Barrett Joyner Halenda Research Articles

Role of a novel cationic gemini surfactant (CGS) on a one-step sol-gel process and photocatalytic properties of TiO2 powders.

TiO2 nanoparticles were prepared using a sol-gel process in combination with a novel cationic gemini surfactant (CGS) with amide functional groups at low temperatures. Titanium (IV) isopropoxide (TIP) and CGS were used as the starting materials and as effective agents, respectively, to orient the nanoparticles during the sol-gel synthesis. To reveal both the structural and morphological properties of the nanopowders prepared in this work, they were characterized using X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), and Brunauer-Emmett-Teller (BET) surface area apparatus. The pore volume and pore size were calculated using the Barrett-Joyner-Halenda (BJH) model on the desorption branch. The experimental results show that the surface area and average crystallite size of the obtained TiO2 nanopowders vary between 160-203 m2/g and 27-49 nm, respectively. It was observed that the N2 adsorption-desorption isotherms for almost all samples of TiO2-X% CGS (X: mass of CGS) show the typical Type I with a hysteresis loop of H4. The photocatalytic activities of the CGS-modified nanocomposites are evaluated not only by the photocatalytic degradation of methyl orange (MO) but also by the reduction of Cr(VI) as model pollutants in the presence of visible light.

Thermal treated sugarcane bagasse for acetylsalicylic acid removal: dynamic and equilibrium studies, cycles of reuse and mechanisms

ABSTRACT Sugarcane bagasse, an abundant residue from ethanol and sugar industry, was used in its natural form (SB) and carbonised (CS) as adsorbent for removing acetylsalicylic acid from aqueous solutions. The surface area, porosity, functional groups and surface charges of the adsorbents were characterised by Brunauer–Emmett–Teller and Barret–Joyner–Halenda methods, Fourier transform infrared spectroscopy and point of zero charge. Analysis indicated that C- and O-containing functional groups may be involved in the adsorption process. Batch experiments were also performed to evaluate the effects of pH, temperature and time on the sorption. The materials exhibited high adsorption efficiency at low pH. Results revealed that the pseudo-first-order kinetic model and pseudo-second-order provided the best fitting to the experimental data for biosorbent SB and biochar CS, respectively. Liu isotherm model describes the adsorption equilibrium for biochar suggesting that the carbonised surface had a heterogeneous nature with Q max of 32.73 mg g−1 at 298 K. Besides, intraparticle diffusion model suggests that adsorption of ASA onto activated carbon was controlled by multiple steps. This study demonstrated that carbonised sugarcane bagasse is a potential adsorbent for removing acetylsalicylic acid from aqueous solutions.

Influence of nano-attapulgite on compressive strength and microstructure of recycled aggregate concrete

In order to solve the problem of waste concrete caused by demolition of old buildings, calcined nano-attapulgite (CNAT) was added into recycled aggregate concrete (RAC) to form nano-attapulgite recycled concrete. In this paper, the experiment was divided into two stages. Stage 1: The influence of activity of nano-attapulgite (NAT) which is calcined at different temperatures was analyzed by thermo-gravimetric analysis (TGA), scanning electron microscope (SEM) and X-ray diffraction (XRD) to find out the optimal activation temperature. Stage 2: The influence of different CNAT content and replacement rate of recycled coarse aggregate (RA) on the compressive strength of RAC were investigated, and the microstructure was analyzed by SEM, XRD and Barret-Joyner-Halenda (BJH) method. The results showed that when the calcination temperature is 500 °C, NAT has the highest activity; the compressive strength of RAC decreases gradually with the increase of replacement rate of RA. When the replacement rate of RA were 30 wt% and 50 wt% and the content of CNAT was 6 wt%, the compressive strength of concrete were the largest and the compressive strength is 13.2% and 16.1% higher than that without CNAT, respectively. Because of its filling effect, surface effect and pozzolanic activity, CNAT can fill the pores and cracks in the old mortar, new mortars and the interfacial transition zone (ITZ) of RAC. The harmful pores of RAC is refined, and the concrete is more dense. Above all, CNAT can increase the macroscopic mechanical properties of RAC by improving its microstructure effectively, which provides a theoretical basis for the further study of RAC.

Novel photocatalyst system to deep desulfurization of petroleum model and gas condensate by Box–Behnken design

In this research, cobalt (Co)/molybdenum (Mo) and nickel (Ni) doped with titanium dioxide (TiO2) were loaded onto multi-walled carbon nanotubes (MWCNTs). Then, the magnetization catalyst, iron oxide (Fe3O4), was loaded on them, which was used for the deep desulfurization of dibenzothiophene (DBT). These catalysts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential reflectance spectroscopy, and Brunauer–Emmett–Teller, Barrett–Joyner–Halenda, and vibrating sample magnetometer techniques. The photocatalytic activity of these catalysts was experienced under visible light using DBT. The response surface methodology based on the Box–Behnken design was used to evaluate parameters, including catalyst dosage (g), time (min), and concentration of DBT (mg L−1). The highest degradation efficiency under optimal conditions for CoMoNi/TiO2/MWCNTs/Fe3O4 catalysts with a catalyst dosage of 0.3 g, a time of 180 min, and a concentration of 50 mg L−1 was 99.99%. Optimum conditions were studied for desulfurization of the gas condensate. The highest desulfurization efficiency (90.33%) was obtained by the CoMoNi/TiO2/MWCNTs/Fe3O4 catalyst.

Non-ionic surfactants As co-templates to control the mesopore diameter of hollow mesoporous silica nanoparticles for drug delivery applications

Hollow mesoporous silica nanoparticles (HMSN) with unique properties are increasingly being applied in drug delivery field. To be able to encapsulate desired agents with different molecular size such as drugs, nucleic acids, polysaccharides and proteins … into the hollow cavity, the control of HMSN’s meso-chennal diameter is one of the pioneering and decisive factors. This study aims to use non-ionic surfactants (S) including Tween 20, Tween 80 and Brij S10 as co-templates with Cetrimonium bromide (CTAB) to control the mesopore diameter. HMSN was synthesized with hard template method following three main steps and S with different molar ratios would be prepare mixed micelles with CTAB and added into the synthesis mixture at the mesoporous coating step. Dynamic Light Scaterring (DLS) measurement was conducted for mixed micelles S-CTAB, meanwhile Brunauer-Emmett-Teller (BET) Surface Area Analysis and Barrett-Joyner-Halenda (BJH) Pore Size and Volume Analysis were conducted for the synthesized HMSN with S-CTAB to evaluate the influence of S on HMSN’s mesopore diameter. Rose Bengal with molecular weight of 1017.64 g/mol was used as the model drug to evaluate drug loading capacity and release profile of the enlarged-mesopore system. Additionally, Zeta potential, SEM, TEM, XRD, FT-IR and cytotoxicity were conducted to characterize the synthesized particles. This study would contribute a meaningful approach to control the mesopore diameter of HMSN using non-ionic surfactants for drug delivery applications.

Synthesis and characterization of UiO-66-NH2 incorporated graphene aerogel composites and their utilization for absorption of organic liquids

This work details the synthesis, materials characterization and absorption capacity of graphene aerogel (GA) loaded with UiO-66-NH2 metal organic framework (MOF). A series of density-tunable MOF/GA composites were synthesized by adjusting the MOF/graphene oxide (GO) mass ratio of the precursors before hydrothermal reduction and subsequent critical point drying to achieve MOF-x%/GA composites, with x, ranging from 0 to 100, denoting the weight percent ratio of MOF to GO in the starting solution. Scanning electron microscopy (SEM) images and Barrett-Joyner-Halenda (BJH) pore size calculations supported that MOF loading enlarged the macroporous (>50 nm) structure of the GA framework but had no influence on the mesoporous (2–50 nm) structure of GA. The degree of MOF loading first decreased and then increased the density of resulting composites, exhibiting a minimum for the 10–30% samples. Such behavior with respect to MOF loading has not been reported previously. MOF-x%/GA samples were further investigated for absorption capacity using various organic liquids. MOF-30%/GA proved to be the best absorbent sample for all solvents tested, achieving the highest capacity for chloroform at 147.0 ± 10.0 mg/mg. The behavior is attributed to the structural changes induced by the MOF incorporation as well as the interactions between the organic molecules and the MOF.

Green synthesis of nano-CuFe2O4/clinoptilolite and its use in benzodiazepine synthesis

In this research, a copper ferrite (CuFe2O4) nanocatalyst stabilized on clinoptilolite (CP) was prepared using green tea (Camellia sinensis) leaf extract. Fourier transform infrared spectra, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray analysis, transmission electron microscopy (TEM), the Brunauer–Emmett–Teller (BET) method, thermogravimetric analysis and differential thermal analysis were used to characterize copper ferrite/CP. After fixation on CP, the crystallite size of copper ferrite was determined to be 48.7 nm using an XRD pattern and the Debye–Scherrer equation. Copper ferrite nanoparticles were successfully placed on CP as evidenced by FESEM and TEM images. Using the Barrett–Joyner–Halenda method, the average diameter of the catalyst pores was found to be 22.2 nm. Using the BET method, the catalyst surface area was estimated to be 43.7 m2/g. The catalytic activity of copper ferrite/CP in the production of benzodiazepine (the reaction of o-phenylenediamine with ketones) was examined. The experimental results showed that this catalyst performs well under mild reaction conditions. Using an external magnetic field, copper ferrite/CP was easily separated from the reaction product and can be reused without appreciably decreasing its catalytic activity.

Simply and effectively control the shell thickness of hollow mesoporous silica nanoparticles by polyethylene glycol for drug delivery applications

AbstractThis study reports for the first time the usage of polyethylene glycol (PEG) as the capping agent to control mesoporous shell thickness of hollow mesoporous silica nanoparticles (HMSN)—a promising nanocarrier. HMSN was synthesized with hard template method and PEG with different molecular weights and concentrations would be added at the mesoporous coating. The samples dSiO2@MSN synthesized with and without PEG were analyzed DLS, field‐emission scanning electron microscopy, Brunauer–Emmett–Teller and Barrett–Joyner–Halenda to characterize their mesoporous shells. Meanwhile transmission electron microscope, Zeta potential, energy dispersive X‐ray spectroscopy, Fourier‐transform infrared, loading capacity, release profile and cytotoxicity analysis was conducted to characterize HSMNs. As PEG's molecular weight or concentration increased, the mesoporous shell thickness gradually raised. Particles synthesized in the presence of 2% PEG 6000 retained the monodispersed spherical morphology with a particle diameter of 95.40 nm and a mesoporous shell thickness of 14.40 nm, which was about 7.0 nm thicker. dSiO2@MSN‐P owned equal mesopore diameter and higher surface area compared to dSiO2@MSN‐0. HMSN‐P showed similar loading capacity but better sustained release profile than HMSN‐0. Moreover, both HMSN‐0 and HMSN‐P performed as biocompatible materials. This study would contribute a simple and effective method to control the shell thickness of HMSN with PEG for drug delivery applications.

Spinel structure of activated carbon supported MFe2O4 composites as an economic and efficient electrocatalyst for oxygen reduction reaction in neutral media

For more sustainability and marketing of microbial fuel cells (MFCs) in wastewater treatment, the sluggish kinetics of cathode oxygen reduction reaction (ORR) and platinum scarcity (with its high cost) should be swept away. So, this work aimed to synthesize metal ferrite (MFe2O4; M = Mn, Cu, and Ni) -based activated carbon composites as inexpensive ORR cathode catalysts. The composites were synthesized using a facile modified co-precipitation approach with low-thermal treatment and labeled as MnFe2O4/AC, CuFe2O4/AC, and NiFe2O4/AC. The as-synthesized catalysts are physicochemically characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared microscopy (FTIR), Barrett-Joyner-Halenda (BJH), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and electron spin resonance (ESR). The electrochemical catalytic performance toward ORR was studied in a phosphate buffer solution (PBS) at neutral media via cyclic voltammetry (CV) and linear sweep voltammetry (LSV). MnFe2O4/AC has the highest onset potential (Eonset) value of − 0.223 V compared to CuFe2O4/AC (− 0.280 V) and NiFe2O4/AC (− 0.270 V). MnFe2O4/AC also has the highest kinetic current density (jK) and lowest Tafel slope (− 5 mA cm−2 and − 330 mV dec−1) compared to CuFe2O4/AC (− 3.05 mA cm−2 and − 577 mV dec−1) and NiFe2O4/AC (− 2.67 mA cm−2 and − 414 mV dec−1). The ORR catalyzed by MnFe2O4/AC at pH = 7 proceeds via a 4e− -kinetic pathway. The ESR is in good agreement with the electrochemical analysis due to the highest ∆Hppvalue for MnFe2O4/AC compared to CuFe2O4/AC and NiFe2O4/AC. Thus, MnFe2O4/AC is suggested as a promising alternative to Pt- electrocatalyst cathode for MFCs at neutral conditions.Graphical

Enhanced photocatalytic degradation of malachite green using manganese oxide doped graphene oxide/zinc oxide (GO-ZnO/Mn2O3) ternary composite under sunlight irradiation.

In this work, photocatalytic degradation of malachite green (MG) dye using manganese oxide doped graphene oxide/zinc oxide (GO-ZnO/Mn2O3) ternary composite under sunlight irradiation is studied. GO-ZnO/Mn2O3 is a novel composite, which is non-toxic and of low cost prepared by the conventional solvothermal route. The synthesized composite was characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), RAMAN spectra, photoluminescence (PL) spectroscopy, Diffuse reflectance spectroscopy (UV-Vis. DRS), and Barrett-Joyner-Halenda (BJH) pore size distribution. The GO-ZnO/Mn2O3 composite has a moderately large surface area of 75.35m2/g and bandgap energy of 1.6eV. Due to more pollutants adsorbed onto the photocatalyst surface and the reduction in bandgap energy, resulted less recombination rate and shifted the light absorption into the visible region to effectively utilize the sunlight and enhanced degradation of 98.75% is achieved within 30min of sunlight irradiation for GO-ZnO/Mn2O3 composite. Using various scavengers, the main oxidizing radicals for the degradation of MG dye are identified as hydroxyl (•OH) and superoxide radical (•O2-). The synthesized composite is stable and reproducible as after five successful cycles, there was a small reduction in its degradation efficiency of 11.65%. Keywords: Graphene oxide; Photocatalyst; Malachite green; Bandgap; Scavengers.

Study on the recycle of steel slag as an adsorbent for COD removal in pulp mill wastewater

This study aims to characterize and investigate steel slag for the removal of its persistent organic pollutants (measured as COD) from pulp mill wastewater. Steel slag and its NaOH-modified states were characterized by Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) surface area analysis, Barrett-Joyner-Halenda (BJH) pore size, and volume analysis. Batch adsorption experiments were conducted to investigate the COD adsorption of slag-based adsorbents. The modification of NaOH was found to improve the COD adsorption capacity (by 1.5 times) of steel slag by generating hydroxyl and carboxyl groups and enlarging the specific surface area and pore size in the steel slag particles. In batch experiments, the suitable conditions for COD adsorption on NS (steel slag) and MS20 (2 M NaOH-modified steel slag) were determined to be pH 6 - 8, contact time 90 minutes, and adsorbent dosage 20 g/L. Langmuir and Freundlich adsorption isotherm models satisfactorily described the adsorption of COD on both NS and MS20 with a good correlation. According to the Langmuir isotherm, the maximum COD adsorption capacity of NS and MS20 were 5.16 and 6.87 mg/g, respectively. Column experiments demonstrated that NS and MS20 had promising potential for COD treatment in pulp mill effluent. According to the column results, 20 g of NS or MS20 was able to keep 300 mL or 525 mL of 125 mg/L COD wastewater, respectively, reaching the threshold of the National Technical Regulation on Industrial Wastewater QCVN 40:2021/BTNMT.

Adsorption of bisphenol A by TiO2-based organic–inorganic hybrid materials

In this study, TiO2-P25 was modified with benzoic acid (BA) and 2-naphthalenecarboxylic acid (NCA), and subsequently used to adsorb bisphenol A (BPA). The relationship between the hydrophobicity of the modified TiO2 and the amount of BPA adsorbed was investigated. The equilibrium adsorption data were analyzed using the Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, Harkins–Jura, and Halsey models. Additionally, TiO2 and TixZr(1-x)O2 of high specific surface area were synthesized via the sol-gel and solvothermal methods. The materials were modified using NCA and used to adsorb BPA. The surface properties of the adsorbent were investigated by Brunauer–Emmett–Teller surface area analysis, Barrett–Joyner–Halenda pore size analysis, CO2 temperature-programmed desorption, and CHN elemental analysis. The specific surface area of TixZr(1-x)O2 (252.1– 455.0 m2/g) was higher than that of TiO2 (157.6 m2/g) and the amount of NCA modified onto TixZr(1-x)O2 (1.106– 1.319 mmol/g) was also higher than that of TiO2 (0.405 mmol/g). The amount of NCA modification onto TixZr(1-x)O2 was promoted by surface base points. The maximum amount of BPA adsorbed was 22.4 mg/L, which was 5.86 times that of TiO2-P25, and approximately 90 % of the BPA was removed from a solution having an initial concentration of 100 mg/L.

Experimental analysis of pore structure and fractal characteristics of soft and hard coals with same coalification

Accurate and quantitative investigation of the physical structure and fractal geometry of coal has important theoretical and practical significance for coal bed methane (CBM) development and the prevention of dynamic disasters such as coal and gas outbursts. This study investigates the pore structure and fractal characteristics of soft and hard coals using nitrogen and carbon dioxide (N2/CO2) adsorption. Coal samples from Pingdingshan Mine in Henan province of China were collected and pulverized to the required size (0.20–0.25 mm). N2/CO2 adsorption tests were performed to evaluate the specific surface area (SSA), pore size distribution (PSD), and pore volume (PV) using Braunuer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH), and Density Functional Theory (DFT). The pore structure was characterized based on the theory of fractal dimensions. The results unveiled that the strength of coal has a significant influence on pore structure and fractal dimensions. There are significant differences in SSA and PV between both coals. The BJH-PV and BET-SSA obtained by N2-adsorption for soft coal are 0.029–0.032 cm3/g and 3.523–4.783 m2/g. While the values of PV and SSA obtained by CO2-adsorption are 0.037–0.039 cm3/g and 106.016–111.870 m2/g. Soft coal shows greater SSA and PV than hard coal, which is consistent with the adsorption capacity ({V}_{mathrm{L}}). The fractal dimensions of soft and hard coal are respectively different. The Ding coal exhibits larger D1 and smaller D2, and the reverse for the Wu coal seam is observed. The greater the value of D1 (complexity of pore surface) of soft coal is, the larger the pore surface roughness and gas adsorption capacity is. The results enable us to conclude that the characterization of pores and fractal dimensions of soft and hard coals is different, tending to different adsorption/desorption characteristics. In this regard, the results provide a reference for formulating corresponding coal and gas outburst prevention and control measures.

Efficient photocatalytic degradation of metronidazole in wastewater under simulated sunlight using surfactant- and CuS-activated zeolite nanoparticles

Hexadecyltrimethylammonium-bromide-activated zeolite nanoparticles coated with copper sulfide (ZEO/HDTMA-Br/CuS) was evaluated as a photocatalyst under sunlight for the degradation of metronidazole (MET). The surface and structural characteristics of ZEO/HDTMA-Br/CuS and other materials used in this study were analyzed using field emission-scanning electron microscopy, Fourier transform infrared and ultraviolet–visible diffuse reflectance spectroscopies, X-ray diffraction, Brunauer–Emmett–Teller surface area and Barrett–Joyner–Halenda pore size and volume analyses, and pH of zero charge test. ZEO/HDTMA-Br/CuS exhibited excellent surface and structural catalytic properties. For a comprehensive study of the degradation process, several parameters, such as the pH (3–11), MET concentration (10–30 mg/L), ZEO/HDTMA-Br/CuS dose (0.005–0.1 g/L), reaction time (5–200 min), and H2O2 concentration (50–200 mg/L), were optimized. ZEO/HDTMA-Br/CuS achieved 100% degradation efficiency when 10 mg/L MET was used under the optimum conditions: pH = 7, ZEO/HDTMA-Br/CuS dose = 0.01 g/L, and reaction time = 180 min. The degradation efficiency increased when the concentration of H2O2 was increased from 50 to 150 mg/L and decreased with further increase to 200 mg/L, indicating that the efficiency of MET degradation highly depends on the concentration of H2O2 in an aqueous solution. The degradation kinetics analysis revealed that the degradation is of the pseudo first-order. Thus, ZEO/HDTMA-Br/CuS proved to be an exceptional catalyst for the photodegradation of MET in aqueous media.

Dry Reforming of Methane on Ni/Nanorod-CeO2 Catalysts Prepared by One-Pot Hydrothermal Synthesis: The Effect of Ni Content on Structure, Activity, and Stability

The nanorod morphology of the CeO2 support has been recognized as more beneficial than other morphologies for catalytic activity in the dry reforming of methane. Ni/nanorod-CeO2 catalysts with different Ni contents were prepared by one-pot hydrothermal synthesis. Samples were characterized by X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), H2-temperature-programmed desorption (H2-TPD), field emission scanning electron microscopy/energy dispersive spectroscopy (FE-SEM/EDS), Brunauer–Emmet–Teller (BET) and Barrett–Joyner–Halenda (BHJ) analysis. The effect of Ni content on the size and the intrinsic strain of ceria was analyzed by the Size–Strain plot and Williamson–Hall plot of XRD data. The average Ni particle size and Ni dispersion were determined by H2-TPD. XRD and H2-TPR analysis revealed a strong Ni–support interaction that limited nickel sintering. The activity for the dry reforming of methane was tested with the stoichiometric mixture CO2:CH4:N2:He = 20:20:20:140, gas hourly space velocity (GHSV) = 300 L g−1 h−1, and temperatures in the range of 545–800 °C. The turnover frequency (TOF) value increased linearly with the average Ni particle size in the range of 5.5–33 nm, suggesting the structure sensitivity of the reaction. Samples with Ni loading of 4–12 wt.% showed high H2/CO selectivity and stability over time on stream, whereas the sample with a Ni loading of 2 wt.% was less selective and underwent rapid deactivation. Only a small amount of nanotubular carbon was observed by FE-SEM after the time-on-stream experiment. Deactivation of the low-Ni-content sample is ascribed to the easier oxidation of the small Ni particles.

Sono-precipitation fabrication of ZnO over modified SAPO-34 zeotype for effective degradation of methylene blue pollutant under simulated solar light illumination

Implementation of hierarchical SAPO-34 zeotype, which was synthesized via a hard-template technique using secondary hard template, as a photocatalyst support for ZnO photocatalyst has been investigated. The ZnO/SAPO-34 (AC-U)-U photocatalyst was applied for photodegradation of dye molecules under simulated-solar-light irradiation. X-ray diffraction (XRD), field-emission scanning-electron-microscope (FESEM), Barrett–Joyner–Halenda (BET-BJH), Differential reflectance spectroscopy (DRS), Temperature-programmed reduction of hydrogen (H2-TPR) and Photoluminescence spectroscopy (PL) analyses have been applied to investigate the physiochemical properties of the catalysts. The BET-BJH results indicated that applying hard-template (active carbon) coupled with sonication leads to a raise in mean pore diameter of sample from 0.5 to 16.6 nm (about 32 folds higher). H2-TPR analysis confirms that the ZnO is dispersed uniformly by utilizing sonication. Furthermore, morphological analyses showed that the sonicated sample have more channel-like defect on the surface. PL analysis demonstrates the lower recombination rate of electrons-holes for the composite structure. The hierarchical architecture compared to the conventional pore structure has significantly increased adsorption capacity of dye from 10.8% to 50.3% by modifying the texture and pore structure. Sonicated photocatalyst showed the highest methylene blue degradation efficiency (95.7%). Hence, the ZnO/SAPO-34 (AC-U)-U nanocomposite photocatalyst depicts as a promising reusable photocatalyst for the photodegradation of dye-polluted water.

Synthesis and Gas Adsorption Properties of γ ‐Fe 2 O 3 Nanoparticles for Mass‐Type Sensing Application

In this study, Fe3O4 nanoparticles are prepared by the co-precipitation method. γ-Fe2O3 and α-Fe2O3 nanoparticles are obtained by calcining Fe3O4 nanoparticles for 6 h at 200 and 600 °C. The physicochemical properties of the prepared nanoparticles are investigated by field-emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, and Barrett–Joyner–Halenda methods. The gas sensors based on a quartz crystal microbalance (QCM) coated with Fe3O4, γ-Fe2O3, and α-Fe2O3 nanoparticles are fabricated and analyzed. The as-fabricated QCM sensors displayed a high capability for detecting SO2 at room temperature. Among the sensors, the γ-Fe2O3 nanoparticles coated QCM sensor exhibited the best response. Moreover, the sensor shows good repeatability and long-term stability. The correlation between the phase composition of the iron oxide nanoparticles and SO2 sensing performance is also discussed in detail.

Analysis of CaCO3 Impregnation on HY Zeolite Surface Area, Pore Size, and Activity in the Catalytic Cracking of Palm Oil to Biofuels

Fossil energy sources are currently decreasing, requiring the development of alternative energy sources. Vegetable oil is a raw material for alternative renewable energy supplies. This study produced biofuels from vegetable oil using calcium carbonate (CaCO3)-impregnated HY catalysts. In addition, this study aimed to investigate the effect of CaCO3 impregnation on the surface area and the catalytic activity of catalysts in the palm oil cracking process to produce biofuels. The HY catalyst was modified by the wet impregnation method in 5 wt% CaCO3 solution and was further calcined at 550°C for three h. Furthermore, the catalysts were tested in a continuous fixed-bed catalytic reactor at 450°C. The catalyst properties were characterized using Brunauer–Emmett–Teller (BET) surface area, Barrett–Joyner–Halenda (BJH) for pore size distribution, and X-Ray Diffraction (XRD) for crystal structure and phases. The results showed that the addition of CaCO3 decreased surface area and pore volume; however, the pore size increased, which resulted in the production of heavy hydrocarbons. Interestingly, the introduction of CaCO3 enhanced the yield of Organic Liquid Product (OLP) and diesel-range hydrocarbons selectivity to reach 79.09% and 30.54%, respectively. Furthermore, the introduction of CaCO3 increased deoxygenation activity.

Hybrid sonoprecipitation fabrication of magnetic ZnO-GO-Fe3O4 nanophotocatalyst for solar-light-driven degradation of dyes in water

ZnO-GO-Fe3O4 as an effective magnetic nanocomposite in photodegradation of water pollutants is prepared via two step procedure and its photocatalytic activity for organic dyes degradation is investigated. The first step is sonoprecipitation synthesis of ZnO over graphene oxide nanosheet and the second step is addition of Fe3O4 nanoparticles by two methods: precipitation synthesis and solvothermal addition. X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Analysis (EDX), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) Surface Area Analysis and Barrett-Joyner-Halenda (BJH) Pore Size and Volume Analysis, Differential reflectance spectroscopy (DRS), Fourier Transform Infrared spectroscopy (FTIR) and Vibrating-Sample Magnetometer (VSM) techniques are employed to examine the characterization of the nanocomposites. The results display high surface area with mesoporous structure and low energy band gap is obtained for ZnO-GO-Fe3O4 synthesized via solvothermal method. Also, ultrasound irradiation increases the available surface area for photoreaction. The degradation percent of eosin yellow and methylene blue are about 60 and 97%, respectively. The effect of initial pH of solution, the amount of loaded photocatalyst and initial dye concentration are investigated in this research.

Removing bromophenol blue from the aqueous environment by TixNiyLamOz photocatalyst under different conditions

A three metallic nuclear nanoparticle (Ti0.51Ni0.08La0.33O0.06) was synthesized by an environmentally friendly method using water solvent. The purpose of this study was the synthesis of nanoparticles with high surface activity (95 m2 g−1) and low energy bandgap (2.25 eV) to develop a powerful photocatalyst for removing organic harmful substances from the aqueous environments. TixNiyLamOz was characterized by various analyses including XRD (X-ray Powder Diffraction), UV–Vis diffuse reflectance spectroscopy, microscopic, FT-IR spectroscopy, Inductively coupled plasma (ICP), Brunauer–Emmett–Teller (BET) surface activity, and the Barrett–Joyner–Halenda method (BJH). The second step of the study involved an accurate method to investigate the photocatalytic ability of TixNiyLamOz considering different effective parameters, including bromophenol blue content (0.0025, 0.005, 0.01 mol), catalyst dosage (0.025, 0.05, 0.1 mol), pH, and irradiation type. The result illustrated that TixNiyLamOz can reduce the concentration of bromophenol blue in all conditions; it operated perfectly in ordinary environments, under sunlight yielding around 50% reduction.