BET Surface Area Research Articles

Innovative porous organic polymer incorporating ferrocene and s-triazine: An effective method for converting nitroarenes to benzimidazoles using visible light

The study introduces a novel porous organic polymer, FeII(Cp)2-POP, synthesized from ferrocene and s-triazine, and characterized through various analytical techniques such as FT-IR, Raman, XRD, XPS, UV–visible, SEM, HR-TEM, EDX, BET surface area analysis, TGA, photocurrent measurements, EIS, and CV. This photocatalyst exhibits reusability, contributing to by-products reduction and resource efficiency. The sustainable methodology adheres to green chemistry principles, promoting eco-friendly synthetic approaches. FeII(Cp)2-POP was utilized in the photocatalytic reduction of nitroarenes to anilines, essential organic chemistry precursors, using N2H4 and visible-light activation under mild conditions. The incorporation of porous organic polymers with a ferrocene framework displayed promising outcomes in enhancing the reduction of nitroarene compounds, with a focus on reducing the nitro-functional group in benzimidazole-based compound.

Synthesis and Characterization of Zinc Oxide Nanoparticle Anchored Carbon as Hybrid Adsorbent Materials for Effective Heavy Metals Uptake from Wastewater

Hybrid material-derived adsorbents have shown a great applicable efficiency in various fields, including industrial uses and environmental remediation. Herein, zinc oxide nanoparticle modified with carbon (ZnO-C) was fabricated and utilized for wastewater treatment through the adsorption of Zn(II), Cd(II), Co(II), and Mn(II). The surface and structural characteristics were examined using TEM, SEM, XRD, FTIR spectroscopy, EDS, and the BET surface area. Kinetics and equilibrium investigations were applied to optimize the adsorptive removal of Zn(II), Cd(II), Co(II), and Mn(II) onto ZnO-C. The results indicated that the formation of ZnO-C in crystalline sphere-like granules with a nano-size between 16 and 68 nm together with carbon matrix. In addition, the spherical granules of zinc oxide were gathered to form clusters. FTIR spectroscopy indicated that the ZnO-C surface was rich with OH groups and ZnO. The adsorption capacity 215, 213, 206, and 231 mg/g for Zn(II), Cd(II), Co(II), and Mn(II), respectively, at the optimal conditions pH between 5 and 6, a contact time of 180 min, and an adsorbent dose of 0.1 g/L. The adsorptive removal data modeling for the uptake of Zn(II), Cd(II), Co(II), and Mn(II) onto ZnO-C showed agreement with the assumption of the pseudo-second-order kinetic model and the Freundlich isotherm, suggesting a fast adsorption rate and a multilayered mechanism. The achieved adsorption capacity using the prepared ZnO-C was more effective compared to ZnO, carbon, Fe3O4, and Fe3O4-C. Real wastewater samples were applied, including valley water, industrial wastewater, and rain wastewater, and evaluated for the applicable uptake of Zn(II), Cd(II), Co(II), and Mn(II) using ZnO-C and Fe3O4-C with effective removal efficiency.

Fixed-bed adsorption of perfluorooctanoic acid from water by a polyamine-functionalized polychlorotrifluoroethylene-ethylene polymer coated on activated carbon

Perfluorooctanoic acid (PFOA) has received extensive attention because of its ubiquitous presence in the aqueous environmental phase and concerns of its impact on human health. An economical and effective adsorption method is in demand to help resolve the issue. In this study, a polyamine-functionalized polychlorotrifluoroethylene-ethylene polymer coated activated carbon (AC) was synthesized via a two-step reaction. The fluoropolymer based on the repeating unit ethylene-chlorotrifluoroethylene (ECTFE) was applied as the binding medium to connect activated carbon with polyethyleneimine (PEI). Hence a dual grafted activated carbon-based sorbent AC-ECTFE-PEI was generated. Through the adsorption evaluation of packed columns by on-line detection flow analysis, the optimum synthetic stoichiometry parameters to produce AC-ECTFE-PEI, based on the longest adsorption breakthroughs, were determined to be the 5:2 AC/ECTFE and 1:1 AC-ECTFE/PEI mass ratios. The new adsorbent has shown a strongly enhanced initial adsorption breakthrough to PFOA compared to AC, 270 min vs. 110 min, under the same adsorption conditions. AC-ECTFE-PEI was also characterized by attenuated total reflectance infrared spectroscopy, BET surface area analysis, and scanning electron microscopy. The functional group alterations during the reactions and the morphology information of the sorbent have also been elucidated. The Thomas, Adams-Bohart, and Yoon-Nelson models respectively were used to describe the adsorption behavior, indicating an PFOA adsorption capacity of 380 mg/g sorbent, 120 mg/L sorbent column, and a 50% average breakthrough time of 350 min for 100 mg/L PFOA removal, under a 1 mL/min flow rate and a 2 cm bed height. The regeneration study of AC-ECTFE-PEI of more than five adsorption-desorption cycles indicates good sustainability and stability. Both electrostatic and hydrophobic interactions of PFOA were justified using selective solvent compositon of the mobile phase as the two main adsorption mechanisms. The electrostatic forces of PFOA on AC-ECTFE-PEI, AC-ECTFE, and AC were also evaluated by their zeta-potential values.

Unraveling lithium-ion intercalation in lead-free bismuth-based vacancy ordered halide perovskites supercapacitors

Halide perovskites have recently gained a lot of attention in energy storage applications because of their unique properties. The difficulty in getting high-performance supercapacitors requires the significant development and customization of electrode materials. This study explores vacancy-ordered lead-free halide perovskites with chemical formula A3B2X9 as electrode material for supercapacitors. Furthermore, we have tuned the X site (X = Br−, Cl−, I−) to see the effect of halide ions on supercapacitor performance. Due to high ionic mobility and BET surface area, Cs3Bi2I9 has a specific capacitance of ∼242 F/g and energy density of ∼140 Wh/kg; however, power density variation is almost the same for all samples, measured in three-electrode systems. We have performed the ex-situ XRD and FTIR to understand the structural changes before and after charging. XPS measurement shows the peak shifting before and after measurement in Lithium-based electrolytes. Further, we have fabricated double perovskite-based symmetric devices with gel electrolyte as a separator. The Cs3Bi2I9 device shows an areal energy density of ∼23 μWh/cm2, the highest among all halide perovskite-based supercapacitor devices reported to date. The flexible device on the S.S. substrate shows 79% and 82% capacitance retention up to 180° bending angle and 200 bending cycles, respectively.

Incorporating porous carbon materials into ionic liquid for high efficiency extraction of polycyclic aromatic hydrocarbons

Ionic liquid is an ideal candidate in the extraction of aromatic compounds. The design and construction of ionic liquids with high extraction efficiency and selectivity towards to the specific aromatics remain crucial question. In this paper, with the aid of orthogonal array experiment, the imidazolium-based ionic liquids with long alkyl chain on the cations were determined to possess high aromatics extraction efficiency. Furthermore, the Lewis acid anion was introduced into the ionic liquid to form 1-dodecyl-3-methylimidazolium ferric chloride ([C12mim][FeCl4]) and performed 62 % and 100 % extractant efficiency of naphthalene (NAP) and anthracene (ANT), respectively. Then the porous carbon materials (P1-1000) derived from hyper-crosslinked porous polymers (HCP) which possessed high BET surface area (1186 m2/g) was dispersed in [C12mim][FeCl4] to form porous ionic liquid. The single extraction efficiency of NAP improved from 62 % to 77 %. The great single extraction efficiency was attributed to the high porosity, additional adsorption sites provided by the Lewis acid anions and the hydrophobic long alkyl chain on the cations. After three times extraction, the concentration of NAP dropped down to 0. The porous ionic liquids also showed good recycle performance. The construction of porous ionic liquids provided an efficient approach for extraction of polycyclic aromatic hydrocarbons from aliphatic hydrocarbon.

The enhancement of photocatalytic hydrogen production over Ag2WO4 modified g-C3N4 with Pt as cocatalyst

ABSTRACT The construction of heterojunction photocatalyst is an effective mean to improve the photoexcited electron–hole pair separation. The Ag2WO4-doped graphitic carbon nitride (g-C3N4, C3N4 for short) composite photocatalysts were fabricated by a simple calcination and in-situ depositing strategy. The composites were characterized by different techniques. The effects of Ag2WO4 content, type of scavengers, pH value of reaction solution and dose of scavenger on photocatalytic hydrogen (H2) generation were studied. It was found that the Ag2WO4 micro-nano particles were highly dispersed on the C3N4 surface. After doping Ag2WO4, the light absorption range of Ag2WO4-C3N4 material was broadened effectively from 440 nm to 448 nm, and the BET surface area of C3N4 was increased from 35.63 to 40.73 cm2·g−1, indicating that Ag2WO4 loading could provide some new BET surface areas. The binding energy of all elements in Ag2WO4-4/C3N4 was clearly shifted due to the charge transfer from C3N4 to Ag2WO4, implying a strong interaction between C3N4 and Ag2WO4. The photocatalytic H2 production rate of the optimized Ag2WO4-4/C3N4 was 6047.4 μmol·g−1·h−1, which was 2.04 and 171.8 times that of C3N4 and Ag2WO4, respectively. While Ag2WO4-4/C3N4 exhibited a poor H2 production performance in the absence of Pt co-catalyst (309.3 μmol·g−1·h−1), indicating the formation of heterojunction among Ag2WO4, C3N4 and Pt.

Enhanced biotoxicity by co-exposure of aged polystyrene and ciprofloxacin: the adsorption and its influence factors.

Microplastics (MPs), as emerging contaminants, usually experience aging processes in natural environments and further affect their interactions with coexisted contaminants, resulting in unpredictable ecological risks. Herein, the effect of MPs aging on their adsorption for coexisting antibiotics and their joint biotoxicity have been investigated. Results showed that the adsorption capacity of aged polystyrene (PS, 100 d and 50 d) for ciprofloxacin (CIP) was 1.10-4.09 times higher than virgin PS due to the larger BET surface area and increased oxygen-containing functional groups of aged PS. Following the increased adsorption capacity of aged PS, the joint toxicity of aged PS and CIP to Shewanella Oneidensis MR-1 (MR-1) was 1.03-1.34 times higher than virgin PS and CIP. Combined with the adsorption process, CIP posed higher toxicity to MR-1 compared to aged PS due to the rapid adsorption of aged PS for CIP in the first 12h. After that, the adsorption process tended to be gentle and hence the joint toxicity to MR-1 was gradually dominated by aged PS. A similar transformation between the adsorption rate and the joint toxicity of PS and CIP was observed under different conditions. This study supplied a novel perception of the synergistic effects of PS aging and CIP on ecological health.

Tetracycline (TC) removal from wastewater with activated carbon (AC) obtained from waste grape marc: activated carbon characterization and adsorption mechanism

In this study, activated carbons were obtained from grape marc for tetracycline removal from wastewater. Activated carbons were obtained by subjecting them to pyrolysis at 300, 500, and 700 °C, respectively, and the effect of pyrolysis temperature on activated carbons was investigated. The physicochemical and surface properties of the activated carbons were evaluated by SEM, FTIR, XRD, elemental analysis, N2 adsorption/desorption isothermal, thermal gravimetric (TG) and derivative thermogravimetric (DTG), and BET surface area analysis. When the BET surface areas were examined, it was found that 4.25 m2/g for activated carbon was produced at 300 °C, 44.23 m2/g for activated carbon obtained at 500 °C and 44.23 m2/g at 700 °C, which showed that the BET surface areas increased with increasing pyrolysis temperatures. The pore volumes of the synthesized activated carbons were 0.0037 cm3/g, 0.023 cm3/g, and 0.305 cm3/g for pyrolysis temperatures of 300, 500, and 700 °C, respectively, while the average pore size was found to be 8.02 nm, 9.45 nm, and 10.29 nm, respectively. A better adsorption capacity was observed due to the decrease in oxygen-rich functional groups with increasing pyrolysis temperature. It was observed that the activated carbon obtained from grape skins can easily treat hazardous wastewater containing tetracycline due to its high carbon content and surface functional groups. It was also shown that the activated carbon synthesized in this study has a higher pore volume despite its low surface area compared to the studies in the literature. Thanks to the high pore volume and surface active groups, a successful tetracycline removal was achieved.Graphical

An effective synthesis of carbon nanotube foams over three ambient atmospherically calcined Fe–Mo/MgO catalysts: Structural characterization with growth mechanism

Our research attempted to investigate the impact of calcination on the synthesis procedure, thickness dependency, and catalytic phases of carbon nanotubes (CNTs) exhibiting a foam-like design. The sol-gel technique of combustion was used to generate three different stoichiometric molar proportions of extremely active Fe:Mo:MgO catalyst significantly powder (namely 1:0.5:13, 1:1:13, and 1:1:50). The crystalline phases of the catalysts were modified by calcination under Air, inert (Ar) and reduced (H2) atmospheres. XRD, scanning electron microscopy (SEM), in addition to Energy Dispersive X-ray (EDX) analysis were utilized to examine the development of the catalytic compounds' morphological phases, size of particles, shape, and composition of elements.The crystalline shapes, sizes and other morphological characteristics of the highly active catalysts were studied by TEM. Additionally, the BET surface area as well as the average particle diameter, volume of pore, and radius of pore were ascertained using the N2 sorption isotherm evaluation. Then, the combination of uncalcined and calcined catalysts were employed to generate CNT foams through CVD approach. The CNT foam development findings were examined using a variety of physicochemical strategies. From these studies, we established the relation between the catalytic phases and the growth of MWCNTs with foam-like morphology. Finally, the change of the growth mechanism and diameter of the MWCNT foams over the active catalysts based on the stoichiometric molar ratios between the catalyst and support was analyzed through TEM studies.

Effect of pretreatment and activation conditions on pore development of coal-based activated carbon

Abundant pore volume and appropriate pore configuration are two crucial characteristics of high-performance carbonaceous adsorbents and catalysts. In this study, influences of pre-treatments (e.g., breaking, sieving and ash removal by acid) and activation conditions (e.g., activation time) on pore parameters (including BET surface area, pore diameter and pore hierarchy degree) of resultant activated carbon were systematically investigated. In addition, the difference between conventional carbonization-activation (i.e., the two-step preparation method) and one-step activation in pore development of activated carbons was revealed. The sample prepared by a 120-minute one-step activation exhibited a BET surface area high to 1038.1 m2/g and a pore hierarchy at 50.7 %. Based on the kinetics analysis using TGA reactor, reaction between the activator (i.e., CO2) and carbon matrix was enhanced in one-step activation, contributing to the generation of mesopores. Remarkably, a new indicator, Effective Activation Rate (EAR) was proposed to accurately describe the activation rate in one-step synthesis after decoupling the release of moisture and volatile compounds. The above conclusions provide guidance for flexibly regulating the pore configurations of activated carbons derived from natural precursors.

Composites of sodium alginate based - Functional materials towards sustainable adsorption of benzene phenol derivatives - Bisphenol A/Triclosan

The present study evaluates the adsorption efficiency of low-cost carbonaceous adsorbents as fly ash (FA), saw dust biochar (SDB) (untreated and alkali - treated), live/dead pulverized white rot fungus Hypocrea lixii biomass encapsulated in sodium alginate (SA) against the commercially available activated carbon (AC) and graphene oxide (GO) SA beads for removal of benzene phenol derivatives - Bisphenol A (BPA)/triclosan (TCS). Amongst bi - and tri - composites SA beads, tri-composite beads comprising of untreated flyash - dead fungal biomass - sodium alginate (UFA - DB - SA) showed at par results with commercial composite beads. The tri - composite beads with point zero charge (Ppzc) of 6.2 was characterized using FTIR, XRD, surface area BET and SEM-EDX. The batch adsorption using tri - composite beads revealed removal of 93% BPA with adsorption capacity of 16.6 mg/g (pH 6) and 83.72% TCS with adsorption capacity of 14.23 mg/g (pH 5), respectively at 50 ppm initial concentration with 6 % adsorbent dose in 5 h. Freundlich isotherm favoring multilayered adsorption provided a better fit with r2 of 0.9674 for BPA and 0.9605 for TCS respectively. Intraparticle diffusion model showed adsorption of BPA/TCS molecules to follow pseudo - second order kinetics with boundary layer diffusion governed by first step of fast adsorption and intraparticle diffusion within pores by second slow adsorption step. Thermodynamic parameters (ΔH°, ΔS°, ΔG°) revealed adsorption process as exothermic, orderly and spontaneous. Methanol showed better desorbing efficiency leading to five cycles reusability. The phytotoxicity assay revealed increased germination rate of mung bean (Vigna radiata) seeds, sprinkled with post adsorbed treated water (0 h, 5 h and 7 h) initially spiked with 50 ppm BPA/TCS. Overall, UFA - DB - SA tri - composite beads provides a cost effective and eco - friendly matrix for effective removal of hydrophobic recalcitrant compounds.

Sequestration of divalent heavy metal ions from aqueous environment by adsorption using biomass-bentonite composites as potential adsorbent: Equilibrium and kinetic studies

Hybrid clay adsorbents have been investigated in recent studies as cheap and effective adsorbents for eliminating micropollutants, such as heavy metal ions from aqueous solution. Here, we modified bentonite (BEN) with palm kernel shell and groundnut shell by calcination to obtain palm kernel shell-modified bentonite (BPKS) and groundnut shell-modified bentonite (BGS). We studied the batch equilibrium adsorption of Pb2+, Cd2+ and Ni2+ ions under the influence of dosage, solution pH, contact time and concentration. Under these conditions, we found that the modified adsorbents (BGS and BPKS) had a higher equilibrium adsorption (qe) for the metal ions than unmodified BEN. BEN exhibited Langmuir adsorption capacities (Qo) of 32.47, 14.04 and 14.16 mg/g for Pb2+, Cd2+ and Ni2+, respectively. BGS and BPKS had Qo values of 29.15, 14.27, 16.61 and 31.75, 17.67, 15.625 mg/g for Pb2+, Cd2+, Ni2+, respectively. Investigations revealed that the rate of adsorption on the three adsorbents is best described by a pseudo-second-order kinetic model, with R2 values ≥ 0.9; the intra-particle diffusion model establishes a surface interaction mechanism involving the exchange of electrons between the surfaces of the adsorbents and the adsorbate. Scanning electron microscopy results suggest porous and heterogeneous adsorbent surfaces, indicating a physio-sorption phenomenon. The modifications increased the surface area of BEN from 78.435 to 194.850 and 140.650 m2/g in BGS and BPKS, respectively, using BET surface area analysis. However, the average pore width of BEN reduces from 3.8 to 3.3 nm in both BGS and BPKS. Also, the modification enhanced the cation exchange capacity in BPKS only. The findings from this study offered invaluable insights into how biomass can enhance the physicochemical properties of BEN, as needed for practical environmental application and/or optimization, during the removal of Pb2+, Cd2+ and Ni2+ ions from aqueous media.

Carbon dioxide-activated mesoporous date palm fronds carbon integrated with MnO2/polyaniline for highly efficient capacitive deionization of water.

The continuous population growth and drying up the freshwater reservoirs around the world are increasing the demand for fresh water. Therefore, there is an urgent need to explore newer technologies able to purify water on large scales for human usage. Capacitive deionization is one of the most promising approaches to generate fresh water by the removal of salt ions from brackish water. In this work, we prepared three different capacitive deionization electrodes using carbonized palm tree fronds (PFC). These PFC activation was achieved using CO2 at 900°C. To generate the deionization electrodes, PFC activated carbon was combined with either polyaniline (PANI), MnO2, or both (PFC-PANI, PFC-MnO2, and PFC-MnO2-PANI). The MnO2 and PANI provided additional functionality and enhanced electrical conductivity, which resulted in much higher Na+ and Cl- ions adsorption. The BET surface area of PFC-MnO2-PANI was estimated to be 208.56 m2/g, which is approximately three times that of PCF-PANI and PFC-MnO2 alone. The morphological analysis showed that the PANI and MnO2 nanorods were well dispersed throughout the PFC network. Although PANI and MnO2 is largely embedded inside the PFC network, some remnants are visible on the surface of the electrodes. The cyclic voltammetry (CV) curves showed capacitive behavior of all electrodes in which PFC-MnO2-PANI showed highest specific capacitance of 84 F/g, while the PFC-MnO2 and PFC-PANI showed 42 and 43 F/g, respectively. Owing to its enhanced functionality and CV characteristics, the PFC-MnO2-PANI showed maximum salt adsorption capacity of 10.5mg/g in contrast to 3.72 and 5.64 mg/g for PFC-MnO2 and PFC-PANI, respectively. Moreover, the measured contact angle for PFC-MnO2-PANI was ~51°, which indicates the hydrophilic nature of electrode that improved ions adsorption. PRACTITIONER POINTS: Date tree fronds were converted into mesopores carbon using CO2 as activation agent. Three composites were prepared with PANI, MnO2, and date palm fronds activated carbon (PFC-MnO2, PFC-MnO2-PANI, and PFC-PANI). Surface area, pore profile, surface morphology, electrochemical behavior, desalination performance, and hydrophilicity of all the electrodes were investigated. The PFC-MnO2-PANI showed maximum salt adsorption capacity of 10.5mg/g in contrast to 3.72 and 5.64 mg/g for PFC-MnO2 and PFC-PANI, respectively.

Advancing in Cesium Retention: Application of Magnesium Phosphate Cement Composites.

A serious risk that harms the safe use of water and affects aquatic ecosystems is water pollution. This occurs when the water's natural equilibrium is disrupted by an excessive amount of substances, both naturally occurring and as a byproduct of human activities, that have varied degrees of toxicity. Radiation from Cs isotopes, which are common components of radioactive waste and are known for their long half-lives (30 years), which are longer than the natural decay processes, is a major source of contamination. Adsorption is a commonly used technique for reducing this kind of contamination, and zeolite chabazite has been chosen as the best adsorbent for cesium in this particular situation. The purpose of this research is to investigate a composite material based on magnesium phosphate cement (MPC). Magnesium oxide (MgO), potassium dihydrogen phosphate (KH2PO4), and properly selected retarders are used to create the MPC. The optimal conditions for this composite material are investigated through the utilization of X-ray diffraction, scanning electron microscopy, BET surface area analysis, and atomic absorption spectroscopy. The principal aim is to enable innovations in the elimination of radioactive waste-contaminated water using effective cesium removal. The most promising results were obtained by using KH2PO4 as an acid, and MgO as a base, and aiming for an M/P ratio of two or four. Furthermore, we chose zeolite chabazite as a crucial component. The best adsorption abilities for Cs were found at Qads = 106.997 mg/g for S2 and Qads = 122.108 mg/g for S1. As a result, zeolite is an eco-friendly material that is a potential usage option, with many benefits, such as low prices, stability, and ease of regeneration and use.

Investigating the potential of ZrO2/MoO3 nanocomposites for efficient hydrogen generation through NaBH4 methanolysis

This work investigates the potential of ZrO2/MoO3 nanocomposites as catalysts for hydrogen production through NaBH4 methanolysis. The samples were prepared by controlled thermal calcination and characterized using various techniques like XRD, FTIR, Raman, SEM, and surface area BET analysis. Rietveld refinements verified the presence of the ZrO2 monoclinic phase with the space group P21/c in all samples and a second orthorhombic MoO3 phase with the space group Pnma. The average crystal size decreased from 44 to 40 nm. FTIR and Raman spectroscopy confirmed the successful preparation of ZrO2/MoO3 nanocomposites. SEM analysis showed ZrO2 particles and MoO3 nanoparticles adhered to the ZrO2 surface, potentially creating a rougher texture. The results confirmed the formation of ZrO2/MoO3 nanocomposites with increasing MoO3 content, leading to an increased surface area of 19–23 m2/g. The catalytic performance evaluation revealed that the sample containing 30 % MoO3 (ZM3) exhibited the highest hydrogen generation rate of 18,451 mL/g. min at 30 °C. The calculated activation energy for ZM3 was 18.78 kJ/mol, suggesting efficient hydrogen generation at moderate temperatures.

PREPARATION AND CHARACTERIZATION OF BENTONITE CLAY CATALYSTS FOR TRANSESTERIFICATION OF WASTE COOKING OIL INTO BIODIESEL

The development of low-cost green catalytic materials is crucial for the conversion of non-edible vegetable oils or waste materials into biodiesel. The research focuses on the preparation and characterization of aluminium pillared clay and NaOH-doped bentonite clay catalysts for biodiesel production from waste cooking oil using XRF, XRD, FTIR and N2 adsorption-desorption techniques. The molecular profile and functional group assessment of the biodiesel were done using GC-MS and FTIR respectively. XRF analysis revealed the presence of oxides in all samples. The amount of SiO2 in all samples was within the range of 35.303–39.199 wt%. Al2O3 increased from 15.560 to 19.11 wt%, while the interlayer cations decreased after pillaring. FTIR revealed the appearance of peaks which are characteristic of bentonite. The pillaring and impregnation of NaOH with bentonite led to a distortion of certain peaks' intensity, as evidenced by FTIR results. The pillaring caused an increase in BET surface area and pore volume compared to bentonite from 302.1 to 366.4 m2/g, and 0.186 to 0.189 cc/g respectively, while a decrease in surface area and pore volume was observed in NaOH/bentonite due to impregnation. The XRD data have shown the increase of basal d-spacing of pillared clay from 12.65 to 16.49 Å relative to bentonite with a decrease to 12.45 in the case of NaOH/bentonite. The catalysts prepared outperformed neat bentonite with NaOH/bentonite, resulting in the highest yield of (83 ± 1.80). GC-MS, FTIR, and physicochemical analyses confirmed the production of fatty acid methyl esters.

Comparing The Catalytic Activity of Mg-BTC Metal Organic Framework and Post Synthetically Modified (TiO2 @ Mg-BTC) Metal Organic Framework for Cyanosilylation of Aldehydes

Metal organic frameworks (MOFs) are an emerging class of porous crystalline hybrid materials synthesised by the coordination of inorganic connectors and organic linkers, which has numerous potential applications in various fields. Here we report a comparative study on Mg-BTC MOF and TiO @Mg-BTC MOF as a heterogeneous catalyst. Mg-BTC MOF was synthesised by solvothermal method and subjected to comparative study with its post synthetically modified (PSM) counterpart to understand their catalytic behaviour for cyanosilylation of aldehydes. The synthesised Mg-BTC MOF and TiO @Mg-BTC MOF were characterised by powder XRD, BET surface area, SEM, FT-IR, TGA techniques. A detailed characterization study was performed to understand the correlation between catalytic activity and morphology of the assynthesized MOF and PSM-MOF. The catalytic activity of the hybrid materials were evaluated by GC-MS analysis. The results of the catalytic reactions revealed that post synthetically modified (TiO @Mg-BTC) MOF exhibited significantly higher catalytic activity compared to Mg-BTC MOF. The enhanced catalytic efficiency is due to the incorporation of TiO nanoparticles, which provides active sites for catalytic reactions under heterogeneous conditions. Even after repeated recycling and reuse, the catalytic ability of the catalyst retains. The impact of TiO on the framework shows variation in texture, surface area, thermal stability and catalytic behaviour on the MOF materials. Thus, our study emphasizes

Highly Porous Carbon Materials Prepared Through KOH‐Assisted CO2‐Activation of Carbonized Waste Tires for Removal of Cr(VI) and Cd(II) from Water

AbstractIn this study, waste tires (WTs) were carbonized under an N2 atmosphere. Subsequently, KOH/WTs‐char with KOH‐assisted CO2 activation was used to prepare activated carbon (AC) as a highly porous carbon material for the removal of Cr(VI) and Cd(II) from water. Various techniques such as elemental analysis, Fourier‐transform infrared spectroscopy, scanning electron microscopy, and N2 adsorption/desorption were employed to investigate the physical and chemical characteristics of the prepared carbons. The WTs‐char activated with KOH under CO2 exhibited a microstructure with a high BET surface area and pore volume of 1841 m2/g and 0.869 cm3/g, respectively, demonstrating excellent adsorbent performance. The maximum removal efficiencies of 99.91 % for Cd(II) and 99.81 % for Cr(VI) were achieved using AC2 carbon under the following conditions: pH 2 for Cr(VI) and pH 5 for Cd(II), contact time of 120 min, adsorbent dose of 0.4 g/100 mL, and temperature of 298 K. The adsorption kinetics followed the pseudo‐second‐order equation, and the equilibrium data fit well with the Redlich–Peterson isotherm equation. The positive values of ▵G indicated that the uptake process for both ions was nonspontaneous and nonfeasible over the temperature studied. Both ions showed negative values of ΔH and ΔS on carbon, suggesting exothermic adsorption and a decrease in disorder. Regeneration studies showed that NaOH was a better desorbing agent than HCl. Cr(VI) desorption resulted in over 90 % removal recovery by AC2 using 1.0 M NaOH even after the fifth cycle. However, the low activation energy indicated that the adsorption was favorable kinetically. Overall, this study demonstrated the effective preparation of highly porous carbon and its successful performance in removing Cr(VI) and Cd(II) ions.

The Effect of Solvent on the Characteristics of FeBTC MOF as a Potential Heterogenous Catalyst Prepared via Green Mechanochemical Process

In this study, the synthesis of FeBTC (BTC = 1,3,5-benzenetricarboxylate) also known as MIL-100 (Fe) metal organic framework (MOF) has been carried out successfully using green mechanochemical method (neat grinding and liquid assisted grinding). The effect of solvent used in the synthesis was investigated for the first time to elucidate the physicochemical properties of FeBTC including crystal structure, thermal stability, pore size and specific surface area. The physicochemical properties of all FeBTC obtained in this study were compared to commercial FeBTC (Basolite F-300), characterized using powder X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and nitrogen physisorption isotherms. All Fe-BTC MOF synthesized in this study showed improved textural properties compared to commercial Basolite F-300 such as higher crystallinity, higher surface area and larger pore size. It was found that the best synthesis method was by using the mixture of ethanol and water with equal volume ratio as solvent. The highest BET surface area of FeBTC synthesized using this method was 972 m2/g for FeBTC-EtOH/H2O. This value is 2.3 times higher than the surface area of commercial Basolite F-300 (418 m2/g). FeBTC with higher surface area is expected to have higher catalytic activity which makes this FeBTC an excellent candidate as a heterogenous catalyst for many reactions such as aldol condensation or esterification reaction. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

In situ impregnation of cobalt‐doped tungstophosphoric acid on MOF‐801 toward enhanced catalytic activity for esterification

Development of an energy‐efficient and economical route is necessary for society to synthesize green biofuels. Herein, cobalt‐doped tungstophosphoric acid (Co‐HPW) is in‐situ impregnated in the Zr‐based metal–organic framework (MOF‐801) forming composite of Co‐HPW/MOF‐801. The chemical composition, morphology, and acidic sites of the Co‐HPW/MOF‐801 composite were analyzed through x‐ray diffractometer (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), energy‐dispersive x‐ray spectroscopy (EDS), thermogravimetric analysis (TG), N2 physisorption, ammonia temperature‐programmed desorption (NH3‐TPD), pyridine‐adsorbed infrared spectra (Py‐FTIR), and x‐ray photoelectron spectroscopy (XPS). The catalytic performance of the as‐synthesized catalyst was explored to catalyze esterification of lauric acid (LA) with methanol. The outcomes revealed that the Co‐HPW/MOF‐801 nanocatalyst achieved a high conversion of 86.3% under the optimized reaction condition (catalyst amount of 0.15 g, temperature of 100°C, time of 4 h, and methanol/LA molar ratio of 20:1). The excellent catalytical performance is mainly due to the large BET surface area, exposure of more active centers from available pore structure, and simultaneous possession of high Lewis and Brønsted acidity. Furthermore, the kinetic study revealed that the reaction process was kinetically controlled and the activation energy was found to be 42.1 kJ/mol. The results suggest that the synthesized Co‐HPW/MOF‐801 nanocatalyst is an environmental greenness, low cost, and suitable for easy scale‐up for the production of biofuels.