H3 Hysteresis Loop Research Articles

Synthesis of "Ice Cube" Shaped Zeolite A Type and Cu2+ Ion-Exchanged Zeolites and Study of Their CO2 Adsorption Performance.

In this study, zeolite type A and four Cu2+ ion-exchanged zeolites were synthesized through cationic ion exchange process with Cu concentrations of 0.05, 0.1, 0.15, and 0.2 M respectively. The physicochemical properties of both the prepared and ion-exchanged zeolites were thoroughly analyzed. Field Emission Scanning Electron Microscopy (FESEM) micrographs revealed that the synthesized zeolites exhibited an "ice cube"-shaped morphology, and this morphology was maintained even after the ion exchange process. N2 adsorption/desorption studies indicated a typical type IV isotherm with an H3 hysteresis loop for both the prepared and Cu2+ ion-exchanged zeolites. CO2 adsorption data followed a type I isotherm, with the highest adsorption capacity of 4.02 mmol/g observed for the 0.1 M Cu2+ ion-exchanged zeolites. The adsorption behavior was modeled using a nonlinear isotherm, with good agreement between experimental and fitted data.

Exploring the superior mild temperature performance of nickel-infused fibrous titania silica for enhanced dry reforming of methane

Carbon (IV) oxide (CO2) and methane (CH4) contribute significantly to greenhouse gas emissions and global warming. One potential approach for reducing their environmental impact is transforming these gases into synthesis gas (CO + H2). This study illustrates the advancement of catalysts supported by fibrous titania silica (FTS), which have nickel loadings of 1%, 3%, and 5%. The FTS support, a modified variant of silica-titania, has a distinct fibrous structure and exhibits mesoporous material properties such as a type IV isotherm and an H1 hysteresis loop. After 72 h of operation, the 1Ni/FTS catalyst converted over 80% of CH4 and CO2 with low coke deposition, outperforming other catalysts. The bare FTS support had reduced CH4 conversion at 600°C, CO2 conversion at 650°C, and H2/CO ratio at 700°C. However, the 5Ni/FTS and 3Ni/FTS catalysts showed consistent increases in CH4 conversion at 600°C. The 1Ni/FTS catalyst, with a pore size of 7.39 nm, had strong metal-support interaction and moderate basicity sites, which helped with reactant dissociation and coke gasification. Despite the slightly higher CH4 conversion of the 3Ni/FTS catalyst and the high basicity of the 5Ni/FTS catalyst, the 1Ni/FTS catalyst demonstrated superior thermal stability and coking resistance, as evidenced by negligible weight loss during TGA analysis. Raman shifts revealed the presence of carbon synthesis and the buildup of disordered amorphous carbon. The Id/Ig ratios of FTS, 1Ni/FTS, 3Ni/FTS, and 5Ni/FTS were 1.01, 0.98, 1.01, and 1.01, respectively. The lower Id/Ig ratio of 1Ni/FTS suggests less disorder. The FTS support promises mild-temperature, carbon-neutral CH4 reforming with long-term catalytic applications. This study demonstrates the efficacy of FTS-supported catalysts in constructing long-term and efficient systems for converting greenhouse gasses.

Comparative study of two mesoporous magnetic and MCM-41 supported Cu complex: High-performance heterogeneous catalysts for aqueous synthesis of tetrazole

The effects of the carrier were studied in the synthesis of tetrazole. Copper catalysts supported on CoFe2O4 and MCM-41 with serine ligands were prepared. Two mesoporous catalysts, CoFe2O4/Ser/Cu and MCM-41/Ser/Cu, (denote Serine with (Ser)) were synthesized and compared the activity of these catalysts in converting nitrile to tetrazole. The prepared material was characterized using powder X-ray diffraction (XRD),field emission scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDS), elemental mapping, vibrating-sample magnetometer (VSM), and nitrogen adsorption–desorption isotherm. The relation between the textural properties of the catalysts and the catalytic performance was investigated. The X-ray diffraction patterns showed the spinel ferrite type for CoFe2O4/Ser/Cu and amorphous SiO2 for MCM-41/Ser/Cu. The distinctive diffraction peaks in the diffraction curves of CoFe2O4/Ser/Cu, and MCM-41/Ser/Cu were identical to those of CoFe2O4, and MCM-41, confirming the preservation of these phases of supports throughout the functionalization processes and formation of -Ser/Cu moiety on the crystalline CoFe2O4 structure and non-crystalline silica structure. FE-SEM images showed the particles in CoFe2O4/Ser/Cu had an average diameter of 20–50 nm and in MCM-41/Ser/Cu had an average diameter of 50–250 nm. The images showed the uniformity and well-ordering of the particles. The slight aggregation in CoFe2O4/Ser/Cu particles implied that their clustering may be the result of modest attraction forces between them. MCM-41/Ser/Cu sample exhibited a type IV isotherm with an H1-type hysteresis loop and diagrams of the CoFe2O4/Ser/Cu showed a type IV isotherm (type H2 hysteresis loop). The MCM-41/Ser/Cu and CoFe2O4/Ser/Cu showed a mesoporous structure and capillary condensation occurred in the nearly cylindrical and ink bottle channels with non-uniform size or shape. The CoFe2O4/Ser/Cu showed surface area by BET and t-plot of 71.17 m2/g and 64.92 m2/g respectively, mean pore size of 14.06 nm, and pore volume of 0.250 cm3/g. The MCM-41/Ser/Cu showed surface area by BET and t-plot of 639.2 m2/g and 484.6 m2/g respectively, with a mean pore size of 5.44 nm, and pore volume of 0.869 cm3/g. The BJH pore size distribution was between 1 and 10 nm for the MCM-41/Ser/Cu and 1–20 nm for the CoFe2O4/Ser/Cu. Two catalysts were used for the synthesis of tetrazole. The CoFe2O4/Ser/Cu shows better activity in the synthesis of 5–substituted 1H-tetrazoles than the MCM-41/Ser/Cu sample despite its lowest surface area (71.17 m2/g). There is no reduction in the conversion of nitrile to tetrazole after the 6 cycles for CoFe2O4/Ser/Cu and after the 4 cycles for MCM-41/Ser/Cu.

Surface‐Modified Mesoporous V2‐xSb2xO5‐δ Ceramics for Improving the Electrostatic Chemisorption of Methylene Blue

AbstractHerein, mesoporous V2‐xSb2xO5‐δ (Sb−V−O) compounds, encompassing a compositional range of x varying between, 0.05≤x≤0.08, with orthorhombic Pmmn space group symmetry, are synthesized by high‐temperature solid‐state reaction method. Scanning electron microscopy indicated the formation of microscale rods and flakes and EDS spectra affirmed the stoichiometric precision of their composition adhering to the formulated chemical formula. Nitrogen adsorption isotherms exhibited the distinctive type IV pattern, accompanied by an H3 hysteresis loop, signifying the formation of mesoporous micro rods and flakes. Brunauer‐Emmett‐Teller measurements demonstrated an augmented surface area, ranging from 16.67–28.74 m2/g, mirroring the effect of the increase in the concentration of Sb cations. The study demonstrated complete Methylene Blue dye removal within a brief 90 minute period, highlighting its efficacy in water remediation. The adsorption kinetics was aptly described by the pseudo‐second‐order model which exhibited a high degree of fit (R2=0.99). Freundlich adsorption isotherm was used to describe the multilayer adsorption of MB dye on the Sb−V−O surface indicating an exponential increase in adsorption active sites. Enhanced cationic MB dye adsorption on negative Sb−V−O surface is attributed to the electrostatic chemisorption by the interaction of NMe2+ on the negative surface modified Sb−V−O compounds.

Enhanced heavy metal adsorption capacity of surface-functionalized Philippine natural zeolite in simulated wastewater

The adsorption efficiency of surface-functionalized Philippine natural zeolite (PNZ) for heavy metal uptake from single and mixed metal ion-simulated wastewater solution is reported in this work. Atomic adsorption spectroscopy (AAS) findings revealed that NaCl-modified PNZ (MPNZ) exhibited the highest zinc ion adsorption of 99.96 % while PNZ yielded an adsorption of 95.61 %. The adsorption isotherms of raw PNZ and MPNZ both show similar shapes that reflect Type IV adsorption-desorption isotherms with Type H2 hysteresis loop which can be observed for micro-mesoporous materials (pore containing 2–50 nm). An increase in PNZ pore size from 10.11 nm to 13.36 nm for NaCl-PNZ and 15.59 for NaOH-PNZ is observed after alkaline treatment. EDS confirmed the decrease in Si/Al ratio from 4.02 to 3.76, indicative of possible higher negative charge in the PNZ framework which is favorable for an enhanced Coulombic or electrostatic interaction with the cationic heavy metals being detected in this study. MPNZ demonstrated an adsorption capacity of 99.96 % for copper in mixed-ion solution while 88.49 % and 86.67 % were obtained for zinc and nickel, respectively. These values are higher compared to PNZ having only 32.21 % uptake for zinc and 38.00 % for nickel. A hierarchy of the average metal adsorption capacity showed the order: copper > nickel > zinc. Rapid adsorption at the first hour of the adsorption reaction was attained in all solutions while samples with pH 9 exhibited the highest Ni2+ and Zn2+ percent removal. Moreover, the increase in initial solution concentration led to lower adsorption efficiency and the maximum uptake was attained at 100 ppm. The equilibrium data of adsorption and mechanism were suitably described by Langmuir isotherm model. With these, surface functionalization of PNZ has further enhanced its cationic adsorption capacity on heavy metals in both single and mixed-ion solution having promising potential for wastewater remediation.

Using industrial waste in porous building materials for indoor humidity control

This study uses waste bricks and waste catalyst as raw materials in the synthesis of humidity control building materials with high structural strength. This paper explores the feasibility of producing porous humidity control materials (PHCM) through the billet sintering of waste brick with various quantities of waste catalyst (0 %–40 %) for indoor construction. N2 adsorption and desorption isotherms revealed that PHCM exhibits Type-IV adsorption with H3 hysteresis loops, indicating a network of interconnected mesopores with diameters ranging from 3 to 17 nm. Humidity control analysis revealed that increasing the waste catalyst content significantly enhanced the equilibrium moisture content and moisture adsorption and desorption capacity. This study determined that the adsorption of moisture within the PHCM relies on capillary condensation within the mesopores. Under 95 % relative humidity (RH), the highest equilibrium moisture content (2.97 kg/kg) and 12-h moisture adsorption capacity (72.41 g/m2) were obtained in specimens prepared at a sintering temperature of 1000 °C with a 40 % spent catalyst. This excellent adsorption capacity can be attributed to the high surface area of the waste catalyst, which increased the surface area of PHCM from 0.013 to 8.529 m2/g. This study demonstrates the benefits of synthesizing PHCM using waste bricks and catalysts in terms of porous properties, mechanical properties, and humidity control performance.

Optimizing the fluoride removal from drinking water through adsorption with mesoporous magnetic calcite nanocomposites

Fluoride (F−) contamination in groundwater is a global concern arising from natural processes and human activities. This study investigates the adsorption of F− using surface-activated magnetic calcite nanocomposites (NCs) synthesized via co-precipitation assisted wet-impregnation (CP-WI). Various Fe3O4 loadings and calcination temperatures (300 °C and 500 °C) were explored to optimize synthesis parameters. Batch adsorption experiments were conducted to assess the performance of synthesized nanoparticles (NPs) and nanocomposites (NCs). BET, FTIR spectroscopy, X-ray diffraction, and SEM characterization techniques were employed to analyze the physicochemical properties, including surface functional groups, crystallite size, and morphology. The adsorption process was investigated using RSM statistical design with adsorbent dose (A) and F− concentration (B) as independent variables. 0.5Fe-C-NC-5, calcined at 500 °C, exhibited superior adsorption capacity (7.81 mg/g) compared to Fe3O4 and calcite NPs (6.57 mg/g and 6.81 mg/g, respectively). Maximum F− adsorption occurred within 10 min of contact time. NPs and NCs that were exposed to higher calcination temperatures, reaching up to 500 °C, showed an increase in crystallite development while experiencing a reduction in surface area and an enlargement of pore size compared to those treated at lower temperatures. The BET analysis revealed a narrow, slit-like mix of microporous and mesoporous surface with a type IV isotherm and H3 hysteresis loop, indicating multilayer adsorption followed by capillary condensation. The SEM images displayed columnar shapes of CaCO3 polymorph in the prepared Fe3O4-calcite NP and Fe–C NP, which can be attributed to lower calcination or synthesis temperatures.

Strategically tailored double S-scheme heterojunction in h-MoO3 doped Bi7O9I3 decorated with Cr–CdS quantum dots for efficient photocatalytic degradation of phenolics

Phenolic compounds are widely used in various industrial processes, but they can be harmful to the environment if released without proper treatment. In this study, we developed a ternary nanocomposite (NCs) consisting of molybdenum trioxide, bismuth oxoiodide, and chromium-doped cadmium sulphide quantum dots h-MoO3/Bi9O7I3/Cr–CdS QDs (MBC) nanocomposite (NCs) to enhance the photocatalytic degradation of p-chlorophenol (p-CP). The nanomaterial morphology, distribution of depositing material, and heterojunction formation were investigated using SEM, TEM, SAED, and elemental mapping. Further, the structural characterization was done by XRD, XPS, and Raman spectroscopy which confirmed its purity, chemical states, bonding nature, and the presence of oxygen vacancies (OVs) and sulphur defects. The 30-MBC NCs exhibited the highest surface area of 354.5 m2/g and pore volume of 0.76 cm3/g, with the H3 hysteresis loop indicating their mesoporous nature. The Kubelka-Munk plot determined the band gap of the NCs to be 2.22 eV and ensured successful visible-light sensitization. PL and ESR studies revealed that 30-MBC NCs had the lowest charge carrier recombination and highest ROS production. The photocatalytic degradation of p-CP by 30-MBC NCs achieved 94% in 300 min. The highest efficiency was observed at 75 mg/L NCs, 150 mg/L p-CP, and pH 6. Additionally, NCs retained activity in the presence of different ions and degraded 82% p-CP even after six consecutive cycles. •O2− was the dominant ROS involved in the degradation process, while OVs and sulphur defects played a crucial role in ameliorating charge transfer in the 30-MBC NCs. GC-MS/MS analysis identified the possible degradation pathways of p-CP, and ECOSAR showed that less toxic by/end products were produced. Overall, this study highlights the promising potential of 30-MBC NCs for extensive wastewater treatment.

Competitive adsorption of VOCs (benzene, xylene and ethylbenzene) with Fe3O4@SiO2-NH@BENZOPHENONE magnetic nanoadsorbents

Volatile organic compounds (VOCs), which are toxic, mutagenic and carcinogenic, are considered a critical factor for air pollution and cause serious harm to the eco-environment and human health. In this study, Fe3O4, Fe3O4@SiO2-NH2, Fe3O4@SiO2-NH@BENZOFENONE were synthesized as new magnetic nanoadsorbents (MNAs) and used for the first time in the removal of gas-phase benzene, xylene and ethylbenzene. The synthesised MNAs were characterized by SEM-EDS, TEM, FTIR, XRD, VSM, TGA and BET analyses. The characterization results showed that the MNAs have mesoporous structure, type IV physioresorption and type H3 hysteresis loop character. In order to clarify the comparative and competitive adsorption behaviour, the adsorption capacity of Fe3O4@SiO2-NH@BENZOFENONE MNA was found to be in the order of xylene > ethylbenzene > benzene in both single, binary and ternary component systems. The adsorption kinetics of benzene, xylene and ethylbenzene with Fe3O4@SiO2-NH@BENZOFENONE MNA were found to be governed by multistep mechanisms. Fe3O4@SiO2-NH@BENZOFENONE MNA showed reuse efficiencies of 83.07%, 84.35% and 82.99% after 5 cycles for benzene, xylene and ethylbenzene respectively. In the framework of the results, Fe3O4@SiO2-NH@BENZOPHENONE MNA, which has a high potential in terms of both adsorption capacity and reuse efficiency, is proposed as a promising adsorbent for the efficient removal of benzene, xylene and ethylbenzene.

Characteristics and controlling factors of pore structure of shale in the 7th member of Yanchang Formation in Huachi area, Ordos Basin, China

To clarify the influence of organic matter and mineral composition on the pore structure of shale reservoirs in the 7th member of the Yanchang Formation (Chang 7 Member) in the Ordos Basin, we characterized the pore structure of Chang 7 shale reservoirs using argon ion polishing-field emission scanning electron microscopy (FE-SEM) and low-pressure nitrogen adsorption (LP-N2A). This characterization was combined with whole-rock mineral composition and organic geochemical experiments to analyze the main controlling factors of the pore structure of Chang 7 Member shale. The results reveal the presence of various pore types in shale, including organic matter pores, intergranular pores, intercrystalline pores, dissolved pores, and micro-cracks. The LP-N2A isotherms of shale consistently exhibit type Ⅱ isotherms with H3 and H4 hysteresis loop characteristics, indicating the relatively developed nature of mesopores and a pore morphology characterized by parallel lamellar and “ink bottle” shapes. The primary determinants of shale pore structure are identified as organic matter, clay minerals, quartz, feldspar, and pyrite. Among these factors, clay mineral phase transformation generates a substantial number of micropores and mesopores within the mineral crystal layers, serving as the main source of shale pores in the study area. Additionally, liquid hydrocarbons generated, solid bitumen, and euhedral pyrite fill inorganic mineral pores, thereby reducing the pore space of Chang 7 shale to a certain extent. These results provide a new cognition into understanding the pore structure characteristics and controlling factors of Chang 7 shale.

Experimental investigation and intelligent modeling of pore structure changes in type III kerogen-rich shale artificially matured by hydrous and anhydrous pyrolysis

The occurrence and enrichment of shale plays are highly controlled by pore characteristics of the formation. In this study, an immature sample rich in kerogen type III from the Damoguaihe formation, Hailar Basin in China is subjected to hydrous and anhydrous pyrolysis (HP and AHP) across an extensive temperature range (300–450 °C). Next, low-pressure N2 adsorption analysis was conducted on the pyrolyzate of each maturity stage to study the pore structures’ evolution during thermal maturity simulation. Moreover, deconvolution and fractal dimension analyses were implemented to study pore families and the complexity of pores within the shale samples. Finally, radial basis function (RBF) neural networks optimized by four evolutionary approaches were applied for modeling N2 adsorption data obtained from the HP and AHP samples. According to the results, the original shale sample and all pyrolyzates obtained with HP and AHP scenarios exhibited type IV isotherm with H3 hysteresis loops. As a whole, BET surface area, micro-, meso- and total pore volume of HP pyrolyzates were higher than AHP ones. The unheated shale sample had seven families containing three mesopore and four macropore groups. Although all pyrolyzates obtained from the pyrolysis had families with similar means, their pore volumes were entirely different, which proves that the pore structure of samples undergoes changes during thermal maturation and the presence of water can also enforce these changes. Both fractal dimensions showed a direct relationship with BET surface area and a negative correlation with the average pore diameter of shale samples. The RBF model optimized by differential evolution (DE) delivered a mean absolute percent relative error (MAPRE) value of 4.84% and determination coefficient (R2) of 0.9946 for the total data set, which outperforms other RBF models in predicting N2 adsorption/desorption tests of pyrolyzates. The outcome of sensitivity analysis suggested that the N2 adsorption/desorption behavior of the pyrolyzates was mostly affected by relative pressure and the pyrolysis type (HP or AHP). Ultimately, the results clearly revealed that the effect of water on the pores' alteration of shales with type III kerogen is greater than the effect of temperature or thermal maturity itself.

Quantitative evaluation of pore connectivity of shales with a type H3 sorption hysteresis loop

Pore connectivity is a key parameter affecting the hydrocarbon yield of shale reservoirs, and a quantitative study on it is helpful to evaluate the exploration and development potential of shale gas. In this paper, the shales from the Jurassic Yangxia and Kezilenur Formations in the Kuqa Depression, Tarim Basin, China, were taken as an example, and organic petrography analysis, X-ray diffraction analysis, field emission scanning electron microscope (FE-SEM), gas adsorption and helium pycnometry were carried out to determine their petrological, organic geochemical characteristics and pore distribution features. A method for estimating the connectivity of shale with isotherm adsorption curves of a H3 hysteresis loop was established and used to characterize the connectivity of shale pores. The results show that the total pore volume of shale ranges from 2.479 × 10-3 to 20.379 × 10-3 cm3/g, and the specific surface area (SSA) ranges from 1.222 cm2/g to 12.668 cm2/g. The samples’ coordination number (Z) is between 1.215 and 3.064, and the percolation cluster length (L) is between 2.429 and 3.859. Shale with more micropores or higher TOC has a larger Z value, indicating that organic matter pores and micropores have better connectivity. There is no correlation between Z and Tmax, meaning that the effect of maturity on Z is insignificant. The impact of TOC on the L value is also not substantial. Besides, Tmax and illite content show a negative correlation with L, indicating that the high maturity and illite content impede the development of the percolation cluster.

Removal of Cu2+ from wastewater using eco-hydroxyapatite synthesized from marble sludge

Rapid development brings environmental problems such as the discharge of industrial and agricultural wastewater. This study demonstrates the synthesis of eco–hydroxyapatite (eco–HAp) through the hydrothermal processing of marble sludge for the removal of Cu2+ from wastewater. FTIR analysis confirmed the existence of O–H and PO43− groups in eco–HAp samples. TEM analysis revealed the importance of Ca/P ratio on the shape and size of particles. Solid–state nuclear magnetic resonance (NMR) spectra revealed NMR 1H representing a single crystal site of (OH) and 31P representing the single crystal position of inorganic phosphorus (PO4). Eco–HAp samples presented Type IV N2 adsorption–desorption isotherms with H3 hysteresis loops, typical of HAp samples with a well–defined capillary step, which is indicative of mesoporous materials. Eco–HAp fabricated at a hydrothermal temperature of 120 °C and Ca/P molar ratio of 1 presented high adsorption capacity of 256.25 mg/g. The correlation between the eco–HAp and the Langmuir adsorption isotherm model was 0.96–0.99. Eco–HAp with a large surface area is thus an excellent adsorbent for the treatment of wastewater containing Cu2+.

Synthesis of MCM-41 Silica Mesoporous Modified with Zn Metal

MCM-41 and Zn-MCM-41 were successfully synthesized using hydrothermal and impregnation methods. The synthesized silica mesoporous was confirmed by characterizing the material using XRD, SEM-EDS, and BET-BJH analyses. XRD results showed three main peaks at angles of 2θ = 2.40° (100), 3.87° (200), and 4.49° (210), which are characteristics of mesoporous materials with hexagonal structures. SEM analysis showed that the surface morphology of Zn-modified MCM-41 formed aggregates of smaller particles. The EDS results showed that the amount of Zn in MCM-41 was 1.25%. Modification with Zn metal also affected the surface area and porosity of MCM-41, where the surface area, pore volume, and pore diameter decreased. Based on the adsorption-desorption analysis of N2 gas, both materials exhibit a type IV isotherm typical for mesoporous materials with an H1 hysteresis loop.

Textural Thermo-gravimetric and Magnetic Properties of Green Synthesised Water Dispersible Pristine and Gold Coated Superparamagnetic Iron Oxide Nanoparticles

Gold-coated magnetic nanoparticles have received a lot of attention in recent years due to their multifunctional attributes and their prospective unique characteristics in environmental and biomedical applications. This paper reports the textural, thermo-gravimetric, and magnetic properties of green synthesized gluconic acid-capped uncoated and gold-coated superparamagnetic iron oxide nanoparticles (SPION@Au). The as-synthesized nanomaterials were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), thermal gravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), and superconducting quantum interference device (SQUID) magnetometry. The XRD and SEM measurements showed that the gluconic acid-capped magnetic core was coated with gold with cubical spinel crystalline structures. TGA results revealed the thermal stability of the nanoparticles. Textural properties indicated that the gold-coated nanoparticles were in naturally mesoporous and exhibited the type IV isotherm with an H2 hysteresis loop. The estimated maximum pore diameter and surface area of SPION@Au were 3.33 nm and 134.02 m²/g respectively. Furthermore, the SQUID results showed the nanocrystals were superparamagnetic with a blocking temperature (TB) of 214 K at 500 Oe and saturation magnetization of 11.38 emu/g. These noteworthy results demonstrated that the as-synthesized SPION@Au are promising nanomaterials for biomedical and analytical applications.

Magnetically separable template assisted iron nanoparticle for the enhancement of latent fingerprints

The article focuses on the cost-effective and high-quality non-destructive template-assisted magnetic mesoporous iron nanomaterial for latent Fingerprint examination (LFPs). The iron nanomaterial is synthesized using the CTAB template by the co-precipitation method. The synthesized nanomaterial is characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 sorption- Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FE-SEM), EDX elemental mapping, Vibrating sample magnetometer (VSM), UV–Visible spectroscopy, and XPS. The N2 sorption showed that the synthesized material is mesoporous with an H1 hysteresis loop. The TEM images showed the spherical shape and particle size to be around 55–65 nm. The VSM analysis successfully established its ferromagnetic nature. The synthesized nanomaterial showed excellent magnetic recovery after its utilization and retained fingerprints for 2–3 months with the same resolution. We collected the fingerprint on both non-porous and non-porous surfaces with better-developed ridges of fingerprints compared to conventional fingerprinting dyes (charcoal).

Effect of Polymer Concentration on the Photocatalytic Membrane Performance of PAN/TiO2/CNT Nanofiber for Methylene Blue Removal through Cross-Flow Membrane Reactor

A photocatalytic membrane combining photocatalyst and membrane technology based on polyacrylonitrile (PAN) and TiO2/CNT has been developed. Such combination is to overcome fouling formation on the membrane, thus prolonging the membrane lifetime and enhancing the efficiency on the waste treatment. PAN nanofiber was prepared by electrospinning method. The precursor solution was dissolved PAN and dispersed TiO2/CNT in N,N-Dimethylformamide (DMF). PAN concentration in the precursor solution was varied at 4.5, 5.5, 6.5, 7.5, and 8.5%. The effect of PAN concentration on the fiber morphology and pore size was discussed. The performance of the resulted membrane on methylene blue (MB) removal was also investigated on a cross-flow system. SEM images of the resulted membrane identified that PAN nanofiber was successfully fabricated with random orientation. The PAN 6.5% showed the highest diffraction intensity of the anatase crystalline phase of TiO2. The additions of CNT and TiO2 lead to the formation of a cluster of beads as confirmed by TEM. Increasing the concentration of PAN increased the fiber diameter from 206 to 506 nm, slightly decreased the surface area and pore size, respectively, from 32.739 to 21.077 m2.g−1 and from 6.38 to 4.75 nm. The PAN/TiO2/CNT nanofibers show type IV of the adsorption-desorption N2 isotherms with the H1 hysteresis loops. Membrane PAN/TiO2/CNT at PAN concentration of 6.5% shows the optimum performance on the MB color removal by maintaining the percentage of rejection (%R) at 90% for 240 min and permeability of 750 LMH. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Zirconium Containing Periodic Mesoporous Organosilica: The Effect of Zr on CO2 Sorption at Ambient Conditions

Two series of zirconium-incorporated-periodic-mesoporous-organosilica (Zr–PMO) materials were successfully prepared, via a co-condensation strategy, in the presence of Pluronic P123 triblock copolymer. The first series of Zr–PMO was prepared using tris[3-(trimethoxysilyl)propyl]isocyanurate (ICS), tetraethylorthosilicate (TEOS), and zirconyl chloride octahydrate(ZrCO), denoted as Zr-I-PMO, where I refers to ICS. The second series was synthesized using bis(triethoxysilyl)benzene (BTEE), TEOS, and ZrCO as precursors, named as Zr-B-PMO, where B refers to BTEE. Zr–PMO samples exhibit type (IV) adsorption isotherms, with a distinct H2-hysteresis loop and well-developed structural parameters, such as pore volume, pore width, high surface area, and narrow pore-size distribution. Structural properties were studied by varying the Zr:Si ratio, adding TEOS at different time intervals, and changing the amount of block copolymer-Pluronic P123 used as well as the calcination temperature. Surface characteristics were tailored by precisely controlling the Zr:Si ratio, upon varying the amount of TEOS present in the mesostructures. The addition of TEOS at different synthesis stages, notably, enhanced the pore size and surface area of the resulting Zr-I-PMO samples more than the Zr-B-PMO samples. Changing the amount of block copolymer, also, played a significant role in altering the textural and morphological properties of the Zr-I-PMO and Zr-B-PMO samples. Optimizing the amount of Pluronic P123 added is crucial for tailoring the surface properties of Zr–PMOs. The prepared Zr–PMO samples were examined for use in CO2 sorption, at ambient temperature and pressure (25 °C, 1.2 bar pressure). Zr–PMO samples displayed a maximum CO2 uptake of 2.08 mmol/g, at 25 °C and 1.2 bar pressure. However, analogous zirconium samples, without any bridging groups, exhibited a significantly lower CO2 uptake, of 0.72 mmol/g, under the same conditions. The presence of isocyanurate- and benzene-bridging groups in Zr-I-PMO and Zr-B-PMO samples enhances the CO2 sorption. Interestingly, results illustrate that Zr–PMO materials show potential in capturing CO2, at ambient conditions.

Morphology, Extraction Yield, and Properties of Biogenic Silica Nanoparticles from Indonesian Rice Husk as Influenced by Solvent Type and Aging Time

Rice husk is a rich source of biogenic silica nanoparticles (SNPs) having excellent physico-chemical properties and numerous potential applications. Extraction yield of the biogenic SNPs may be influenced by many factors. In this study, morphology and the influence of solvent type (sodium hydroxide/NaOH, potassium hydroxide/KOH) and aging time (0, 6, 12, 18, 24h) on extraction yield and properties of selected biogenic SNPs from Indonesian rice husk were investigated. The biogenic SNPs were produced by a simple sol-gel method. The presence of biogenic SNP aggregates in the rice husk tissues was successfully identified by SEM-EDX micrographs. NaOH produced better SNPs extraction results than KOH. Aging time for 6h was the optimum condition for production of SNPs. The TEM image showed that SNPs from the best treatment were approximately spheroidal with particle sizes in the range of 20–50nm. The XRD patterns revealed the amorphous nature of the SNPs. Nitrogen adsorption–desorption analysis showed that the SNPs had BET surface area of 235,78m2/g, total pore volume of 0.58cc/g, and average pore radius of 4.91nm. The SNPs exhibited a type IV isotherm and H1 hysteresis loop indicating a characteristic of mesoporous materials. The results suggest that the sol-gel method developed could provide a simple and relatively fast extraction technique producing biogenic amorphous mesoporous SNPs that could extend their potential applications and increase the economic benefits of utilizing rice husk.

Chirality Transfer from Chiral Mesoporous Silica to Perovskite CsPbBr 3 Nanocrystals: The Role of Chiral Confinement

Chirality Transfer from Chiral Mesoporous Silica to Perovskite CsPbBr ₃ Nanocrystals: The Role of Chiral Confinement