N2 Adsorption Desorption Research Articles

Synergistic adsorption and photocatalytic degradation of tetracycline using a Z-scheme kaolin/g-C3N4/MoO3 nanocomposite: A sustainable approach for water treatment

This research focuses on the synthesis and application of a novel kaolin-supported g-C3N4/MoO3 nanocomposite for the degradation of tetracycline, an important antibiotic contaminant in water systems. The nanocomposite was prepared through a facile and environmentally friendly approach, leveraging the adsorption and photocatalytic properties of kaolin, g-C3N4 and MoO3 nanoparticles, respectively. Comprehensive characterization of the nanocomposite was conducted using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and optical spectra. The surface parameters were studied using N2 adsorption-desorption isotherm. The elemental composition was studied using X-ray photoelectron spectroscopy. The efficiency of the developed nanocomposite in tetracycline degradation was evaluated and the results revealed an efficient tetracycline degradation exhibiting the synergistic effects of adsorption and photocatalytic degradation in the removal process. The tetracycline degradation was achieved in 60 min. Kinetic studies and thermodynamic analyses provided insights into the degradation mechanism, suggesting potential applications for the nanocomposite in wastewater treatment. Additionally, the recyclability and stability of the nanocomposite were investigated, demonstrating its potential for sustainable and long-term application in water treatment.

Degradation of clofibric acid by ozonation assisted by Co-Ce-SBA-15: Role of interfacial electron migration

Restrained by the sluggish Ce redox cycle, Ce-SBA-15 exhibited the low electron transfer toward O3 activation. To this end, cobalt‑cerium co-doped SBA-15 with three-dimensional pore structure was designed using urea-assisted hydrothermal method and its activity was evaluated using Clofibric acid (CA) as target pollutant. XRD and N2 adsorption-desorption characterizations suggested that Co-Ce-SBA-15 possessed a three-dimensional pore structure with high order degree. py-FTIR, O2-TPD, H2-TPR, and in situ electrochemical characterizations indicated that compared with Ce-SBA-15 and Co-SBA-15, Co-Ce-SBA-15 had greater Lewis acid strength, electron transfer ability and oxygen reducibility. Co-Ce-SBA-15/O3 achieved the greater CA removal and mineralization rate, with 98.7 % CA removal and 58.3 % TOC removal were obtained in 90 min. Co-Ce-SBA-15/O3 process would be inhibited by the coexisting Cl−, NO3− and SO42−. Co-Ce-SBA-15 demonstrated the greater ozone utilization rate than those of monometallic SBA-15. Lewis acidic sites of Co and Ce were the main sites for activating O3. DFT results suggested that the obvious electron transfer existed among O3, Co and Ce Lewis acid sites. The conversion of Co3+/Co2+ and Ce4+/Ce3+ accelerated the interfacial electron transfer, which favored for conveying O3 into •OH. •OH was the primary reactive oxygen species involved in degrading CA. 8 kinds of intermediates were found during CA degradation and the possible degradation route was proposed. This study deepened the understanding of the cooperative effect of Co and Ce in catalytic ozonation process.

Efficient removal of cadmium from aqueous solution by chitosan grafted pillared bentonite

Developing an environmentally friendly adsorbent with high adsorption capacity and economic advantages is crucial for the treatment of cadmium (Cd)-contaminated wastewater. In this study, Bentonite (Bt), which is widely distributed in nature, was used to prepare a new type of chitosan (CS)-grafted polymerized aluminum-pillared bentonite (i.e., Al@Bt): CS@Al@Bt. This new material effectively addresses the issues of chitosan’s poor mechanical strength, limited load capacity, and the weak adsorption properties of raw bentonite for Cd. The effects of synthesis conditions on Cd adsorption by modified bentonite were investigated through batch experiments. The adsorption mechanism was revealed by characterization tests such as X-ray diffraction (XRD), N2 adsorption-desorption experiments, Scanning and Transmission electron microscopy (SEM-TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results showed that compared to raw Bt, when the ratio of Al in polymerized aluminum to the cation exchange capacity (CEC) of Bt was increased to 5 (i.e., Al/CEC=5), the specific surface area (SSA) of Bt increased from 78.46 m²/g to 195.99 m²/g. Additionally, the interlayer spacing and total pore volume increased by 1.22 and 1.13 times, respectively. After grafting chitosan onto Al@Bt, CS@Al@Bt reached adsorption equilibrium rapidly within 15 min, achieving a removal rate of up to 99.82% (initial concentration of Cd(II) was 20 mg/L, and the solid-liquid ratio was 1 g/L). Additionally, CS@Al@Bt showed good adsorption performance over a wide pH range. The rich pore structure of CS@Al@Bt and the complexation between amino (-NH2) and hydroxyl (-OH) groups with Cd(II) were the main mechanisms for the removal of Cd(II) from the solution. The application showed that CS@Al@Bt effectively reduced Cd-containing mining wastewater from class V to class II quality, underscoring its significant potential for treating Cd(II)-contaminated wastewater.

Low temperature activation of methane to hydrogen depending on tailored electron transfer over Ni–Cr composite oxide

Current industrial use of methane depends mainly on high-temperature conversion, resulting in high energy consumption and catalyst sintering inactivation. In this paper, metal oxide catalysts with different Ni/Cr ratios were obtained by the sol-gel method for the methane activation reaction. The structure-property relationships of the catalysts were investigated by XRD, XPS, H2-TPR, TG, N2 adsorption-desorption, and CV, focusing on the interaction between Ni–Cr in the composite oxide catalysts. The results showed that Ni0–NiCrO3/Cr2O3 structure was formed after the Ni–Cr oxides underwent the reduction and calcination process, which provided a structural support for electron transfer between the two metals. The least prone to sintering nickel metal particles and the highest content of high-valent chromium ions were present in Ni1Cr2. XPS confirmed that this counterpart acts as the donor and acceptor for electron transfer in the catalysts, accelerating oxidation-reduction reaction over the catalyst. The catalyst exhibited the most excellent conversion and product selectivity in the methane activation reaction.

Synergistic Effect of Co and Ni Co-Existence on Catalytic Decomposition of Ammonia to Hydrogen—Effect of Catalytic Support and Mg-Al Oxide Matrix

Hydrotalcite-derived mixed metal oxides containing Co and Ni and containing these metals supported on MgO and Al2O3 were prepared and tested as catalysts for the decomposition of ammonia to hydrogen and nitrogen. The obtained samples were characterised in terms of chemical composition (ICP-OES), structure (XRD), textural parameters (low-temperature N2 adsorption–desorption, SEM), form and aggregation of transition-metal species (UV-Vis DRS), reducibility (H2-TPR) and surface acidity (NH3-TPD). The catalytic efficiency of the tested systems strongly depends on the support used. Generally, the alumina-based catalyst operated at lower temperatures compared to transition metals deposited on MgO. For both series of catalysts, a synergistic effect of the co-existence of cobalt and nickel on the catalytic efficiency was observed. The best catalytic results were obtained for hydrotalcite-derived catalysts; however, in the case of these catalysts, an increase in the Al/Mg ratio resulted in a further increase in catalytic activity in the decomposition of ammonia.

Synthesis of Cu doped NiO for their antioxidant and photocatalytic properties: Green synthesis using Lycopodium Linn

Metal oxide nanoparticles produced by plant extracts are more stable and biocompatible in comparison with those produced by physical and chemical methods. This research focuses on the synthesis of pure and Cu doped NiO nanoparticles (NPs) using Phytolacca dodecandra L'Herit (P.d) leaf extract and evaluation of their antioxidant and photocatalytic activities. The obtained Cu-doped NiONPs have been characterized through X-ray diffraction (XRD), Transmission electron microscope (TEM), Fourier transform infrared (FT-IR), Ultraviolet-visible (UV–Vis), N2 adsorption-desorption and X-ray photoelectron spectra (XPS) analyses in different concentrations (1, 3, and 5 %) of copper at an optimum temperature of 400 °C. The photocatalytic activity of prepared samples was studied by degradation of Rose Bengal (RB) and Methylene Blue (MB) dye aqueous solutions. Under UV radiation for 60 min. 5-Cu-NiO nanophotocatalyst showed degradation efficiency of 98.7 % (0.5 mol/L), high apparent constant (0.9871 min−1) and long term stability towards MB dye. In the antioxidant test, NiO NPs and Cu−NiO NPs prevented the oxidation of 50 % of the H2O2 molecules at a concentration of 363.96 and 350.29 μg/mL, respectively. Moreover, the enhancement of the antioxidant activity of the biosynthesized NiO NPs might be an effect of copper ions present in the particles. Facile and green synthesis process with the excellent degradation performance demonstrates that the Cu doped NiO NPs have a great potential for wastewater treatment applications.

Enhancing the selectivity for light olefins through catalytic cracking of n-hexane by phosphorus doping on lanthanum-modified ZSM-5

Naphtha, as the primary raw material in the production of light olefins, could well accommodate their increasing demand through the energy-efficient process of catalytic cracking with ZSM-5. In the current work, different amounts of lanthanum and phosphorous were loaded on ZSM-5 using the wet impregnation method to tune the acidic properties of ZSM-5 for selective catalytic cracking of n-hexane to produce light olefins. Various characterization techniques such as X-ray diffraction (XRD), Al nuclear magnetic resonance (NMR), temperature-programmed desorption of NH3 (NH3-TPD), Py-Fourier transform infra-red (Py-FTIR), inductively coupled plasma optical emission spectroscopy (ICP-OES), N2 adsorption–desorption, X-ray photoelectron spectra (XPS), and scanning electron microscopy were adopted to investigate the modified zeolites. It was found that adding La to ZSM-5 (0.25 wt% to 1 wt%) improved the catalytic life and increased the n-hexane conversion (to 99.7%), while the further addition had a negative impact, reducing the conversion rate and deviating the product selectivity towards a substantial, undesired benzene, toluene, and xylene (BTX) fraction (33%). On the other hand, a 64% selectivity for light olefins was achieved on phosphorous-doped ZSM-5 (at a loading amount of 1 wt%) while reducing the BTX fraction (2.3%) and converting 69% of the n-hexane. A dual metal-modified ZSM-5 with optimal loading amount, 1P0.25LaZ5 (phosphorus 1 wt% and La 0.25 wt%), helped boost the light olefin selectivity to 62% in the tuned Lewis acid sites at an n-hexane conversion of about 77% while decreasing the undesired BTX selectivity to 3% by reducing the number of Brønsted sites. Thus, the current study reveals that tuning the acidic sites of ZMS-5 by dual metal augmentation with P.La is an effective way of controlling the amount of undesirable BTX produced at a stable n-hexane conversion rate and substantial olefin selectivity.

Synthesis and characterization of Ionic liquid supported on Zeolitic Imidazolate Framework-8 (ZIF-8) as a highly effective additive for visbreaking of petroleum vacuum bottom

In this present work, a zeolitic imidazolate framework, ZIF-8, an oil-soluble long chain Ionic Liquids, [OMIM][NTf2], was separately synthesized and characterized. Ex-situ preparation of [OMIM][NTf2]-ZIF8 (IL@ZIF8) nanostructures were performed solvothermal, and the products were specified by the several techniques including XRD, FESEM, H-NMR, FTIR, TGA and N2 adsorption-desorption. The products were evaluated as a highly effective material in visbreaking process of petroleum vacuum bottoms (PVBs). To best our knowledge, no was reported in survey on the literature for MOFs as conversion enhancer and viscosity modifier in a visbreaking process especially for atmospheric pressure and elevated temperatures of 375 -400 °C during maximum 120 min. Injection of a little amount of the synthesized products to PVBs caused to produce gaseous compounds, naphtha, middle distillates, lubricating oil and tar. However, viscosity measurement results revealed that IL@ZIF8 was ideally suited for viscosity reduction of PVBs up to 321% after cracking and conversion of PVBs to its distillates up to 1400%. Catalytic upgrading with IL@ZIF-8 also yielded a liquid with 50% light hydrocarbon without any further coke formation.

Management of caffeine in wastewater using MOF and perovskite materials: optimization, kinetics, and adsorption isotherm modelling

AbstractPharmaceuticals and personal care products (PPCPs) have been increasingly used all over the world and they have been reported on water cycle and cause contamination. Among these pharmaceuticals is caffeine (CAF). In this work, CAF removal from aqueous samples by metal–organic framework (UIO-66) and perovskite (La0.7Sr0.3FeO3) was achieved. Detailed studies on the preparation of MOFs and perovskite oxides compounds have been presented. Extensive characterizations such as X-Ray diffraction (XRD), field emission scanning electron microscope (FESEM), Fourier transform infrared spectra (FT-IR), N2 adsorption–desorption isotherms were also carried out to assure proper formation and to better understand the physico-chemical behavior of the synthesized samples before and after adsorption. Batch experiments of CAF adsorption onto both MOFs and perovskite were performed to compare the effectiveness of both materials on the removal competence of the CAF residue at different conditions including the effect of pH, initial concentration, and contact time. It was observed that the adsorption capacity of CAF by MOF increased with increasing acidity. On the other hand, the adsorption capacity of perovskite is stable in pH 4–10. The maximum adsorption capacities of UiO-66 and perovskite toward CAF are high as 62.5 mg g−1 and 35.25 mg g−1, respectively. Equilibrium isotherms were investigated by numerous models: Langmuir, Freundlich, Temkin, Redlich-Peterson, Sips, Langmuir-Freundlich, Toth, Kahn, Baudu, and Fritz Schlunder. Moreover, the kinetics of the CAF@MOF and CAF@Perovskite systems have been studied by five kinetic models (Pseudo-1st -order (PFO), Pseudo-2nd -order (PSO), Mixed 1st, 2nd-order, Intraparticle diffusion and Avrami). The best model described the adsorption of CAF onto both of MOF and perovskite was the mixed 1st, 2nd-order model. The metal–organic framework and perovskite were applied to quickly extract CAF from water samples successfully. The maximum removal percentage obtained for MOF and perovskite was 0.89% and 0.94% respectively within 30 min contact time which suggests that these materials are considered as promising adsorbents for CAF.

Alkylation of Phenol with Methanol over ZSM‐5 Zeolite

AbstractThe catalytic performance of different molecular sieves in the alkylation of phenol with methanol to produce p‐cresol was evaluated, and the acidity and structure of the catalysts were characterized using N2 adsorption–desorption and Fourier transform infrared spectroscopy techniques. It was shown that the catalytic activity of molecular sieves was closely related to their acidic site number, specific surface area, and pore structure. Since Zeolite ZSM‐5 (Zeolites Socony Mobil No. 5) has a relatively small amount of strong acid as well as a small pore size, it is favorable for the diffusion of p‐cresol out of the pores. Therefore, focusing on ZSM‐5, the effects of operating conditions such as weight hourly space velocity (WHSV), phenol/methanol (P/M) ratio, and reaction temperature on the catalytic performance were investigated. The results showed that increasing the WHSV, P/M ratio, and reaction temperature improved the selectivity to cresol. In addition, X‐ray diffraction and Thermal Gravity/Differential Thermal Gravity characterization methods were also carried out for ZSM‐5, and it was found that the deactivation of ZSM‐5 was due to coke deposition and pore blockage on the active site and that the selectivity to cresol could be restored by regenerating the catalyst and covering the strong acid site, which resulted in the reduction of the strong acid site to increase the selectivity of the product.

Modification of new magnetic nanocomposites Bi2WO6/CuFe2O4 and its excellent catalytic reduction for toxic nitroaromatic compounds and chromium (VI)

New magnetic Bi2WO6/CuFe2O4 nanocomposites were synthesized using hydrothermal method. The specific features of Bi2WO6/CuFe2O4 nanocomposites were studied using various analytical techniques such as Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and N2 adsorption desorption analyses, Brunauer-Emmett-Teller (BET). The BET analysis demonstrates that embedded CuFe2O4 nanoparticles in Bi2WO6 structure have increased the pore diameters and surface area for better adsorption of NaBH4 and catalytic performance. The VSM analysis confirms the magnetic behavior of nanocomposite which showed that Bi2WO6/CuFe2O4 could be separated and recoverd easily by an external magnet after catalytic reactions. The catalytic performance of nanocomposites was investigated for the reduction of nitroaromatic compounds including 4-nitroaniline (4-NA), 4-nitrophenol (4-NP), 2-nitroaniline (2-NA) and 2-nitrophenol (2-NP) and chromium (VI) in aqueous solution. The results show the nanocomposites have excellent ability to reduces Cr(VI) to Cr(III) and nitroaromatic compounds to the corresponding amines in green water solution at room temperature. The best performance observed for the 100% conversion of 4-nitrophenol reduction belongs to Bi2WO6/CuFe2O4 20%, which completes in 6 min, and its rate constant is about 0.67 min−1. In addition, the Bi2WO6/CuFe2O4 nanocomposite can be appropriately recycled and reused several times without changing its structure and activity, which is essential for practical applications.

One-pot synthesis of quinazolinone heterocyclic compounds using functionalized SBA-15 with natural material ellagic acid as a novel nanocatalyst

The nanoporous compound SBA-15 was functionalized using (3-aminopropyl)trimethoxysilane (APTES). Then the obtained product was modified with ellagic acid (ELA), a bioactive polyphenolic compound. The structure of the prepared nanoporous composition SBA-15@ELA was extensively characterized and confirmed by various techniques, such as Fourier-transform infrared (FT-IR) spectroscopy, Energy dispersive X-ray (EDX) elemental analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption–desorption isotherms (BET). The novel, recoverable, heterogenous SBA-15@ELA nanoporous compound was used to investigate its catalytic effect in the synthesis of 4-oxo-quinazoline derivatives (19 examples) with high yields (78–96%), as an important class of nitrogen-containing heterocyclic compounds. The use of an inexpensive mesoporous catalyst with a high surface area, along with easy recovery by simple filtration are among the advantages of this catalysis research work. The catalyst has been used in at least 6 consecutive runs without a significant loss of its activity.

Feasibility study of replacing part of cement by igneous rock powder as cementitious material: based on mortar macroscopic properties and microstructure

To address the increasing demand for cement and promote sustainable development, the utilization of igneous rock powder as a supplementary material to partially replace cement has emerged as an effective strategy. In this study, the fluidity and mechanical properties of the igneous rock powder-cement (IRP-OPC) composite system were investigated, and the hydration product and microstructure of IRP-OPC were analyzed by using TG/DSC, N2 adsorption-desorption curve (BET) and SEM. The experimental findings demonstrate that the performance of the andesite powder-cement composite cementing system (AP-OPC) surpasses that of tuff powder-cement slurry (TP-OPC) and granite powder-cement slurry (GP-OPC). When the dosage of andesite powder (AP) is 5%–15%, the flowability, flexural strength and compressive strength of cement mortar are improved. When the dosage is 10%, the 28-day compressive strength is 48.3 MPa. Under the condition of low content (10%), part of Ca(OH)2 is fully consumed by active SiO2 in AP and reacts to form C-S-H. Hydration products and AP particles with small particle size are filled into the structural gap, which refines the pore structure of cement slurry, and the increase in compactness provides support for the development of strength in the later stage. The use of 5%–15% AP instead of OPC can improve fluidity and meet the strength requirements of P.O 42.5 Portland cement. This substitution not only reduces engineering costs but also enhances resource utilization.

Synergy between Fe-Co oxide catalysts supported over HZSM-5 for direct conversion of methane to methanol

The direct conversion of methane to methanol over iron and cobalt oxide based composite catalysts supported over HZSM-5 was carried out in a fixed-bed micro reactor under changing process parameters and catalyst compositions. The prepared catalysts were well characterized by various techniques including N2 adsorption desorption, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), pyridine FTIR, X-ray photoelectron spectroscopy (XPS), UV–vis spectroscopy and temperature programmed reduction (H2-TPR). The characterization results revealed the presence of various reducible iron and cobalt oxide species depending on the Fe/Co molar ratio and total metal oxide loading. Moreover, the XPS and UV–vis spectroscopic results also confirmed the variation of Fe2+/Fe3+ and Co2+/Co3+ species depending on the Fe-Co molar ratio which had strong influence on the performance of the composite catalysts. It was found that the cobalt species favours the formaldehyde formation whereas the iron species promotes the formic acid formation in their respective pure supported oxide catalysts. However, the synergistic effect of iron and cobalt oxide in equimolar ratio in composite catalysts appeared as effective for achieving highest yield of methanol. The methanol selectivity was also influenced by the alteration of various studied process parameters. The higher reaction temperature favoured the overoxidation of methanol to CO2 whereas the methanol selectivity increased with increasing the methane to oxygen ratio. The lattice to adsorbed oxygen ratio also had strong influence on the activity of composite catalysts and methanol selectivity. The highest methanol yield of 1.87% was achieved at the methane conversion of 42.81 % with the 20Fe1Co1Z catalyst at 873 K reaction temperature with CH4/O2 ratio of 2:1 and WHSV of 1030 ml hr−1 gcat−1.

Noble metal modified copper-exchanged mordenite zeolite (Cu-ex-MOR) catalysts for catalyzing the methane efficient gas-phase synthesis methanol

Copper mordenite catalysts are key for methane oxidation to methanol, yet lack sufficient activity. In this paper, noble metal (Au, Ru, Pt and Pd) modified copper ion-exchanged mordenite catalysts were prepared by the ion-exchange method for further improving the methanol yield in the gas-phase continuous catalytic direct partial oxidation of methane to methanol reaction, and the role of noble metal doping on Cu-ex-MOR catalysts was investigated. Experimental results showed that the doping of Ru resulted in a significant increase in the methanol yield of Ru/Cu-ex-MOR catalyst to 157.36 μmol/gcat/h compared to that of Cu-ex-MOR catalyst (12.89 μmol/gcat/h). SEM, XRD, FT-IR, N2 adsorption-desorption, XPS, NH3-TPD and H2-TPR results showed that Ru/Cu-ex-MOR had uniformly dispersed Ru elements and the largest number of surface acidic and oxidation sites, which facilitated the adsorption and activation of methane. Additionally, it was found by TEM, in situ FT-IR and DFT characterization that Ru played a role in stabilizing the Cu active sites, the adsorptive activation of water on the Ru site and the H-transfer process reduced the energy required for breaking C–H bond of CH4 at the Cu active site, which significantly improved the methane activation capacity of the Ru/Cu-ex-MOR catalysts, resulting in higher methanol yields.

Influence of nickel contents on synthesis gas production over nickel-based catalysts supported by treated activated carbon in dry reforming of methane

This study focuses on the utilization of activated carbon (AC) as a catalyst support after undergoing treatment with HNO3. The treated AC exhibited a microporous structure and a high specific surface area (SBET) of 1483.8 m2 g−1. In this study, supported nickel-based catalysts were synthesized using the wet impregnation method with varying amounts of NiO (2.5, 5, 7.5, 10, 12.5, and 15 wt%). The calcined catalyst samples were then evaluated for their performance in the dry reforming of methane (DRM). Characterization of the catalysts was conducted through FESEM, TPO, H2-TPR, XRD, and N2 adsorption-desorption (BET) analyses. The results revealed that catalytic efficiency increased with an increase in the nickel loading percentage, up to 12.5 wt%. The NiO (12.5)/AC catalyst demonstrated the highest CH4 (60%) and CO2 (68%) conversions and exhibited good stability at 700 °C during 10 h of reaction. Additionally, the catalyst's efficiency decreased with an increase in the calcination temperature from 400 to 600 °C. However, alterations in the CH4/CO2 molar ratio from 0.5 to 1.5 indicated that CH4 and CO2 conversions decreased from 85% to 40% and increased from 63% to 74% at 700 °C, respectively. Moreover, the findings demonstrated that elevating the gas hourly space velocity (GHSV) from 12,000 to 18,000 ml h−1.g−1cat resulted in a decline in catalytic efficiency at a temperature of 700 °C. Moreover, the catalytic efficiency declined with an increase in the reduction temperature from 500 to 600 °C.

Mesoporous silica aerogels for sunflower oil refining and investigation of their adsorption performance

AbstractInvolving a succession of oil refining stages for edible oil production, a notable constraint lies in the necessity to employ diverse adsorbents at various steps within these processes. This study investigates the synthesis of mesoporous silica aerogels from rice husk ash, comparing their efficacy in physical sunflower oil refining with earth clay (Bentonite) and commercial silica (Trisyl). Tetraethyl orthosilicate (TEOS) impact during aging was analyzed using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and N2 adsorption-desorption analyzer to examine alterations in the structure of silica aerogels. The surface areas of TEOS-doped silica aerogel (TSA) and non-TEOS-doped silica aerogel (NTSA) were 296.18 and 267.06 m²/g. Mesoporous silica aerogels were evaluated for their ability to reduce free fatty acids (FFA), peroxide value (PV), phosphorus, and color pigments in sunflower oil. TSA and NTSA demonstrated significant FFA removal, with TSA at 3 wt.% achieving the highest performance of 32.2%. TSA also effectively reduced PV and phosphorus compared to NTSA, Bentonite and Trisyl, exhibiting performance similar to Bentonite in the bleaching process. TEOS-doped silica aerogels have shown promise as adsorbents for impurity removal in sunflower oil and has emerged as the potential adsorbent that can comprehensively and effectively meet the requirements of many edible oil physical refining applications in a singular step. Graphical Abstract

Amine-free synthesis of high-silica ZSM-5 assisted with calcined silicalite-1 and ethanol with the investigation of mechanism

Amine-free synthesis of high silica ZSM-5 with high crystallinity and well-defined morphology was challenging. In this work, ZSM-5 with the fed silica-alumina ratio (SAR) of 100 was rapidly synthesized with the assistance of the calcined silicalite-1 seed and ethanol, and their crystal structures, morphology and microporous properties were characterized by XRD, SEM, FT-IR, ICP and N2 adsorption-desorption and so on. Firstly, the crystallization temperature was optimized between 140 and 180 °C at a certain alkalinity and ethanol content, and 160 °C was selected to not only provide high crystallization rate but also ensure the stability of high-silica skeleton. Secondly, the influences of the EtOH/SiO2 ratio, Na2O/SiO2 ratio and crystallization time on the crystallization of high-silica ZSM-5 were investigated at 160 °C. The results showed well-crystalline high-silica ZSM-5 could be synthesized within a wide range of the EtOH/SiO2 ratios (0.5–2.0) and the increase of ethanol content slightly inhibited the growth of ZSM-5 along b-axial of hexagonal prisms due to the preferential adsorption of excess ethanol on the {010} crystal plane and the formation of Si–O–C2H5; high alkalinity was favorable for the preparation of a small-sized and well-crystalline ZSM-5 due to the rapid depolymerization of calcined seed and the contribution of mass nucleation sites; meanwhile, excellent micropore characteristic of high-silica ZSM-5 further proved that the synthetic strategy of seed + ethanol was feasible. Finally, the synergistic action mechanism of calcined seed and ethanol for the synthesis of high-silica ZSM-5 was revealed that silicalite-1 with MFI structure unit combined with Na+(H2O/EtOH) with larger radius were very important for rapidly assembly of a large number of silica species into MFI framework.

Development of novel microporous guanazole complex for CO2 adsorption

A novel complex, resulting from the synthesis of a guanazole ligand coordinated with Zn(II), has been successfully synthesized through an environmentally friendly method and carefully characterized using a combination of analytical techniques, including Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), N2 adsorption–desorption, scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). The Brunauer–Emmett–Teller surface area of the guanazole complex is determined to be approximately 407.50 m2/g, featuring pore diameters and pore volume of 1.84 nm and 0.187 cm3/g, respectively. The emergence of micropores in the guanazole complex significantly enhances its CO2 adsorption capacity. The maximum CO2 adsorption capacity of the complex is observed to be 3.18, 2.08, and 1.51 mmol/g at temperatures of 273, 298, and 313 K, respectively. This study presents novel prospects for the controlled synthesis of nitrogen-rich complexes and their potential application in CO2 capture.

Construction of Bi2WO6/g-C3N4/Cu foam as 3D Z-scheme photocatalyst for photocatalytic CO2 reduction

Photocatalytic CO2 reduction to hydrocarbon fuels represents a promising solution to CO2 emission challenges. However, photocatalytic CO2 reduction systems face hurdles in practical utilization for the low efficiency of photocatalysts and challenge in catalyst immobilization. Therefore, a novel monolithic three-dimensional Z-scheme photocatalyst was synthesized by fabricating Bi2WO6/g-C3N4 heterojunction on Cu foam substrate (Bi2WO6/g-C3N4/Cu foam) via thermal polymerization and electrophoresis deposition. A series of characterization results, including X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and N2 adsorption–desorption, illustrate the crystalline properties, pore structure, and morphology of the composite photocatalyst. Consequently, Bi2WO6/g-C3N4/Cu foam achieved CO production yield of 33.84 μmol/g cat under visible light illumination for 6 h and retained 96.2 % of initial photocatalytic activity after 30 h of reaction. UV–Vis diffuse reflection spectra, photoluminescence spectra and photoelectrochemical analysis was involved to reveal the mechanism of the photocatalytic activity of composite photocatalyst.The synergistic effect of the Z-scheme mechanism and the hierarchical macroporous structure improves the light absorption, light-induced electron-hole pair separation, and charge transmission. This catalyst construction strategy provides a viable approach for facilitating practical photocatalytic CO2 reduction.