N2 Sorption Research Articles

Glycogen-assisted biosynthesis of MnO2 for adsorptive elimination of methylene blue from water

A novel biosynthesis of manganese dioxide (MnO2) NPs was achieved by oxidizing glycogen with KMnO4 in an alkaline medium. X-ray powder diffraction, Fourier-transform infrared spectroscopy, N2 sorption, and transmission electron microscope (TEM) techniques were utilized to assess the physicochemical characteristics of the prepared MnO2. The impacts of different adsorption parameters, including contact time, pH, concentration, temperature, and adsorbent dose, on methylene blue (MB) elimination utilizing the prepared MnO2 NPs, were investigated. It was found that the Langmuir model well describes how the dye molecules arrange themselves on the MnO2 surface compared to other models. This proposes a single layer of dye forms, with each molecule attaching to a specific site on the MnO2. Additionally, the results were well-matched with a pseudo-2nd-order model, demonstrating that chemical reactions had a significant role in the adsorption experiment. Under specific conditions (RT, natural pH of the dye solution, and 30-minute contact time), the MnO2 could hold up to 40.85 mg of dye per gram of MnO2 (mg/g). Further analysis reflected that the adsorption procedure was spontaneous, which means it happened favorably without needing extra energy input. This suggests that biosynthesized MnO2 has great potential as an eco-friendly material for cleaning up MB dye contamination in water.

Mesoporous SBA‐15 Supported CdS through Organosilane Ligand for Photo Driven Cleavage of Aryl Ether in Lignin and its Model Compound

AbstractMesoporous silica (SBA‐15) was synthesized hydrothermally followed by calcination and then functionalization with 3‐(triethoxysilyl)‐1‐propanethiol through surface grafting. The thiol moiety of the grafted ligand was utilized for the uniform anchoring of cadmium into the channels of the material. The synthesised material was subjected for its photo catalytic applications after characterization through standard characterization protocol. The synthesised mesoporous silica (i.e. SAB‐15), ligand modified material (i.e.SBA‐15‐S and Cd loaded ( i.e. SAB‐15‐CdS) materials were characterized through standard characterization protocol like powder XRD, FT‐IR, UV‐DRS, MAS NMR, N2 sorption, FE‐SEM, HR‐TEM and TG‐DTA studies. After successful characterization, the screening of the catalyst was carried out on a model reaction involving photo catalytic cleavage of α‐O‐4 aryl ether linkage present in benzyl phenyl ether, which is an important lignin model compound. The catalyst exhibited good efficiency along with the selectivity for desired monoaromatic platform chemicals. The synthesized catalyst was also carried out for the photo catalytic depolymerization of alkali lignin at the optimized reaction conditions which further showed the promising results for getting value added chemicals from lignin. The reaction products were characterized by using Gas chromatography‐mass spectrometry (GC‐MS) techniques.

Stability of Iodine Species Trapped in Titanium-Based MOFs: MIL-125 and MIL-125_NH2.

Two titanium-based MOFs MIL-125 and MIL-125_NH2 are synthesized and characterized using high-temperature powder X-ray diffraction (PXRD), thermogravimetric analysis(TGA), N2 sorption, Fourier transformed infrared spectroscopy (FTIR), Raman spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), and electron paramagnetic resonance (EPR). Stable up to 300°C, both compounds exhibited similar specific surface areas (SSA) values (1207 and 1099m2g-1 for MIL-125 and MIL-125_NH2, respectively). EPR signals of Ti3+ are observed in both, whith MIL-125_NH2 also showing ─NH2 ●+ signatures. Both MOFs efficiently adsorbed iodine in continuous gas flow over five days, with MIL-125 trapping 1.9g.g-1 and MIL-125_NH2 trapping 1.6g.g-1. MIL-125_NH2 exhibited faster adsorption kinetics due to its smaller band gap (2.5 against 3.6eV). In situ Raman spectroscopy conducted during iodine adsorption revealed signal evolution from "free" I2 to "perturbed" I2, and I3 -. TGA and in situ Raman desorption experiments showed that ─NH2 groups improved the stabilization of I3 - due to an electrostatic interaction with NH2 ●+BDC radicals. The Albery model indicated longer lifetimes for iodine desorption in I2@MIL-125_NH2, attributed to a rate-limiting step due to stronger interaction between the anionic iodine species and the ─NH2 ●+ radicals. This study underscores how MOFs with efficient charge separation and hole-stabilizer functional groups enhance iodine stability at higher temperatures.

A zirconium metal–organic framework functionalized with a S/N containing carboxylic acid (MOF-808(Zr)-Tz) as an efficient sorbent for the ultrafast and selective dispersive solid phase micro extraction of chromium, silver, and rhodium in water samples

Metal-organic frameworks (MOFs) are good adsorbents for targeted chemicals with their adjustable properties. Herein, we prepared a zirconium based MOF (MOF-808(Zr)) and functionalized it employing 2-mercapto-4-methyl-5-thiazolacetic acid (MOF-808(Zr)-Tz). The prepared MOFs were characterized by XRD, FTIR, SEM-EDX, TGA, N2 sorption, zeta potential measurements, and elemental analysis. The surface area of MOF-808(Zr)-Tz was 1348 m2/g. Dispersive solid-phase micro-extraction (D-SPµE) method based on MOF-808(Zr)-Tz was firstly developed and applied to the extraction of chromium, silver, and rhodium in waters. The determination of the analytes was done by FAAS. The optimal pH and eluent for analytes were 7.0 and 3 mL of 2 mol L−1 HCl, respectively. The contact times were 1 min for adsorption and 3 min for elution. The LOD and PFs of the D-SPμE for analytes were 2.3 μg L−1 and 13.3 for chromium, 2.1 μg L−1 and 13.3 for silver, and 3.1 μg L−1 and 13.3 rhodium, respectively. The D-SPμE method was verified with analyses of NW-TMDA-54.6 Lake water and SPS-WW1 Batch 114 Wastewater and with spiked dam water, river water, well water, sea water, and wastewater. The recoveries of the analytes changed from 89 to 108 %. The results indicated that the method is selective, simple, effective, and rapid for extracting chromium(III), silver(I) and rhodium(III) in waters.

Hydrophilic phthalocyanine covalent organic frameworks for enhanced electrocatalytic H2O2 production

The electrocatalytic 2e− oxygen reduction reaction (ORR) is considered as a promising pathway to replace conditional anthraquinone process for hydrogen peroxide (H2O2) manufacture. However, the efficient electrocatalysts towards 2e− ORR remain urgently desired. Herein, hydrophilic two-dimensional cobalt phthalocyanine (CoPc) covalent organic frameworks (COFs), denoted as CoPc-2SO3H-COF and CoPc-SO3H-COF, were afforded via the imidization reaction of 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato cobalt(II) with hydrophilic building blocks 2,5-diaminobenzenesulfonic acid and 1,4-benzenedisulfonic acid, respectively. Powder X-ray diffraction, transmission electron microscope, and N2 sorption experiment results reveal the crystalline and porous structure of these two COFs. Moreover, the water contact angle and proton conduction measurements demonstrate the hydrophilic properties of these two COFs owing to the introduction of −SO3H into their skeleton. This, in combination with the high-efficiency active Co-N4 sites towards 2e− ORR, endows these two COFs with enhanced 2e− ORR activity in the aqueous electrolyte. In particular, CoPc-2SO3H-COF exhibits outstanding electrocatalytic H2O2 production performance with a stable H2O2 selectivity of 88.3 % under a high current density of 125 mA cm−2 for 20 h in a flow cell.

Facile synthesis of mordenite zeolites from bamboo leaves ash for acetalization of benzaldehye and glycerol using non-microwave instant heating

BackgroundsBamboo leaves ash (BLA) is a cheap and sustainable silica source but under-utilized. In this work, mordenite zeolites with various morphologies synthesized from BLA are reported. MethodologyOur strategy involves merely mixing of silicate and aluminate solutions where parametric crystallization study successfully captured three mordenite synthesis recipes. The prepared solids are then characterized with XRD, SEM, XRF, FTIR, TGA/DTG, N2 sorption and TPD-NH3 before their catalytic behavior is tested in acetalization . Significant findingsMordenites with three distinct shapes (nanostick, intergrown bulky ball, nanorod) are successfully synthesized via parametric crystallization study. Some mordenite zeolites contain hierarchical micro/mesoporosity which is beneficial in acetalization of benzaldehye and glycerol. The nanorod-like mordenite is the best catalyst (80.2 ± 2.4 % conversion, 54.4 ± 0.3 % selective towards 2-benzyl-4-hydroxymethyl-1,3-dioxolane) and its catalytic performance is better than those of classical homogeneous and zeolite catalysts with high recyclability.

Photocatalytic-Driven Antiviral Activities of Heterostructured BiOCl0.2Br0.8 - BiOBr Semiconductors.

Numerous methods for eliminating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are being extensively examined in recent years as a result of the COVID-19 pandemic and its adverse effects on society. Photocatalysis is among the most encouraging solutions since it has the capacity to fully annihilate pathogens, surpassing conventional disinfecting methods. A heterostructured photocatalytic composite of (70%W BiOCl0.2Br0.8 with 30%W BiOBr) was prepared via a simple synthetic route that yielded microspheres ∼3-4 μm in diameter. The composite was evidenced to inactivate stubborn enveloped viruses. By utilizing scanning electron microscopy, transmission electron microscopy, N2 sorption, and X-ray diffraction, the morphology and the chemical composition of the heterostructured composite was revealed. Full elimination of SARS-CoV-2 occurred 5 min following the light-activation of the photocatalytic mixture. Illumination absence bared a slower yet effective result of full viral decomposition at a time span of 25 min. A comparable efficacious outcome was observed in the study case of vesicular stomatitis virus with complete diminishing within 30 min of visible light exposure.

Photocatalytic Decomposition of Amoxicillin Using Zinc Ferrite Nanoparticles

Catalysts enriched in Zinc ferrite (ZFO) were synthesized using coprecipitation and hydrothermal methods. Mixtures of crystalline nanoparticles (ZFO and α-Fe2O3, several allotropic varieties of FeO) were characterized by various techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM, SEM), N2 sorption, UV-visible spectrophotometry (UV-Vis) and X-ray photoelectron spectroscopy (XPS). After detailed characterizations, the catalytic performance of the solids (1 g/L) in the degradation of amoxicillin (AMX) (10 mg/L) as an antibiotic pollutant in water was evaluated. In addition, we used air as the oxygen source and adjusted the pH to 5.0. Consequently, the catalysts obtained via the hydrothermal method HT-ZFO had a high activity (100% of AMX removal in less than 100 min when an LED (75 W) light was used) compared to a similar mixture of oxides with graphene HT-ZFO-GO (a longer time of 150 min) that was necessary for the complete degradation of AMX. Impregnation with an aqueous solution containing 80 mg of GO obtained using Hummer’s method, reduced into RGO by an ultrasound treatment, enhances the initial reaction rate but is associated with a prolonged time for complete AMX removal (10 ppm in water) that we attribute to its spontaneous corrosion.

From abandoned mines to carbon sinks: Assessing the CO2 storage capacity of Austrian low-rank coal deposits

This study represents the first assessment of CO2 storage potential in Austrian coal seams. Coal samples were taken from Fohnsdorf and Leoben abandoned coal mines, with particular emphasis on the Fohnsdorf coal since Leoben coal reserves were largely mined during previous coal production. Several methods were used to compare coal characteristics, including Rock-Eval pyrolysis (RE), organic petrography, and low-pressure N2 and CO2 sorption measurements. Both Fohnsdorf and Leoben coal samples show low sulfur and ash yields, as well as correspondingly high total organic carbon (TOC) contents. The pyrolysis Tmax and vitrinite reflectance values agree with a low coal rank for both sites. According to the N2 adsorption measurements at 77 K, low-lying mire coals from Fohnsdorf show a higher BET-specific surface area (BET-SSA) and BJH pore volume compared to raised-mire coals from Leoben. However, sapropelic shales and high-ash coals from Leoben show the highest BET-SSA and BJH pore volumes of all investigated samples and considerably exceed the N2 adsorption volumes of pure coals from both locations (N2 uptake up to 16 cm3/g; avg. for all samples 5.4 cm3/g). In contrast, the mean adsorbed CO2 uptake measured at 273 K and ∼ 1 bar followed the order of Fohnsdorf low-lying mire coals > Leoben raised-mire coals > Leoben sapropelic coals and shales, ranging at ∼0.8 mmol/g, ∼0.7 mmol/g, and ∼ 0.2 mmol/g, respectively. This shows that BET-SSA and BJH equations did not allow for adequate estimation of CO2 adsorption capacity trends in the investigated sample set. Furthermore, based on the existence of a hysteresis loop between CO2 adsorption and desorption branches for all investigated samples, the occurrence of weak chemisorption phenomena during CO2 adsorption is indicated. This effect helps to increase CO2 uptake and storage safety since the chemisorption process is not fully reversible upon pressure decrease. Ultimately, the theoretical CO2 sequestration potential of the remaining unmined Fohnsdorf coal reserves was estimated at 4.65 million tons, with an additional potential for enhanced coal bed methane production due to the gas-rich nature of Fohnsdorf coals with an estimated 1.2 billion m3 of CH4 in place.

Insights into the Synthesis of Spiral Beta Zeolite with Enhanced Catalytic Performance in VOC Abatement.

The rational synthesis of zeolites with designed morphology is a highly challenging task. In this study, we propose 1,5-bis(methylpiperidine)pentylammonium hydroxide (BMPPAOH) as an organic structure-directing agent (OSDA) based on theoretical calculations. The morphology of zeolite samples is characterized by XRD, SEM, TEM, N2 sorption isotherms, and UV Raman spectroscopy. This simple bis-quaternary ammonium salt favored the formation of spiral morphology in Beta zeolite spheres (S-Beta). The crystallization of zeolite in the presence of BMMPAOH is a two-stage process, where nanoparticles agglomerate into spheres in the early stages followed by the emergence of S-Beta crystals with spiral morphology. The synthesized Pt-S-Beta catalysts show higher catalytic activity in VOC abatement compared with other Pt-Beta samples.

Promoted catalytic performance of sugarcane bagasse ash supported by γ‐alumina as efficient, stable, and ecofriendly catalyst for dehydration of methanol to dimethyl ether

AbstractThe aim of this study was to use different proportions (1% to 20% by weight) of γ‐alumina to modify sugarcane bagasse ash (SCBA) for the production of dimethyl ether (DME) through the dehydration of methyl alcohol. A simple precipitation method was utilized to fabricate (1–20 wt.%) Al2O3/SCBA catalysts. X‐ray fluorescence, X‐ray diffraction, Fourier‐transform infrared spectroscopy, transmission electron microscopy, and N2 sorption were used to explore the structural, spectroscopic, morphological, and textural features. The XRD pattern of Al2O3/SCBA catalysts showed a new peak that corresponded to the formation of γ‐Al2O3. In addition, the average crystallite sizes of pure SCBA and 10% and 20%Al2O3/SCBA catalysts were calculated and found to be 20.1, 21.6, and 22.6 nm, respectively. To evaluate the acidity of these catalysts, the dehydration of isopropyl alcohol and the chemisorption of basic probe molecules were employed. The acidity test results displayed that these catalysts have weak to moderate acidic sites. The 10% Al2O3/SCBA catalyst calcined at 400°C showed high efficiency for the conversion of methyl alcohol to DME, attaining 89% conversion with 100% selectivity. This observation can be attributed to the even distribution of active sites and the acid–base equilibrium on the surface. Moreover, its catalytic activity and selectivity remain unchanged over a continuous 2‐week operation without coke formation, demonstrating its extremely high stability. A strong correlation was observed between the catalytic activity and both the surface area and acidity of the catalysts.

Phyto-synthesis of tin oxide nanoparticles using Diospyros mollis leaves extract doped graphitic carbon nitride for photocatalytic methylene blue degradation and hydrogen peroxide production

In this study, tin oxide nanoparticles (SnO2 NPs) were combined with graphitic carbon nitride (gCN) to produce the SnO2/gCN composite for photocatalytic methylene blue (MB) degradation and H2O2 production. Specifically, SnO2 NPs were initially prepared using a biological pathway from Diospyros mollis leaves extract, followed by the incorporation on gCN via calcination treatment. Characterization of SnO2/gCN was conducted through analytical methods, including scanning electron microscopy, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, N2 sorption isotherm, photoluminescence spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS). The optical band gap of the nanocomposite was also evaluated to be 2.44 eV using the Tauc plot and UV-DRS, which is lower than pristine gCN. The photocatalytic performance over the optimal 1.0SnO2/gCN sample was resultingly investigated, reaching over 99.76 % of MB degradation efficiency within 120 min, and 4060.78 μM/g.h of H2O2 production rate under visible light radiation. Insights into the mechanism revealed the vital participation of reactive radicals, especially •O2− and •OH, in the degradation of MB molecules, while the reusability of 1.0SnO2/gCN was also maintained after 4 succeeding photocatalytic cycles. Such findings affirm the promising applicability of the constructed SnO2/gCN material in many industries, namely the environmental remediation and cleaner production sectors.

Boosting Solvent-Free Aerobic Oxidation of Benzylic Compounds into Ketones over Au-Pd Nanoparticles Supported by Porous Carbon

The exploitation of highly efficient solvent-free catalytic systems for the selective aerobic oxidation of benzylic compounds to produce corresponding ketones with molecular oxygen under mild conditions remains a great challenge in the chemical industry. In this work, Au-Pd nanoparticles supported on porous carbon catalysts were fabricated by the borax-mediated hydrothermal carbonization method and the chemical reduction method. The physicochemical properties of Au-Pd bimetallic samples were examined by XRD, N2 sorption, SEM, TEM, and XPS techniques. The Au-Pd nanoparticles have successfully immobilized on the spherical carbon support with a porous structure and large surface area. A solvent-free catalytic oxidation system was constructed to selectively convert indane into indanone with Au-Pd nanocatalysts and O2. In contrast with a monometallic Au or Pd catalyst, the resulting bimetallic Au-Pd catalyst could effectively activate O2 and exhibit improved catalytic activity in the controlled oxidation of indane into indanone under 1 bar O2. A total of 78% conversion and >99% selectivity toward indanone can be achieved under optimized conditions. The synergistic effect of Au and Pd and porous carbon support contributed to the high catalytic activity for aerobic benzylic compound oxidation. This work offers a promising application prospect of efficient and recyclable Au-Pd nanocatalysts in functional benzylic ketone production.

Exploration of cephalexin adsorption mechanisms onto bauxite and palygorskite and regeneration of spent adsorbents with cold plasma bubbling

The aim of the present study was the direct comparison of two popular minerals, bauxite and palygorskite, as adsorbents for the removal of cephalexin (CPX) from aqueous solutions and the regeneration of the spent adsorbents through cold atmospheric plasma. Batch kinetics and isotherm studies were carried out to evaluate the effect of contact time, initial CPX concentration, adsorbent dosage, pH and temperature. The adsorbents were characterized by ATR-FTIR, N2 sorption, SEM and XRD, while several isotherm, kinetic and thermodynamic models were evaluated attempting to shed light on the adsorption mechanisms. CPX adsorption on both adsorbents was better described by Langmuir model, with an adsorption capacity of 112.36 mg/g for palygorskite and 11.79 mg/g for bauxite. Thermodynamics revealed the endothermic and the spontaneous character of the process, indicating chemisorption as the main adsorption mechanism for both adsorbents. The pseudo-second-order and the Elovich models fitted satisfactorily the adsorption onto bauxite, while adsorption onto palygorskite was well presented by Weber–Morris model, indicating that pore diffusion is also involved in the process. The adsorption capacity of both minerals decreased significantly after being used for several adsorption cycles and then almost completely recovered (regeneration efficiency was 99.6% and 98% for palygorskite and bauxite, respectively) inside a novel cold plasma microbubble reactor energized by high-voltage nanopulses, revealing the potential of these adsorbents to be reused. In addition to the regeneration of the adsorbents, the cold plasma completely eliminated the CPX transferred from the solid to the aqueous phase during the regeneration process.

Removal of phenoxy acid herbicide from water by magnetic mesoporous silicate

Superparamagnetic iron (II,III) oxide (Fe3O4)–MCM-41 was successfully synthesised using a direct hydrothermal route and was utilised as an excellent adsorbent for the removal of the herbicide 2,4-dichlorophenoxyacetic acid from aqueous solution. The superparamagnetic mesoporous adsorbent was fully characterised using X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, nitrogen (N2) sorption and vibrating-sample magnetometry (VSM). The synthesised adsorbent exhibited a high specific surface area of 444 m2/g, making it a suitable candidate for adsorption, where it provided a higher adsorption capacity. Based on the VSM study, the recorded saturated magnetisation was 15.9 emu/g, which confirmed the viability of easily separating the adsorbent from an aqueous medium using a magnet. The ability of iron (II,III) oxide–MCM-41 to adsorb the herbicide 2,4-dichlorophenoxyacetic acid from water was tested considering various parameters, such as pH, adsorbent dosage, contact time and pollutant concentration. The effectiveness of iron (II,III) oxide–MCM-41 in removing the herbicide reached its highest peak at pH = 5, 0.05 g adsorbent, 60 min contact time and 10 mg/l 2,4-dichlorophenoxyacetic acid. The maximum removal efficiency under optimum conditions was 94.8%. Based on the experimental data and kinetic studies, the adsorption process followed a pseudo-second-order kinetic and Langmuir isotherm model.

Pd-loaded hierarchical titanosilicalite-1 catalysts on CO2 cycloaddition with epoxides: Experimental and DFT investigations

This work presents the synthesis of Pd-loaded microporous titanosilicalite-1 (Pd/TS-1) and Pd-loaded hierarchical titanosilicalite-1 (Pd/HTS-1) with abundant mesopores (2–30 nm) inside the framework via hydrothermal method using polydiallydimethyl ammonium chloride as the non-surfactant mesopore template. XRD, N2 sorption, FT-IR, FESEM-EDX, TEM, XPS, and DR-UV techniques were used to characterize the morphological and physicochemical properties of the synthesized materials. These materials were tested as heterogeneous catalysts, along with tetrapropylammonium bromide as co-catalyst, for cycloaddition reactions of CO2 with epoxides to produce cyclic carbonates. It was found that the epoxide conversions were influenced by acidity and pore accessibility of the catalysts. Using Pd/HTS-1 facilitated bulky substrates to access active sites, resulting in higher conversions than Pd/TS-1. Over 85 % conversions were achieved for at least five consecutive cycles without significant loss in catalytic activity. The interaction between the Pd active surfaces and epichlorohydrin (ECH) was further studied by DFT calculations. The existence of Pd(200) was more influential on adsorbing epichlorohydrin (ECH) and subsequent formation of dissociated ECH (DECH) intermediate than Pd(111) surface. However, Pd(111) was dominant in enhancing the activity of DECH species for capturing CO2. Therefore, the co-existence of Pd(200) and Pd(111) surfaces was needed for cycloaddition of CO2 with ECH.

Elucidating the role of micropore-generating backbone motifs and amine functionality on H2S, CO2, CH4 and N2 sorption

Microporous polymers have transformed the field of membrane-based gas separations over the past two decades. However, applying sorbent materials as membranes presents a unique challenge in quantifying emergent phenomena, such as how strongly sorbing penetrants influence transport of co-permeating species. These mechanistic features are of urgent concern for many current and emerging applications, yet they remain significantly understudied. In previous work, amine-functionalized PIM-1 (PIM-NH2) has proven to be an exemplar of these effects, exhibiting CO2/CH4 mixed-gas selectivities that are 2.6 times higher than selectivities calculated from pure-gas measurements. Here, we investigate the generalizability of this sorption-induced emergent phenomena through the synthesis of a novel amine-functional microporous poly(arylene ether) (PAE-NH2). The effects of amine functionalization on gas transport were analyzed through variable-temperature pure-gas sorption tests, ternary mixed-gas sorption modeling, and dual-mode sorption analysis for N2, CH4, CO2, and H2S. Compared to its nitrile-functional counterpart (PAE-CN), pure-gas sorption for PAE-NH2 was 69 % higher for CO2 and 26 % higher for H2S at 1 atm and 35 °C, suggesting increased affinity to both CO2 and H2S. However, the higher total sorption for H2S resulted in strong competitive sorption effects, decreasing permeability of both CO2 and CH4 for mixture experiments, which was reported in our complementary study on the mixed-gas separation performance of the same materials in this work. The strength of gas–polymer interactions were quantified by evaluating experimental isosteric heats of sorption for the acid gases in PIM-1, PIM-NH2, PAE-CN, and PAE-NH2. Amine-functionalized samples showed highly exothermic interactions, with minima in isosteric heats of approximately −44 kJ mol−1 for CO2 and −34 kJ mol−1 for H2S. Leveraging microporosity and amine-functionality in membranes are general approaches to access competitive sorption for many industrially relevant gas separations.

Eco-friendly removal of methyl tert-butyl ether from contaminated water using steam and CO2-activated carbons

AbstractPetrol frequently contains the additive methyl tertiary butyl ether (MTBE). Because of its significant health risks, MTBE pollution of surface and ground water is a severe concern for the environment. Highly porous physically activated carbons, particularly CO2-activated carbon (CO2-AC) and steam-activated carbon (Steam-AC), were obtained from date stones as potential eco-friendly adsorbents for MTBE from contaminated water. The chemical composition, microstructure, textural, and structural characteristics of adsorbents were characterised by elemental analysis, SEM, N2 sorption, XRD, and FTIR. The adsorption process evaluation based on the initial MTBE concentration, liquid-to-solid ratio, and equilibrium contact time. CO2-AC and steam-AC adsorbents have high surface areas of 819.5 m2/g, and 567.7 m2/g, respectively. At 40 °C, CO2-AC has an adsorption capability of 181.36 mg/g. The adsorption result was best fitted by the Freundlich model. The two-step intraparticle diffusion process prevailed the adsorption process, and the pseudo-second-order model presented an optimal fit for the adsorption kinetics models. Spontaneous physical adsorption was endothermic when CO2-AC adsorbs at 40 °C because ∆G was − 6.34 kJ/mol. Finally, the water quality improved and the salt content, the alkalinity, and the hardness decreased with the use of CO2-AC as an environmentally friendly adsorbent for removing MTBE from the polluted water.

Ag‐Nanocatalysts Based on Porous Organic Polymers in Chemical Fixation of CO2 for the N‐Methylation and N‐Formylation of Amines

AbstractChemical fixation of CO2 for the synthesis of valuable chemicals is very demanding in the context of green and sustainable chemistry. Herein, we report highly efficient silver‐loaded porous organic polymer catalysts for the exclusive N‐formylation and N‐methylation of amines under ambient reaction conditions using CO2 as a green C1 source. By adjusting the solvent and temperature of the reaction, the successful production of formamides and methylamines could be accomplished with high levels of selectivity and efficiency. POP‐based materials Ag@TTP‐1 and Ag@PAN‐T are utilized as low‐cost catalysts for both the N‐methylation and N‐formylation of primary and secondary amines and the product yields up to 98 % could be achieved. Ag@TTP‐1 demonstrated superior catalytic efficiency compared to Ag@PAN‐T in the N‐methylation and N‐formylation reactions. This result suggests that the grafting of Ag nanoparticles onto POP surface with a high surface area plays a crucial role in these CO2 fixation reactions. The above‐mentioned catalysts (Ag@TTP‐1 and Ag@PAN‐T) are characterized through powder XRD, FT IR spectroscopy, FE‐SEM, TEM, thermogravimetric techniques, N2 sorption and XPS analysis. Ag‐nanocatalysts demonstrated heterogeneous nature and high recycling efficiency for several cycles in this CO2 fixation reaction.

Understanding and Controlling Molecular Compositions and Properties in Mixed-Linker Porphyrin Metal-Organic Frameworks.

Porphyrin-based metal-organic frameworks (MOFs) are attractive materials for photo- and thermally activated catalysis due to their unique structural features related to the porphyrin moiety, guest-accessible porosity, and high chemical tunability. In this study, we report the synthetic incorporation of nonplanar β-ethyl-functionalized porphyrin linkers into the framework structure of PCN-222, obtaining a solid-solution series of materials with different modified linker contents. Comprehensive analysis by a combination of characterization techniques, such as NMR, UV-vis and IR spectroscopy, powder X-ray diffraction, and N2 sorption analysis, allows for the confirmation of linker incorporation. A detailed structural analysis of intrinsic material properties, such as the thermal response of the different materials, underlines the complexity of synthesizing and understanding such materials. This study presents a blueprint for synthesizing and analyzing porphyrin-based mixed-linker MOF systems and highlights the hurdles of characterizing such materials.