Barrett Joyner Halenda Research Articles

Rapid Microwave Synthesis of β-SnWO4 Nanoparticles: An Efficient Anode Material for Lithium Ion Batteries

We report a facile synthesis of β-SnWO4 nanoparticles via a microwave heat treatment using SnCl2 and H2WO4 in the presence of tamarind seed powder. An X-ray diffraction analysis confirmed a crystalline nature revealing a cubic structure of β-SnWO4 nanoparticles. The morphological features were visualized using a scanning electron microscope that exhibited homogenously distributed clusters of nanoparticles, which were further confirmed using a transmission electron microscope. The micrographs also displayed some porosity. Energy dispersive X-ray spectroscopy confirmed the elemental contents such as tin, oxygen and tungsten in the same stoichiometric ratio as expected by the respective empirical formula. A high-resolution transmission electron microscope was used to find the d-spacing, which was ultimately used to analyze the structural parameters. The spectrum obtained using Fourier transform infrared spectroscopy illuminated different stretching vibrations. Additionally, a Barrett–Joyner–Halenda analysis was carried out to investigate the N2 adsorption-desorption isotherm as well as to govern the pore size distribution. Cyclic voltammetry measurements were implemented to analyze the ongoing electrode reactions throughout the charge/discharge for the β-SnWO4 nanostructures. The galvanometric charge/discharge curves for β-SnWO4 are also discussed. A high specific capacitance (600 mAhg–1 at 0.1 C) and excellent columbic efficiency (~100%) were achieved.

High sensitive electrochemical sensor for imatinib based on metal-organic frameworks and multiwall carbon nanotubes nanocomposite

A new sensitive electrochemical sensor has been constructed based on glassy carbon electrode (GCE) modified by nanocomposite of multiwall carbon nanotubes (MWCNTs) and metal–organic frameworks of copper (CuMOFs). The voltammetric response of the offered sensor (CuMOFs-MWCNTs/GCE) exhibited the catalytic effect toward imatinib (IMB). To characterize the structure and morphology of the constructed sensor, the procedures of electrochemical impedance spectroscopy (EIS) and field emission scanning electron microscopy (FE-SEM) were applied. The porosity of CuMOF was described by Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) technique. This sensor depicted an excellent electrocatalytic response for IMB detection under optimized conditions of solution pH, scan rate, accumulation potential, and time. Two linear segments in the calibration plot have been obtained for ranges of 0.01–20 and 20–220 µM with the limit of detection (LOD) 4.1 nM. The prepared sensor results were acceptable for the quantitative measurement of IMB in human blood serum (HBS), urine, and pharmaceutical dosage (Tablet), and it compared well with the reported HPLC method.Finally, the fabricated sensor demonstrated an acceptable accuracy, reproducible behaviour, and also, high stability in all electrochemical evaluations. Besides, analytical parameters were determined, and the results were compared with the reportages of similar methods.

Direct Sunlight Catalytic Decomposition of Organic Pollutants via Sm- and Ce-Doped BiFeO3 Nanopowder Synthesized by a Rapid Combustion Technique

In the development of photocatalytic processes towards waste water treatment, we have been long faced three foremost obstacles, including catalyst mass production, photon-energy cost and finally catalyst separation process after the treatment. In this study, such problems were addressed through the development of samarium and cerium-doped BiFeO3 (BFO) nanoparticles (NPs) (BixRExFeO3; RE = Sm, Ce, x = 0.00, 0.01, 0.03, 0.05;) employing a rapid solution combustion synthesis (SCS). This technique is greatly capable of large scale nanopowder production at low temperature. In the SCS procedure, different amount of oxidant-to-fuel (glycine-to-nitrate ion, Gly/NO3−) were investigated (Gly/NO3− = 0.2, 0.3, 0.37, 0.56, and 0.8). Moreover, a catalytic sunlight irradiation was employed to study the effect of Sm and Ce dopant contents on the photodegradation of benzene and methyl orange (MO) in the aqueous solution. The as-synthesized catalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), UV–Visible diffuse reflectance spectroscopy (UV–Vis DRS) and Brunauer–Emmett–Teller (BET)/Barrett-Joyner Halenda (BJH) techniques. The band gap energy of BFO decreaed from 2.14 to 2.06 eV with the increase of Sm3+ contents while it increased up to 2.22 eV in the case of Ce-doped BFO. The solar decomposition of the organic pollutants demonstrated the superior performance of Bi1-xSmxFeO3 photocatalyst rather than using cerium in the BFO crystalline structure which is attributed to the increased surface area and visible light harvesting.

Effect of growth-time on electrochemical performance of birnessite manganese oxide (δ-MnO2) as electrodes for supercapacitors: An insight into neutral aqueous electrolytes

This study demonstrates successful synthesis of nanoflower-like birnessite δ-MnO2 materials through a simple and effective hydrothermal technique. Characterization of the flower-like materials grown at various dwell times were carried out by employing scanning electron microscopy (SEM), X-ray diffractometry (XRD), Brunauer-Emmett-Teller (BET) and Barrett–Joyner–Halenda (BJH) models, and electrochemical analysis to understand the effect of different growth time on their morphological, structural, surface area along with pore size distribution and electrochemical characteristics as electrodes for electrochemical capacitors. Attention is mainly based on electrochemical assessment of the as-synthesized materials with an insight into some neutral aqueous electrolytes, mainly lithium sulphate (1 M Li2SO4) and sodium sulphate (1 M Na2SO4) solutions as potential medium owing to their non-corrosive nature, cost-effectiveness, electrochemical stability and environmentally friendliness. Significant charge propagation, with a high specific capacitance of 387.1 F g-1 was achieved for the half-cell electrode in 1 M Li2SO4 alongside excellent cycling stability for up to 5 000 cycles performed at 3 A g-1 specific current. A comprehensive electrochemical assessment is performed to understanding the relationship between solvated and diffused ions of the neutral electrolytes that could result in fast charge storage kinetics as well as high specific capacitance.

Influence of thermal treatments on the absorption and thermal properties of a clay mineral support used for shape-stabilization of fatty acids.

This paper reports the research carried out about the influence of thermal treatments on the porosity of a powder and granulated clay mineral support, used for shape-stabilization of phase change materials. The supports were calcined at 400 °C, 500 °C, 600 °C, 900 °C, and 1100 °C in order to study their surface area, pore volume, and pore size through Brunauer-Emmet-Teller (BET) and Barrett-Joyner-Halenda (BJH) analysis. Subsequently, the supports were used to prepare several shape-stabilized phase change materials (SS-PCMs) using lauric/myristic acid eutectic. The leakage percentage and thermal properties of the SS-PCMs were measured using the filter paper method and differential scanning calorimetry (DSC), respectively. The powder support calcined at 600 °C presented the best conditions for shape-stabilization with a leakage <2% and a good latent heat of fusion of 51.63 kJ/kg. Moreover, two more SS-PCMs were produced using capric/myristic and palmitic/stearic acids, and the support calcined at 600 °C. The best impregnation percentage found for all the PCMs was 35% wt. Further characterization with modulated DSC (MDSC) was used to determine the heat capacities and a leakage cycling was proposed until 16 h.

Simple and efficient method for the determination of Cr(VI) ions in water samples using m-MWCNT@APTMS through dispersive magnetic solid phase extraction

ABSTRACT This work describes the synthesis and characterisation of a promising adsorbent nanocomposite based on magnetic multiwalled carbon nanotubes (m-MWCNTs) functionalised with 3-aminopropyltrimethoxysilane (APTMS). Was developed a method based on dispersive magnetic solid phase extraction (DMSPE). It also details its use in the development of a rapid and simple preconcentration method for Cr(VI) ions in water samples with FAAS detection. The nanocomposite was characterised using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM); the textural data measurements were obtained using the Brunauer-Emmett-Teller (BET) and Barret-Joyner-Halenda (BJH) analyses. The maximum adsorption capacity of the m-MWCNT@APTMS nanocomposite for Cr(VI) ions was 13.37 mg g-1 at an equilibrium time of 20 min. The adsorption process followed the dual-site Langmuir-Freundlich model, while the kinetic data were well fitted by the pseudo-second-order model. The important variables that affect the performance of the MSPE method, such as the pH of the sample, adsorbent mass, preconcentration and elution time, and type of eluent were univariately optimised. Under the optimised condition, an aliquot of 20 mL of sample was preconcentrated using 40 mg of m-MWCNT@APTMS for 4 min under vortex agitation. After this, the nanoparticles were separated from the solution with a magnet, then, the adsorbed Cr(VI) ions in the adsorbent were eluted with 1.0 mL of 2.0 mol L-1 HNO3 for 1.0 min and submitted to FAAS detection. The linear range studied was of 0.02 -0.2 mg L-1. When the enrichment factor was 20, the LOD and LOQ to Cr(VI) ions were 3.18 and 10.7 µg L-1, respectively, presenting RSD of 0.18% and 0.28% for solutions of Cr(VI) at 0.08 mg L-1 and 0.18 mg L-1. Finally, the proposed method was applied for the speciation of Cr(VI) in water samples and the results were compared with reference technique (GF AAS).

Tungstic acid (H4WO5) immobilized on magnetic‐based zirconium amino acid metal–organic framework: An efficient heterogeneous Brønsted acid catalyst for l‐(4‐phenyl)‐2,4‐dihydropyrano[2,3c]pyrazole derivatives preparation

A new magnetic nanocatalyst based on the immobilization of tungstic acid onto new design robust, cost‐effective, green, and scalable zirconium‐L‐aspartate amino acid metal–organic framework (MOF)‐grafted L‐(+)‐tartaric acid stabilized magnetite nanoparticles (Fe3O4/tart‐NPs) was synthesized by two successive solvo (hydro)‐thermal methods. This catalyst was characterized by Fourier‐transform infrared (FT‐IR), energy‐dispersive X‐ray spectroscopy (EDS), X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller (BET), Barrett–Joyner–Halenda (BJH), zeta potential, Thermogravimetry Analysis‐Differential Thermal Analysis (TGA–DTA), and vibrating sample magnetometer (VSM) analyses. This catalyst is outstanding to prepare l‐(4‐phenyl)‐2,4‐dihydropyrano[2,3‐c] pyrazole derivatives in aqueous media due to the open metal sites, high and steady proton conductivity in the zirconium‐MOF, MIP‐202(Zr), and MOF and also due to Brønsted acid properties of tungstic acid. This acidic catalyst can easily be extracted by an outward magnetic field after completion of the reaction without any deactivation or selectivity loss. The products were characterized by spectroscopic analysis (FT‐IR,1H‐NMR, and13C‐NMR). The optimized reaction conditions and a possible reaction mechanism are outlined.

Exploring Rapid Photocatalytic Degradation of Organic Pollutants with Porous CuO Nanosheets: Synthesis, Dye Removal, and Kinetic Studies at Room Temperature

In this work, we report the facile, environmentally friendly, room-temperature (RT) synthesis of porous CuO nanosheets and their application as a photocatalyst to degrade an organic pollutant/food dye using NaBH4 as the reducing agent in an aqueous medium. Ultrahigh-resolution field effect scanning electron microscopy images of CuO displayed a broken nanosheet-like (a length of ∼160 nm, a width of ∼65 nm) morphology, and the lattice strain was estimated to be ∼1.24 × 10–3 using the Williamson–Hall analysis of X-ray diffraction plots. Owing to the strong quantum size confinement effect, CuO nanosheets resulted in an optical energy band gap of ∼1.92 eV, measured using Tauc plots of the ultraviolet–visible (UV–vis) spectrum, resulting in excellent photocatalytic efficiency. The RT synthesized CuO catalyst showed a high Brunauer–Emmet–Teller surface area of 30.88 ± 0.2313 m2/g (a correlation coefficient of 0.99972) with an average Barrett–Joyner–Halenda pore size of ∼20.385 nm. The obtained porous CuO nanosheets exhibited a high crystallinity of 73.5% with a crystallite size of ∼12 nm and was applied as an efficient photocatalyst for degradation of the organic pollutant/food dye, Allura Red AC (AR) dye, as monitored by UV–vis spectrophotometric analysis and evidenced by a color change from red to colorless. From UV–vis spectra, CuO nanosheets exhibited an efficient and ultrafast photocatalytic degradation efficiency of ∼96.99% for the AR dye in an aqueous medium within 6 min at RT. According to the Langmuir–Hinshelwood model, photodegradation reaction kinetics followed a pseudo-first-order reaction with a rate constant of k = 0.524 min–1 and a half-life (t1/2) of 2.5 min for AR dye degradation in the aqueous medium. The CuO nanosheets showed an outstanding recycling ability for AR degradation and would be highly favorable and an efficient catalyst due to the synergistic effect of high adsorption capability and photodegradation of the food dye.

Effect of calcination temperature on the properties and applications of bio extract mediated titania nano particles

In order to deal with the arising environmental issues across the globe at present nano particles with unique properties laid a benchmark in the name of nano catalysis. In this work the significance of calcination temperature on the thermal, electronic, structural and surface properties of a nano catalyst produced by sol–gel method using ultrasonic radiation against the disposal of toxic textile pollutants is studied in detail. The extract of tea leaves has been used as a bio-template during the synthesis to revise the crystallite size, surface area, optical absorption potential, and rate of agglomeration of nano sized grains by regulating their physico-chemical and surface properties. The influence of calcination in the transformation of single phased anatase titania to mixed phase anatase–rutile titania and the corresponding outcome in its photocatalytic activity employed in water treatment applications have been verified. The nano catalyst obtained is characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transition electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), Thermo gravimetric analysis (TGA), Brunaueur Emmett Teller (BET) analysis, UV–Vis diffused reflectance spectroscopy (DRS-UV–Vis) etc. The mesoporosity of the particle was examined using Barrett Joyner Halenda (BJH) model. The enhanced photo catalytic efficiency (about 97.7%) of templated nano titania due to calcination is verified against Congo red, a textile dye under optimized conditions. The nano catalyst produced can be easily separated, recycled to support its economic feasibility.

MoO3/SnO2Nanocomposite-Based Gas Sensor for Rapid Detection of Ammonia

Ammonia is harmful to human health, however, the detection limit of the sensor based on traditional semiconductor gas sensors is high and the speed is slow. Constructing heterostructure is an effective method to improve the performance of sensors. In this article, 1-D MoO3 nanorods and SnO2 nanoparticles are successfully combined to obtain MoO3/SnO2 nanocomposite. The 1-D structure can increase the speed of electron transport, while the nanoparticles on the surface increase the specific surface area, more importantly, the structure maximizes the interface area between the two materials which can transfer electronic more efficiently. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and Barrett–Joyner–Halenda (BJH) are used to analyze the microstructure and elemental composition of MoO3/SnO2. The diameter of MoO3/SnO2 nanocomposite is approximately 200 nm and the distribution is uniform. The response of MoO3/SnO2 nanocomposite to 100-ppm NH3 is 12.7 at 280 °C, and the response/recovery time is 13/2 s. The detection limit for NH3 can reach 10 ppb (response 1.3), which enables rapid detection of NH3 at low concentration. Electron transport requires more energy to overcome the contact barrier between pure SnO2 nanoparticles, which can also lead to electron emission and noise increase. However, the sensitive electrons of MoO3/SnO2 nanocomposite can transmit electrons along the 1-D rod-like structure of MoO3, which undoubtedly accelerates the efficiency of electron transmission. Moreover, n-n heterojunction formed between MoO3 and SnO2 to bend the SnO2 band and show better sensitivity to NH3. Therefore, MoO3/SnO2 nanocomposite shows a low detection limit and a rapid response/recovery speed. Nevertheless, the nanoparticles on the surface of MoO3/SnO2 nanocomposite begin to agglomerate with the increase of SnO2 content, which leads to the decrease of gas-sensitive response. The formation process of MoO3/SnO2 composites is also discussed in this article. The excellent gas sensing results show that MoO3/SnO2 composites are a promising gas sensing material.

Reordering of Depolymerized Silicates as Adsorbents for Large Nitrogen Compounds

The adsorption capacities of two synthesized zeolites (crystalline ZSM-5 and semi-crystalline faujasite Y) for a mixture of indole, quinoline and carbazole were studied. The different samples obtained show different crystalline degree, mesoporosity and Si/Al ratios. The synthesis procedure is based on the simultaneous depolymerization of a mixture of high surface area silica, such as rice hull ashes (RHA), and a crystalline zeolite, such as clinoptilolite or faujasite. The depolymerization step is followed by a partial reorganization induced by a structure-directing agent. A model mixture of nitrogenous compounds was prepared, then it was mixed with the zeolite samples and the amount adsorbed of nitrogenous compounds was determined by gas chromatography. Analysis of the adsorbed molecules reveals selectivity in favor of quinoline, followed by indole and then carbazole. The best adsorbent properties correspond to the solid with highest porous volume. The samples obtained were characterized by X-ray diffraction, 29Si and 27Al magic-angle spinning nuclear magnetic resonance, X-ray fluorescence and Fourier transform infrared spectroscopy. The Barrett-Joyner-Halenda (BJH) pore size distribution and the Brunauer-Emmet-Teller (BET) surface area values were obtained from N2 adsorption/desorption isotherms.

Examining slit pore widths within plasma-exfoliated graphitic material utilising Barrett–Joyner–Halenda analysis

BJH analysis is shown to be a highly useful method to estimate the distance between stacks within plasma-exfoliated graphitic material, and is shown to coincide with data obtained from SEM, AFM and XRD analysis.

Cheap Nano-Adsorbents Based on Zno/Mineral Nanocomposites for Removal of Chloroform from Water Solution

Background: Chloroform, as a hazardous chemical, can contaminate water resources via the reaction of chlorine as an antiseptic chemical with humic acids resulted from agricultural activities. In humans, chloroform may cause dizziness, heart disorders, and disorders of the nervous system. Hence, its removal is of crucial importance. Objectives: The current study aimed to propose cheap and efficient adsorbents to remove chloroform from water. Methods: Four different nanomaterials (ZnO, ZnO/graphene oxide (ZnO/GO), ZnO/GO/Zeolite, and GO/Zeolite nanocomposites) were prepared and characterized with X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) images. Textural properties of the nano- adsorbents were evaluated using Brunauer Emmet Teller (BET) and Barrett-Joyner-Halenda (BJH) techniques. Different isotherms and kinetic models were studied. The effect of pH on the removal efficiency of the nano-adsorbents was tested. Regenerability of the nano-adsorbents towards the removal of the chloroform was also evaluated. Results: XRD patterns and FESEM images of the nanocomposites confirmed lattice structures and nanoscale particle size of the prepared nanocomposites. According to the BET and BJH models, all samples had mesoporous structures. The BJH cumulative surface area of pores of ZnO, ZnO/GO, ZnO/GO/Zeolite, and GO/Zeolite nanocomposites were 8.5, 26.4, 17.2, and 20.8 m2/g, respectively. The best removal speed and efficiency were obtained according to the different isotherm and kinetic models for the removal of chloroform ZnO/GO nanocomposites. All adsorbents revealed characteristic adsorption in the pH range of 7 to 8. Conclusion: The ZnO/GO, a cheap and efficient nanocomposite, showed the best performance to remove chloroform from water samples due to its superior textural property. Hence, it can be used to remove chloroform from water for up to 5 cycles.

Hierarchical NiO@Ni(OH)2 nanoarrays as high-performance supercapacitor electrode material

A binary metal oxide/hydroxide as a hierarchical NiO@Ni(OH)2 nanoarrays was synthesized through several steps. Firstly, ZnO nanorods were prepared through a facile electrodeposition method on Ni foam (NF), and then the obtained ZnO nanorods were used as sacrificed template to deposit NiO nanotubes around them. The obtained nanotubes served as ideal 1D superhighways for charge storage and ion delivery. After that, chemical bath deposition was used to decorate Ni(OH)2 nanoflakes on top of NiO nanotubes acting as an ion reservoir. The prepared electrodes were evaluated by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) methods. More advanced characterizations of the NF/NiO nanotubes and NF/NiO@Ni(OH)2 nanoarrays were performed using Fourier transform infrared (FT-IR) and Raman spectroscopy, Thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods. Compared with the single NiO nanotubes or Ni(OH)2 nanoflakes, the NiO@Ni(OH)2 nanoarrays exhibited a high specific capacitance (Csp) of 2509 mA cm-2 at 1 mA cm-2. Long term cycling stability observed over 5000 cycles without negligible loss of Csp. This study shows that hierarchical covering metal oxide channels with the metal hydroxide flakes can open up new strategies for the design of high-performance supercapacitor electrode materials.

Novel ZIF67/Mn/MWCNTs decorated with layer double hydroxide supercapacitor electrodes

Nanoflakes of bimetal metal-organic framework (MOF) with different multiwall carbon nanotubes (MWCNTs) contents decorated by layer double hydroxide (LDH) (Ni-ZIF670.75(1-X%)/Mn0.25(1-X%)/MWCNTX%-LDH) were synthesized using solvothermal technique as supercapacitor electrodes. The structural properties, adsorption/desorption of surface area, porosity, morphology and elemental analysis of these nanocomposites were investigated by Fourier transforms infrared spectrum (FTIR), X-ray diffractometer (XRD), Brunauere-Emmett-Teller (BET) test, Barrett-Joyner-Halenda (BJH) test, scanning electronic microscope (SEM), and energy dispersive X-ray analysis (EDX), respectively. SEM image of Ni-ZIF6772.75%/Mn24.25%/MWCNT3%-LDH nanocomposite electrode showed an agglomeration of hollow nanoflakes shape of LDH with high porous structure and an average diameter of 1.15 µm. The electrochemical performance of the fabricated nanocomposites was assessed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrical impedance spectroscopy (EIS). It was found that the Ni-ZIF6772.75%/Mn24.25%/MWCNT3%-LDH electrode provided a superior specific capacitance of 2395 Fg−1(1077 C/g) at 1 Ag−1 and 2732 Fg−1 (1639 C/g) at 5 mV/s. The stability of this electrode had capacitance retention of 92% after 1000 cycles with energy density of 70 Wh/kg and power density of 244 W/kg.

Batch and Fixed-Bed Column Studies on Palladium Recovery from Acidic Solution by Modified MgSiO3.

Effective recovery of palladium ions from acidic waste solutions is important due to palladium’s intensive usage as a catalyst for different industrial processes and to the high price paid for its production from natural resources. In this paper, we test the ability of a new adsorbent, MgSiO3 functionalized by impregnation with DL-cysteine (cys), for palladium ion recovery from waste solutions. The Brunauer–Emmett–Teller (BET) surface area analysis, Barrett–Joyner–Halenda (BJH) pore size and volume analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and Fourier-Transformed Infrared (FTIR) spectroscopy have been performed to characterize this material. Firstly, the maximum adsorption capacity of the new obtained material, MgSiO3-cys, in batch, was studied. To establish the adsorption mechanism, the obtained experimental data were fitted using the Langmuir, Freundlich and Sips adsorption isotherms. Studies on the adsorption of palladium ions on the synthesized material were performed in a dynamic regime, in a fixed-bed column. The Pd(II) recovery mechanism in the dynamic column regime was established based on Bohart–Adams, Yoon–Nelson, Thomas, and Clark models. The obtained equilibrium adsorption capacity was 9.3 (mg g−1) in static regime (batch) and 3 (mg g−1) in dynamic regime (column). The models that best describe the Pd(II) recovery process for batch and column adsorption are Sips and Clark, respectively.

Desulfurization of gas condensate under visible light using synthesized photocatalysts of Mn/TiO2/MWCNTs and Ni/TiO2/MWCNTs

In this study, Manganese (Mn) and Nickel (Ni) doped on titanium dioxide (TiO2) were loaded on Multi-Walled Carbon Nanotubes (MWCNTs). These catalysts were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), Scanning electron microscope (SEM), Transmission electron microscopy (TEM), X-ray energy dispersive spectrometer/Mapping (EDS/Map), Brunauer, Emmett, Teller (BET)/Barrett, Joyner, Halenda (BJH) and Diffuse Reflectance Spectroscopy (DRS) methods. A batch reactor was designed and photoactivity of these materials prepared under visible light irradiation was tested using dibenzothiophene (DBT). The Response Surface Methodology (RSM) based on Box–Behnken Design (BBD) was used to evaluate parameters including catalyst mass (g), time (h) and dopant percentage (wt%). The best point for maximum degradation efficiency was obtained under optimum conditions for Mn/TiO2/MWCNTs and Ni/TiO2/MWCNTs catalyst masses of 0.25 and 0.22 (g), time of 5.30 and 4.56 (h), and dopant percentage of 4.22 and 7.82 (wt%) with an efficiency of 92.82 and 98.26%, respectively. Under optimal conditions for the degradation of DBT sulfur, was investigated desulfurization of gas condensate. The highest desulfurization efficiency was obtained by Ni/TiO2/MWCNTs catalyst at 89.11%. The results of kinetic studies show that the Blanchard model has the best agreement with the experimental data.

Porous SnO2 ceramic-based hydroelectric cells for green power generation

Recently, it has been observed that few drops of water on the surface of oxide materials can generate electricity which is eco-friendly and cost effective. This hydroelectric cell (HEC) may serve as an unconventional source of electrical energy. HEC production cast is very low. Porous SnO2 samples for hydroelectric cell have been prepared by solid-state sintering method. Phase formation and structural analysis of the sample was confirmed by X-ray diffraction pattern using Rietveld analysis. The surface morphology of the sample was determined using field emission scanning electron microscopy. Average grain size of porous sample was depicted 65 nm using image j software. The pore size distribution and specific surface area of SnO2 nanoparticles were examined by the Barrett–Joyner–Halenda technique. A circular pellet having diameter of 2 inch and a square pellet having a side of 2 cm was prepared to study the hydroelectric properties. Peak current value 72.1 mA was observed in circular pellet with almost constant voltage of 0.981 V whereas peak current and voltage values for the square pellet were 12.5 mA and 0.972 V respectively. Dissociation of water and conduction phenomenon have been confirmed using dielectric and DC conductivity behavior of samples.

Pore structure typing and fractal characteristics of lacustrine shale from Kongdian Formation in East China

Nine as-received core samples were selected from four wells drilled in the lacustrine Kongdian Formation, which is a source rock located in Cangdong Sag, Bohai Bay Basin, China, and their geochemistry and pore structure characteristics were investigated by Rock-Eval pyrolysis, low-pressure nitrogen physisorption (LNP), mercury intrusion porosimetry (MIP), and spontaneous imbibition (SI) tests. Various models were employed to investigate the fractal characteristics of pore systems, and discuss the relationships between pore structure parameters and fractal dimension (Df). The results show that the samples can be divided into two groups (A and B) according to the different types of hysteresis loops from LNP isotherms, as well as geochemistry and pore structure parameters of samples. Negative relationship among BJH (Barrett-Joyner-Halenda) pore volume and S1 value, and obviously higher average pore diameter of Group B samples with significantly higher S1 values, indicate a blockage of residual hydrocarbons on small pores. According to the different Df−MIP values from MIP tests, the pore-throats of samples can be divided into four categories of A to D in the following sequence: microscopic (diameters less than 50 nm), small (50 nm-8 μm), medium (8 μm–20 μm) and large (greater than 20 μm) pore-throats/pores. The difference of Df from LNP and MIP tests is probably due to different sample sizes used and pore types assessed, while the difference of Df between MIP and SI tests is attributed to the mixed wettability of pores in shale samples. In addition, from the results of LNP tests with a measurable pore size of 2–200 nm, obvious positive relationships exist between Df−LNP−C (LNP test-derived Df value for Region C) and BJH pore volume, BET (Brunauer-Emmett-Teller) surface area and average pore size, as well as microscopic pore volume and percentage. The Df−LNP−C can be considered as an effective parameter to reflect the degree of development of microscopic pores in samples.

RETRACTED ARTICLE: Investigation of the structural properties and bioactivity of P2O5–CaO–Na2O–TiO2 glass and glass-ceramics synthesized via a novel sol–gel method by acetone and DMF solvents

Because of the significant effect of the sol–gel method on the glass morphology at the relatively low processing temperature, in the present work, phosphate glass and glass-ceramic nanopowders with the general formula of (P2O5)55–CaO)25–(Na2O)20−x–(TiO2)x, (x = 5, 10, and 15 mol%) have been synthesized via a facile sol–gel method. For this purpose, acetone and dimethylformamide (DMF) have been used as a polar and non-protic solvent. The proportion of triethylphosphate to acetone or DMF has been selected 1:3 that they have been synthesized at 25 °C and pH = 5–6. The glass powders have been dried at 315 °C. Then, the powders synthesized by acetone have been calcined at 500 and 750 °C, and the powders synthesized by DMF have been calcined at 550, 650, and 750 °C. The glass and glass-ceramic nanopowders have been analyzed by several techniques, X-ray powder diffraction (XRD), Differential thermal analysis (STA), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller and Barrett–Joyner–Halenda (BET–BJH), and Scanning electron microscopy (SEM-EDS). The XRD results have been confirmed the amorphous nature of all glass samples, while after calcination, the samples have been shown the peaks assigned to β-TCP and hydroxyapatite. The SEM images have shown that the synthesized glass and glass-ceramic powders by both acetone and DMF solvents have a particle size below 50 nm and spherical morphology. Also, the glass and glass-ceramic powders, after soaking in the simulated body fluid (SBF) for 7 days, depicted the formation of hydroxyapatite and carbonated-hydroxyapatite layer on the surface of the glass and glass-ceramic powders, respectively.