Fixed-bed Flow Reactor Research Articles

Energy Optimization of Dimethyl Ether (DME) Production Process from Methanol Dehydration

The increasing demand for sustainable and clean alternative fuels has driven the focus on dimethyl ether (DME), an environmentally friendly and non-toxic chemical with high potential as a fuel and industrial solvent. DME can be produced from various raw materials such as natural gas, methanol, biomass, and coal. This study investigates the optimization of DME production from methanol dehydration using a fixed-bed plug flow reactor and γ-Al₂O₃ catalyst, emphasizing energy efficiency improvements. Modifications were implemented in the Aspen HYSYS simulation by replacing the conventional heater with heat exchanger and utilizing heat generated during cooling process for another heating process. The results demonstrated a significant reduction 65.8 % in net energy consumption from 8.54×106 kJ/h to 2.92×106 kJ/h, validating the effectiveness of these modifications by leveraging Aspen HYSYS simulations, the proposed design achieved high process efficiency while maintaining the target DME purity of 99.95 % produced. This research highlights the potential of heat integration strategies to enhance the economic and environmental performance of DME production processes. Copyright © 2024 by Authors, Published by Universitas Diponegoro and BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Conversion of ethylene to propylene over NiO-MoO3/Al2O3 catalyst

The effect of operating conditions of ethylene conversion to propylene on the yield of products, activity and stability of NiO-MoO3/Al2O3 catalyst was studied. The catalytic tests were carried out in a fixed-bed flow reactor at temperatures of 100-250 °C, atmospheric pressure and weight hourly space velocity of 0.25-2 h-1. The maximum propylene yield of 57 wt.% is achieved at 150 °C and 0.25 h-1. Under these conditions the degree of ethylene conversion reaches 90 %. The kinetic model for the process has been proposed, which described the formation of the main reaction products. It has been shown that carbonaceous deposits are formed on the catalyst surface during the ethylene conversion. The amount of these deposits increases with increasing temperature and contact time. Moreover some Mo species change the oxidation state from +6 to +4/+5.

Efficient degradation of emerging organic pollutants via activation of peroxymonosulfate over Fe-N co-doped carbon materials: Singlet oxygen and electron-transfer mechanisms

Singlet oxygen (1O2) is widely recognized as an effective reactive species for the targeted oxidation of organic contaminants. However, producing 1O2 with high selectivity and efficiency remains a significant challenge. This study describes the synthesis of a N-C-loaded Fe catalyst (Fe/NC) loaded with nitrogen-doped carbon materials. The Fe/NC catalyst efficiently produces 1O2 via the activation of peroxymonosulfate (PMS), demonstrating exceptional degradation capabilities for p-chlorophenol (4-CP). Compared to the control samples of nitrogen-doped carbon (NC) and Fe/NC-x under identical conditions, the Fe/NC/PMS produced a significantly greater degradation rate (0.794min-1) for 4-CP (50mg⋅L-1) within 14min. The content of zinc was regulated to enhance the degradation of 4-CP. The durability of the catalyst was tested with a fixed-bed flow reactor, maintaining almost 100% removal efficiency over 36h on stream. The 4-CP degradation within this system was shown to be a non-radical process predominated by 1O2 and electron transfer, as shown by electrochemical methods, quenching studies, and electron paramagnetic resonance test (EPR). Moreover, Fe/NC demonstrated exceptional resistance to pH changes (3-10), natural organics, and inorganic ions while degrading organic contaminants. The degradation process of 4-CP over the Fe/NC catalyst was examined using liquid chromatography-mass spectrometer. The results of the phytotoxicity evaluation indicated a significant decrease in their toxicity within the Fe/NC/PMS/4-CP system. The satisfactory activity, stability, and universality enabled Fe/NC to serve as a promising candidate for PMS activation. This study presents a novel approach for the selective production of 1O2, enabling targeted pollutant degradation in wastewater treatment.

Defects and oxygen functional groups on sludge biochar synergistic activation of PMS for degradation of sulfamethoxazole and practical application

As one of the by-product, residual sludge needs to be utilized urgently. For this purpose, sludge biochar (ASBC-1) abundant oxygen functional groups (OFGs) with edge defects was designed to reuse the residual sludge. The ASBC-1/ Peroxymonosulfate (PMS) system removed 94.63 % of sulfamethoxazole (SMX) within 30 min and had strong pH versatility, interference resistance, and stability. Raman and X-ray photoelectron spectroscopy (XPS) analysis revealed that the degree of defects and the content of OFGs were influenced by different acidification conditions. Furthermore, the relationship between degradation performance and the degree of defects or OFGs was confirmed by Pearson correlation analysis. DFT calculations revealed that the degree of defects and OFGs synergistically promoted the activation of PMS. A continuous flow fixed-bed reactor with gel pellets as packing material was constructed, and the removal rate of SMX was suitable under different water matrix backgrounds. This method provided a treatment and disposal solution for reusing sludge resources in accordance with the principles of sustainable development.

Performance of mesoporous ceria supported Ru catalysts for oxidative degradation of aqueous solution of plastic monomer bisphenol A in a fixed bed flow reactor: Structure-activity insights, optimization of reaction conditions, kinetics, catalyst stability, and characterization

One of the important defects is the oxygen vacancy on metal oxide surfaces, and the defects function as the active sites in different catalytic reactions. Herein, Ru/CeO2-rod and Ru/CeO2-cube catalysts were prepared via the ESI method, and CeO2-rod and CeO2-cube supports were synthesized by hydrothermal processes. The activity of these catalysts was tested in a high-pressure fixed-bed reactor, and the oxidative degradation of industrial organic raffinate containing the plastic chemical bisphenol A (BPA) was compared with their oxygen vacancy concentration estimated after calcination. The Ru/CeO2-rod catalyst showed higher catalytic activity with 90 % BPA conversion at 453 K, 30 bar, 0.5 % Ru metal content, 15 O2 to BPA molar ratio, and 2 g−1.h−1 BPA feed weight hourly space velocity (WHSV). In contrast, 80 % BPA degradation was achieved using the Ru/CeO2-cube catalyst under similar reaction conditions. The higher oxygen vacancy concentration and the higher interfacial surface area between metal and the support of the CeO2-rod supported Ru catalyst triggered the higher BPA degradation at low oxidation conditions. Besides, the atomic ratio, Ce3+/Ce4+, is lower in the Ru/CeO2-rod catalyst than that of the Ru/CeO2-cube catalyst, indicating the higher Ce4+ available in the catalyst, leading to the higher degradation of BPA. Moreover, the Ru/CeO2-rod catalyst possesses {111} planes that boost the generation of energetic Ru to improve the pursuit of the catalyst. The Weisz-Prater modulus and Thiele modulus values indicated that the surface reaction is the rate limitation step and there is no diffusion limitation. TEM, HRTEM, XPS, Raman, H2-TPR, XRD, CO chemisorption and BET surface area analyzers were used to characterize the catalysts.

3D-printed devices for continuous-flow lithium recovery of brines

Adsorption processes were widely used in the recovery of lithium from salt lakes. Fixed-bed continuous flow reactors were mainly used in adsorption due to their simple structure and stable reaction. 3D printing, due to its ability to greatly reduce the packing and fixed-bed reactor design cycle and cost, was gradually becoming as one of the key technologies for intelligent manufacturing of fixed beds. This work utilizes the advantages of digital preparation by 3D printing to address the low elution efficiency and adsorption capacity of titanium-based lithium-ion sieves (Ti-LIS) in fixed-bed lithium recovery. 3D printed fixed bed packing with high adsorption capacity were prepared using an in-situ growth strategy, acidic gel and reactor design were utilized to achieve efficient elution of Ti-LIS. The dynamic adsorption showed that the adsorption capacity of 3D printed fixed bed packing could reach 16 mg·g−1 and the elution efficiency can be increased from 78 % to 95 % with the same amount of acid.

Enhanced ozonation of nitrobenzene in water using natural iron ores: Efficiencies, mechanisms and stability

Natural minerals show potential for catalytic ozonation in industrial wastewater treatment. In this study, the efficiencies and mechanisms of two natural iron ores in catalytic ozonation processes (COPs) for aqueous nitrobenzene degradation were initially investigated. Compared with single ozonation process, the removal of TOC increased by about 60 % and 35 % in COPs with natural magnetite and pyrite, respectively. Both natural magnetite and pyrite could promote O3 decomposition to form hydroxyl radicals and 1O2. But the inner reaction pathways were different. The natural magnetite facilitated O3 decomposition through the Lewis acids and the electron transfer between Fe(II)/Fe(III) on the catalyst surface, while electron transfer was the only pathway for O3 decomposition by natural pyrite. Continuous flow fixed-bed reactor was adopted to provide better simulation of the practical operation conditions, so that the potential of engineering application could be evaluated. The natural magnetite exhibited excellent catalytic activity and stability during long period continuous operation in fixed-bed reactor. The removal of TOC maintained at 81.9 % under the optimized operating parameters of hydraulic retention time (2.84 h), O3 velocity (0.25 L min−1) and O3 concentration (30 mg L−1). HCO3− and PO43− obviously inhibited the TOC removal efficiencies through radical scavenging and surface –OH occupying. While low concentration of Cl− and SO42− showed negligible effect on the mineralization of aqueous nitrobenzene. After the continuous operation for 672 h, the removal of TOC for nitrobenzene solution in the magnetite-COP system was still stable at about 80 %. The present study demonstrated the engineering application prospect of the natural iron ores in catalytic ozonation treatment of recalcitrant chemical wastewaters.

Catalytic Decomposition of CH4 to Hydrogen and Carbon Nanotubes Using the Pt(1)-Fe(30)/MCM-41 Catalyst

The catalytic decomposition of CH4 to H2 and carbon nanotubes (CNTs) was investigated regarding Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41 using a fixed-bed flow reactor under an atmosphere. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), and Raman spectroscopy were used to characterize the behavior of Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41. The hydrogen yield of Pt(1)-Fe(30)/MCM-41 was 3.2 times higher than that of Fe(30)/MCM-41. When 1 wt% of Pt was added to Fe(30)/MCM-41(Mobil Composition of Matter No. 41), the atomic percentage of Fe2p increased from 13.39% to 16.14% and the core Fe2p1/2 electron levels of Fe0 and Fe2+ chemically shifted to lower energies (0.2 eV and 0.1 eV, respectively) than those of Fe(30)/MCM-41. The Fe, Pt, Si, and O nanoparticles were uniformly distributed on the catalyst surface, and the average iron particle sizes of the Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41 were about 33.4 nm and 58.5 nm, respectively. This is attributed to the uniform distribution of the nano-sized iron particles on the MCM-41 surface, which was due to the suitable metal-carrier interaction (SMCI) between Fe, Pt, and MCM-41 and the high reduction degree of Fe due to the spillover effect of H2 from Pt to Fe. Pt(1)-Fe(30)/MCM-41 produced multiwalled CNTs and bamboo-shaped CNTs with high crystallinity and graphitization degree using the tip-growth mechanism, with an ID/IG ratio of 0.93 and a C(101)/C(002) ratio of 0.64.

Unraveling the impact of phosphate doping on surface properties and catalytic activity of gold supported on mixed iron-niobium oxide in gas phase methanol oxidation

In recent decades, there has been notable interest in understanding the influence of the support composition on the reactivity of gold species in oxidation processes. This study fits in with this scientific trend and investigates the effects of incorporating phosphate ions into Au catalysts supported on mixed iron-niobium oxides in methanol oxidation. All materials were thoroughly characterized using XRD, ICP-OES, DR-UV-Vis, N2 physisorption, HRTEM, HAADF-STEM, SEM-EDX, XPS, TPD-NH3, TPD-CO2, and in situ FTIR combined with adsorption of NO. Activity of the catalysts was evaluated using a fixed-bed flow reactor combined with gas chromatography and operando FTIR-MS system. It was observed that the phosphate-doped catalyst supported on mixed Fe-Nb oxide exhibited significantly higher activity than phosphate-free sample. This improvement resulted from increased electron mobility, enhanced acidity, and optimized distribution of gold nanoparticles on the former catalyst. Knowledge resulting from this work can lead to the development of more efficient gold catalysts.

Role of cation in catalytic decomposition of ammonia over Ni supported zeolite Y catalysts

A series of nickel (Ni) catalysts were prepared using zeolites Y with different cation types (Na, Mg, Ca, Sr, Ba, Ce, and La) as supports and characterized by using XRD, BET, ICP-OES, XPS, and TEM, as well as NH3-TPD, CO2-TPD, and H2-TPR techniques. Their catalytic performances in decomposition of ammonia (NH3) to hydrogen (H2) were evaluated with a fixed-bed flow reactor system. The catalytic activities of the prepared catalysts for NH3 decomposition decreased in the order of Ni/SrY > Ni/BaY > Ni/LaY > Ni/CaY > Ni/NaY > Ni/MgY > Ni/CeY. The high activity of Ni/SrY catalyst may be attributed to its small Ni nanoparticle size, high basicity and strong interaction between highly dispersed Ni nanoparticles and SrY support. At 600 °C and GHSV of 9000 mLNH3·gcat−1·h−1, 98.0 % NH3 conversion with about 105.2 mmol min−1·gNi−1 H2 formation rate can be accomplished over Ni/SrY catalyst.

Morphologically tuned CuO-ZnO-CeO2 catalyst for CO2 hydrogenation to methanol.

Morphologically modified composite CuO-ZnO-CeO2 catalysts were synthesized using a single-step hydrothermal technique. The study highlights the influence of solvent on the structural and physico-chemical properties of the catalysts. Various techniques, such as XRD, FE-SEM, BET, XPS, and H2-TPR, were used to analyze the catalyst properties. Among the synthesized materials, the catalyst, prepared with a N,N-dimethyl formamide (DMF)-to-metal nitrates ratio of 20 (named as CZC-1), showed enhanced active sites in the form of surface features such as nanowire-like morphology, large surface area, low crystallite size, increased oxygen vacancies, and high CuO dispersion. A bench-scale fixed-bed flow reactor was used to examine the catalytic performance of the catalysts. At 225 °C reactor temperature, 30 bar reactor pressure, and with a space velocity of 6000 cm3 gcat-1 h-1, the CZC-1 catalyst showed 13.6% CO2 conversion and 74.1% methanol selectivity. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis confirmed the carbonate-formate-methoxy reaction pathway for methanol formation using the CZC-1 catalyst.

From waste to raw chemicals: Catalytic transformation of fusel oil by mixed metal oxides

In this study, we detail a catalytic process for the conversion of fusel oil (FO), a by-product of ethanol production considered as waste, into valuable organic compounds, including aldehydes, alkenes, ketones, and alkylbenzenes spanning a carbon chain length from C6 to C12. The reaction was carried out in a fixed bed flow reactor at atmospheric pressure, employing mixed metal oxides (MMO) derived from hydrotalcites (HTC) as catalysts. The HTC were readily synthesized by co-precipitation method involving Mg2+ and Al3+, wherein 20 mol% Mg2+ was substituted by M2+ = Mn, Fe, Co, Ni, Cu, and Zn, and MMO obtained by HTC calcination. These catalysts offer cost-effectiveness compared to noble metal-containing ones while exhibiting remarkable activity in dehydrogenation, hydrogenation, and dehydration reactions pivotal for alcohol reactivity. The proposed methodology holds promise for large-scale industrial use and pioneers a fresh avenue for deriving value-added raw chemicals from a renewable carbon source.

Noble-Metal-Free Carbon Encapsulated CoNi Alloy Catalyst for the Hydrogenation of 5-(Hydroxymethyl) Furfural to Tetrahydrofurandiol in Aqueous Media.

The selective hydrogenation of 5-(hydroxymethyl)furfural (HMF) into 2,5-bis-(hydroxymethyl)tetrahydrofuran (BHMTHF) in flow reactor using water as a green solvent, has been achieved on a non-noble metal catalyst based on monodispersed CoNi alloy nanoparticles covered by a thin carbon layer. The alloyed catalyst containing CoNi (molar ratio 1 : 1) was prepared in a one-step synthesis following a hydrothermal method. Total conversion of HMF with 91 % selectivity to BHMTHF was achieved. The reaction network has been stablished, in which the carbonyl group of HMF is first reduced to alcohol giving the 2,5-bis-(hydroxymethyl)furan (BHMF) with an apparent activation energy of 25 KJ/mol, and then the double bonds of the furan ring are hydrogenated (apparent Ea=31 KJ/mol). Formation of byproducts, mainly proceed from furan ring opening and ring rearrangement processes of BHMF, promoted by water. BHMTHF resulted a compound highly stable under reaction conditions. The fixed bed flow reactor was maintained operational for 65 h without observing any loss of catalytic activity and selectivity.

Advancing continuous flow techniques in effective trimethoprim oxidation: combatting bacterial resistance in wastewater.

This work describes an innovative catalytic process for aqueous trimethoprim degradation, using a fixed-bed continuous flow reactor packed with a manganese(III) meso-substituted porphyrin covalently immobilized functionalized aminopropyl silica gel as the catalyst and H2O2 as a green oxidant. It exhibits remarkable activity and stability, maintaining its performance over extended periods (up to 8 hours) and achieving significant reductions in total organic carbon (TOC = 80%). Importantly, microbiological assays confirmed that this degradation process effectively converts trimethoprim into non-resistance-inducing products.

CoZr nanocomposites in a ceramic-metal AlOx(OH)y/Al matrix with a different Co/Zr ratio and its potential for syngas processing.

We investigated the possibility of synthesizing Co nanoparticles in CoZrnH/AlOx(OH)y/Al ceramic-metal catalysts and controlling the catalytic properties of these nanoparticles in syngas conversion by changing the Co/Zr ratio. The CoZr nanocomposites were obtained from metal powders by mechanochemical activation in a high-energy mill under an argon atmosphere, followed by treatment with hydrogen at high pressure and room temperature. Ceramic-metal catalysts were prepared by mixing the corresponding CoZrnH powder nanocomposite (30 wt%) with powdered aluminum (70 wt%), hydrothermal treatment of the mixture and subsequent calcination. The materials were characterized with a set of physicochemical methods: powder X-ray diffraction, scanning electron microscopy, 59Co internal field nuclear magnetic resonance spectroscopy, and temperature programmed reduction. Catalytic studies were performed in a laboratory fixed-bed flow reactor at 2 MPA and 210-270 °C. It is shown that the activity in syngas conversion to C5+ hydrocarbons and selectivity to methane and C2-C4 hydrocarbons depend on the Co/Zr ratio. Thus, with an increase in the zirconium content in the samples, the interaction of metal cobalt with metal zirconium improves in the process of mechanical activation and subsequent treatment with hydrogen. The destruction of the agglomerates of crystallites of metallic cobalt in the form of β-Co (Cofcc) occurs as well as their transformation to α-Co (Cohcp) particles active in the syngas conversion to C5+ hydrocarbons. This can explain the highest specific yield of C5+ hydrocarbons on a cermet with the lowest Co/Zr ratio.

High-dispersed CeOx species on mesopores silica to accelerate Ni-catalysed CO2 methanation at low temperatures

CO2 methanation is a key step in the power-to-gas technology for storing and distributing renewable energy as energy vectors. Due to thermodynamic constraints, highly active catalysts below about 300 °C are necessary. We demonstrate that their preparation is possible by supporting Ni nanoparticles over highly dispersed CeOx species decorating mesopores silicate (mSiO2) obtained by a template-free method. The CeOx decorated mSiO2 exhibits a 3-fold increase in activity and enhanced CH4 selectivity (98.7 % at 300 °C) compared to the Ni/mSiO2 catalyst. The performances are superior compared to the literature data. A systematic characterisation by physisorption, XPS, XAFS, UV–Vis and HR-TEM shows a uniform dispersion of highly dispersed CeOx within the mesoporous silica framework. The CO2 hydrogenation properties were investigated in a fixed-bed flow reactor and complemented by CO2-TPD, CO2-TPSR, in-situ FTIR, and D2 kinetic isotope experiments. The results show that highly dispersed CeOx exhibits excellent CO2 adsorption and dissociation abilities. The inverse kinetic isotope effect indicates that CO2 activation is the rate-determining step of the reaction. CO2 is strongly adsorbed on CeOx to form bidentate carbonate, which accelerates the generation of CO while avoiding the adsorption of CO2 on Ni nanoparticles.

Tuning Cu+ species/Brønsted acids of copper phyllosilicate by K+ doping for selective hydrogenation of methyl palmitate to hexadecanol

Selective hydrogenation of methyl palmitate to hexadecanol can be manipulated by tuning Cu+ species and Brønsted acid sites (BAS) of copper phyllosilicate (CuPS) catalysts with K+ doping. The catalysts were prepared by impregnating K+ onto reduced and non-reduced CuPS. The reactions were carried out in a fixed-bed flow reactor at 250 °C under atmospheric H2. In situ TR-XANES and Py-IR suggest that the presence of K+ could stabilize Cu+ species and neutralize BAS. As compared to the non-reduced sample, K+ loading (0.01–0.10 wt%) on the reduced CuPS provide higher Cu+ fraction (10–16%), lower BAS (0.82 to 0.16μ mol/g) and lower Cu dispersion (75 to 52%). A balance between Cu0 active surface and Cu+ content provides an optimum hydrogenation activity (up to 80 %). The increased Cu+ species, together with the decreased BAS, does not only enhance the catalyst stability, but also hexadecanol selectivity (from 35 to 60%, at ∼50% conversion).

Cu-Ni bimetallic nanoparticles anchored on halloysite nanotubes for the environmental remediation

Hereby, we report the synthesis of CuNi bimetallic nanoparticles (NPs)-decorated halloysite nanotubes (CuNi/HNTs) for the catalytic reduction of 4-nitroaniline (4-NA) and rhodamine B (RhB) dye in an aqueous medium at room temperature. In this work, CuNi/HNTs composites with different wt% of CuNi NPs were synthesized and characterized by various techniques such as SEM, EDS, XRD, TEM and XPS. The TEM characterization confirmed that the CuNi bimetallic NPs (∼ 11 nm) were successfully anchored onto the outer surface of HNTs. Among the prepared catalysts, Cu0.75Ni0.25/HNTs catalyst displayed highest catalytic activity in the reduction of 4-NA to its corresponding amino derivative in the presence of NaBH4 with a maximum conversion efficiency of >99% and an apparent rate constant kapp of 0.152 s−1 within 30 s of reaction time. Notably, even after 15 cycles of catalytic reduction of 4-NA and RhB, there was no apparent deactivation of the catalytic activity of the Cu0.75Ni0.25/HNTs catalyst, demonstrating the excellent catalytic reusability and stability. The presence of CuNi NPs with low Ni content enhanced the catalytic activity due to the synergetic effect. Moreover, the continuous flow fixed bed reactor designed with Cu0.75Ni0.25/HNTs catalyst exhibited the potential application for the reduction of 4-NA and RhB dye under mild reaction conditions. Furthermore, the present catalytic system could be applicable for the treatment of various wastewater effluents.

High-performance Cu/Mn modified ceramsite as a persulfate activator to degrade oxytetracycline in batch Erlenmeyer flask and continuous-flow fixed-bed column systems: An exploration of its practicability and non-radical mechanisms

Persulfate non-radical oxidation have excellent catalytic capability for degrading specific contaminants in complicated water environments. Nevertheless, the preparation of high-performance activators and their application in actual water treatment in continuous flow mode are still scarce and unsatisfactory. In this work, copper-, manganese-, and copper/manganese-doped ceramsites (Cu–C, Mn–C and Cu/Mn–C), successfully fabricated through a facile impregnation-calcination approach, were characterized and evaluated for their performance to activate potassium peroxydisulfate (PDS) and degrade oxytetracycline (OTC) under different pH, ceramsite dosages, and PDS dosages. Compared with Cu–C and Mn–C, Cu/Mn–C showed the highest OTC degradation rate (0.0264 min−1) via activating PDS with an OTC removal efficiency of 98.2% in 240 min at an initial OTC concentration of 40 mg/L. The removal efficiency of OTC by Cu/Mn–C only decreased to 92.8% after 5 cycles; the activating ability of the used Cu/Mn–C was almost completely recovered through 2 h of calcination at 500 °C. The results of electron paramagnetic resonance and radical quenching suggest that singlet oxygen (1O2) was unveiled to be the dominant reactive oxygen species (ROS) for contaminant degradation, originating from the regrouping of superoxide ions or reduction of active Cu/Mn sites. Synergies between Cu and Mn species to enhance ROS yield were the primary activating mechanisms. Six possible routes of OTC decomposition were inferred. Additionally, Cu/Mn–C behaved excellently in treating an actual wastewater using a continuous flow fixed-bed reactor. It is believed that this novel Cu/Mn–C/PDS system may create a fresh path to design effective and cheap metal-ceramsite hybrid activators for degrading recalcitrant contaminants in the actual application process.

Improvement of n-Butene Yield in Dimethyl Ether-to-Olefin Reaction Using Ferrierite Zeolite Catalysts

Various ferrierite zeolites were investigated as catalysts for the dimethyl ether (DME)-to-olefin (DTO) reactions to efficiently synthesize n-butene, such as 1-butene, trans-2-butene, and cis-2-butene except for iso-butene using a fixed-bed flow reactor. Twenty P-loaded ferrierite zeolites with different structural parameters and acidic properties were prepared by the impregnation method by varying the P content and the temperature of air calcination as a pretreatment. The zeolites were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, and NH3 temperature-programmed desorption (NH3-TPD). Micropore surface area, external surface area, total pore volume, micropore volume, and weak and strong acid sites affected the DTO reaction behavior. A high n-butene yield (31.2 C-mol%) was observed, which is higher than the previously reported maximum yield (27.6 C-mol%). Multiple regression analysis showed that micropore surface area and strong acid sites had a high correlation with n-butene yield. Based on our findings, we explained the reaction mechanism for selective n-butene synthesis except for iso-butene in the DTO reaction by the dual cycle model.