Surface Area Values Research Articles

Evaluation and 3D imaging of mineral structure changes of the rabbit (New Zealand) skull during developmental periods.

This study aimed to determine the morphometric measurements anatomically and CT images of skulls of healthy male and female rabbits during postnatal development, to analyse the data statistically and to demonstrate the structural changes in bone. A total of 40 rabbits (20 females and 20 males) were divided into four groups including prepubertal period (group I (0-1 month)), period between adolescence and adulthood (group II (3-5 month)) and later (young adult period as group III (1-3 years) and old adult period as group IV (3-5 years)), with five animals in each group. After the morphometric measurements, the surface area and volume values of the skull were calculated. The skulls were reconstructed using a 3D Slicer (5.0.2), which is used for 3D modelling. The cranial bones in each group were then crushed using a grinder so that the powdered samples were obtained for XRF (X-ray fluorescence technique). The p-value was statistically highly significant between group and gender (p < 0.001). In morphometric measurements, males were generally higher than females. Only PL, GBOC and GNB measurements were higher in females. The p-value between groups (in all measurements), between genders (in TL, GLN, FL, VL, OZB and GBN parameters) and between groups and genders (in TL, DL and VL parameters) was statistically highly significant (p < 0.001). The p-value between the groups, p-value between sexes and p-value between group and sex in Si, P, K, Ca, Ni, Zn, Sr, Sr and Ca/P elements were statistically significant (p < 0.001). Consequently, metric, volume and surface area measurements were taken through 3D modelling of skull bone in prepubertal period (group I), period between adolescence and adulthood (group II) and later (young adult period as group III and old adult period as group IV) of rabbits and the change in the mineral structure during postnatal development and effect of sex on this change were investigated. This might be the first study to assess both metric and mineral changes at four age intervals taken during the life span of rabbits.

Organo acid-activated clays for water treatment as removal agent of Eosin-Y: Properties, regeneration, and single batch design absorber

Organoclays have been proposed as efficient removal agents for colored wastewater treatment. In this study, organo-acid-activated clays were investigated for their ability to remove eosin Y dye molecules. Firstly, the clay was acid activated using sulfuric solution at 90 °C for overnight. Secondly, the resulting materials were treated by hexadecyltetramethylammonium bromide solutions to obtain organo-acid-activated clays. Several techniques were used, such as X-ray diffraction, carbon hydrogen nitrogen analysis, silicon-29 and carbon-13 solid-state nuclear magnetic resonance, and nitrogen adsorption isotherms. The cation exchange capacity values were reduced and the specific surface area values increased from 80.1 m2/g to 183.2 m2/g during the acid activation process. The resulting organo-acid-activated clays had a similar expansion of interlayer spacing of 3.90 nm with less intercalated hexadecyltetramethylammonium surfactants, ranging from 0.80 mmol/g to 1.22 mmol/g; 13C solid NMR indicated that the intercalated surfactants exhibited different degree of conformation. Many factors, including the solid dose, solution pH, amount of intercalated surfactants, and starting eosin-Y concentrations, were studied in relation to the removal capabilities of organo acid-activated clays. Based on the Langmuir model, the removal capacity of the organo acid-activated clays ranged from a minimum of 43.5 mg/g to a maximum of 79.3 mg/g, dependent on the surfactant quantities and acid activation degree. , and the pH. The removal percentage of eosin-Y was increased from 50.5 % to 80.8 % by treating the organo acid-activated clay with HCl solution before the removal procedure. Regeneration and reuse of two selected organo acid-activated clays were carried out for seven successive cycles, and a reduction in the initial efficiency was in the range of 26.4 %–30.1 %. However, for organoclay (without acid activation), approximately 52.1 % efficiency was maintained. Using the Langmuir model and mass balance equations, a single-stage adsorber design was suggested for different dye volumes at a constant starting concentration.

ПРОГРАММНО-АЛГОРИТМИЧЕСКОЕ ОБЕСПЕЧЕНИЕ ИНТЕЛЛЕКТУАЛЬНОЙ СИСТЕМЫ ТЕХНИЧЕСКОГО ЗРЕНИЯ ДЛЯ ОПРЕДЕЛЕНИЯ ПАРАМЕТРОВ КОРНЕПЛОДОВ САХАРНОЙ СВЕКЛЫ ПРИ СОРТИРОВКЕ ПЕРЕД УКЛАДКОЙ НА ХРАНЕНИЕ

The application of methods of long-term storage of sugar beet for a period of more than 2 months is justified. It has been found that small root crops are more susceptible to temperature fluctuations and relative humidity of the environment, which leads to a change in the partial pressure of water vapor between the surface of sugar beet and the surrounding air. During storage in a sugar beet mound, the relative humidity reaches from 90 to 95% due to the removal of moisture from the surface of root crops, which is a source of beet mass losses. The criteria for the size of sugar beet root crops have been determined. The necessity of creating a method for sorting trucks at the receiving point of sugar factories is shown. It was revealed that when determining the requirements for sugar beet entering storage, it is necessary to take into account, in addition to physical and chemical parameters, the value of the specific surface area of the root crop. Therefore, it is recommended to send large root crops weighing more than 570 g to kagats. The purpose of the article is formulated, which is to develop software and algorithmic support for determining the parameters of sugar beet root crops when sorting trucks. The process of distribution of trucks at the receiving point of sugar factories by man at the present time is described. A block diagram of the algorithm of the intelligent vision system program is presented and described. The features of the created software are described, such as working with sensors, processing software or hardware errors. According to the results of the study, an algorithm for the operation of the program and software of an intelligent vision system for determining the parameters of sugar beet root crops have been developed [1].

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.

Chrysanthemum‐Flowers‐Like Bimetal Oxide Based Electrocatalyst for Methanol Oxidation Reaction

Transition metal oxides have garnered attention for the methanol electro‐oxidation reaction owing to their easy availability, high catalytic applicability, and multiple oxidation capabilities. Bimetal‐based catalysts further enhance the performance of the methanol oxidation reaction. In this context, a chrysanthemum‐flower‐like MoO2/WO3 is synthesized through a solvothermal and annealing strategy. The morphology attests to the rough surface and pores in the catalyst, augmenting its surface area for reactions and enhancing catalytic applicability. Electrochemical oxidation of methanol yields an optimal current density of 0.99 mA cm−2 and 2.07 mA mg−1 at a potential of 0.57 V versus Ag/AgCl. The catalyst exhibits a remarkably low Tafel slope of 37.45 mV dec−1, affirming its rapid reaction kinetics. Electrochemical impedance spectroscopy (EIS) reveals an equivalent electronic circuit of R(Q(R(QR)Q(RW))), confirming low charge transfer resistance (Rct) and diffusion‐controlled kinetics attributable to the pores in the sample. The sample also demonstrates an electrochemically active surface area (ECSA) value equal to 0.122 mF cm−2 and long‐term stability over continuous 5000 s, exhibiting no change and high resistance to CO poisoning. All these characterizations and obtained results collectively affirm that the chrysanthemum‐flower‐like MoO2/WO3 serves as a highly suitable electrocatalyst for the electrochemical oxidation of methanol.

Structure and properties of self-assembled graphene oxide–detonation nanodiamond composites

The properties of graphene oxide–detonation nanodiamond composites obtained as a result of heterocoagulation of graphene oxide and hydrogenated detonation nanodiamonds in aqueous mixtures were studied. The resulting composites with different proportions of graphene oxide and detonation nanodiamond were subjected to drying and subsequent heat treatment in a vacuum, converting graphene oxide into graphene. The structure of the composites was studied using electron microscopy and Raman spectroscopy. The specific surface area and porosity of the obtained samples were studied by analyzing nitrogen adsorption isotherms. A model for the composite formation and a possible technology for producing a material based on it with different specific surface area values and pore structure are proposed. It is shown, that the largest possible specific surface area of two-component structures of the «DND/GO» type does not exceed 500 m2·g−1. It was also concluded that it is necessary to achieve a uniform distribution of detonation nanodiamond particles over the surface of graphene sheets.

Preparation of Activated Biocarbons from Cones and their Potential Application for Adsorption of Antibiotics (Tetracycline).

The pine cones (PC), spruce cones (SC) and fir cones (FC) were used for biocarbons preparation. Chemical activation with sodium hydroxide was applied to prepare activated biocarbons. All the materials under investigation were characterized by the N2 adsorption, scanning electron microscopy (SEM), elemental analysis (CHNS), infrared spectroscopy (ATR FT-IR), and the Boehm's titration method. Moreover, pHpzc (the point of zero charge) was determined. It was shown that cones are a good, cheap precursor from which biocarbons with a developed porous structure, characterized by good adsorption properties, can be obtained. All the obtained adsorbents are characterized mainly by a microporous structure. Moreover, they contain both acidic and basic surface functional groups (acidic ones prevail over basic ones). The tested activated biocarbons have large specific surface area values ranging from 578 to 1182 m2 g-1. The efficacy of selected materials in the adsorption of an essential contaminant of increasing concern, tetracycline (TC), was investigated. The experimental data were described using the Langmuir and Freundlich adsorption isotherm models. The maximum adsorption capacity of the tested biocarbons ranges from 200 to 392 mg g-1. Thermodynamic studies proved that adsorption is a spontaneous and endothermic process. In summary, economical and environmentally friendly adsorbents were obtained.

Synthesis of green-engineered silver nanoparticles using Cymbopogon citratus (lemongrass) and its antibacterial activity against clinical Pseudomonas aeruginosa

Background and Aim: The use of bioengineered nanocomposites as antimicrobials has increased in recent years, but very few investigations have been conducted to test their effectiveness against Pseudomonas aeruginosa, a pathogen presenting public health risks that can impact both humans and animals. The aim of this study was to assess the antimicrobial potential of phytofabricated silver nanoparticles synthesized using lemongrass extract against clinical isolates of P. aeruginosa. Materials and Methods: The extraction of active compounds from the leaves of Cymbopogon citratus was performed using ethanol (80%) as a solvent, high-performance liquid chromatography-mass spectrometry was used to analyze the chemical composition of the extract, the synthesis of silver nanoparticles (AgNPs) was done using silver nitrate (AgNO3) as a precursor, and the antimicrobial and antibiofilm activity of the extract and the AgNPs phytofabricated was assessed against 10 clinical strains of P. aeruginosa. Results: Lemongrass extract was found to consist of the following main compounds: Caffeic acid (445.21 ± 32.77 μg/g), p-coumaric acid (393.32 ± 39.56 μg/g), chlorogenic acid (377.65 ± 4.26 μg/g), quinic acid (161.52 ± 17.62 μg/g), and quercetin-3-glucoside (151.35 ± 11.34 μg/g). AgNPs were successfully phytofabricated using 2.5 mM AgNO3. The ultraviolet (UV)-visible absorption spectra of the AgNPs showed a localized surface plasmon resonance at 464 nm with an absorbance of 0.32 A. The 50x hydrodynamic diameter was 50.29 nm with a surface area value of 120.10 m2/ cm3, and the volume mean diameter and Sauter mean diameter were 50.63 nm and 49.96 nm, respectively. Despite the compound found in lemongrass extract, no antimicrobial activity was observed with the extract, while AgNPs exhibited noteworthy dose-dependent antimicrobial activity with inhibition diameters up to 24 mm and minimum inhibitory concentration (MIC) and minimum bactericidal concentration ranging from 2 to 16 and 4–64 µg/mL, respectively. AgNPs also demonstrated significant antibiofilm activity by inhibiting biofilms up to 99% between MIC/2 and 2MIC. Conclusion: The present study suggests that lemongrass is a good candidate for the synthesis of AgNPs with good physicochemical characteristics and having a strong anti-pseudomonas activity. Further research is needed to assess the stability and safety of these AgNPs. Keywords: antibiofilm capacity, antimicrobial activity, green synthesis, lemongrass, Pseudomonas aeruginosa, silver nanoparticles.

Effect of emulsifier on growth performance, nutrient digestibility, intestinal morphology, faecal microbiology and blood biochemistry of broiler chickens fed low-energy diets.

This study hypothesizes that a natural multicomponent emulsifier (Lipidol) could improve production performance in broiler chickens by aiding lipid digestion and addressing digestive system limitations. The study aimed to investigate the effects of dietary emulsifier inclusion on the growth performance, nutrient digestibility, intestinal morphology, faecal microbiology, blood biochemistry and liver enzyme activities of broiler chickens fed low-energy diets. The experiment involved 144 one-day-old male broiler chickens split into 4 treatments. Four diets were used: standard metabolizable energy (ME) as a control diet and three low-ME diets, reducing by 100kcal/kg by adding 0.5, 1 and 1.5g/kg of exogenous emulsifier (Em). No significant differences were observed in body weight gain and feed intake. However, during the finisher period (25-42 days), supplementation emulsifier to low-ME diets notably improved feed efficiency. Although crude protein, organic matter and ash digestibility remained unaffected, dry matter (DM) digestibility significantly increased in broilers fed low-ME diets with emulsifier. Broilers receiving 0.5g/kg of emulsifier showed the highest villus width and surface area values. Moreover, including 1.5g/kg of emulsifier led to the highest villus height to crypt depth ratio. Faecal microbiota, blood biochemistry and liver enzyme activities showed no significant differences. Emulsifier supplementation compensated for the energy reduction and enhanced performance, DM digestibility and some intestinal morphology parameters in broiler chickens fed low-ME diet. Using 0.5g/kg of emulsifier per 100kcal of ME reduction in broiler diets is suggested.

In English

Samples of MnOx-Na2WO4/SiO2 based on a mesoporous silica matrix were synthesized using manganese acetate, sodium tungstate, tetraethoxysilane (TEOS) as precursors and cetyltrimethylammonium bromide (CTAB), citric acid and triethanolamine as pore generating agent and characterized by scanning electron microscopy with energy dispersive elemental analysis (SEM/EDS), X-ray diffractometry (XRD), electron magnetic resonance (EMR), N2 adsorption-desorption measurements and tested as a catalyst for the reaction of oxidative condensation of methane (OCM). It is shown that the MnNaW/SiO2 catalyst consists of Mn2O3, MnO2, Na2WO4 and SiO2 phases. The EMR and SEM/EDS data indicate a noticeable effect of the reaction conditions on the surface structure and the distribution of catalytically active components in the catalyst structure. Significant changes in the values of the specific surface area and pore volume of the samples with increasing temperature and duration of the reaction were found (the values of the specific surface area and pore volume, respectively, 116.8 m2/g and 0.590 cm3/g - up to and 46.1 m2/g and 0.232 cm3/g after 15 hours of catalyst operation in the OCM reaction at 800 °C). It has been shown that under the conditions of the OCM reaction, the elemental composition of the surface of the MnOx-Na2WO4/SiO2 catalyst changes, and the degree of change depends on the duration of the OCM reaction. Under the influence of the reaction mixture CH4/O2, the content of Mn and W decreases in the first two hours, and the trend towards a decrease in their amount on the catalyst surface with an increase in the duration of the OCM reaction is generally preserved. A detailed X-ray phase analysis also indicates a change in the phase composition of this catalyst under the influence of the CH4/O2 reaction mixture. It is assumed that under the reaction conditions (700–800 °C) the MnOx-Na2WO4/SiO2 catalyst is silicon dioxide particles basely with the cristabolite structure, the surface of which is coated with molten sodium tungstate containing nanosized particles of MnOx structures activated by sodium ions and WOx.

Removal of COD from petroleum refinery wastewater by adsorption using activated carbon derived from avocado plant

In the present work, removing of COD from wastewater generated via Al-Diwanya petroleum refinery plant located in Iraq by adsorption with activated carbon (AC) derived from avocado seeds was successfully performed via a two-step approach. In the first step, AC was prepared from avocado seeds via impregnating with H3PO4 at 400 °C where effects of H3PO4 concentration and calcination time on the specific surface area of AC were studied. Additionally, properties of the prepared AC were examined by XRD, SEM, and FTIR to knowledge the features of the internal structure of AC. Results showed that the prepared AC has mesopores structure with pore diameters in the range between 30.07 and 50.8 µm. Increasing the weight percent of H3PO4 led to an increase in the specific surface area of AC to reach a maximum value beyond which a decrease in the specific surface area was happened with further increasing in H3PO4 percent. Increasing the time resulted in an increase in the AC specific surface area to reach a maximum value beyond which a decrease in specific surface area was happened. The best value of AC specific surface area was 436.6 m2/g which obtained at 70 %H3PO4 and 4 h. At the second step, the performance of the prepared AC in removing of COD by adsorption process was evaluated via studying the effects of three operating parameters, namely adsorbent dosage (1–5 g/L), pH (3–9), and shaking speed (100–400 rpm) on the removal of COD(RE%) using a response surface methodology (RSM). Increasing AC dosage led to an increase in RE% while increasing each of pH and shaking speed resulted in lowering RE%. The optimum conditions for higher RE% were AC dosage of 5 g/L, pH of 3, and shaking speed of 100 rpm in which a removal efficiency of 94.54 % was obtained. The degradation of COD with time was found to obey a second order kinetic confirming the chemisorption is the rate limiting step in the adsorption process.

Polyacrylonitrile‐based porous polymer spheres and their conversion to N‐doped carbon materials for adsorption and electrocatalysis

AbstractBecause of their tunable porosity and specific surface area, porous materials are of high interest for the purification of wastewater by adsorption as well as in electrocatalysis, where, in particular, developing metal‐free carbon‐based catalysts for the oxygen reduction reaction (ORR) is researched. The carbon spheres presented here can meet these two requirements simultaneously. Porous polyacrylonitrile (PAN) spheres were firstly prepared by droplet shaping cum nonsolvent induced phase separation. Then, they were converted to nitrogen‐doped carbon spheres by two‐step carbonization via preoxidation and pyrolysis. During the pyrolysis step, carbon dioxide was used to reopen the pores of the materials that had been blocked after the preoxidation step. By this way, specific surface area values of carbon spheres of more than 1000 m2/g could be obtained. Best performing carbon materials (C#3) showed high adsorption capacity (e.g., 296 mg/g for methyl orange at solute equilibrium concentration of 24 mg/L in water). The XPS analysis revealed that only quaternary (N‐Q) and pyridinic (N‐6) nitrogen sites were found in these carbon spheres. The best ORR performance was found also for C#3 carbon spheres, with a potential of 0.81 V versus reversible hydrogen electrode (RHE) at −1 mA/cm2 and electron transfer number of 3.5 at 0.6–0.8 V versus RHE, as determined by rotating disk or rotating ring disk electrode tests. In conclusion, all results confirm that these PAN‐derived carbon spheres are potentially valuable materials for both wastewater treatment by adsorption and electrocatalytic oxygen reduction.

Thermodynamic Investigations for Combustion-Assisted Synthesis of Lithium Orthosilicate Powders

The study investigates the combustion-assisted synthesis of lithium orthosilicate (Li4SiO4) powders for potential CO2 capture applications. Technical-grade lithium carbonate and metallic silicon powders were used as starting materials. Synthesis conditions were explored across temperatures ranging from 500 to 900 °C and different holding durations. Thermodynamic modeling using FactSage 8.2 software suggested that Li4SiO4 production is feasible at temperatures of 700 °C and higher with metallic silicon as the silicon source, which was confirmed experimentally. Characterization of the synthesized powders involved X-ray diffraction, specific surface area determination, particle size distribution analysis, scanning electron microscopy, and CO2 uptake tests. Despite having the lowest Li4SiO4 content as 83.7%, the sample synthesized at 700 °C with 45 min of holding time showed the best CO2 uptake performance as 12.80 wt% while having the lowest crystallite size value (126.58 nm), the highest specific surface area value (4.975 m2/g) and the lowest average particle size value (10.85 µm) which are highly effective on the CO2 uptake performance of such solid sorbents. The study concludes that while challenges remain in achieving optimal CO2 capture performance, it lays a foundation for utilizing lithium orthosilicate in carbon capture applications.Graphical

Application of Infrared Pyrolysis and Chemical Post-Activation in the Conversion of Polyethylene Terephthalate Waste into Porous Carbons for Water Purification.

In this study, we compared the conversion of polyethylene terephthalate (PET) into porous carbons for water purification using pyrolysis and post-activation with KOH. Pyrolysis was conducted at 400-850 °C, followed by KOH activation at 850 °C for samples pyrolyzed at 400, 650, and 850 °C. Both pyrolyzed and post-activated carbons showed high specific surface areas, up to 504.2 and 617.7 m2 g-1, respectively. As the pyrolysis temperature increases, the crystallite size of the graphite phase rises simultaneously with a decrease in specific surface area. This phenomenon significantly influences the final specific surface area values of the activated samples. Despite their relatively high specific surface areas, pyrolyzed PET-derived carbons prove unsuitable as adsorbents for purifying aqueous media from methylene blue dye. A sample pyrolyzed at 650 °C, with a surface area of 504.2 m2 g-1, exhibited a maximum adsorption value of only 20.4 mg g-1. We propose that the pyrolyzed samples have a surface coating of amorphous carbon poor in oxygen groups, impeding the diffusion of dye molecules. Conversely, post-activated samples emerge as promising adsorbents, exhibiting a maximum adsorption capacity of up to 127.7 mg g-1. This suggests their potential for efficient dye removal in water purification applications.

Biodiesel Production by Methanolysis of Rapeseed Oil-Influence of SiO2/Al2O3 Ratio in BEA Zeolite Structure on Physicochemical and Catalytic Properties of Zeolite Systems with Alkaline Earth Oxides (MgO, CaO, SrO).

Alkaline earth metal oxide (MgO, CaO, SrO) catalysts supported on BEA zeolite were prepared by a wet impregnation method and tested in the transesterification reaction of rapeseed oil with methanol towards the formation of biodiesel (FAMEs-fatty acid methyl esters). To assess the influence of the SiO2/Al2O3 ratio on the catalytic activity in the tested reaction, a BEA zeolite carrier material with different Si/Al ratios was used. The prepared catalysts were tested in the transesterification reaction at temperatures of 180 °C and 220 °C using a molar ratio of methanol/oil reagents of 9:1. The transesterification process was carried out for 2 h with the catalyst mass of 0.5 g. The oil conversion value and efficiency towards FAME formation were determined using the HPLC technique. The physicochemical properties of the catalysts were determined using the following research techniques: CO2-TPD, XRD, BET, FTIR, and SEM-EDS. The results of the catalytic activity showed that higher activity in the tested process was confirmed for the catalysts supported on the BEA zeolite characterized by the highest silica/alumina ratio for the reaction carried out at a temperature of 220 °C. The most active zeolite catalyst was the 10% CaO/BEA system (Si/Al = 300), which showed the highest triglyceride (TG) conversion of 90.5% and the second highest FAME yield of 94.6% in the transesterification reaction carried out at 220 °C. The high activity of this system is associated with its alkalinity, high value of the specific surface area, the size of the active phase crystallites, and its characteristic sorption properties in relation to methanol.

Room temperature oxidation of gaseous formaldehyde over silver-doped manganese oxide catalyst

A wide amount of existing building materials and consumables contains formaldehyde (HCHO) that may be released as a gas even after installation. The produced gas may concentrate in housing and offices, leading to a long-term exposure of the occupants. Living in such an environment, even at low concentrations less than 0.5 ppm, may lead to carcinogenic effects and damages of the human central nervous system. As a consequence, the development of methods that oxidize and neutralize the formaldehyde at ambient temperature is welcome. The catalytic oxidation method at ambient temperature is preferred over other available techniques due to its ease of operation and high efficiency. In this work, different weight percentages, ranging from 1 up to 5%, of silver-doped manganese oxides (Ag/MnOx) were synthesized by a co-precipitation process followed by a calcination at 450 °C for 4 h. The XRD and BET analysis results show that the sample at 4% wt of Ag doped in the MnOx matrix exhibit highest crystallinity, surface area and highest dispersion values, very near to theoretical ones. The removal performance of HCHO was tested in a silicon wool bed continuous flow reactor characterized by an inner diameter of 4 mm and a length of 12.5 cm. At ambient temperature a removal efficiency and an amount of produced CO2 of 94% and 66%, respectively.

Super capacity of ligand-engineered biochar for sorption of malachite green dye: key role of functional moieties and mesoporous structure.

This study synthesized a new thiomalic acid-modified rice husk biochar (TMA-BC) as a versatile and eco-friendly sorbent. After undergoing chemical treatments, the mercerized rice husk biochar (NaOH-BC) and TMA-BC samples showed higher BET surface area values of 277.1 m2/g and 305.8 m2/g, respectively, compared to the pristine biochar (BC) sample, which had a surface area of 234.2 m2/g. In batch adsorption experiments, it was found that the highest removal efficiency for malachite green (MG) was achieved with TMA-BC, reaching 96.4%, while NaOH-BC and BC exhibited removal efficiencies of 38.6% and 27.9%, respectively, at pH 8. The engineered TMA-BC exhibited a super adsorption capacity of 104.17mg/g for MG dye at pH 8.0 and 25°C with a dosage of 2g/L. The SEM, TEM, XPS, and FTIR spectroscopy analyses were performed to examine mesoporous features and successful TMA-BC carboxylic and thiol functional groups grafting on biochar. Electrostatic forces, such as π - π interactions, hydrogen bonding, and pore intrusion, were identified as key factors in the sorption of MG dye. As compared to single-solution adsorption experiments, the binary solution experiments performed at optimized dosages of undesired ions, such as humic acid, sodium dodecyl sulfate surfactant, NaCl, and NaSCN, reflected an increase in MG dye removal of 2.8%, 8.7%, 5.4%, and 12.7%, respectively, which was attributed to unique mesoporous features and grafted functional groups of TMA-BC. Furthermore, the TMA-BC showed promising reusability up to three cycles. Our study indicates that mediocre biochar modified with TMA can provide an eco-friendly and cost-effective alternative to commercially accessible adsorbents.

Synergistic Effect of Electrocatalyst for Enhanced Oxygen Reduction Reaction: Low Pt-Loaded CuPt Alloy Nanoparticles Supported on N-Doped Hierarchical Porous Carbon.

It is challenging to synthesize oxygen reduction reaction (ORR) electrocatalysts that are highly efficient, affordable, and stable for use in proton exchange membrane fuel cells. To address this challenge, we developed a low platinum-loading (only 6.68% wt) ORR catalyst (PtCu1-NC), comprising CuPt nanoparticles (average size: 1.51 nm) supported on the N-doped carbon substrates. PtCu1-NC possesses a high specific surface area of 662 m2 g-1 and a hierarchical porous structure, facilitating efficient mass transfer. The synergistic effect from introduced copper and the electron effect from nitrogen modify the electronic structure of platinum, effectively accelerating the ORR reaction and enhancing stability. Density functional theory calculations demonstrate the catalytic mechanism and further verify the synergistic effect. Electrochemical assessments indicate that PtCu1-NC exhibits specific activity and mass activity 5.3 and 5.6 times higher, respectively, than commercial Pt/C. The half-wave potential is 27 mV more positive than that of commercial Pt/C. The electrochemical active surface area value is 104.3 m2 g-1, surpassing that of Pt/C. Approximately 78% of current is retained after 10,000 s chronoamperometry measurement. These results highlight the effectiveness of alloying in improving the catalyst performance.

NH4Cl assisted gC3N4 nanosheets for improved photodegradation of dyes in pure water under visible light

ABSTRACT Porous gCNNCl nanosheets were synthesised using a simple bottom-up chemical route with varying NH4Cl: melamine ratios (2:1, 1:1, 1:2). FTIR, XRD, TRPL, PL spectra, ESR, BET, and UV-DRS techniques investigated the inherent properties of the catalysts. Notably, gCNNCl (2:1) nanosheets exhibited an enhanced surface area (26.68 m2/g) and bandgap value (2.65 eV), both favourable for photocatalysis. Their exceptional properties extended to a longer lifetime, coupled with enhanced crystallinity and improved optical characteristics compared to other ratios. The NH3 gas released during gCNNCl nanosheet formation likely contributes to these enhanced properties. These gCNNCl nanosheets were employed for photodegradation of Rhodamine B (REB), Methylene Blue (MEB), and Methyl Orange (MEO). Remarkably, gCNNCl (2:1) achieved complete MEB degradation (98%) within 25 minutes, significantly faster than gCNNCl (1:1) (40 minutes) and gCNNCl (1:2) (60 minutes, respectively). Similarly, gCNNCl (2:1) displayed superior performance for REB degradation, reaching 92% removal in 40 minutes compared to 85% for both gCNNCl (1:1) (45 minutes) and gCNNCl (1:2) (60 minutes, respectively). For MEO, gCNNCl (2:1) achieved a maximum removal of 60% in 75 minutes, outperforming gCNNCl (1:1) (46% in 110 minutes) and gCNNCl (1:2) (42% in 110 minutes, respectively). Further, five repeated trials with fresh catalyst confirmed the reusability of gCNNCl (2:1) for MEB degradation, although a 10% reduction in activity was observed.

Magnetic Mesoporous Silica for Targeted Drug Delivery of Chloroquine: Synthesis, Characterization, and In Vitro Evaluation.

Malaria is a dangerous tropical disease, with high morbidity in developing countries. The responsible parasite has developed resistance to the existing drugs; therefore, new drug delivery systems are being studied to increase efficacy by targeting hemozoin, a parasite paramagnetic metabolite. Herein, magnetic mesoporous silica (magMCM) was synthesized using iron oxide particles dispersed in the silica structure for magnetically driven behavior. The X-ray diffractogram (XRD) and Mössbauer spectra show patterns corresponding to magnetite and maghemite. Furthermore, Mössbauer spectroscopy revealed superparamagnetic behavior, attributed to single magnetic domains in particles smaller than 10 nm. Even in the presence of iron oxide particles, the hexagonal structure of MCM is clearly identified in XRD (low-angle region) and the channels are visible in TEM images. The drug chloroquine (CQ) was encapsulated by incipient wetness impregnation (magMCM-CQ). The N2 adsorption-desorption isotherms show that CQ molecules were encapsulated in the pores, without completely filling the mesopores. BET surface area values were 630 m2 g-1 (magMCM) and 467 m2 g-1 (magMCM-CQ). Encapsulated CQ exhibited rapid delivery (99% in 3 h) in buffer medium and improved solubility compared to the non-encapsulated drug, attributed to CQ encapsulation in amorphous form. The biocompatibility assessment of magMCM, magMCM-CQ, and CQ against MRC5 non-tumoral lung fibroblasts using the MTT assay after 24 h revealed no toxicity associated with magMCM. On the other hand, the non-encapsulated CQ and magMCM-CQ exhibited comparable dose-response activity, indicating a similar cytotoxic effect.