Average Crystal Size Research Articles

Processing of new efficient Cr1-xNaxO3 catalysts for sodium borohydride methanolysis

This study reports the development of a novel Cr1-xNaxO3 catalyst using a simple cost-effective method for hydrogen production from NaBH4 methanolysis. The properties of the nanocomposites were investigated by employing XRD, FTIR, SEM and XPS characterization techniques. The XRD diffraction peaks confirmed the rhombohedral crystal structure of Cr1.xNaxO3 nanoparticles. The average crystal size of these nanoparticles was found to be ranging from 25.0 to 20 nm. FTIR analysis showed the characteristic absorption bands of Cr1.xNaxO3 nanoparticles. The SEM images of Cr2O3 and Cr1.7Na0.3O3 demonstrated that the nanoparticles are irregular in shape, while Cr1.4Na0.6O3 has a porous surface texture. XPS spectra of Cr2O3, Cr1.7Na0.3O3 and Cr1.4Na0.6O3 confirmed the presence of chromium, oxygen, and sodium in the samples. The optical band gaps of Cr2O3 Cr1.7Na0.3O3 and Cr1.4Na0.6O3 nanoparticles were approximately 3.28 eV, 1.61 and 0.81 eV, respectively. Cr1.4Na0.6O3 exhibited the most significant level of activity in terms of hydrogen production of 19144 mL/g.min.

Rapid Electrochemical Investigation of Gemfibrozil Using NiONPs/Multiwalled Carbon Nanotube Modified Carbon Paste Electrode: Analysis of Human Urine Sample and Antimicrobial Activity

AbstractIn this study, nickel oxide nanoparticles (NiONPs) were produced by the co‐precipitation method and characterized by scanning electron microscopy, X‐ray diffraction (XRD), Fourier transform‐infrared and Ultraviolet‐visible spectroscopy. XRD analysis showed an average crystal size of 6 nm, while SEM analysis exemplified the oblong form with a particle size of 12 nm. As‐prepared NiONPs were combined with multiwalled carbon nanotubes (MWCNTs) and graphite powder to prepare NiONPs‐MWCNTs modified carbon paste electrode (MCPE). The fabricated NiONPs‐MWCNTsMCPE sensor was used to analyze Gemfibrozil (GEM) in pharmaceutical formulations. Electrochemical methods such as cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy employed in sensor characterization and electroanalysis of GEM. The sensor exhibited excellent electrochemical behavior towards GEM. It showed a lower limit of detection (LOD, 2.7×10−8 M), the limit of quantification (LOQ, 9.07×10−8 M), higher sensitivity, higher linear range, and long‐term stability compared to the reported methods. The NiONPs‐MWCNTsMCPE sensor was evaluated for practical application by performing spiking tests in pharmaceutical formulations and human urine samples, demonstrating significant recovery, high effectiveness, and accuracy. Further, nanoparticles manifested promising antibacterial action against Staphylococcus aureus, E. coli, Klebsiella aerogenes, Pseudomonas aeruginosa, and Klebsiella aerogenes.

Unveiling the effect of Nb and Zr additions on microstructure and properties of β Ti-25Ta alloys for biomedical applications

This study aims to analyze the influence of niobium and zirconium in the structure, microstructure, and mechanical properties of quaternary Ti-25Ta-Zr-Nb alloys system: Ti-25Ta, Ti-25Ta-10Zr-15Nb, and Ti-25Ta-20Zr-30Nb (wt%). The structural and microstructural analyses were performed using X-ray diffraction, as well as optical, scanning and transmission electron microscopy. Rietveld method was used for calculating the volume fractions of crystalline phases and values of β lattice parameters. Williamson-Hall's equation calculated the micro-strain and average size of the β-phase crystallite. The mechanical properties were analyzed by microhardness and Young's modulus measurements. The results show that the different heat treatments influence the structure of the materials and the mechanical properties: Rapid cooling treatments induced the formation of α″ and β for Ti-25Ta-10Zr-15Nb (TTZN1), while the treatments with slow cooling induced the formation of α phases. The Ti-25Ta-20Zr-30Nb (TTZN2) alloy is a stable β, so heat treatments could not change the crystalline structure. To Ti-25Ta alloy, in all study conditions, the alloy has α + α″ phases. Regarding the lattice parameters, adding niobium to the alloys increased the lattice parameter of the β phase. Concerning the β phase micro-strain and average crystal size, the heat treatments increased the average size and micro-strain due to the crystallization of the crystals. β-Ti alloys in the solubilized heat treatment condition, followed by rapid cooling, showed better mechanical biocompatibility results due to the low elastic modulus, highlighting the metastable β Ti-25Ta-10Zr-15Nb alloy, which showed a low elastic modulus of 50 GPa.

Influence Annealing Process on Structural and Optical Properties of SnS Thin Films

Thin film technology has helped offer an understanding of the crystalline structure of substances, further to the characteristics of electronic transitions and how they are used effectively in different applications. This research focused on the effect of the process of annealing on the structural and optical characteristics of tin sulfide (SnS) thin films. The technique of thermal evaporation was used to synthesize the film samples under a vacuum of about 10–7 mbar. The coated SnS thin films were annealed at 200 °C and the structural and optical characteristics parameters, such as absorbance and transmittance, as well as optical bandgap and band-tail energies in the range )300–1150( nm, were discussed. Under the influence of the annealing process, the average crystal size changed from 14 nm to 11 nm. The energy gap value increased from 1.53 eV to 1.85 eV, while Urbach energy was seen to reduce from 0.913 eV for fabricated samples to be 0.824 eV after the annealing process.

Impact of the Sc3+/In3+ co-substitution on the structural, magnetic, and microwave characteristics of Co0.5Ni0.5Fe2O4 nanospinel ferrites

In this article, In3+ and Sc3+ ions dual-substituted NiCo nanospinel ferrites (ScIn→CoNiFe2O4 NSFs) have been synthesized through citrate-gel auto combustion method to investigate the effect of In3+ and Sc3+ ions on magnetic, and microwave characteristics. The following techniques TEM, SEM, EDX, and XRD were applied to characterize surface morphology, chemical composition, phase identification, and crystallinity of products, respectively. The XRD verified a phase formation of spinel structure with a minor amount of Sc2O3 was observed for products having x ≥ 0.04. The average crystal size (DXRD) of the products was estimated within the 33–68 nm range using the Scherrer equation. SEM and HR-TEM analyses exhibited accumulating sphere-shaped particles. By fitting the room-temperature spectra obtained from Mössbauer spectroscopy (Moss), Hyperfine interactions were determined. The cation distribution shows that there is a migration of In3+ ions in the lattice in an A→B direction with increasing concentrations while the B site is preferred by the larger Sc+3. M−H plots for 300 and 10 K illustrated all products carried out with a ferrimagnetic character. An enhancement in saturation magnetization (Ms) was remarked with Sc–In doping ratio up to 0.04 and thereafter a drop as the Sc–In concentration increased. The tendency in Ms values might be described by correlating it to the cation distribution amongst Oh and Td (octahedral and tetrahedral, respectively) sublattices. Temperature-dependent magnetization measurements were also investigated, which further confirmed the maintenance of the ferrimagnetic character throughout the temperature range 10–300 K. The peculiarities of the microwave properties have been analyzed by the measured S-parameters in the range of 6–18 GHz. It was assumed that the energy losses due to reflection are a combination of electrical and magnetic losses due to polarization processes and magnetization reversal processes in the region of inter-resonant processes. The average value of the reflection coefficient is −14.48 … −14.24 dB. A significant attenuation of the reflected wave energy opens up broad prospects for practical applications as coatings for providing electromagnetic compatibility.

Reduction of graphene oxide (GO) to reduced graphene oxide (rGO) at different hydrothermal temperatures and enhanced photodegradation of zinc oxide/rGO composites

Scholars are shifting their attention to the development of environmentally friendly materials with a high degradability of environmental pollutants. Among various photocatalytic materials, zinc oxide (ZnO)/reduced graphene oxide (rGO) nanomaterials can meet these requirements. In this study, ZnO/rGO nanomaterials with different hydrothermal temperatures were fabricated through a hydrothermal method. We determined the hydrothermal temperature variations to create different structures and identify the morphologies and sizes of the ZnO/rGO material. The average crystal size of ZnO/rGO nanomaterials decreased from 32.25 nm to 30.30 nm when the hydrothermal temperature was increased from 100 °C to 180 °C. The detailed x-ray diffraction (XRD) study showed that the diffraction peak position of ZnO decreased, the lattice constant increased, and the unit cell volume increased with the increase in hydrothermal temperature. rGO-related diffraction peaks were also observed in the XRD patterns of ZnO/rGO samples, which indicates the formation of a ZnO/rGO crystalline structure. Fourier transform infrared spectra revealed the chemical bonding of ZnO and rGO materials. The photoluminescence (PL) spectra of ZnO/rGO nanocomposites presented two characteristic emission peaks at 383 and 558 nm. The Raman scattering spectra of ZnO/rGO nanomaterials exhibited ZnO-related peaks at 329, 436, and 1123 cm−1 and rGO-related peaks at 1352, 1579, 2706, and 2936 cm−1. The ultraviolet-visible (Vis) absorption spectra of ZnO/rGO nanomaterials manifested the characteristic absorption peaks of ZnO and rGO at 381 and 291 nm, respectively. The photocatalytic properties of ZnO/rGO nanomaterials were studied through the decomposition of methylene blue (MB) under Vis light. The effect of hydrothermal temperature on the properties of ZnO/rGO materials and the photodecomposition mechanism of MB were investigated in detail.

Studying the structural, optical, and electrical characteristics of Zn2SnO4 films using a direct current magnetron sputtering method

In this study, the characteristics of ZTO films are examined by varying the substrate temperature at an Ar ambient pressure of 3 × 10−3 Torr. The elemental content of Zn, Sn, and O in the generated Zn2SnO4 films was confirmed using X-ray dispersive and X-ray photoelectron spectroscopy. The result reveals that the Zn/Sn ratio for the film formed at 300 °C reaches 2. The (222) and (311) lattice planes validated the cubic inverse spinel structure of ZTO films in the X-ray diffraction investigation. Atomic force microscopy was used to measure surface roughness, and the RMS rose in a range of 1.34–4.79 nm as the substrate temperature increased. Field-emission scanning electron microscopy revealed that the average crystal grain size grew in the region of 60–95 nm as the substrate temperature increased. The UV–vis absorption edge shift validates the Burstein-Moss shift rule, with a bandgap of ZTO-300 achieving the greatest value of 3.75 eV, corresponding to the largest carrier concentration. Electrical characteristics were investigated using Hall measurements. Film conductivity was primarily determined by the electron concentration or the presence of oxygen vacancies. The lowest resistivity measured was 5.4 × 10−3 Ω cm, which corresponded to an electron concentration of 8.57 × 1019 cm−3. The current-voltage characteristics of the ZTO/p-Si junction proved its rectifiable quality. Because of the low resistivity of the ZTO-300 sample, the ZTO-300/p-Si heterojunction has the largest photocurrent (4.72 10−3 A), making it suitable for use in optoelectronic devices.

Harnessing the Power of Sn-Doped ZnO Rice-Shaped Nanomaterials for Microbial Defense

Hydrothermally synthesized Sn-doped ZnO nanorices underwent comprehensive characterization, encompassing structural, morphological, compositional, optical, and vibrational features using advanced techniques. Field Emission Scanning Electron Microscopy (FESEM) revealed nanorices with dimensions 0.5—0.9 μm length and 80—150 nm width and distinctive morphology, displaying tapered or pointed ends, flower-like agglomeration, and a textured surface. X-ray Diffraction (XRD) confirmed the wurtzite hexagonal phase, and the Debye-Scherer equation estimated an average crystal size of 9.17 nm. Antibacterial assessment against Bacillus cereus exhibited a notable dose-dependent effect, with substantial zones of inhibition (ZOI) at 90 μg/mL, comparable to standard antibiotics like Ciprofloxacin. Antifungal evaluation against Candida albicans demonstrated a dosedependent trend, indicating a potent hindrance of fungal growth at higher concentrations. Comparative analysis against the standard antifungal agent, Itraconazole, revealed a marginally superior antimicrobial effect of Sn-doped ZnO nanorices at the highest concentration tested. The nanorices exhibited comparable or superior efficacy compared to standard drugs, highlighting their potential as effective and tailored antimicrobial agents.

Goethite (α-FeOOH) nanoparticles wrapped on reduced graphene oxide nanosheet for sensitive electrochemical detection of arsenic(III)

The goethite (α-FeOOH) nanoparticles were wrapped on the reduced graphene oxide (rGO) to synthesize the α-FeOOH/rGO nanocomposites. The nanocomposites (NCs) were initially examined for their optical, structural, and morphological properties. The XRD data obtained the crystallite size of the α-FeOOH, showed that the average crystal size for pristine α-FeOOH and α-FeOOH/rGO nanocomposites were about 85 and 90 nm, respectively. The transmission electron microscope confirmed the nanoparticles (NPs) were evenly distributed throughout the reduced graphene oxide sheets. The nanocomposites improved glassy carbon electrodes (GCE), making them efficient sensors for detecting the arsenic(III) (As+3) in a pH 5 phosphate buffer solution with an Ag/AgCl reference electrode. The detection limit for As+3 was 0.07 μgL−1 and the resulting sensitivity was 0.39 μA−1 μgL−1 in the linear dynamic range of 0.1–10 μgL−1. The α-FeOOH/rGO/GCE was more sensitive than its original and showed a synergistic effect due to the influence of α-FeOOH on the properties of rGO. The α-FeOOH/rGO NCs-modified GCE electrode performed as a promising sensor, by separating the common interfering ions. Moreover, the modified electrode exhibited remarkable stability, repeatability, and potential real-time application towards the detection of arsenic(III). Additionally, the proposed approach has been successfully applied to the detection of As+3 in the real water sample.

Ni-BaMnO3 Perovskite Catalysts for NOx-Assisted Soot Oxidation: Analyzing the Effect of the Nickel Addition Method

In this study, we analyzed the role of a series of BaMn1−xNixO3 (x = 0, 0.2, and 0.4) mixed oxide catalysts, synthesized using the sol–gel method, in NOx-assisted diesel soot oxidation. ICP-OES, XRD, XPS, and H2-TPR techniques were used for characterization and Temperature-Programmed Reaction experiments (NOx-TPR and Soot-NOx-TPR), and isothermal reactions at 450 °C (for the most active sample) were carried out to determine the catalytic activity. All samples catalyzed NO and soot oxidation at temperatures below 400 °C, presenting nickel-containing catalysts with the highest soot conversion and selectivity to CO2. However, the nickel content did not significantly modify the catalytic performance, and in order to improve it, two catalysts (5 wt % in Ni) were synthesized via the hydrothermal method (BMN2H) and the impregnation of nickel on a BaMnO3 perovskite as support (M5). The two samples presented higher activity for NO and soot oxidation than BMN2E (obtained via the sol–gel method) as they presented more nickel on the surface (as determined via XPS). BMN2H was more active than M5 as it presented (i) more surface oxygen vacancies, which are active sites for oxidation reactions; (ii) improved redox properties; and (iii) a lower average crystal size for nickel (as NiO). As a consequence of these properties, BMN2H featured a high soot oxidation rate at 450 °C, which hindered the accumulation of soot during the reaction and, thus, the deactivation of the catalyst.

Experimental investigation of neutron irradiation effects on α- alumina nanoparticles in water-based nanofluid for a light water reactor coolant

Nanoparticles offer several advantages in terms of heat transfer, stability, safety, and efficiency, making them an attractive option for reactor coolants. The feasibility of using α-alumina (α-Al2O3) nanoparticles as a component of coolant for a light water reactor was investigated under the high neutron flux conditions of a TRIGA Mark II research reactor. To achieve this, highly thermally conductive α-Al2O3 nanoparticles were synthesized using the sol-gel method. X-ray diffraction spectra analysis confirmed the crystal structure and the alpha (α) phase of the sample. The average crystal size was determined to be 55.5 nm. Transmission electron microscope analysis revealed that the nanoparticles had sizes ranging from 40 to 60 nm, although the shape of the particles was irregular. Thermogravimetric analysis indicated a weight loss of less than 0.5% over a temperature range from 30 °C to 1200 °C. Dynamic light scattering showed two intensity peaks at 129.6 nm and 623.2 nm, resulting in a Zeta average (Z) value of 474.9 nm and a polydispersity index of 0.688. In the TRIGA Mark II research reactor, the synthesized nanoparticles were exposed to a thermal neutron flux of 5.28 × 1012 n/cm2/s using a pneumatic transfer irradiation channel (rabbit system). This irradiation resulted in the formation of various activated products, including 28Al, 24Na, and 27Mg, with abundances of 50.5 ± 0.3%, 0.18 ± 0.02%, and 1.59 ± 0.06%, respectively. All of these nuclides are radioactive, with half-lives ranging from minutes to hours. The induced radioactivity in the reactor core area poses a risk of secondary radiation. The physicochemical interaction of these induced products, especially sodium (24Na), with the coolant and other components, is not safe, as sodium is a highly reactive element that can undergo an exothermic reaction with water. These findings suggest that the use of α-Al2O3 in water as a reactor coolant should be further examined from the viewpoints of neutron irradiation effects and the physicochemical interaction of activated products with core materials.

Sonochemical synthesis of heterostructured ZnO/Bi2O3 for photocatalytic desulfurization

In this study, metal oxides nanoparticles heterogeneous photocatalysts prepared by coprecipitation and ultrasonic techniques were used for diesel desulfurization. They were characterized by scanning electron microscope, powder X-ray diffraction, energy dispersive analysis, diffused reflectance spectra, photoluminescence analysis and BET surface area. The surface area of catalyst B is larger than catalyst A confirming its higher reactivity. X-ray reflectance spectroscopy was used to analyze the sulfur contents in feed. Thiophene was used as a model fuel to evaluate the photocatalytic activity of catalysts A and B. Using the Scherrer equation, sharp and intense signals suggesting their higher degrees of crystallinity, with average crystal sizes for ZnO, Bi2O3, catalysts A and B, respectively; of 18, 14.3, 29.7, and 23.8 nm. The operational parameters of the desulfurization process were optimized and have been studied and the maximum sulfur removal was achieved via a further solvent extraction step. A diesel fuel with a 24 and 19 ppm sulfur content and hence a total sulfur removal of 94.6% and 95.7% was acquired for catalysts A and B, respectively (sulfur compounds concentration in diesel fuel feedstock was 450 ppm). These findings demonstrated that photocatalysts A and B are good and effective catalysts for desulfurization of diesel fuel.

Superior photocatalytic degradation of MB dye using BiVO4 nanoparticles under solar light irradiation

An inexpensive and straightforward co-precipitation technique was employed to produce BiVO4, utilizing Bi(NO3)3 5H2O and NH4VO3 as precursors. Comprehensive analysis of the crystal structure, morphology, and optical properties was conducted via XRD, FTIR, FE-SEM, and UV-DRS methods. The XRD results confirmed the crystalline nature of the catalyst, with a prominent peak at 28.7 degrees. The average crystal size was determined to be 34.8 nm. UV-DRS analysis revealed an absorption peak in the range of 280–400 nm and a bandgap energy of 2.7 eV. The photocatalytic activity of the catalyst was found to be highest in a pH∼11 solution of 20 ppm MB dye, with a catalyst dosage of 20 mg over a duration of 80 min.

Influence of coal-measure kaolinite with different types on the preparation of kaolinite nanotube

Coal-measure kaolinite with different types were selected to explore the influence of raw mineral on the preparation of intercalation compounds and kaolinite nanotubes. Types of coal-measure kaolinite were feldspar-pseudomorph kaolinite (HSS), worm-like kaolinite (XY), brain striatum kaolinite (CBM), mica-pseudomorph kaolinite (CBM) and crypto crystalline kaolinite (HW and HY), respectively. And the average crystal size of coal-measure kaolinite after grinding of HSS, XY, CBM, HW and HY were 2.60 μm, 6.81 μm, 3.28 μm, 0.52 μm and 0.32 μm, respectively. Characterization methods of XRD, FTIR and SEM were utilized to reveal the change in the crystal structure of kaolinite before and after intercalation reactions, the vibrational pattern of the chemical bond and the surface morphology characteristics of raw minerals and kaolinite nanotubes. Results showed that intercalation effects were significantly different among the selected coal-measure kaolinite, and the intercalation rates of intercalation compound of HSS-KD, XY-KD, CBM-KD, HW-KD and HY-KD were 80.71%, 83.33%, 82.99%, 55.13% and 65.23%, respectively. That is to say, Intercalation rates of feldspar-pseudomorph kaolinite, worm-like kaolinite, brain striatum kaolinite and mica-pseudomorph kaolinite were significantly higher than those of crypto crystalline coal-measure kaolinite which were reflected from intercalation compound of coal-measure kaolinite/dimethyl sulfoxide. Furthermore, the intercalation rates of the precursor intercalation compounds affect the intercalation effect of macromolecular intercalation agents and the yield of kaolinite nanotubes. According to the SEM patterns of kaolinite nanotubes, yield of kaolinite nanotube of HSS, XY, CBM, HW and HY were 80%, 88%, 72%, 28% and 35%, respectively. It could be concluded that yield of kaolinite nanotube of coarse crystalline coal-measure kaolinite was higher than that of crypto crystalline coal-measure kaolinite.

Influence of Electron Beam Treatment on Structure and Phase Composition of TiB2–Ag Coating Deposited by Electrical Explosion Spraying

Due to many factors, the electrical explosion spraying process is not stable, which directly causes unstable coating quality and structure. Electron beam treatment may be used to improve the surface and modified structure of coatings sprayed by electrical explosions. In this study, a new TiB2–Ag metal matrix composite coating was deposited by electrical explosion spraying and modified by electron beam treatment. The prepared coatings were characterized by surface macro- and microanalysis, XDR, cross-section SEM, and TEM. The composition of the spray-coating phase differs from sample to sample. The electron beam treatment normalized the phase composition. Ag TiB2 B2O became the main phase in the modified coating. Increasing the pulse energy density and duration leads to a reduction in the low-melting Ag phase and the formation of copper contact phases due to heating and melting of the copper substrate by excess electron beam energy. The coating structure consists of a silver matrix and TiB2 inclusions. The electron beam treatment did not affect the structure; however, the microstructure of the coating transformed into a cellular crystallization structure. The silver matrix nanostructure was transformed into a nanocrystalline structure with an average crystal size ranging from tens to hundreds of nanometers.

Membrane crystallization for recovery of lithium carbonate crystals: Study on process parameters and salts effect for Li2CO3-NaCl-KCl-LiCl solutions

In this work, membrane crystallization (MCr) process was employed for recovery of lithium carbonate (Li2CO3) crystals from synthetic brine solutions. First, the effect of the main operating conditions in MCr, including feed temperature (40, 50, and 60 °C) and flowrate (0.81, 1, and 1.3 L/min) was investigated on the crystallization of Li2CO3 in a binary solution. Next, the effect of main inorganic salts in the brine solutions (i.e., NaCl, KCl, and LiCl) and the mixture of them on the MCr performance and crystallization of Li2CO3 were investigated. In-line microscope, light microscope, scanning electron microscope, and X-ray diffraction test were used to observe the crystallization and characterize the obtained crystals. The obtained results revealed that feed temperature is the main parameter to dominate the nucleation and crystal formation and growth. Thus, the higher the feed temperature, the faster the crystal formation and the larger the crystals. The average crystal size increased from 9.59 to 30.51 μm, when the feed temperature increased from 40 to 60 °C, respectively. However, smaller crystals were observed with adding NaCl and KCl to the solution. Moreover, none of the operating parameters nor the salts additives did affect the crystals shape and the obtained Li2CO3 crystals possess needle-like shape.

X-ray/gamma absorption and Anticancer Properties of Fe[formula omitted]O[formula omitted] nanoparticles

The current study reports the synthesis of Fe2O3 NPs by the co-precipitation method and the evaluation of the anticancer activity and X-ray/gamma absorption study. PXRD analysis confirmed the formation of monophase trigonal-shaped NPs, and the average crystal size is computed using both Scherrer equation and W-h plot and found to be 45 nm and 54 nm respectively. The direct energy gap is computed from the Wood-Taucs plot and found to be 1.76 eV. FTIR analysis confirmed the functional groups present in NPs. Surface morphology studies confirmed by SEM and EDAX analysis confirmed the chemical composition. Anti-cancer studies verified the efficacy of Fe2O3 NPs in cell viability and cell death when compared with Cisplatin. Finally, a NaI(Tl) detector is used to evaluate Mass attenuation co-efficient of the X-ray and gamma radiation shielding characteristics. Shielding requirements are comparable to those for lead. Thus, the synthesized Fe2O3 nanoparticles can be used for anticancer activities, particularly in tailored drug delivery systems, and radiation shielding instead of toxic lead shielding.

Preparation, Characterization, and Antibacterial Properties of Cu-Fibreboards

In the present study, copper modified fibreboards were prepared and their existing phase, morphology, and antibacterial behaviour were investigated. The copper content and the physical and mechanical properties of fibreboards (thickness, bending strength, and swelling) were determined. X-ray diffraction analysis (XRD) showing diffraction peaks typical for cellulose, Cu2S, and Na2SO4, depended on the preparation conditions. The average size of the Cu2S crystals varied between 20 and 50 nm. The morphology of the obtained fibreboards, as well as the size and shape of copper particles, were observed by scanning electron microscopy (SEM) and transition electron microscopy (TEM). The antibacterial activity was tested against Gram-positive (Bacillus subtilis 3562) and Gram-negative (Escherichia coli K12 407) bacteria. The tests showed that the materials had higher antibacterial activity against E. coli, which depended on their preparation conditions. Based on these results, the obtained copper fibreboards can be used as antibacterial agents in the packaging and building industry.

Optimal synthesis of dolochar derived faujasite zeolite X for highly effective Cd(II) removal

Cadmium-induced water pollution is a major environmental issue because of its persistent nature and adverse ecological impacts. Adsorption is a highly favored method due to its versatility and high efficacy in cadmium removal. Hence, the present work aims to develop a low-cost, highly effective adsorbent-dolochar-derived nanoporous zeolite to easily and effectively purify Cd(II) polluted water. The work focuses on the Cd(II) batch adsorption study using the optimal hydrothermal synthesis of a crystalline faujasite Zeolite X (ZX) from dolochar. The synthesis parameters were optimized using Response Surface Methodology, specifically Box Behnken Design (RSM-BBD), to maximize the crystallinity percentage. Variables such as initial Cd(II) concentration, solution pH, dosage, time, and temperature were studied for the Cd(II) batch adsorption study. The optimum conditions for synthesizing ZX include NaOH/Dolochar, crystallization temperature, and crystallization time of 1.375, 100 °C, and 11 h, respectively. The resultant XRD structure exhibited an average crystal size and crystallinity of 0.79 μm and 87.231 %, respectively. The average pore size, micropore volume, micropore area, and total surface area were 3.316 nm, 0.311 cc. g−1, 567.226 m2 g−1, and 583.117 m2 g−1, respectively. The maximum removal was accomplished with optimum conditions of 0.25 g.L−1 dosage, 80 min, at 313.15 K, and 6.5 pH. Adsorption isotherm results agreed with those hypothesized by Freundlich isotherm, with a maximum adsorption capacity of 714.285 mg g−1, and the pseudo-second-order kinetic model describes the adsorption kinetics well. The relevance of the results highlights the importance of using this dolochar-derived nanoporous zeolite as an adsorbent to effectively treat Cd(II) containing wastewater.

Dynamic evolution investigation on crystal size and morphology of sodium sulfate based on a combination of ultrasonic and image on-line testing

Crystallization is widely used in the fine chemical processes of purification and separation, where the crystal size variation, together with the crystallization temperature, plays a crucial role. An online measurement system for the simultaneous characterization of crystal size and other morphological parameters was studied, in which an ultrasonic spectrometer and image analysis was effectively combined for the monitoring and understanding of key parameters during the entire crystallization of sodium sulfate solution. The change in crystallization temperature, crystal size, and morphology at different cooling rates and stirring rates were analyzed, which shows that the cooling rate plays a dominant role in the variation of the critical time of crystal precipitation and average crystal size. In the middle stage of the crystallization, the median diameter change obtained by the ultrasonic and image analysis is close together, with a relative deviation of less than 10%. While the aspect ratio is mainly distributed in the range of 1–1.6, the crystal size has a relatively stable growth rate. An ultrasonic spectrometer can be used to measure particle size distribution of higher concentrations compared with image analysis. The combination actually provides an effective complement to implementing straightforward testing during the relatively complete crystallization process.