Brunauer Emmett Teller Technique Research Articles

Combustion process for magnetic copper–cobalt ferrite and its Congo red adsorption property

A rapid combustion process was introduced for the preparation of magnetic copper–cobalt ferrite, which was characterized using X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Brunauer–Emmett–Teller techniques (BET). The prepared magnetic copper–cobalt ferrite showed a large specific surface area (104.6 cm2 g−1) and nanoscale particle size (55.4 nm), with a saturation magnetization of 19.6 Am2 kg−1. The nanoparticles were used to adsorb and remove Congo red (CR) from dyestuff wastewater, and the adsorption mechanism was revealed. Compared with the pseudo-first-order kinetic model and intraparticle diffusion kinetic model, the pseudo-second-order kinetic model was better at describing the CR adsorption process on the Cu0.5Co0.5Fe2O4 nanoparticles, while the Temkin isotherm best fitted the CR adherence on the Cu0.5Co0.5Fe2O4 nanoparticles. All data suggested that the adsorption of CR on the Cu0.5Co0.5Fe2O4 nanoparticles followed the mono-multilayer hybrid chemisorption mechanism. In addition, as the pH increased from 2 to 10, the adsorption capacity of the Cu0.5Co0.5Fe2O4 nanoparticles for CR decreased, indicating that an acidic environment was beneficial for the adsorption of CR on the Cu0.5Co0.5Fe2O4 nanoparticles. When recycling the Cu0.5Co0.5Fe2O4 nanoparticles after adsorbing CR, the relative adsorption rate was still 62.5% of the initial adsorption capacity after five cycles, revealing the reusability and promising applicability of Cu0.5Co0.5Fe2O4 nanoparticles in sewage treatment.

Immobilization of nickel on Kryptofix 222 modified Fe3O4@PEG core‐shell nanosphere for the clean synthesis of 2‐Aryl‐2,3‐dihydroquinazolin‐4(1H)‐ones

The development of green‐based nanostructures is extremely compelling for their implementation in the catalytic arena. In this study, a new type of magnetically core‐shell nanocomposite was successfully designed to be used as a green catalyst for the synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones under ultrasonic irradiation. Initially, magnetic Fe3O4 nanoparticle (NP) cores were fabricated via the co‐operation method and subsequently coated with polyethylene glycol (PEG). After that, the macro‐bicyclic Kryptofix 222 (KP222) functionalized on the surface of Fe3O4@PEG for graft and stabilization of nickel metal. The obtained Ni@KP222/Fe3O4@PEG nanocomposite was characterized by FT‐IR (Fourier Transform Infrared), wide‐angle XRD (X‐ray Powder Difraction), FESEM (Field Emiossion Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), VSM (Vibrating‐Sample Magnetometer), TGA‐DTA (Thermogravimetrtic Analysis‐ Differential Thermal Analysis), DLS (Dynamic Light Scattering), and BET (Brunauer–Emmett–Teller) spectroscopy and technique. The findings indicated that high‐affinity KP222 ligand in the stabilization of Ni2+ and ultrasound irradiation catalyzed synergistically the formation of the 2,3‐dihydroquinazolin‐4(1H)‐ones. The benzaldehydes with electron‐withdrawing and electron donor groups could react well with the amino benzamide under ultrasound irradiation in 5 min, indicating that the reaction was not sensitive to the electronic effects. Furthermore, the reusability test for the Ni@KP222/Fe3O4@PEG catalyst revealed successful recyclability for six runs. The current study provided a rational design and synthesis of multifunctional catalysts for catalytic applications.

CoFe2O4@Methylcellulose/AC as a New, Green, and Eco-friendly Nano-magnetic adsorbent for removal of Reactive Red 198 from aqueous solution

• Methylcellulose (MC) was played an essential role to improve the nanomagnetic adsorbent structure for the Reactive Red 198 (RR198) adsorption. • CoFe 2 O 4 @MC/AC was synthesized as a novel nanomagnetic adsorbent with a facile, simple, and green microwave-assisted coprecipitation method. • The physical and chemical structure of CoFe 2 O 4 @MC/AC were approved with FTIR, FESEM, EDS, Mapping, Line Scan, XRD, VSM, and BET techniques. • The isotherm, kinetic and thermodynamic of RR198 adsorption were investigated. • CoFe 2 O 4 @MC/AC exhibited good chemical stability and reusability. Methylcellulose (MC) is the most common commercial cellulose ether and the most attractive biopolymer due to its cheap cost of biodegradability, biocompatibility, hydrophilicity, and lack of toxicity. In this study, CoFe 2 O 4 @MC/activated carbon (AC) was synthesized as a unique magnetic nano-adsorbent in the presence of MC biopolymer for Reactive Red 198 (RR198) dye removal. The nano-magnetic adsorbent was characterized by FESEM (Field emission scanning electron microscopy), EDS (Energy-dispersive X-ray spectroscopy), Mapping, Linescan, BET (Brunauer–Emmett–Teller), FTIR (Fourier Transform Infrared Spectroscopy), XRD (X-Ray Diffraction), and VSM (Vibrating-Sample magnetometer). For simple separation by external magnetic fields, the Ms value was 57.91 emu/g. According to XRD analysis, the nano-adsorbent maintains its crystal structure, with an average crystal size of 11 nm. The maximum removal efficiencies of RR198 for synthetic and real wastewater samples under optimal conditions (an initial concentration of 10 mg/L, pH 3, contact time of 10 min, nanocomposite dose of 1.5 g/L, and a temperature of 25 °C) were 92.2% and 78%, respectively. The adsorption experiments were fitted well with the Freundlich isotherm (R 2 = 0.989) and pseudo -second-order kinetic (R 2 = 0.995). The values of entropy changes (ΔS = 35.087 kJ/mol.k), enthalpy changes (ΔH = -9.862 kJ/mol), and negative Gibbs free energy changes (ΔG) showed that the adsorption process was exothermic. Finally, the reusability findings showed that after six recovery cycles, the efficiency decreased slightly (90.1%). In the end, it can be concluded that the prepared CoFe 2 O 4 @Methylcellulose/AC can be used as an efficient adsorbent for the removal of RR198 from an aqueous solution.

Improvement of mechanical strength of mortars by different morphological zinc oxide nanoparticles

This study presents novel nano-mixtures containing zinc oxide (ZnO) nanoparticles (NPs) to enhance the mechanical properties of cement mortars. Different morphological ZnO NPs were synthesised through the green sonochemical method, using tragacanth gum/Kappa carrageenan (TG/κ-C) and tragacanth gum/chitosan (TG/CS) as biopolymer matrices. The ZnO NPs were characterised using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, X-ray diffraction, Zetasizer and Brunauer–Emmett–Teller techniques. The intrinsic viscosities of TG/κ-C-ZnO and TG/CS-ZnO NPs were investigated to determine the miscibility of the polymeric blends in aqueous solution as affected by sonication time and composition ratios. The average diameters for the spherical and prism-like ZnO NPs were around 266 nm and 355 nm, respectively. Seven different cement mortar specimens containing TG/κ-C-ZnO and TG/CS-ZnO NPs were prepared in ratios of 0, 0.1, 0.5 and 1% by weight, and the flexural and compressive strengths of the specimens were determined at the ages of 7 and 28 days. The results indicate that there is a significant improvement in the mechanical performance of different morphological ZnO NP-based cement mortar composites. In comparison, it was observed that specimens containing TG/κ-C-ZnO NPs had much better results than TG/CS-ZnO NPs. Moreover, the workability problem encountered by using only ZnO NPs has been overcome with the presented biopolymers used in this study.

MXene modulated SnO2 gas sensor for ultra-responsive room-temperature detection of NO2

Continuous exposure to high concentration of nitrogen dioxide (NO2) severely affects the human respiratory system. Besides, NO2 has been recently observed to foster COVID-19, resulting in increased fatality rate; thus highly selective gas sensors are required for detecting NO2 at sub-ppb level. In this direction, we have synthesized two-dimensional MXene-based tin oxide (SnO2) heterostructures with varying MXene wt% (10–40 wt%) using a facile hydrothermal method for room-temperature NO2 detection. The synthesized heterostructures have been structurally, optically, and electrically characterized using a suite of characterization techniques, namely, X-ray diffraction, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and Brunauer–Emmett–Teller techniques. The optimal incorporation of MXene in SnO2 nanoparticles effectively decumulates them, increasing the specific surface area of heterostructures and thereby exposing large number of adsorption sites. 20-wt% SnO2/MXene heterostructures-based sensor exhibits nearly five times higher response (231%) toward 30-ppb NO2 at room temperature with shorter response time (146 s) and recovery time (102 s) than pristine SnO2. Moreover, the sensor showed high selectivity, sensitivity, repeatability, reproducibility, and stable sensing response under humid conditions. The assembly of these results suggests that SnO2/MXene platform provides a pathway for realizing highly responsive NO2 sensors. Herein, possible gas sensing mechanism based on the formation of SnO2/MXene heterostructures has been discussed.

Synthesis of sponge like Gd3+ doped vanadium oxide/2D MXene composites for improved degradation of industrial effluents and pathogens

Current report is based on the synthesis of Gd +3 doped V 2 O 5 nanostructures (GVO) along with fabrication of GVO/MXene binary nanocomposite. As synthesized GVO and GVO/MXene were characterized by XRD (X-ray diffraction), FESEM (Field emission scanning electron microscopy), EDX (Energy dispersive X-ray), BET (Brunauer Emmett Teller technique) and UV–Visible spectroscopy. Diffraction and elemental analysis confirmed the substitution of Gd +3 ions in VO layers. Orthorhombic phase of VO was observed in both GVO and GVO/MXene samples with crystallite size range of 17.02–17.51 nm. FESEM analysis indicated asymmetrical VO particles and sheets distributed on MXene layers, giving out a sponge like appearance. Surface area of GVO and GVO/MXene was enhanced to 20.46 and 23.69 nm, respectively. Effect of Gd +3 contents was significant on optical properties, which reduced the band gap energy of VO to 2.33 eV. The photocatalytic performance of prepared samples was analysed by the degradation of Methylene blue (MB) under direct sunlight. Gd +3 ion doping was found useful to enhance degradation of MB up to ∼71%. Among all samples, GVO/MXene showed maximum degradation (∼92%) within 120 min. Meanwhile, GVO/MXene showed good recyclability for successive five cycles. In addition, GVO and GVO/MXene were effective antibacterial agents against Gram positive (S. aureus) and Gram negative (P. vulgaris) strains of bacteria. The results suggested that the GVO and GVO/MXene could serve as potential candidates for large scale treatment of organic pollutants and pathogens.

Effect of Fe/Cu catalysts supported on zeolite/active carbon hybrid on bio-oil quality derived from catalytic pyrolysis of granular bacteria biomass

Catalytic conversion of granular bacteria biomass to biofuel through pyrolysis was thoroughly studied. The hybrid of beta zeolite and active carbon (ZAC) resulted a support of catalyst with the BET surface area of 302 cm2/g. The highly active bimetallic Fe/Cu catalysts were prepared using wetness incipient impregnation on ZAC hybrid support (Fe5CuXZAC, X = 0.5, 1 and 2). To compare the activity of catalysts, catalytic pyrolysis tests of granular bacteria was performed. The pyrolysis tests in presence of Fe5Cu2ZAC remarkably decreased nitrogen compounds and total oxygenates of the bio-oil from 41.6 and 24.7 to 30.0 and 15.6 area%, respectively. Also, good selectivity of bimetallic Fe/Cu catalysts supported on ZAC toward aromatization reactions with the maximum yield for Fe5Cu2ZAC has made it a novel catalyst for pyrolytic conversion of granular bacteria biomass to aromatic hydrocarbons.The synthesized samples were characterized by Fourier transform infrared (FTIR) spectrometer, field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectroscopy (ICP), BET (Brunauer–Emmett–Teller) and temperature-programmed desorption (TPD) techniques. The products were analyzed by a gas chromatography-thermal conductivity detector (GC-TCD), a gas chromatography-mass spectrometry (GC–MS) and CHNS. Temperature-programmed oxidation (TPO) analysis was performed to study probable deposited carbon on the used catalysts.

Ce-Modified Mo/γ-Al2O3 Catalysts for Production of Elemental Sulfur through Reducing SO2

A series of metal-modified Mo/γ-Al2O3 catalysts were fabricated using the impregnation method. The influence of Ce content on the catalytic performance was systematically studied in a fixed-bed reactor. The catalysts were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, and the Brunauer–Emmett–Teller technique. The reduction ability of the catalysts was recorded via H2 temperature-programmed reduction. The valence state of Mo was raised to 6+ by the addition of Ce. What is more, the effect of temperature and GHSV were considered, and the evaluation of the optimized catalyst life catalyst was tested. A sulfur yield of 88.27% was achieved at 350 °C with SO2/H2 = 1:3.

Removal of metronidazole antibiotic from aqueous solution by ammonia-modified activated carbon: adsorption isotherm and kinetic study

Abstract This article was aimed at investigating the removal of metronidazole (MNZ) from aquatic solutions by modified activated carbon (MAC) with amine groups. The effect of various parameters on the adsorption rate such as the initial pH, adsorbent dose and initial concentration of MNZ and contact time were scrutinized. MAC was characterized by Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller techniques. The obtained results illustrated that under the optimum conditions (pH = 3, contact time = 50 min, initial MNZ concentration = 5 mg/L and MAC dose = 0.5 g/L), the maximum adsorption efficiency was 95%. Furthermore, the kinetic studies indicated the applicability of the pseudo-second-order kinetic model, whereas the adsorption isotherm fitted well with the Freundlich model (0.996), and the maximum adsorption capacity was 66.22 mg/g. The SBET and the total pure volume of MAC were 706.92 m2/g and 0.532 cm3/g, respectively. Also, the regeneration tests demonstrated that MAC had good stability after five cycles (73%). It can be concluded that MAC, as an effective adsorbent, has a high ability to remove MNZ from aqueous solutions.

Experimental and computational studies on the removal of crystal violet dye from aqueous solution using juglans regia leaves treated with acetic acid and L-arginine

ABSTRACT In this study, the leaves of juglans regia chemically treated with acetic acid and L-arginine were used as adsorbents for removal of crystal violet dye from aqueous solution. The adsorbents were characterised using powder x-ray diffraction, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller techniques. The adsorption isotherm, kinetics and thermodynamic parameters were examined for adsorption of dye on various adsorbents. The effect of initial dye concentration on adsorption capacity was studied and maximum adsorption capacity of adsorbents as per Langmuir linear fit was found for (JRACD: 263.85 mg g−1, JRACCHR: 273.97 mg g−1 and JRLRG: 290.70 mg g−1) at an initial dye concentration of 300 ppm, pH of dye solution 8, dosage of adsorbent 0.3 g, contact time of 70 minutes and at temperature of 303.15 K. It was observed that Freundlich isotherm fitted well for adsorption of dye on all the adsorbents compared to Langmuir isotherm. The kinetics of adsorption was found to follow the linear pseudo-second-order rate equation (R2 ≥ 0.9967). The Gibbs free energy was spontaneous in nature for the three adsorbents. The response surface methodology was also applied for all the adsorbents and optimisation of initial dye concentration (100, 200, 300) ppm, dosage of adsorbent (0.1, 0.3, 0.5) g and pH of dye solution (2, 5, 8) led to the development of quadratic models. The maximum adsorption capacity as per response surface model was found as 260.12 mg g−1 for JRLRG under optimum conditions. The significance of these models was also characterised by analysis of variance test. Additionally, density functional theory was used to support the experimental analysis and using Fukui function analysis the site for adsorption has been proposed.

Electrochemical Detection of Celestine Blue Based on Screen Printed Carbon Electrode Modified with Molecular Imprinted Polymer and NiO Nanoparticles

A simple and rapid electrochemical method was developed for the detection of trace amount of Celestine blue (CB) at the surface of modified screen-printed carbon electrode (SPCE) with nickel oxide (NiO) nanoparticles and molecular imprinted polymer (MIP). Various types of electrochemical methods; containing, differential pulse voltammetry (DPV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in order to probe the characteristics of the sensor toward CB was employed. The selectivity, real sample analysis (efficiency), the linear concentration range, and the detection limit of CB at the MIP/NiO-NPs/SPCE were evaluated by DPV method. FT-IR spectroscopy was applied in order to characterize the synthesized CB-MIP and non-molecular imprinted polymers (NIP). Scanning electron microscopy (SEM) and BET (Brunauer-Emmett-Teller) techniques were used for surface morphology and porosity properties of CB-MIP and NIP. A linear range was presented by the sensor for CB concentration between 2-150 µM with detection limit (S/N=3) of 0.35 µM. The sensor is able to selectively detect the CB molecules over the potential interferences. The sensor was used to determine CB in the real sample with acceptable results.

Sonochemical Synthesis of Vaterite-Type Calcium Carbonate Using Steamed Ammonia Liquid Waste without Additives.

Herein, metastable spheroidal vaterite calcium carbonate (CaCO3) was prepared using a simple ultrasound technique. The fabricated material comprises an irregular nanoparticle aggregate when steamed ammonia liquid waste, that is, (CaCl2) and (NH4)2CO3, is used as the raw material at atmospheric temperature, without any surfactants. The effects of ultrasound amplitude, probe immersion depth, and solution volume on particle properties were investigated. The obtained samples were identified and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and the Brunauer–Emmett–Teller technique. Our experiments show that the probe immersion depth and the reaction volume are the key parameters that impact the diameter size and size distribution of the fabricated spheroidal vaterite CaCO3 particles. The ultrasound amplitude considerably affected the particle size and the specific surface area. A possible formation mechanism for pure vaterite is proposed herein, which suggests that simple vaterite CaCO3 is formed owing to the special properties of steamed ammonia liquid waste and the synergistic effects of the ultrasonic system. This study may provide a new method for vaterite CaCO3 synthesis.

A simple and cost-effective new synthesis method of copper molybdate CuMoO4 nanoparticles and their catalytic performance

Nanopowders of copper molybdate, α-CuMoO 4 , were prepared through calcination of an oxalate complex in static air at 550 °C. The oxalate complex was investigated by Fourier transform infrared spectroscopy and thermal gravimetric analysis. The as-prepared copper molybdate was characterized by X-ray powder diffraction and the Brunauer–Emmett–Teller technique. Its catalytic effectiveness was verified by the oxidation reaction of methylene blue (MB) with hydrogen peroxide (H 2 O 2 ) and by the reduction reaction of para-, meta-, and ortho-nitrophenol. The prepared copper molybdate exhibited exceptionally high catalytic performance of the oxidation of methylene blue dye and of the reduction reaction of the three isomers of nitrophenol to the three corresponding aminophenol isomers. The evolution of the catalytic activity was controlled by utilizing UV-Vis absorption spectroscopy. • Copper molybdate, CuMoO 4 , nanoparticles were prepared successfully via a new and simple process, without resorting to any solvent at relatively low temperature. • CuMoO 4 nanocatalyst exhibits high efficiency for the reduction reaction of the three isomers of nitrophenol to the three corresponding aminophenol isomers. • The copper molybdate exhibits exceptionally high catalytic performance of the oxidation of methylene blue dye.

CO2 utilization by dry reforming of CH4 over mesoporous Ni/KIT-6 catalyst

Abstract The mesoporous Ni/KIT-6 catalysts with different composition were prepared by altering reduction temperatures. In addition, their physicochemical properties were characterized by X-ray diffraction, in-situ X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller techniques. The results shown that the specific surface area, composition and metallic Ni crystallinity of the Ni/KIT-6 catalyst were significantly affected by reduction temperatures. The catalytic performances of the prepared Ni/KIT-6 catalysts were evaluated via the CO2 reforming of CH4 into syngas and followed the order: RT0 < RT250 < RT300 < RT350 < RT400 < RT450 ≈ RT500. The specific surface area, pore volume, pore diameter, and Ni0 content of the most representative RT450 catalyst among of them were 646.7 m2 g−1, 0.92 cm3 g−1, 6.5 nm, and 30.9%, respectively. The CH4 and CO2 conversions of RT450 catalyst reached to 69.0 and 39.4% under a reaction temperature of 600 °C, respectively. The CO selectivity was greater than 49% and the RT450 catalyst had good stability.

A Novel Manganese-Rich Pokeweed Biochar for Highly Efficient Adsorption of Heavy Metals from Wastewater: Performance, Mechanisms, and Potential Risk Analysis

A novel manganese-rich pokeweed biochar was prepared at different temperatures from manganese-rich pokeweed plants collected at manganese tailings, resulting in materials identified as BC300, BC400, and BC500. The synthetized biochar materials were investigated as regards their potential for removing Cu2+, Pb2+, and Cd2+, specifically in terms of adsorption performances, adsorption kinetics, adsorption isotherms, and potential environmental pollution risk. The results showed that the sorption process fitted well to the pseudo-second-order kinetic and Langmuir models, and the maximum adsorption capacities of BC500 were 246, 326, and 310 mg·g−1 for Cu2+, Pb2+, and Cd2+ respectively. The physicochemical characteristics of the biochars, and the adsorption mechanisms, were revealed by using scanning electron microscopy-energy spectrometer, elemental analysis, Brunauer–Emmett–Teller techniques, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The sorption mechanism of these three heavy metal ions onto biochars included ion exchange, electrostatic adsorption, chemical adsorption, and precipitation. Besides, the potential pollution risk of manganese-rich pokeweed biochars was significantly reduced after pyrolysis. Therefore, it is feasible to transform manganese-rich pokeweed biomass into manganese-rich pokeweed biochar with potential for heavy metals removal, showing high adsorption capacity, recyclability, and low environmental pollution.

Heating temperature effect on the hygroscopicity of expanded vermiculite

The hygroscopicity of expanded vermiculite is one of major influence factors for thermal insulating performance. To explore the water absorption properties of expanded vermiculite prepared via electrical heating method, heating temperature effect on the hygroscopicity of expanded vermiculite was investigated under various humidity circumstances. The influencing mechanisms were analyzed by means of Thermogravimetric Analysis-Differential Scanning Calorimeter technique (TG-DSC), Fourier-Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and the Brunauer–Emmett–Teller technique (BET) for the measurement of the specific surface area. The results of water absorption experiments indicated that the hygroscopicity of vermiculite showed an inversely proportional relationship to heating temperature and the water absorption content of EV-900 was only 6.206 mg/g with a dramatic decline of 91.5% in comparison with that of RV. This decline of water absorption capacity was mainly attributed to the decrease of interlamellar spacing and specific surface area. In addition, environment humidity had a significant effect on water absorption capacity and velocity. The water absorption content of EV-400 sample increased dramatically from 48.414 mg/g at the humidity of 55%–72.929 mg/g at the humidity of 95%, and the equilibrium time reduced from 3 h to 0.5 h. This study will provide a new perspective and theoretical guidance for the development of vermiculite based thermal insulating materials.

Hybrid Materials Based on Multi-Walled Carbon Nanotubes and Nanoparticles with Antimicrobial Properties.

In this study, multi-walled carbon nanotubes (MWCNTs) were decorated with different types of nanoparticles (NPs) in order to obtain hybrid materials with improved antimicrobial activity. Structural and morphological analysis, such as Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy, environmental scanning electron microscopy/energy-dispersive X-ray spectroscopy and the Brunauer–Emmett–Teller technique were used in order to investigate the decoration of the nanotubes with NPs. Analysis of the decorated nanotubes showed a narrow size distribution of NPs, 7–13 nm for the nanotubes decorated with zinc oxide (ZnO) NPs, 15–33 nm for the nanotubes decorated with silver (Ag) NPs and 20–35 nm for the nanotubes decorated with hydroxyapatite (HAp) NPs, respectively. The dispersion in water of the obtained nanomaterials was improved for all the decorated MWCNTs, as revealed by the relative absorbance variation in time of the water-dispersed nanomaterials. The obtained nanomaterials showed a good antimicrobial activity; however, the presence of the NPs on the surface of MWCNTs improved the nanocomposites’ activity. The presence of ZnO and Ag nanoparticles enhanced the antimicrobial properties of the material, in clinically relevant microbial strains. Our data proves that such composite nanomaterials are efficient antimicrobial agents, suitable for the therapy of severe infection and biofilms.

Mechanical and Microstructural Properties of Ordinary Concrete with High Additions of Crushed Glass.

This study investigates the use of crushed glass waste as partial cement replacement in ordinary concretes. Six concrete mixes were designed and prepared: a reference without substitution and five substitution percentages of crushed glass waste ranging from 5% to 25%. The made concrete mix design underwent different tests, namely: slump test, mechanical strength, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) determination and finally, water porosimetry, in order to evaluate the influence of the use of crushed glass waste on the properties of fresh and hardened concrete. Mechanical strengths results show that the use of 15% of the crushed glass waste improves the mechanical strength. TGA analysis confirms this result by highlighting a higher hydration degree. The latter contributes to the reduction of the porosity and, consequently, the mechanical strength increases. Also, it can be caused by the increasing amount of chromium which, if added a little, accelerates the hydration of C3S and leads to an increase of the mechanical strength. The BET technique and porosimetry tests showed that the use of crushed glass waste reduces the global porosity of concrete. This is due to the filling effect of the glass powder.

Catalytic wet peroxide oxidation of a real textile azo dye Cibacron Red P-4B over Al/Fe pillared bentonite catalysts: kinetic and thermodynamic studies

In the present work, Al/Fe pillared clay catalysts (Al/Fe-PILCs) with different active metal ratios (Fe/(Fe + Al) molar ratio in the intercalating solution) were prepared by using bentonite clay from Ordu (Fatsa) area in Turkey. Batch experiments were performed to study the catalytic wet peroxide oxidation of Cibacron Red P-4B azo dye on the obtained heterogeneous catalysts. The raw bentonite and catalyst samples were characterized by means of XRD (X-ray diffraction), XRF (X-ray fluorescence), DTA (differential thermal analysis), TG (thermogravimetric analysis), BET (Brunauer–Emmett–Teller), SEM (scanning electron microscopy), EDS (energy dispersive spectrometry) and FTIR (Fourier transform infrared) techniques. The basal spacing (d001) of Al/Fe-PILCs increased with the increase in active metal ratio up to 17.2 A for the catalyst with 12% active metal ratio (NaBAlFe12). The BET specific surface area and the micropore volume of NaBAlFe12 showed a decrease compared to raw bentonite. The color removal ratio increased with increasing active metal ratio and reached to 99.24% after 4 h reaction for the NaBAlFe12 catalyst. The pseudo-first order kinetic model was well obeyed the experimental data (k = 0.0075 min−1 at 25 °C). The activation energy (Ea) was calculated as 12.26 ± 0.78 kJ mol−1. It was also found that the catalytic oxidation process was endothermic (ΔH = 9.64 ± 0.76 kJ mol−1) and nonspontaneous (ΔG = 95.35 ± 1.46 kJ mol−1). The catalysts were chemically stable and reusable with low release of iron.

Synthesis and Investigation of Template Effects on Nanoporous Bi2O3 Morphologies by Sol Gel Method as Photocatalysts for Degradation of Some Organic Dyes as Water Pollutants

Effect of triethanolamine, n-octylamine, starch, polyethylene glycol and hexadecyltrimethylammonium bromide as template have been investigated on the formation of Bi2O3 prepared via sol gel method. The prepared catalysts were characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared, UV–visible diffuse reflectance and Brunauer–Emmett–Teller techniques and subsequently used as photodegradation catalyst to purify contaminated water by Congo red and methylene blue as phenolic dyes. It was found that whereas Bi2O3-starch, Bi2O3-CTAB and Bi2O3-PEG have the most photodegradation effect on methylene blue under visible irradiation, Bi2O3-starch and Bi2O3-CTAB are the most active catalysts for Congo red under UV irradiation. In other word, the type of organic dyes, photocatalyst morphologies and templates are important factors on the photodegradation and adsorption phenomena.