Differential Scanning Calorimetry Thermogravimetric Analysis Research Articles

Synthesis and study of optimization of amidoximated PAN‐DVB‐EGDMA beads for the sorption of uranium from aqueous media

Environmental and economic considerations have made the sorption of uranium from aqueous media a very time demanding area of research from last few decades. In this particular work, amidoximated polyacrylonitrile beads were synthesized by the reaction of hydroxyl amine hydrochloride (OH‐NH2.HCl) with macroporous crosslinked polyacrylonitrile beads, prepared through suspension polymerization techniques, using acrylonitrile (AN) as monomer and divinylbenzene and ethyleneglycoldimethacrylate as crosslinkers, in a variety of relative compositions, to modify suitably the hydrophilicity and physicochemical stability. These beads were also characterized by FT‐IR, scanning electron microscope, and thermogravimetric analysis–differential scanning calorimetry techniques to explain the morphology and chemical functionality. The beads reached its saturation capacity towards uranyl ions well within 1 h of equilibration at ~25°C, under near neutral pH conditions and the observed maximum sorption capacity was found to be ~18 mg g−1. The beads were also used for the sorption of uranium from various real water samples and showed good sorption from these samples. Reusability of the beads was also established up to the studied four cycles. These synthesized beads can potentially serve the dual purpose of the decontamination of uranium contaminated potable well water as well as to treat acidic radioactive waste generated in nuclear industry before final discharge to environment. POLYM. ENG. SCI., 59:863–872, 2019. © 2018 Society of Plastics Engineers

Unlock the Compact Structure of Lignocellulosic Biomass by Mild Ball Milling for Ethylene Glycol Production

Ball milling pretreatment was found to be an efficient method to promote the catalytic conversion of lignocellulosic biomass to ethylene glycol (EG). After 3–6 h ball milling of Miscanthus at 450 rpm, the EG yield reached about 52%, which is comparable to the result of pure cellulose conversion. The reasons of the promotion effect were investigated by characterizing the structure of biomass and the reaction residuals with X-ray diffraction, scanning electron microscopy, particle size distribution analyzer, contact angle measurement, thermogravimetric analysis-differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The mild ball milling liberated (hemi)cellulose from the compact plant tissues without affecting the crystallinity of cellulose. It reduced the size of biomass to 30 μm and improved the accessibility of (hemi)cellulose, leading to a hydrophilic surface and high energy state of biomass for catalytic conversion. During the catalytic conversion, the mass transfer between sugar intermediates and heterogeneous hydrogenation catalysts were improved. Correspondingly, the self-reaction of sugar intermediates, and the reactions between sugar intermediates and lignin fractions were suppressed, resulting in the high EG yield.

High Performance Acetylene Sensor with Heterostructure Based on WO₃ Nanolamellae/Reduced Graphene Oxide (rGO) Nanosheets Operating at Low Temperature.

The development of functionalized metal oxide/reduced graphene oxide (rGO) hybrid nanocomposites concerning power equipment failure diagnosis is one of the most recent topics. In this work, WO3 nanolamellae/reduced graphene oxide (rGO) nanocomposites with different contents of GO (0.5 wt %, 1 wt %, 2 wt %, 4 wt %) were synthesized via controlled hydrothermal method. X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analyses-derivative thermogravimetric analysis-differential scanning calorimetry (TG-DTG-DSC), BET, and photoluminescence (PL) spectroscopy were utilized to investigate morphological characterizations of prepared gas sensing materials and indicated that high quality WO3 nanolamellae were widely distributed among graphene sheets. Experimental ceramic planar gas sensors composing of interdigitated alumina substrates, Au electrodes, and RuO2 heating layer were coated with WO3 nanolamellae/reduced graphene oxide (rGO) films by spin-coating technique and then tested for gas sensing towards multi-concentrations of acetylene (C2H2) gases in a carrier gas with operating temperature ranging from 50 °C to 400 °C. Among four contents of prepared samples, sensing materials with 1 wt % GO nanocomposite exhibited the best C2H2 sensing performance with lower optimal working temperature (150 °C), higher sensor response (15.0 toward 50 ppm), faster response-recovery time (52 s and 27 s), lower detection limitation (1.3 ppm), long-term stability, and excellent repeatability. The gas sensing mechanism for enhanced sensing performance of nanocomposite is possibly attributed to the formation of p-n heterojunction and the active interaction between WO3 nanolamellae and rGO sheets. Besides, the introduction of rGO nanosheets leads to the impurity of synthesized materials, which creates more defects and promotes larger specific area for gas adsorption, outstanding conductivity, and faster carrier transport. The superior gas sensing properties of WO3/rGO based gas sensor may contribute to the development of a high-performance ppm-level gas sensor for the online monitoring of dissolved C2H2 gas in large-scale transformer oil.

Fabrication of Bifunctional Chitosan-Based Flocculants: Characterization, Assessment of Flocculation, and Sterilization Performance.

In this study, a series of chitosan-based quaternary ammonium graft flocculants, namely chitosan-graft-poly(acrylamide and methacryloyl ethyl trimethyl ammonium chloride) [CTS-g-P(AM-DMC)], was successfully synthesized by plasma initiation, and the as-prepared [CTS-g-P(AM-DMC)] had both flocculation and sterilization functions. Various characterization techniques were used to study the structure and physicochemical properties of the chitosan-based flocculants. 1H nuclear magnetic resonance spectroscopy (1H NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), and thermogravimetric analysis/differential scanning calorimetry (TG/DSC) confirmed the successful synthesis of CTS-g-P(AM-DMC). Scanning electron microscopy (SEM) analysis exhibited that CTS-g-P(AM-DMC) contained a smooth convex and porous structure with an enormous surface area. CTS-g-P(AM-DMC) was then used to flocculate the simulated wastewater of the kaolin suspension and the Salmonella suspension. Besides external factors, such as the dosage of flocculant and pH, the effect of the internal factor graft ratio was also evaluated. The experimental results showed that CTS-g-P(AM-DMC) also revealed a strong sterilization effect, aside from the excellent flocculation effect. Moreover, the sterilization mechanism was investigated through a series of conductivity measurements and the analysis of fluorescence-based cell live/dead tests. The results indicated that CTS-g-P(AM-DMC) destroyed the cell membrane of Salmonella through its grafted quaternary ammonium salt, thereby exhibiting sterilization property.

Thermal decomposition behavior of nickel-iron hydrotalcite and its electrocatalytic properties of oxygen reduction and oxygen evolution reactions

The thermal decomposition behavior of NiFe layered double hydroxide (LDH) was investigated by thermogravimetric analysis-differential scanning calorimetry (TG-DSC). The calcined product at 500 °C was mainly NiO/FeOx composite oxide, of which FeOx was amorphous oxide; the calcined product at 650 °C was mainly NiO/NiFe2O4 composite oxide. The polarization curves and chronopotentiometry stated that the NiO/FeOx and NiO/NiFe2O4 showed good electrocatalytic OER and ORR activity; the OER activity of NiO/FeOx was better than that of NiO/NiFe2O4; the ORR activity of NiO/NiFe2O4 was better than that of NiO/FeOx.

Sacrificial template-based synthetic approach of polypyrrole hollow fibers for photothermal therapy

In the present work, polypyrrole hollow fibers (PPy-HFs) were fabricated by sacrificial removal of soft templates of electrospun polycaprolactone (PCL) fibers with polypyrrole (PPy) coating through chemical polymerization of pyrrole monomer. Different physicochemical properties of as-fabricated PPy-HFs were then studied by Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infra-red (FT-IR) spectroscopy, Differential scanning calorimetry/Thermogravimetric analysis (DSC/TGA), and X-ray photoelectron spectroscopy (XPS). The photothermal activity of PPy-HF was studied by irradiating 808-nm near infra-red (NIR) light under different power values with various concentrations of PPy-HFs dispersed in phosphate buffer solution (PBS, pH 7.4). These PPy-HFs exhibited enhanced photothermal performance compared with polypyrrole nanoparticles (PPy-NPs). Furthermore, these PPy-HFs showed photothermal effect that was laser-power- and concentration-dependent. The photothermal toxicity of the resulting nanofiber was evaluated using cell counting kit-8 (CCK-8) and live and dead cell assays. Results showed that these PPy-HFs were more effective in killing cancer cells under NIR irradiation. In contrast, hollow-fiber showed no cytotoxicity without NIR exposure. Among different nanofiber formulations, PPy-160 exhibited the highest photothermal toxicity. It could be explained by its enhanced photothermal performance compared to other specimens. The resulting PPy-HFs showed superior drug-loading capacity to PPy-NPs. This might be attributed to adequate binding of the drug into both luminal and abluminal hollow-fiber surfaces. Fabrication of this substrate type opens a promising new avenue for architectural design of biocompatible organic polymer for biomedical field.

A Series of Octahedral First-Row Transition-Metal Ion Complexes Templated by Wells-Dawson Polyoxometalates: Synthesis, Crystal Structure, Spectroscopic, and Thermal Characterizations, and Electrochemical Properties.

Three Wells-Dawson polyoxotungstates-based hybrid compounds of general formula [M(C3H7NO)6][{M(C3H7NO)5}2(μ-P2W18O62)]· nC3H7NO· n'H2O [with M = MnII (1), FeII (2), CoII (3) ; n = 2, 2, 3 and n' = 0, 0, 1, respectively] were synthesized at room temperature by a facile method and characterized by IR and 1H and 31P NMR spectroscopy studies, thermogravimetric analysis-differential scanning calorimetry thermal analyses, UV-vis, X-ray diffraction (XRD) powder and single-crystal XRD analyses, and cyclic voltammetry studies. From the X-ray study, it was established that the metal (M = Mn, Fe, Co) is located on an inversion center, being octahedrally coordinated to six dimethylformamide (DMF) molecules to form the complex cation [M(dmf)6]2+. Also, in the dinuclear complex anion [{M(dmf)5}2(μ-P2W18O62)]2-, the M atoms are coordinated to five DMF molecules through the oxygen atoms, while the sixth coordination site is occupied by a terminal oxygen atom of the Wells-Dawson anion [P2W18O62]6- that plays the role of a bridging ligand. The crystal components are connected through numerous weak C-H···O hydrogen bonds to construct a three-dimensional network. The UV-vis shows the two characteristic absorption bands for the three compounds at 266-268 and 297 nm. These two strong bands are attributed to the charge-transfer absorption band of Ot-W and Ob/c-W, respectively. Cyclic voltammetry study of compounds (1), (2), and (3) reveals at least two reduction reversible peaks ascribed to a Wells-Dawson cluster.

Mechanical reinforced fiber needle felt/silica aerogel composite with its flammability

Fiber needle felt–silica aerogel composite was successfully prepared by via sol–gel process based on water glass. The thermal conductivity show V-type variation tendency with the increase of water to Si. Thermogravimetric analysis-differential scanning calorimetry analysis revealed that the thermal stability was up to approximately 390.58 °C. It has been found that the fire hazard of the composites decreased with the increased ratio of water to Si according to the cone calorimeter test, which can be characterized by peak heat release rate, fire performance index, and fire growth rate index. The fiber needle felt/aerogels present greatly improved compressive and flexural strength (elastic modulus: 0.1–0.97 MPa; flexural modulus: 0.33–0.66 MPa) while keeping inherent properties of pure silica aerogel: low bulk density (0.166 g/cm3), low thermal conductivity of 0.0236 W/m·K, and high specific surface area (1091.62 m2/g). As a result, the as-prepared composite shows a great potential to be applied in the thermal insulation field.

Moderate thermal oxidation of iron oxide found in nature as raw materials for ferrite magnets

Iron oxide found in nature with high iron oxide content has potential to be utilized as raw material for magnetic application. In this study, an attempt has been made to increase hematite content through thermal oxidation or roasting in moderate temperature with additional oxygen gas to accommodate oxidation. Iron oxide powders were milled in 6 hours then washed and dried. Roasting processwere performed at four varying temperatures of 480°C, 520°C, 560°C, and 600°C with oxygen influx 3L min-1, preceded by isothermal holding at 385°C. TGA-DSC (thermogravimetric analysis – differential scanning calorimetry) and XRD (X-Ray Diffraction) characterization has been performed to understand iron oxide behavior in response to thermal oxidation at moderate temperature. It is observed that two main reactions are clearly distinguished. In DTG curve, first peak indicate reduction followed by oxidation at the second peak. XRD results has shown that the highest content of α Fe2O3 was achieved by roasting at 600 °C for 1 hour which produced hematite portion of 31 wt. %, yet it is still insufficient to be utilized as raw material for ferrite based magnets fabrication. To prevent reduction reaction of Fe3O4 which will retard the oxidation process, it is suggested to avoid isothermal run or lower heating rate at temperature below 406°C

Poly (Butylene Succinate)‐g‐Poly(Hydroxypropyl Methacrylate) as a New Meloxican Delivery System

The use of biopolymer‐based drug delivery systems is increasing in the pharmaceutical area due to them biodegradable and biocompatible properties. In this work, a poly (butylene succinate) (PBS) grafted with poly (hydroxypropyl methacrylate) (PHPMA), PBSgPHPMA, is prepared using maleic unsaturations inserted in the PBS chain during its synthesis. Several characterization techniques are used to study the homopolymers and the grafted material. Among them, Fourier Transform Infrared (FTIR), Thermogravimetric analysis (TGA) Differential scanning calorimetry (DSC), and X‐ray diffraction (XRD) allowed inferring the obtaining of the aimed materials. Also, the copolymer is used to prepare microparticles containing Meloxicam by emulsification and solvent evaporation method. These microparticles are tested as drug delivery systems under pH 8.5 (gastrointestinal) and pH 5.5 (skin). The primary results allowed inferring that the grafted material can be used as a drug delivery system, showing that the release rate at pH 5.5 allowed the slower delivery rate among tested materials.

Exploring a solvated dimer of Gefitinib: a quantitative analysis.

Gefitinib or Iressa is an orally administered anilinoquinazoline used in cancer chemotherapy for the treatment of lung and breast cancer. It is reported to exist in two polymorphic forms, a stable form I and a metastable form II. Both of the forms belong to the triclinic P-1 space group. In this work, we report the crystallization of Gefitinib to form a methanol solvate [systematic name: N-(3-chloro-4-fluorophenyl)-7-methoxy-6-[3-(morpholin-4-yl)propoxy]quinazolin-4-amine methanol hemisolvate, C22H24ClFN4O3·0.5CH3OH] that was theoretically and experimentally investigated. The unit cell is composed of two independent Gefitinib molecules (A and B) that form a stable molecular complex with methanol in the crystal lattice. To understand the crystal lattice stabilization, a combination of techniques, namely X-ray diffraction, IR spectroscopy, thermogravimetric/differential scanning calorimetry (TG-DSC), Hirshfeld surface analysis and CLP-PIXEL methods were used. The analysis of the crystal structure of this dimer revealed a three-dimensional isostructurality with the already reported form II. The A and B molecules are connected via trifurcated C-H...O and N-H...O hydrogen bonding. In addition, the presence of the methanol molecule stabilizes the crystal structure via C-H...O, N-H...O and C-H...Cl interactions between the two monomers. The IR analysis of the dimer has shown characteristic fingerprint values when compared to the commercial form. The TG-DSC analysis of the solvated dimer is in good agreement with the patent reporting cocrystals of Gefitinib. Finally, theoretical calculations by the CLP-PIXEL method and Hirshfeld surface and two-dimensional (2D) fingerprint plot analysis were carried out in order to quantify the different intermolecular interactions and their energies in the crystal packing.

Compositional and Structural Evolutions of Zn-Based Metal–Organic Frameworks During Pyrolysis

Metal–organic framework (MOF)-derived nanostructures for electrochemical applications have attracted tremendous attention; therefore, understanding of the decomposition mechanism of MOFs during thermal treatment is crucial for the design and synthesis of MOF-derived nanomaterials. Here, a systematic investigation was carried out to study the pyrolysis process of a Zn-based metal–organic framework (Zn-MOF), which revealed the compositional and structural evolution by in situ diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis–differential scanning calorimetry, and X-ray diffraction methods. The continuous change of the nature of surface of pyrolytic Zn-MOF at different temperatures was also studied by the cyclic voltammetry method, described by the fractal concept of electrochemical surface. The results show that the pyrolysis of Zn-MOF occurs at ca. 450 °C and the decomposition products are amorphous carbon and ZnO. The pyrolysis temperature plays a decisive role in the...

Enhanced catalytic properties of Cu-based composites for NOx reduction with coexistence and intergrowth effect

Cu-based composites were prepared by a facile preparation method and were employed as reactive catalysts for the elimination of NOx. The characterizations of XRD (X-Ray Diffraction), BET (Brunauer-Emmet-Teller), LRS (Laser Raman Spectra), H2-TPR (H2-Temperature-Program-Reduction), TGA-DSC (Thermo Gravimetric Analyzer-Differential Scanning Calorimetry), ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectroscopy), HRTEM (High Resolution Transmission Electron Microscope), O2-TPD (O2-Temperature-Program-Desorption) and in situ FT-IR (in situ Fourier Transform Infrared Spectroscopy) show the formation of CuAl2O4 spinel during the calcination process and the coexistence and intergrowth effect among three-phases CuO-CuAl2O4-CeO2, promoting the increase of the amount of surface active sites. These results further present that the composite CCA800 exhibits the best catalytic performance in the elimination of NOx, completely converting NO to N2 at only 220 °C, which exhibits more excellent catalytic properties than the same type of Cu/Ce/Al catalysts applied in the field of the elimination of NOx. The coexistence and intergrowth effect among three-phases CuO-CuAl2O4-CeO2 greatly promotes the catalytic performance in the elimination of NOx.

Dehydration Study of Piracetam Co-Crystal Hydrates

A hydrate of co-crystal of piracetam and 3,5-dihydroxybenzoic acid was obtained via crystallization from water. Single-crystal X-ray data show that piracetam/3,5-dihydroxybenzoic acid tetrahydrate (P35TH) crystallizes in the triclinic system with a P1 space group. The physicochemical properties of co-crystal hydrate were characterized using powder X-ray diffractometry, differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA), and FTIR spectroscopy. The dehydration kinetics of P35TH was monitored at various temperatures and heating rates by DSC and TGA. Activation energy of P35TH dehydration was obtained using temperature ramp DSC, isothermal and nonisothermal TGA methods. Kinetic analysis of isothermal TGA data was fitted to various solid-state reaction models. Mechanistic models derived from isothermal dehydration kinetic data are best described as a 2-dimensional diffusion mechanism. A correlation was noted between the dehydration behavior and the bonding environment of the water molecules in the crystal structure. This study is a good demonstration of complexity of co-crystal hydrate and their dehydration behavior.

Preparation of a monodisperse poly (N-phenylmaleimide–acrylonitrile–styrene) structural nanolatex for heat-resistant modification of PVC

A monodisperse poly ( N-phenylmaleimide–acrylonitrile–styrene) (PNAS) nanolatex was synthesized via seed microemulsion polymerization. The obtained PNAS nanolatex was then directly used as an organic nanofiller to prepare polyvinyl chloride (PVC)/PNAS hybrid composite through water blending and melt compounding. The characteristics of PNAS nanolatex were analyzed by Fourier transform infrared (FTIR) spectrometer, elemental analysis, scanning electron microscope, transmission electron microscope (TEM), dynamic laser lighting scattering (DLS), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA). FTIR and elemental analysis confirmed the formation of PNAS copolymer with high monomers conversion; meanwhile, for the PNAS nanoparticles, the morphology of a well-defined core–shell spherical structure with average diameter ranging from 156 nm to 249 nm was observed. DSC analysis and TGA indicated that both polymers had excellent compatibility, and the corresponding heat resistance of PVC was greatly improved with the addition of PNAS. When PNAS loading was 50 wt%, the glass transition temperature value of PVC/PNAS hybrid composite was increased by 22.4°C, compared with that of pristine PVC. The mechanical properties of the PVC composite were also enhanced with the addition of PNAS.

Experimental study on thermo-responsive inhibitors inhibiting coal spontaneous combustion

Due to its strong fluidity and easy evaporation characteristic, high water-cut physical inhibitors (HWPIs) cause the decrease in moisture content of coal, so that its inhibitory effect on coal spontaneous combustion weakens or even fails. Aiming at solving the problem, this paper proposes to inhibit coal spontaneous combustion using thermo-responsive inhibitors (TRIs). These inhibitors are sensitive to specific temperatures and can retain their effects as long as the temperatures have not been reached. Besides, when the temperatures are reached, they are able to absorb heat and undergo physical and chemical changes to release H2O and inert gases (defined as gases that are not involved into the coal oxidation reaction in this paper) such as NH3 and CO2, so as to inhibit the low-temperature oxidation of coal. Based on the temperature-programmed experiment of coal spontaneous combustion, this paper analyzed the effects of types and amounts of TRIs on coal spontaneous combustion by using differential scanning calorimetry (DSC), scanning electron microscope (SEM), thermogravimetry-derivative thermogravimetric analysis-differential scanning calorimetry (TG-DTG-DSC) and nitrogen adsorption test methods. The results show that CaCl2•6H2O achieves the most stable inhibitory effect, as its inhibiting rate rises steadily in the heating process to reach a maximum value of 79.9% at 200 °C.

Formation of AgI/Ag3PO4 solid solution on alumina for enhancing radioactive iodine adsorption at high temperatures

Radioiodine-131 is one of the pernicious radionuclides released during nuclear accidents, as its radioactivity can potentially affect public health and safety. To prevent radioiodine-131 from being released into the environment, the use of adsorbents that are highly efficient at high temperatures is significantly important. The radioactive gas from the nuclear core in an accident, such as the Fukushima nuclear accident, is usually released occurs under high-temperature conditions. Therefore, in this study, a 10 wt% silver phosphate-loaded alumina (Ag3PO4/Al2O3) adsorbent was prepared. Further, its performance toward radioiodine adsorption was tested at high temperatures up to 750 °C, using Al2O3 and traditional 10 wt% Ag/Al2O3 adsorbent as controls. The results of the iodine adsorption test indicated that the 10 wt% Ag3PO4/Al2O3 adsorbent showed a higher decontamination factor than did the 10 wt% Ag/Al2O3 adsorbent by two orders of magnitude at 650 and 750 °C. Results of the iodine desorption test revealed that the new adsorbent could be effectively used at 750 °C. The characteristic powder X-ray diffraction, nitrogen adsorption–desorption isotherm, X-ray photoelectron spectroscopy, and thermogravimetric analysis–differential scanning calorimetry data indicated that the enhanced adsorption ability at high temperatures was attributed to the formation of a solid solution between silver iodide and Ag3PO4.

Nanofibers of cellulose bagasse from Agave tequilana Weber var. azul by electrospinning: preparation and characterization

In this study, cellulose of bagasse from Agave tequilana Weber var. azul was extracted to elaborate nanofibers by the electrospinning technique. Fiber characterization was performed using Transmission Electron Microscopy (TEM), x-ray, Fournier Transform-InfraRed (FT-IR) spectroscopy, and thermal analysis by Differential Scanning Calorimetry-Thermogravimetric Analysis (DSC-TGA). Different diameters (ranging from 54.57 ± 0.02 to 171 ± 0.01 nm) of nanofibers were obtained. Cellulose nanofibers were analyzed by means of x-ray diffraction, where we observed a total loss of crystallinity in comparison with the cellulose, while FT-IR spectroscopy revealed that the hemicellulose and lignin present in the agave bagasse were removed. Thermal analysis showed that nanofibers exhibit enhanced thermal properties, and the zeta potential value (−32.5 mV) demonstrated moderate stability in the sample. In conclusion, the nanofibers obtained provide other alternatives-of-use for this agro-industrial residue and could have potential in various industrial applications, among these encapsulation of bioactive compounds and reinforcing material, to mention a few.

A facile and green method for the synthesis of hierarchical ZSM-5 zeolite aggregates from rice husk ash

Hierarchical ZSM-5 zeolite has been successfully synthesized from rice husk ash by a facile and solvent-free method. The obtained samples were characterized by X-ray diffraction, X-ray fluorescence, scanning electron microscopy, magic angle spinning nuclear magnetic resonance, X-ray photoelectron spectroscopy, ultraviolet raman spectroscopy, thermogravimetric analysis–differential scanning calorimetry, Brunauer–Emmett–Teller (BET) analysis and temperature-programmed desorption of ammonia. The influences of synthesis time on ZSM-5 crystal growth and ZSM-5 zeolite properties were evaluated. The results suggested that the ZSM-5 synthesis process was solid-phase conversion and the crystallization was accomplished within 72 h at 150 °C. The Si, Al and Fe are tetrahedral coordinated and minute quantities of non-framework octahedral coordinated aluminium exist in synthetic ZSM-5, and it has weak and strong acid sites. The resultant ZSM-5 aggregates exhibited well-defined crystallinity and porosity, and possessed micro-/mesoporous structures. The BET surface area of the synthetic ZSM-5 zeolite was 308.41 m2/g, slightly less than that synthesized from a hydrothermal approach (320.69 m2/g). Moreover, this hierarchically porous ZSM-5 zeolite show a high-hierarchy factor up to 0.18. The proposed synthetic route in this work provides novel green alternative for the synthesis of hierarchical ZSM-5 zeolite from rice husk ash.

Microstructure, morphology, and methylene blue degradation over nano-CuFe2O4 synthesized by a modified complexometric method

Nanodimensional copper ferrite has been successfully synthesized via a modified complexometric method using ethylenediaminetetraacetic acid and citric acid as the complexing agent and the fuel, respectively. The physical and chemical behaviors of this spinel ferrite material have been explored by using different kinds of techniques including thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), high-resolution transmission electron microscopy (HR-TEM), vibrating sample magnetometry (VSM), and N2 adsorption–desorption isotherm. The crystallite size falls in the range 13–30 nm depending on the calcination temperature required for phase formation. The surface morphology of the polycrystalline ferrite material is almost spherical. The band gap value and BET-specific surface area are determined to be 1.40 eV and 32 m2 g−1, respectively. This spinel ferrite behaves as a mesoporous (2–50 nm) material, and the material formed at a higher calcination temperature has agglomeration tendency. The CuFe2O4 exhibits typical soft ferromagnetic behavior with saturation magnetization value of 52 emu g−1. Of interest, it has the capability to degrade 96% of methylene blue in acidic medium (pH = 4) in 45 min under the visible light in presence of H2O2 as oxidant.