry and accessibility. The Fe3+-magMCM-41 and Fe3+-MCM-41 displayed comparable adsorption capacity and selectivity. Both adsorbed only As(V) and Cr(VI) oxyanions (i.e., 1.0 and 2.0 mmol g−1, respectively), and none of the Cu(II). The magnetic adsorbent was easily dispersed in aqueous solution and can be removed by a magnet (1550 G) at a rate of 1 cm min−1compared to 0.004 cm min−1by gravity.

Au–Mn co-precipitates were dried at different temperatures and in different atmospheres. The co-precipitates were tested for low-temperature CO oxidation without any additional thermal treatment. While samples dried at 120°C in air exhibited the highest activity for CO oxidation, samples dried at room temperature under vacuum were less active. The catalytic properties of most fresh samples improved after the first light-off test, during which a temperature of 400°C was reached. To investigate the physical and chemical state of gold and manganese support, dried samples were examined by 197Au Mössbauer spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The 197Au Mössbauer spectra showed that gold existed only in metallic form and was produced during the co-precipitation procedure. XRD and XPS analyses demonstrated that fresh samples contained manganese carbonate and oxides such as MnO2. The carbonate was converted to manganese oxides after the light-off test. TEM analysis indicated that the manganese support was present in plate-like shapes and the shape of gold particles was rectangular with rounded corners. Au particle sizes were in the range 4.5–6.5 nm before the light-off test. After heat treatment at 400°C, catalytic activity improved and a strong interaction between gold particles and the MnOxsupport was induced.

STM studies of chemically impregnated model Pt catalysts supported on HOPG substrate reveal the dynamics of morphological transformation from catalyst-intermediate to metal crystallites of near-equilibrium shape. Both the morphology and aspect ratio distribution of the crystallites undergo significant changes for catalysts reduced for 0.5, 2, and 60 h at similar pretreatment conditions. The aspect ratio distribution shows that majority (60–70%) of the crystallites have metastable shapes. Another model Pt catalyst was prepared by vacuum deposition of Pt metals onto the graphite substrate. Prior to H2 pretreatment, the Pt particles have random, irregular morphologies which transform to regular spherical shapes after H2 treatment at 250 °C for 30 min.

Inorganic membrane reactors combine reaction and separation operations in a single unit. Preferential permeation of a product species through the membrane enhances equilibriumlimited reactions beyond the thermodynamic limit. Proper catalyst formulation and spatial distribution also enhance membrane reactor performance. To minimize reactant loss due to high gas permeation, the thickness of the γalumina layer in a composite alumina membrane Membralox was increased to 17 μm by slipcasting with alumina sol. Among the catalysts investigated a formulation of 1.10 wt. Pt and 1.36 wt. Sn supported on γalumina pellets yielded the highest activity, selectivity, and stability for the dehydrogenation of ethane to ethylene. Using this catalyst composition, various nonuniform platinum distributions within the pellets were prepared by solution impregnation, while maintaining a uniform distribution of Sn. The effect of nonuniform catalyst distribution on dehydrogenation of ethane in a packedbed membrane reactor PBMR under wellmixed, isothermal conditions was evaluated both experimentally and theoretically. Reactor performance is maximized when the catalyst is concentrated near the surface of the support. Supraequilibrium conversions, about 80 beyond equilibrium values, were obtained with the narrow surface–step catalyst pellets. Experimental results agree well with theoretical predictions, obtained without the use of any adjustable parameters. The effect of membrane thickness on reactor performance was also investigated, by comparing the 17μm alumina membrane with a 1.2mmthick porous Vycor glass, using pellets with the narrow surfacestep distribution. For the experimental conditions employed, relatively low permeation through the porous Vycor resulted in conversions near fixedbed reactor values.

The issue of optimal catalyst distribution was studied experimentally for the ethylene epoxidation reaction network on a Ag/α-Al2O3catalyst in the presence of 1,2-dichloroethane (DCE). For a fixed amount of silver, the influence of location and width of the catalytic layer on the conversion of ethylene, and on the selectivity and yield to ethylene oxide, was investigated for different concentrations of DCE (0–2 ppm) using a single-pellet reactor. Two levels of ethane in the feed (0 and 0.5 vol%) and a temperature range between 210 and 270°C were studied. Depending on the experimental conditions, promotion, inhibition, and poisoning effects of DCE were observed. The catalyst distribution and the concentrations of DCE and ethane in the feed, which provide high selectivity and yield, were identified. XPS analysis was also conducted to determine the state and composition of the silver catalyst, both prior and subsequent to reaction.

Ionic liquids are promising materials for gas sorption and separation, and supported ionic liquid phase (SILP) on porous substrate provides a practical route for their application. Structurally and chemically diverse materials, including metal–organic frameworks, porous silicas and aluminas, polymers, and carbons, have served as support materials for SILP adsorbents and membranes. This review focuses on the latest development in SILP for the separation, removal, and capture of air pollutants, including carbon dioxide, hydrogen sulfide, ammonia, and volatile organic compounds.

Free-standing silicalite-1 Sil-1 zeolite micromembranes have been successfully fabricated onto silicon substrate. Gas permeation test using permanent gases i.e., helium, hydrogen, argon and nitrogen and hydrocarbons i.e., methane and n-butane indicates that the micromembranes have excellent permeance flux and high permselectivity.

Free-standing silicalite-1 (Sil-1) zeolite micromembranes have been successfully fabricated onto silicon substrate. Gas permeation test using permanent gases (i.e., helium, hydrogen, argon and nitrogen) and hydrocarbons (i.e., methane and n-butane) indicates that the micromembranes have excellent permeance flux and high permselectivity.

A facile method was established using composition-gradient pattern on zeolite surface to guide the deposition and formation of chemical and biomolecular patterns with features as small as five microns.

A multi-channel membrane microreactor was fabricated and tested for Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate using Cs-exchanged faujasite NaX as the catalyst; the membrane microreactor achieves supra-eqiulibrium conversion at higher product purity.

Using a new fabrication strategy, novel, self-enclosed microporous silicalite-1 zeolite microtunnel and microchunnel architectures were successfully prepared.

A zeolite-based microengineered reactor was fabricated and tested for 1-pentene epoxidation over titanium silicalite-1 (TS-1) catalyst, which has been selectively incorporated within the microreactor channel using a new synthesis procedure.

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