BET Theory Research Articles

Adsorption studies of methylene blue using mangosteen shell porous biochar as adsorbent

The biomass of mangosteen shells was utilized as a raw material to prepare activated carbon based on mangosteen shells through a two-step process of mixed alkali carbonization and activation. This study aimed to investigate the efficacy of the activated carbon in removing methylene blue. The optimum preparation conditions for the study are KOH : NaOH : MSC = 1 : 1 : 1 with a particle size of 80 mesh. The activated carbon exhibits a BET specific surface area of 1432.699 m2/g and a Langmuir maximum specific surface area of 2066.130 m2/g. It demonstrates excellent adsorption performance for methylene blue, with a maximum adsorption amount of 985.5 mg/g. Characterization of the activated carbon is conducted using various techniques including Scanning Electron Microscope, X-ray Diffraction Instrument (XRD), Raman Spectrometry (RMS), Fourier IR Spectrometry (FT-IR), XPS, and BET theory. The adsorption results were consistent with the Freundlich model and the pseudo-first-order kinetic model, indicating that the carbon material exhibits multilayer physical adsorption characteristics for methylene blue. The prepared material offers a large specific surface area, good environmental economics, and excellent adsorption performance, making it a promising choice for adsorption material preparation compared to other biomass activated carbons.

Comprehensive evaluation of the physicochemical properties and pyrolysis mechanism of products from the slow pyrolysis of waste coffee shells

Slow pyrolysis is an efficient method for converting agricultural and forestry wastes into valuable resources, thereby addressing energy shortage and environmental pollution. In this study, a slow-pyrolysis experiment of coffee shells (CS) at 450–850 °C was conducted in a tube furnace. The resulting pyrolysis products were comprehensively characterized via FTIR, Raman spectroscopy, nitrogen adsorption analysis via BET theory, SEM, XPS, and PY-GC-MS. Moreover, the pyrolysis reaction mechanism and N transformation pathway of CS were proposed. The results showed that with the increase in pyrolysis temperature, the yield of biochar gradually decreased, and the yield of biogas gradually increased. At 850°C, the yields of biochar, bio-oil and biogas of CS were 27.13, 35.16 and 37.71 %, respectively (on a dry, ash-free basis). The bio-oil yield was highest at 550 °C, reaching 35.7 %. Notably, biochar exhibited favorable characteristics such as high specific surface area and porosity, demonstrating its potential as both a biomass fuel and an adsorption material. Acetone (78.30 %) and caffeine (8.29 %) was the predominant substance in bio-oil. Biogas was predominantly composed of CO2, CO, CH4 and H2. The pyrolysis process of CS mainly involved the degradation of macromolecules into small molecules, the repyrolysis of small molecules, dehydrogenation, deoxygenation, alkylation, isomerization, and self-condensation. These results provide a theoretical basis for the recycling of waste biomass CS, which has environmental protection significance and economic value.

Investigate Performance of ATGF nanocomposite based on guar gum polymer for adsorption of Congo Red dye and alpha lipoic acid drug from wastewater: study kinetics and simulation

AbstractIn this study, the synthesized nanocomposite novel arginine/thiourea/guar gum/ferrite (ATGF) adsorbent was evaluated for the adsorption of alpha lipoic acid (ALA) and Congo Red (CR) from wastewater. The synthesized nanocomposite was examined by Brunauer–Emmett–Teller theory (BET), Termal gravimetric analysis (TGA), Fourier transform infrared spectrometer (FT‐IR), field emission scanning electron microscopy (FE‐SEM), X‐ray Diffraction (XRD), Vibrating sample magnetometer (VSM), and energy dispersive X‐ray (EDX). For the removal of ALA and CR from aqueous solution, the capacity of the nanocomposite was investigated by working on a series of experiments such as the effect of adsorbent dose, initial concentration, contact time, pH and temperature. The adsorption kinetics of these two pollutants were investigated using pseudo‐first‐order and pseudo‐second‐order velocity equations. The nanocomposite kinetics follow pseudo‐second‐order. Langmuir and Freundlich isotherms were investigated. The results show that the Langmuir isotherm model gives the maximum adsorption capacity of ALA as 96.93 mg g−1 and of CR as 229.34 mg g−1 on the nanocomposite. © 2024 Society of Chemical Industry.

Synthesis of innovative Daphne mucronata extract/Cu-MOF/PVA-PVP nanofiber as high-performance anticancer and antimicrobial agent

Nanofibers’ unique physical properties include mechanical strength, compressive strength, and high specific surface area, making them highly valuable and significant. Nanofiber can be containing nano compounds such as metal nano oxides, metal–organic framework, etc., as well as plant extracts. Plant extracts have had a special place in human life since the past and used in traditional medicine. The synthesis of new nanofibers containing plant extracts and metal–organic framework was the idea that we focused on it. For this purpose, Daphne mucronata extract and copper metal–organic framework, considering the high biological properties were used. For the synthesis of Daphne mucronata extract/Cu-MOF/PVA-PVP nanofiber, electrospinning method and polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) were used. The final product’s structure was examined and verified using XRD (X-Ray diffraction analysis), EDAX (Energy dispersive X-ray analysis), CHNO EA (Carbon, hydrogen, nitrogen, and oxygen elemental analysis), SEM (Scanning electron microscope images), BET (Brunauer-Emmett-Teller theory), FT-IR (Fourier transform infrared spectroscopy), contact angle (Hydrophilic properties), mechanical strength and compressive strength. The specific surface area of the synthesized nanofiber and the diameter size of the synthesized particles were observed to be area 1102 m2/g and 80 nm, respectively. High hydrophilic properties (29°), high flexural strength (17.3 N/mm2), and high compressive strength (65.7 N/mm2) were among other characteristics of the synthesized nanofiber. Biological properties of the synthesized nanoparticle, such as anti-skin cancer, anti-bacterial, and anti-fungal properties, were tested. In the anticancer study, IC50 was 21 μg/mL, and in the antimicrobial studies (antibacterial and antifungal activity), the MIC was between 2 μg/mL and 64 μg/mL. Thus, the synthesized nanofiber can be incorporated as a bioactive compound in the medical industry, such as being utilized as bioactive medical bandages after other tests have been completed.

Study on Spontaneous Combustion Characteristics and Microstructure of Bituminous Coal under Water Immersion.

The stagnant water above the coal seam flows into the goaf, causing the goaf coal to be soaked by water for a long time. Compared with dry raw coal, water-soaked coal has a stronger tendency for spontaneous combustion, which poses a serious threat to mining operators. To unravel the impact of water immersion on coal's self-heating properties, an investigation was conducted employing techniques such as simultaneous thermogravimetric analysis/differential scanning calorimetry (TG/DSC), scanning electron microscopy (SEM), low-temperature nitrogen adsorption based on the BET theory, and Fourier transform infrared spectroscopy (FTIR). The variations in the characteristic temperature, microphysical structure, and active functional groups of bituminous coal with water immersion degrees of 10, 30, 50, and 100% were studied, and the experimental results showed that (1) during the initial stage of coal self-ignition oxidation, moisture can cause a delay in the characteristic temperature points of bituminous coal. When the degree of water saturation in bituminous coal reaches 100%, both the critical temperature (T 1) and the cracking temperature (T 2) peak at 48.14 and 205.06 °C, respectively. However, after the water evaporation phase is complete, water soaking promotes the spontaneous combustion of bituminous coal. (2) The number of pores and fractures in bituminous coal is positively correlated with the amount of water soaked, with the average pore diameter increasing from 10.124 nm in raw coal to 15.547 nm in the A4 coal sample. Moreover, when the degree of water immersion reaches 100%, the proportion of mesopores and macropores increases to 38.89 and 19.95%, respectively. (3) Compared to untreated coal, the number of functional groups in water-soaked coal samples increases. With the increase in water immersion, the hydroxyl (-OH) content of raw coal and four kinds of bituminous coal with different degrees of immersion was 40.8, 41.3, 42, 43.9, and 42.9%, respectively, showing a trend of increasing first and then decreasing. When the degree of water immersion of bituminous coal is 50%, the natural tendency is the strongest. These findings contribute to elucidating the underlying mechanism of water immersion's impact on coal self-ignition, thereby holding significant implications for enhancing fire safety measures in mine working areas.

Identification of Crystal Structure, Surface Area, and Magnetic Properties of Mn<sub>0.25</sub>Fe<sub>2.75</sub>O<sub>4</sub>/rGO Nanocomposites

The aim of this research is to identify the crystal structure, surface area, and magnetic properties of The Mn0.25Fe2.75O4-rGO (reduced Graphene Oxide) nanocomposites (NCs). The synthesis of Mn0.25Fe2.75O4-rGO nanocomposites used the co-precipitation method. The rGO was obtained from the chemical reduction of GO by hydrazine hydrate as the reduction agent. The ratio between Mn0.25Fe2.75O4 nanoparticles and rGO was 1:1 that ultrasonicated at 200 Hz for an hour. The IR spectra of NCs from the FTIR instrument showed that the absorption band around 580 cm-1 and 1622 cm-1 corresponds to the stretching mode of Fe-O and C=C respectively. According to X-Ray Diffraction (XRD) pattern analysis, peak of Mn0.25Fe2.75O4 was detected on 2θ at 30.1°, 35.5°, 53.5°, 57.1°, 62.7° and the peak of rGO phases was amorphous that detected on 2θ between 17º and 30º. The XRD pattern analysis and FTIR spectra have proved the completion of NC’s synthesis. The crystallite size was between 10.3 nm by Scherer's formula. The Specific Surface Area showed that the surface area of the nanocomposites was 100.61 m2/g and the Molecular cross-sectional area was 0.162 nm2 by BET Theory. The Magnetic properties show that the NCs were Superparamagnetic material that has a saturation magnetization of 9.34 emu/g. The material has many potentials to be explored by the researcher around the world.

Unveiling the non-equilibrium process in multilayer mixture adsorption

The Brunauer–Emmett–Teller (BET) theory [S. Brunauer et al., “Adsorption of gases in multimolecular layers,” J. Am. Chem. Soc. 60, 309–319 (1938)] constitutes a cornerstone in gas-adsorption physics. Recently, the kinetic BET equation of single-kind adsorbate has been proposed [H. Yu and X. Zhang, “Molecular-kinetic study of multilayers gas-adsorption in a rarefied gas environment,” Phys. Fluids 34, 123106 (2022)], while its counterpart of mixed adsorbates is currently unknown. Gas mixtures are commonly found in both natural and artificial systems. To address this limitation, we have proposed a kinetic BET theory for adsorbate mixtures in this paper. Moreover, we gave an analytical solution addressing low gas pressure conditions. In this condition, we predicted the “over-adsorption” of one species in the mixture with a higher desorption rate over time, and the “inertia effect” during the crowed-out process of the fast-desorbing species. Further, we also simulated the reciprocal influence of multilayer gas adsorption on the non-equilibrium fluids. Our findings provide valuable insights into gas-adsorption experiments and can facilitate technological advancements.

Equilibrium of sorption of Tribulus Terrestris steroid saponins on a natural polymer sorbent – chitosan

Steroidal saponins have a wide spectrum of pharmacological action and therefore are widely used in pharmacological practice. Chitosan is a unique material. Its biocompatibility, biodegradability, non-toxicity, as well as its cationic nature reveal the potential of this biopolymer as a carrier of drugs for their targeted delivery. The immobilization of biologically active substances can be carried out in a variety of ways - nanomicelles with an encapsulated drug or their polyelectrolyte complexes with oligochitosans, depending on the nature of the active substance. The study of the sorption of saponins by chitosan under equilibrium conditions was studied. An analysis of the equilibrium curves of sorption of Tribulus Terrestris saponin on chitosan was carried out. The presence of a local minimum on the isotherm in the region of solution concentrations corresponding to micellization was revealed. It has been established that the course of the saponin sorption isotherm is determined by competing association processes in a solution and on the surface of chitosan. The pH of the solution did not change, which indicated the absence of ionic interactions involving the protonated amino group of chitosan. The moisture content of chitosan during the sorption of saponin was studied. The antibatic nature of the absorption curves and moisture content curves of chitosan was revealed. An analysis of the saponin sorption isotherm was carried out using the adsorption theories of Langmuir, Freundlich, and BET. High values of the correlation coefficients allowed us to use the Freundlich equation for a quantitative description of the isotherm in the initial section, and to analyse the entire isotherm using the BET theory, which takes into account the polymolecular nature of sorption. The results obtained for the description of the sorption isotherm of saponin were consistent with the proposed mechanism of its absorption by chitosan. Using IR spectroscopy, it was established that the interaction in the sorbent-sorbate system was due to the emerging hydrogen bonds between the amino and hydroxyl groups of chitosan and the hydroxyl groups of saponin carbohydrates. The results obtained, as well as literature data, confirm the formation of cavities in polysaccharides into which saponin is “incorporated”. In our case, the presence of cavities formed by seven monomer fragments of chitosan, the stability of which is fixed by hydrogen bonds was discussed.

Effect of adsorption-catalytic deformation and partial deactivation on the determination of the absolute activity of a liquid phase hydrogenation catalyst

Objectives. To take into account the change in the number of active sites during the adsorptioncatalytic deformation and deactivation of a catalyst surface by means of a catalytic poison when calculating the turnover frequency (TOF) of a hydrogenation catalyst.Methods. The activity was determined by a static method, using a titanium reactor having a volume of 400 mL, an experimental temperature controlled using a liquid thermostat with an accuracy of 0.5 K, with a paddle stirrer rotation speed of 3600 rpm and system hydrogen pressure equal to atmospheric. The consumption of hydrogen used to reduce the model compound was taken into account via the volumetric method. The heats of hydrogen adsorption were determined using a reaction calorimeter with an operating mode close to that of a chemical reactor. After measuring the specific surface area using low temperature nitrogen adsorption, the results were processed using Brunauer–Emmett–Teller theory approximations. Deactivation was carried out by introducing dosed amounts of catalytic poison into the system in titration mode.Results. A kinetic experiment for the reduction of a multiple carbon bond in a sodium maleate molecule using aqueous solutions of sodium hydroxide with additions of monohydric aliphatic alcohols as solvents under conditions of partial deactivation of the catalyst was carried out. The obtained values of heats of hydrogen adsorption on skeletal nickel in the course of the experiment are given. The described approach is used to calculate TOF values taking into account changes in the number of active surface sites during the course of a catalytic reaction and upon the introduction of a deactivating agent. A refined equation for the correct calculation of TOF is proposed along with its mathematical justification. The results of TOF calculations under various assumptions for a number of catalytic systems are shown.Conclusions. When calculating absolute activity values, a change in the number of active sites has a significant effect on the obtained values. The physical meaning of a number of constants in the proposed equation relates the activity of the catalyst to the distribution of hydrogen on its surface in terms of heats of adsorption.

Development of a chitosan-multi-walled carbon nanotubes composite for application in solid-phase adsorption toxin tracking of microcystins

Contamination of water and food with cyanotoxins poses human health risks, and hence the need for sensitive early warning tools to monitor these in water. A composite of glutaraldehyde-crosslinked chitosan and multi-walled carbon nanotubes (ChMWCNTs) was synthesised and tested for potential use as a solid-phase adsorption toxin tracking (SPATT) adsorbent for monitoring microcystins (MCs) in fresh water. The composite was characterised by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller theory and scanning electron microscopy. Batch adsorption experiments to assess the effect of contact time, adsorbent dosage and initial microcystin-LR (MC-LR) concentration were conducted. The composite was found to be efficient in adsorbing MC-LR, showing 97% removal and a maximum adsorption capacity of 4.639 μg/g under optimised conditions of 5 μg/L of MC-LR, adsorbent dose of 0.03 g/5 mL and 30 min contact time. The adsorption kinetics were better explained by a pseudo-second-order model, inferring chemisorption adsorption. The isotherm data better fitted the Langmuir isotherm model, thus inferring monolayer surface adsorption. For desorption, 100% methanol was the most effective, with an efficiency of 84.71%. The composite effectively adsorbed and desorbed three congeners of MCs (–LR, –RR and –YR) when tested in raw dam water, regardless of its lower maximum adsorption capacity compared to those of other adsorbents used for similar purposes. Significance: Monitoring of microcystins is problematic in large reservoirs and rivers. Chitosan can be crosslinked and modified to enhance its adsorption properties. Composites of chitosan and carbon nanotubes efficiently adsorb and desorb microcystins. This study is possibly the first to apply a chitosan-based sorbent in solid-phase toxin tracking (SPATT) to be used as an early warning tool in passive monitoring of microcystins in water resources. Open data set: https://doi.org/10.6084/m9.figshare.20992291.v1

Efficient aqueous media Suzuki–Miyaura cross-coupling reaction using ligand-free and environmentally-friendly palladium-doped ceria–zirconia mixed metal oxide nanocatalyst

A palladium ceria–zirconia Pd0.05Ce0.5Zr0.475O2 catalytic based nanomaterial was produced by co-precipitation method. To compare the effect of each atom, Pd0.1Ce1.45O3 and Pd0.1Zr1.45O3 were synthesized. Several techniques were used (TGA, XRD, N2 adsorption/desorption (BET theory), XPS, SEM and TEM and HR-TEM microscopy) to characterize the samples. Pd0.05Ce0.5Zr0.475O2 exhibits the highest BET surface area, 117 m2/g compared to the two mentioned materials. According to XRD and XPS analysis, the oxidation state of palladium was +2 in this oxide. Compared to other materials, Pd0.05Ce0.5Zr0.475O2 was the most efficient catalyst for a wide range of aryl bromides and aryl boronic acids in aqueous media without the use of any ligand. Very good yields were achieved and could easily reach a value of 93% in the case of iodobromides. Pd0.05Ce0.5Zr0.475O2 showed also a good stability and could be easily separated and reused with high catalytic activity after three cycles. In addition, no leaching of Pd2+ was observed which confirmed the highly heterogeneous nature of our catalyst.

Modified Scherrer equation to calculate crystal size by XRD with high accuracy, examples Fe2O3, TiO2 and V2O5

A key parameter in the analysis of compounds and the study of their physical, chemical, and mechanical properties is the knowledge of the crystal size. There are two common techniques for determining this size: transmission electron microscopy (TEM) and Brunauer-Emmett-Teller theory (BET). These methods are time-consuming and expensive; thus, the calculation of this size by X-ray diffraction (XRD) is proposed. There are several methods for calculating the crystal size by X-ray diffraction, but not all peaks were considered and the errors were very large. In this study, the Modified Scherrer method is practically explained, and three important rules for obtaining crystal size values with high accuracy are introduced and applied. For better understanding, this study explains the Modified Scherrer method for iron oxide (Fe2O3), titanium oxide (TiO2) and vanadium oxide (V2O5) powders as examples. Crystal size values were calculated using the modified Scherrer method for Fe2O3, TiO2, and V2O5 as 30.94, 16.57, and 24.30 nm, respectively. Furthermore, the extracted crystal size values of ∼ 31, 18 and 30 nm for Fe2O3, TiO2, and V2O5 were tandemly recorded by TEM. Moreover, the crystal size values for Fe2O3, TiO2, and V2O5 were calculated to 32.96, 15.87 and 16.66 nm by BET tandemly. The results show that the Modified Scherrer method has high accuracy and agreement with the analyses of TEM and BET. Thus, this method is proposed for calculating each crystalline compound as it has high accuracy and XRD analysis is available and cheaper.

Synthesis of a chitosan@hydroxyapatite composite hybrid using a new approach for high-performance removal of crystal violet dye in aqueous solution, equilibrium isotherms and process optimization

BackgroundNovel chitosan and hydroxyapatite-based bio composites were studied as potential adsorbents for the removal of crystal violet, a cationic dye, present in an aqueous solution employing various experimental metrics such as initial concentration, pH, adsorbent mass, contact time, temperature, and effect of agitation. MethodsThe biosorbent was analyzed by several techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), specific surface by BET theory, thermal analysis ATG and X-ray energy dispersal (EDS). Significant FindingsThe present study focuses on the synthesis of chitosan, a polymer extracted from shrimp shells, and its association with synthesized hydroxyapatite to form a Cs@Hap composite effective for the adsorption of a cationic dye, crystal violet. The physical and functional properties of the composite were studied using several techniques. X-ray diffraction confirmed the formation of the composite by its crystalline structure, infrared analysis revealed the presence of NH, OH and PO functional groups responsible for the adsorption, SEM coupled with EDS as well as BET and ATG allowed to characterize the surface of the composite as porous, rough and heterogeneous, with an SSA of 138.47 m2g−1, perfect for the adsorption of the given dye. The resulting adsorption efficiency is high and was able to reach a maximum of 93.21% through the optimization of the parameters affecting the adsorption, namely an adsorbent mass of 0.1 g at a pH value equal to 6.5. The kinetic, isothermal and thermodynamic study showed that the adsorption was endothermic and follows the pseudo-second order and Redlich-Peterson models. The regression coefficient R²= 0.9219 showed the validity of the response surface methodology coupled to the Box Behnken design (RSM-BBD) in predicting the percent removal of CV by adsorption.

Adsorption-Reduction of Cr(VI) with Magnetic Fe-C-N Composites

In this study, the iron-based carbon composite (hereafter FCN-x, x = 0, 400, 500, and 600 calcination) was synthesized by a simple high-temperature pyrolysis method using iron-containing sludge coagulant generated from wastewater treatment settling ponds in chemical plants. The FCN-x was used for the adsorptive reduction of aqueous phase Cr(VI) effectively. The FCN-x was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier infrared spectrometer (FT-IR), X-ray photoelectron spectrometer (XPS), and Brunauer-Emmett-Teller theory (BET). FCN-x adsorption of Cr(VI) was examined in batch experiments using CrO42− as a function of physicochemical parameters. The chemical kinetics of Cr(VI) adsorption by FCN-500 were modeled by 1st and 2nd order empirical pseudo kinetics. Based on these experiments, FCN-500 has been selected for further studies on Cr(VI) adsorptive reduction. The maximum Cr(VI) adsorption by FCN-500 was 52.63 mg/g showing the highest removal efficiency. The Cr(VI) adsorption by the FCN-500 was quantified by the Langmuir isotherm. XPS result confirmed the reduction of Cr(VI) to Cr(III) by the FCN-500. The iron-based carbon composites have high reusability and application potential in water treatment. The electroplating wastewater with 117 mg/L Cr(VI) was treated with FCN-500, and 99.93% Cr(VI) was removed within 120 min, which is lower than the national chromium emission standard of the People’s Republic of China. This work illustrates the value-added role of sludge generated from dye chemical plants to ensure environmental sustainability.

BET and Kelvin Analyses by Thermogravimetric Desorption.

Porous solids with nanometer-sized pores and large surface areas are a highly important class of materials. Uses of such materials include filtration, batteries, catalysts, and carbon sequestration. These porous solids are characterized by their surface areas, typically >100 m2/g, and pore size distributions. These parameters are typically measured using cryogenic physisorption, frequently referred to as Brunauer-Emmett-Teller (BET) analysis when BET theory is applied to interpret experimental results. Cryogenic physisorption and related analysis elucidate how a particular solid interacts with the cryogenic adsorbate, but this can be a poor predictor of how that solid will interact with other adsorbates, limiting the applicability of the results. Additionally, the cryogenic temperatures and deep vacuum required for cryogenic physisorption can cause kinetic limitations and experimental difficulties. This method nevertheless remains the standard technique to characterize porous materials for a wide variety of applications due to limited other options. In this work, a thermogravimetric desorption technique for determining surface areas and pore size distributions of porous solids available to adsorbates having boiling points above ambient temperature at ambient pressure is presented. A thermogravimetric analyzer (TGA) is used to measure temperature-dependent adsorbate mass loss, and isotherms are derived. For systems that exhibit multilayer formation, BET theory is applied to isotherms to derive specific surface areas. For systems that do not exhibit multilayer formation, the Kelvin equation is applied to determine pore size distributions and surface areas for the porous materials. In this study, the thermogravimetric method is applied to four adsorbents and two adsorbates─water and toluene─and results are compared to cryogenic physisorption results.

Preparation of ternary polyaniline@CuO−zeolite composite, discussion of characteristics, properties and their applications in supercapacitors and cationic dye adsorption

AbstractCopper oxide−zeolite (CuO−ZT) reinforced polyaniline (PANI) matrices were prepared by in situ oxidative polymerization and the samples were characterized by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, XRD, TGA, UV–visible spectrophotometry, SEM and Brunauer–Emmett–Teller theory; the optical bandgap was also evaluated. Moreover, the synthesis and exploration of electrodes are increasingly being considered for the development of conducting‐polymer‐based supercapacitors, which has attracted significant interest in energy conversion and storage technology. Here, hybrid materials used in the preparation of the electrode materials on the capacitive properties were investigated. It is found that the PANI@CuO exhibits a high specific capacitance of 311.5 F g−1 at 1.0 A g−1 current density between 0.0 and 1.0 V compared to PANI@CuO−ZT (222.7 F g−1). Further, the PANI@CuO presented an excellent cycling stability at 1.0 A g−1 (1500 cycles; 81.9%) in a two‐electrode system. Accordingly, producing a PANI matrix on CuO presented a simple and viable way to ameliorate the capacitive performance of the supercapacitor. Conversely, the adsorptive removal of malachite green and methyl violet dyes by PANI@CuO−ZT adsorbent could be described by the pseudo‐first‐order and Temkin models. The maximum adsorptive capacity of malachite green and methyl violet dyes was 249.7 and 198.2 mg g−1, respectively. © 2023 Society of Industrial Chemistry.

Production of Ni0.5Co0.5Fe2O4/activated carbon@chitosan magnetic nanobiocomposite as a novel adsorbent of methylene blue in aqueous solutions

Methylene blue is a cationic dye, not degraded naturally due to its aromatic rings. Accordingly, biological, chemical, and physical water treatment methods have been proposed for its removal. Adsorption is an economical and effective method in this regard. In this study, the nickel–cobalt ferrite/activated carbon@chitosan magnetic nanobiocomposite was synthesized as an adsorbent. The nano-adsorbent was evaluated with FESEM, which estimated the particle size at ~ 16.64 nm. According to EDAX analysis, the purity of particles was 99%. XRD characterization showed the successful coverage of chitosan, correct placement of nickel–cobalt ferrite, and the nono-structure of crystallites. The specific surface area was 316 m2/g using the BET theory and 285 m2/g using the Langmuir theory, and the porosity volume was 0.18 cm3/g. According to the VSM analysis, magnetic reluctance and coercive force were 1.1 emu/g and 499 Oe, respectively. The FTIR analysis showed that the reaction was successful, and methylene blue was present on the adsorbent surface. The methylene blue adsorption test indicated that 388 mg/g of the dye was adsorbed (97% dye removal), and the final concentration reached 6 mg/L after 8 h. The point of zero charge (pHpzc) was 6.8.

SnO2-Based Porous Nanomaterials: Sol-Gel Formation and Gas-Sensing Application

Porous nanocomposites using two (tin dioxide-silica dioxide) and three (tin dioxide-indium oxide-silica dioxide)-component systems for gas sensors were created with the sol-gel method. To understand some of the physical-chemical processes that occurred during the adsorption of gas molecules on the surface of the produced nanostructures, two models-the Langmuir model and the Brunauer-Emmett-Teller theory-were used to carry out calculations. The results of the phase analysis concerning the interaction between the components during the formation of the nanostructures were obtained through the use of X-ray diffraction, thermogravimetric analysis, the Brunauer-Emmett-Teller technique (to determine the surface areas), the method of partial pressure diagrams in a wide range of temperatures and pressures and the results of the measurement of the nanocomposites' sensitivity. The analysis allowed us to find the optimal temperature for annealing nanocomposites. The introduction of a semiconductor additive into a two-component system based on tin and silica dioxides significantly increased the sensitivity of the nanostructured layers to reductional reagent gases.

Co/SBA-16 coating supported on a 3D-printed ceramic monolith for peroxymonosulfate-activated degradation of Levofloxacin

This study reports a simple method for anchoring dispersed Co nanoparticles on SBA-16 mesoporous molecular sieve coating grown on the 3D-printed ceramic monolith (i.e., Co@SBA-16/ceramic). The monolithic ceramic carriers with a designable versatile geometric channel could improve the fluid flow and mass transfer but exhibited a smaller surface area and porosity. The SBA-16 mesoporous molecular sieve coating was loaded onto the surface of the monolithic carriers using a simple hydrothermal crystallization strategy, which can increase the surface area of the monolithic carriers and facilitate the loading of active metal sites. In contrast to the conventional impregnation loading method (Co-AG@SBA-16/ceramic), dispersed Co3O4 nanoparticles were obtained by directly introducing Co salts into the as-made SBA-16 coating (containing a template), accompanied by conversion of the Co precursor and removal of the template after calcination. These promoted catalysts were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Brunauer–Emmett–Teller theory, and X-ray photoelectron spectroscopy. The developed Co@SBA-16/ceramic catalysts exhibited excellent catalytic performance for the continuous removal of levofloxacin (LVF) in fixed bed reactors. Co/MC@NC-900 catalyst exhibited a ∼ 78% degradation efficiency in 180 min compared to that of Co-AG@SBA-16/ceramic (17%) and Co/ceramic (0.7%). The improved catalytic activity and reusability of Co@SBA-16/ceramic was because of the better dispersion of the active site within the molecular sieve coating. Co@SBA-16/ceramic-1 exhibits much better catalytic activity, reusability and long-term stability than Co-AG@SBA-16/ceramic. After a 720 min continuous reaction, the LVF removal efficiency of Co@SBA-16/ceramic-1 in a 2 cm fixed-bed reactor was stable at 55%. Using chemical quenching experiments, electron paramagnetic resonance spectroscopy, and liquid chromatography–mass spectrometry, the possible LVF degradation mechanism and degradation pathways were proposed. This study provides novel PMS monolithic catalysts for the continuous and efficient degradation of organic pollutants.

The effect of synthesis parameters on pore diameter of superhydrophobic silica aerogel prepared at ambient pressure

Silica aerogels were prepared by the sol-gel method and dried at ambient pressure with sodium silicate precursor. The prepared aerogel is superhydrophobic. The effect of various synthesis conditions on pore structure and diameter was investigated. The results of N2 adsorption-desorption isotherms, BET theory, BJH method, and field emission scanning electron microscopy images showed that by changing the surface modification method, the porosity of the samples changes. The order of increasing the average pore diameter for different protic solvents is isopropanol < methanol < ethanol. The specific surface area and total pore volume also increase with the increasing concentration of citric acid citric. The sample surface modified with HMDZ has smaller average pore diameters and total pore volume than the sample surface modified with TMCS. With increasing temperature, the average pore diameter and total pore volume increase, and the BET surface decreases.