Co-precipitation Technique Research Articles

Ball-Milling Enhanced UV Protection Performance of Ca2Fe-Sulisobenzone Layered Double Hydroxide Organic Clay.

Using a co-precipitation technique, the anionic form of sulisobenzone (benzophenone-4) sunscreen ingredient was incorporated into the interlayer space of CaFe-hydrocalumite for the first time. Using detailed post-synthetic millings of the photoprotective nanocomposite obtained, we aimed to study the mechanochemical effects on complex, hybridized layered double hydroxides (LDHs). Various physicochemical properties of the ground and the intact LDHs were compared by powder X-ray diffractometry, N2 adsorption-desorption, UV-Vis diffuse reflectance, infrared and Raman spectroscopy, scanning electron microscopy and thermogravimetric measurements. The data showed significant structural and morphological deformations, surface and textural changes and multifarious thermal behavior. The most interesting development was the change in the optical properties of organic LDHs; the milling significantly improved the UV light blocking ability, especially around 320 nm. Spectroscopic results verified that this could be explained by a modification in interaction between the LDH layers and the sulisobenzone anions, through modulated π-π conjugation and light absorption of benzene rings. In addition to the vibrating mill often used in the laboratory, the photoprotection reinforcement can also be induced by the drum mill grinding system commonly applied in industry.

Exploring the molecular biology of zinc-doped hydroxyapatite nanocomposites as fillers for dental materials: a self-defensive approach targeting bacterial DNA

Abstract Infections during or after the denture filling pose a serious threat to recovery later, and antibiotics are scanty for quick healing. The antibacterial potential of Zn has convinced us to fabricate its composites with hydroxyapatite (HA), which has distinct biological properties. The main aim of the study is to evaluate the antibacterial potential of Zn-doped HA and investigate its molecular interaction with bacterial strains to enhance its defensive ability against bacterial attack. This study investigates the synthesis of zinc-doped hydroxyapatite nano-powder (Zn-HA) as coating and filling materials for dental applications. The co-precipitation technique was used in this regard to obtain the purest form of nanoparticles. The as-prepared Zn-HA samples were characterized by FTIR spectroscopy to assess the interaction of functional groups between components, X-ray diffraction (XRD) to determine percentage crystallinity, SEM to explore the surface morphology of composites, and EDX to confirm the incorporation of Zn in the apatite structure. The crystalline size of Zn-HA decreases from 99 nm to 40 nm with an increase in the doping of Zncl2 from 0 to 2.5g. With increasing the concentration of Zn doping, the effectiveness of antibacterial potential was increased. Due to an increased in the concentration of doped Zn, the Zn ions effectively rupture the bacterial membrane and destroy its DNA. Meanwhile, it shows the highest antibacterial activity against Pseudomonas (20.2±0.02), Klebsiella (25.8±0.05), Bacillus (18.3±0.09), S. aureus (24±0.03), and E. coli (19.3±0.09) with Zn/HA5.It showed that by increasing the concentration of Zinc ions in hydroxyapatite, the antibacterial potential increased. This increased concentration of zinc ions in HA enhances its-defensive ability against the attack of various bacterial strains, this makes it a potential material and enhances its efficacy in dental applications like coating, filling material, or dental restoratives, in inhibiting the growth of bacterial colonies and biofilm formation in the oral cavity. In this way, Zn/HA as an efficient dental composite as a restorative material with enhanced antibacterial potential may help to mitigate the risk of dental infections, promote dental as well as oral health, and overall improve the life of dentine.

Oxygen vacancies, hydroxyl groups and fluorine ions in the local environment of Yb3+ ions doped in CeO2 nanoparticles

The local environment of Yb3+ ions doped into ceria (CeO2) nanoparticles, synthesized by two different methods, was determined using EPR spectroscopy. It was found that the charge compensator for the Yb3+ ion located in the nearest environment can be a vacancy, a hydroxyl group, or a fluorine ion. The EPR spectra of Yb3+ ions at concentrations of 0.1 mol% and 0.5 mol% in ceria nanoparticles, prepared using the coprecipitation technique from an aqueous solution, are mainly due to cubic sites, which indicate the remote location of the charge compensators. The EPR lines resulting from trigonal sites in these samples suggested that the charge compensation is associated with a hydroxyl group. The FTIR measurements correlate with this supposition. After annealing the samples in a vacuum furnace, EPR lines from trigonal sites related to oxygen vacancies were observed. The second type of ceria nanoparticle was prepared by annealing CeF3 nanoparticles in air. EPR spectra of Yb³⁺ ions at concentrations of 0.1 mol% and 0.5 mol% in these samples revealed that the lines from trigonal sites were mainly associated with fluorine ions in the nearest environment.

Enhancement of magnesium aluminate-based nickel and cobalt nanostructured catalysts with iron for improved performance in carbon dioxide methanation

This study investigates the performance of Ni and Co catalysts based on Fe-promoted MgAl2O4 for CO2 methanation, which is a crucial step in mitigating environmental carbon dioxide levels. The MgAl2O4 support was modified with various Fe loading (5, 10, and 15 ​wt%) and fabricated via a novel coprecipitation technique with the help of ultrasonic waves and chosen as support for 15 ​wt% Ni and Co active phases. Examination of the BET surface properties of the catalysts showed an increase in surface area in the range of 54–82 ​m2/g and 73–85 ​m2/g with an increasing Fe loading for Ni and Co catalysts, respectively. Among the Ni-based catalysts, the 15Ni/10FeMgAl2O4 specimen exhibited the best performance (with a 73.31 ​% CO2 conversion and 95.61 ​% selectivity rate) and remarkable lifetime during 10 ​h at 400 ​°C due to the better reducibility and the increase in hydrogen consumption. However, a rise in Fe amount to 15 ​wt% led to a reduction in the CO2 conversion to 34.43 ​%. The catalytic outcomes also demonstrated that the presence of Fe in Co/MgAl2O4 catalysts negatively affects catalytic performance. The unpromoted Co/MgAl2O4 sample demonstrated the best performance, achieving a conversion rate of 52.41 ​% at 350 ​°C.

Thermophysical Properties of (Y1-xErx)TaO4 Ceramics

A series of (Y1-xErx)TaO4 ceramics (x=0/6, 1/6, 2/6, 3/6, 4/6, 5/6, 6/6) were prepared using powders synthesized by the reverse co-precipitation technique. Investigations were conducted into the phase compositions, microstructure, and thermophysical characteristics. In contrast to yttria-stabilized zirconia (YSZ) ceramics, (Y1-xErx)TaO4 ceramics demonstrate reduced thermal conductivity and Young's modulus, along with greater coefficient of thermal expansions (CTEs). The impact of Er and Y elements on separation interferes with the parabolic relationship between thermal conduction and the composition of (Y1-xErx)TaO4 ceramics, modifying their thermal diffusion and conductivity patterns. Furthermore, the performance of (Y1-xErx)TaO4 ceramics was optimized by adjusting the ratio of Er/Y, from which (Y1-xErx)TaO4 ceramics exhibited lower thermal conductivity (1.38∼1.72 W·m-1·K-1 @ 800 °C), higher CTEs (9.24×10-6∼10.9×10-6 K-1 @ 1000 °C) and more excellent mechanical properties comparable to YSZ. Herein, (Y1-xErx)TaO4 ceramics show great potential for thermal barrier coating applications.

Improving high-voltage cycling and stabilizing the electrode-electrolyte interface of nickel-rich layered cathodes by magnesium doping

Next-generation lithium-ion batteries will rely on nickel-rich layered oxides as cathode materials, but these materials are associated with structural and voltage losses. Magnesium (Mg) doping helps improve the performance of the nickel-rich layered cathode material. The Mg-modified LiNi0·90Mn0·05Co0·05O2 (NMC-90) has been successfully synthesized through a co-precipitation technique followed by calcination at 850 °C. Modified NMC-90 exhibits better-organized layers and improved interfacial properties than pristine ones based on structural, chemical, and morphological studies. In a voltage range of 2.8–4.5 V, Mg (0.01 mol%)-doped NMC-90 (NMC-M1) composite cathode shows an excellent discharge capacity of 211.11 mAh/g, whereas pristine NMC-90 (NMC-M0) attains only 210.59 mAh/g at 0.1C with an initial coulombic efficiency of 89.5 % for NMC-M1 and 87.5 % for NMC-M0 cathode. The NMC-M1 cathode demonstrated an impressive enhancement in cyclability after 60 cycles compared to the NMC-M0 at 1C rate, in which the NMC-M1 cathode attains a high capacity retention of 80 % while the NMC-M0 cathode shows only 37 %. This study illustrates the importance of studying the effects of elemental doping on cell performance. It will drive the future development of cathode materials with high Ni and low Co content.

Probing the performance of Co-precipitated Co3(PO4)2@W3(PO4)4/GO electrodes for supercapacitor application

A critical first step in realizing high-performance supercapacitors is the growth of functional electrodes that are inexpensive, stable, and extremely active. To create a variety of electrodes, we present here an inventive approach to fabricating an ordered microporous Co3(PO4)2@W3(PO4)4/GO composites electrode on a nickel foam (NF) substrate that was first created via co-precipitation techniques for nanoparticles and then drop casting method for fabrication of these electrodes. The Co3(PO4)2@W3(PO4)4/GO composite electrodes show good electrochemical activity in three electrode configurations, thanks to its abundant active sites, and high specific surface area provided by graphene oxide (GO) structured microporous structure that facilitates the charge/mass transfer processes. Additionally, Co3(PO4)2@W3(PO4)4/GO composite electrodes are rightly employed as binder-free electrodes for supercapacitor applications, providing excellent specific capacitances, energy and power densities as well as good electrochemical firmness. The Co3(PO4)2@W3(PO4)4/GO electrode exhibits excellent performance, delivering a high specific capacitance of 1230 F/g from cyclic voltammetry (CV), 1420 F/g from galvanostatic charge-discharge (GCD) and long-term cycling stability of over 74.7 % after 10, 000 complete cycles.

Preparation of magnetite nanoparticles and their application in the removal of methylene blue dye from wastewater

Wastewater is discharged in large amounts from different industries; thus, wastewater treatment is currently one of the main concerns, advanced oxidation is a promising technique for wastewater treatment. This research aims to synthesize magnetite nanoparticles and study their application in wastewater treatment via adsorption and advanced oxidation processes. Magnetite nanoparticles were synthesized via coprecipitation technique between ferric and ferrous sulfate at a molar ratio of 2:1. The prepared sample was characterized using FTIR, XRD, TEM, BET surface area, zeta potential, VSM, and UV‒visible spectroscopy. XRD confirmed the formation of a single face-centered cubic (FCC) spinel structure of Fe3O4. TEM revealed an average particle size of 29.2 nm and a BET surface area of 70.1 m2 g−1. UV‒visible spectroscopy revealed that the UV–visible peak of the sample was obtained at 410 nm. VSM confirmed the attraction of the sample to a magnet with a magnetization of 60 (emu/g). The removal efficiency of methylene blue was studied using adsorption and advanced oxidation methods. For adsorption, the studied parameters were dye concentration 2–10 ppm, 3–10 pH, and 50:300 mg Fe3O4/L. For advanced oxidation, peroxide was used with nanomagnetite as a catalyst, and the studied parameters were pH 2–11, magnetite dose 20–200 PPM, and peroxide dose 500–2000 PPM. The removal efficiency by adsorption reached 95.11% by adding 50 mg of Fe3O4/L and 10 ppm dye conc at 6.5 pH; on the other hand, in advanced oxidation, it reached 98.5% by adding 110 PPM magnetite and 2000 ppm H2O2 at pH 11. The magnetite nanoparticles were reused for ten cycles of advanced oxidation, for a 10% reduction in removal efficiency at the tenth cycle.

Highly efficient CuNi-ZrO2 nanocomposites for selective hydrogenation of levulinic acid to γ-valerolactone.

CuNi-ZrO2 nanocomposites were prepared by a simple coprecipitation technique of copper, nickel and zirconium ions with potassium carbonate. The structures of the nanocomposites were characterized by N2 physical adsorption, XRD, H2-TPR and STEM-EDS. The Cu0.05Ni0.45-ZrO2 nanocomposite showed outstanding catalytic performance in hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL), especially NaOH solution (0.5 mol L-1) as a solvent. 100% LA conversion and > 99.9% GVL selectivity are achieved over Cu0.05Ni0.45-ZrO2 catalyst at 200 °C, 3 MPa for 1.5 h. Characterization results suggest that the excellent reactivity of the Cu0.05Ni0.45-ZrO2 may be due to a better reducibility of nickel oxide in the CuONiO-ZrO2, dispersion of Ni in the Cu0.05Ni0.45-ZrO2 compared to nickel oxide in the NiO-ZrO2 and Ni in the Ni0.5-ZrO2 and promotion of OH-. The results demonstrate that the Cu0.05Ni0.45-ZrO2 nanocomposite has potential to realize high efficiency and low-cost synthesis of liquid fuels from biomass.

An enhanced electrochemical sensor using ZnO nanoparticles to measure mycophenolate mofetil: A cyclic voltammetric investigation

Zinc oxide nanoparticles (ZnO Nps) were prepared in the current work utilizing a chemical co-precipitation technique with the aim of electrochemically detecting mycophenolate mofetil (MMF). The synthesized nanoparticles showed increased crystallinity with particle diameters of roughly 25.26 nm when analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and EDAX tests. Throughout the research, the physiological pH of 7.4 was kept constant. ZnO Nps-incorporated carbon paste electrode exhibits a significant electroactive surface area (0.0378 cm2), better sensitivity, and consistent current responses as compared to the bare carbon paste electrode (0.0285 cm2). Furthermore, a multitude of additional experiments were carried out, such as sweep rate, concentration, and pH studies, which demonstrated decreased LOD and LOQ, or 0.6 and 1.99 µM, respectively. The modified electrode showed superior stability at 94 % by maintaining its activity. The designed electrode showed a greater recovery of mycophenolate mofetil (MMF) in the 96–98.5 % range, when tested further for an actual sample analysis of MMF in a human urine research.

An insight into synergistic effects of Cu and Ag co-doping in nanocrystalline MgFe2O4 for enhancing the photocatalytic degradation of crystal violet and benzimidazole

Herein, the optical bandgap of magnetically separable, reusable and visible light active photocatalyst i.e. soft and n- type spinel ferrite MgFe2O4 is tailored to enhance its catalytic efficacy. The un-doped spinel ferrite MgFe2O4, and doped spinel MgFe2O4 i.e. Cu@MgFe2O4 (Cu0.05Mg0.95Fe2O4), Ag@MgFe2O4 (Ag0.1MgFe1.9O4), and Cu/Ag@MgFe2O4 (Cu0.05Ag0.1Mg0.95Fe1.9O4) were prepared by facile co-precipitation technique. Powder X-ray Diffraction (PXRD) and Fourier Transform Infrared (FTIR) spectroscopy were performed to confirm the successful synthesis of all prepared materials. The fabricated samples were used as photocatalysts for the degradation of Crystal violet (azo dye) and Benzimidazole (colorless pollutant). The results of photocatalytic experiment obtained from UV-Visible analysis showed about 71 %, 82 %, 85 %, and 93 % degradation of crystal violet by MgFe2O4, Cu@MgFe2O4, Ag@MgFe2O4, and Cu/Ag@MgFe2O4 respectively. Hence, the transition metal (Cu) and noble metal (Ag) co-doped MgFe2O4 exhibited about 22 % increase in its catalytic activity against crystal violet as compared to pure MgFe2O4. The highest catalytic performance of Cu/Ag@MgFe2O4 could be assigned to its decreased crystallite size (18 nm) and moderate band gap (2.17 eV) as compared to its counter parts i.e. MgFe2O4 (26 nm, 2.0 eV), Cu@MgFe2O4 (22.5 nm, 2.03 eV), and Ag@MgFe2O4 (21 nm, 2.05 eV). Furthermore, ∼84 % degradation of benzimidazole was observed using Cu/Ag@MgFe2O4 as catalyst. The enhanced degradation activity of Cu/Ag@MgFe2O4 (Cu0.05Ag0.1Mg0.95Fe1.9O4) photocatalyst for both dye and colorless compound could be accredited to the synergistic effects of structural engineering and optical bandgap tuning by the co-doping of Cu and Ag in MgFe2O4. Hence, Cu0.05Ag0.1Mg0.95Fe1.9O4 could be a remarkable photocatalyst in future for the removal of harmful industrial pollutants.

Investigating the physicochemical, optical and microstructural properties of sodium doped CdO nano powders fabricated by co-precipitation technique for blue emission and antimicrobial applications

A series of cubic structured pristine and sodium doped CdO nanoparticles (Cd1-xNaxO NPs) with varying dopant concentrations have been synthesized using simple Co-precipitation process. Crystal structure and the connection between various structural parameters are evidenced using powder XRD diffractograms. The crystallite size is evaluated with different models and the mean crystallite size was reduced with Na ions doping concentration due to severe lattice distortion. The existence of various vibrational modes and functional groups were demonstrated through FTIR characterization. The signature of Cd–O and Na–O stretching modes were confirmed with FTIR. Raman spectra also confirmed the formation of metal–oxygen bond and the second order vibration features. The direct bandgap of the CdO material increased from 2.132 to 2.40 eV with an increase in the Na dopant content which presents the appearance of a blue shift as probed through UV–Vis spectroscopy. The surface morphology and microstructure of the samples were studied using FESEM and HRTEM images, respectively. EDAX measurements revealed the presence of Cd, and O in the host lattice and Cd, O and Na in the doped CdO constructions. The SAED concentric ring pattern of Cd1-xNaxO nanoparticles demonstrated the polycrystalline nature of the samples. PL study revealed the impression of intrinsic defects and the photoluminescence colour emission of the Cd1-xNaxO materials shifted more towards bright blue region as the Na doping concentration increased. CIE color coordinates of Na-doped CdO NPs shows intense bluish color and extending its applications in commercial UV lighting, blue LEDs and Fluorescent biological labelling and tagging. Cd1-xNaxO nanoparticles exhibited enhanced antibacterial activity with increasing Na doping content towards gram-positive, and gram-negative bacteria. Further, the antifungal analysis against C. albicans, and A. niger authenticate that Na+ substituted CdO nanoparticles shows excellent antifungal activity. The mechanism of the above observed results is examined in detail in this article.

Degradation of 2,4-dinitrotoluene from aqueous solutions by three-dimensional electro-Fenton with magnetic activated carbon particle electrodes (GAC/Fe3O4)

Abstract 2,4-Dinitrotoluene (2,4-DNT) is a broadly applied nitroaromatic compound with multiple applications, and its simple production has resulted in its extensive utilization in producing explosives, dyes, and rubber. This substance is hazardous and induces genetic mutations in humans, fish, and microorganisms. Thus, this research was done to assess the effectiveness of the three-dimensional electro-Fenton (3D/EF) process employing magnetic activated carbon particle electrodes (GAC/Fe3O4) in eliminating 2,4-dinitrotoluene from water-based solutions. In this experimental investigation, Fe3O4 nanoparticles were created using the chemical co-precipitation technique. The G/β-PbO2 anode was fabricated by electrochemically depositing PbO2 layers on graphite sheets. G/β-PbO2 and stainless steel were utilized as the anode and cathode, respectively. The structure, particle size, and properties of the GAC/Fe3O4 nanocomposite were analyzed using FESEM, XRD, and EDX. The morphology of the G/β-PbO2 electrode was also examined using SEM. The Taguchi experimental design method was employed to identify the optimal conditions. The outcomes demonstrated that higher reaction time and current density, as well as lower pH and pollutant concentration, resulted in improved 3D/EF efficiency. Accordingly, the optimum values of parmeters were identified to be a concentration of 2,4-DNT = 50 mg/L, pH = 3, electrolysis time = 100 min, and current density = 8 mA/cm2. With these parameters, the degradation efficiency of 2,4-DNT through the examined system was 98.42 %, alongside removal efficiencies of 84.69 % for COD and 79.67 % for TOC. Additionally, the results indicated an increase in the average oxidation state (AOS) (from 1.27 to 1.95) and carbon oxidation state (COS) (from 1.27 to 2.75) in the 3D/EF process, along with a decrease in the COD/TOC ratio (from 1.81 to 1.36), indicating the effectiveness of the 3D/EF system in enhancing the biodegradability of 2,4-DNT. Overall, the combined 3D/EF process with a G/β-PbO2 anode has relatively high efficiency in degrading solutions containing DNT and can be considered a viable treatment option for wastewater containing substances such as 2,4-DNT.

Copper substituted manganese Prussian blue analogue composite nanostructures for efficient aqueous zinc-ion batteries

Aqueous zinc (Zn)-ion batteries (AZIBs) are considered a promising green energy storage alternative due to their large capacity, low cost, and exceptional safety. Prussian blue analogues (PBAs) with a robust three-dimensional structure and extensive ion channels are highly favorable for Zn2+ insertion/extraction, surpassing manganese (Mn) and vanadium oxides. Herein, copper (Cu) substituted Mn PBA (CuMn PBA) composite nanostructures are synthesized via a simple water-based co-precipitation technique using different concentrations of Cu and Mn sources. The partial substitution of Cu and the formation of Mn vacancies prevent Jahn-Teller distortions of MnN6 octahedra, extending the lifespan. The CuMn PBA-2 electrode exhibits a high discharge capacity of 175.14 mA h g−1 at 0.5 A g−1, superior rate capability of 89.08 mA h g−1 at 2.4 A g−1, and robust cycling stability, maintaining 73.15 mA h g−1 over 2000 cycles at 3 A g−1. Furthermore, the distinct structure provides numerous active sites and reduces volume volatility during cycling. The presence of Cu enhances electrode conductivity, thereby promoting a higher rate of Zn-ion diffusion between electrodes. The reversible intercalation and deintercalation of Zn2+ ions in the CuMn PBA-2 cathode are substantiated by ex-situ analysis methods. This work presents a novel approach for producing high-performance and stable PBA cathode materials for AZIBs.

Selective catalytic reduction of NOx by NH3 at low temperature over Mn0.5Zr(0.5-x)Fex catalyst with different Fe/Zr ratios

ABSTRACT Through a basic co-precipitation technique, a series of Mn0.5Zr(0.5-x)Fex ternary oxide catalysts with different Fe/Zr ratios have been prepared and applied to the selective catalytic reduction of NOx. The results of catalytic activity test show that the Mn0.5Zr0.2Fe0.3 catalyst with a molar ratio of Fe/Zr of 3:2 has the most effective denitrification activity at low temperature and displays considerable tolerance to SO2 and H2O. The Mn0.5Zr0.2Fe0.3 catalyst exhibits a combination of physical and chemical attributes, including an elevated specific surface area and a homogeneously distributed active component, which collectively furnish additional points of interaction for the reacting gases, thus improving the catalytic performance. In addition, the high Mn4+/Mnn+ and Fe2+/Fen+ ratios, strong redox capacity, and more acidic sites on the surface of the catalyst also have positive effects on its denitrification performance. Meanwhile, the reaction process on Mn0.5Zr0.2Fe0.3 catalyst is driven by the Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms. This study provides an important reference for the design of Mn-based catalysts with high denitration performance and excellent resistance to SO2 and H2O.

Carbon Decorated MOF for Low-Cost Aqueous Al-Ion Supercapacitors: Effect of Redox Additives

The performance enhancement of ZIF-67 based Al-ion supercapacitors using conductive additives is presented. By using the simple co-precipitation technique, the porous ZIF-67 and composites of ZIF-67 with two distinct forms of carbon rGO and CNS were synthesized. Physiochemical characterizations like XRD, BET, FTIR, etc., were performed to confirm the successful synthesis of ZIF-67 and its composites. The electrochemical measurements were performed in the three-electrode configuration using 0.5 M AlCl3 electrolyte. Out of all, the composite of ZIF-67 with rGO (ZIF-67_rGO) outperformed all other materials because of its larger specific surface area and enhanced electrical conductivity. Further, the electrolyte modification was performed in 6 mM KFCN as a redox additive for ZIF-67_rGO composite. Here, the specific capacitance of ZIF-67_rGO composite enhanced from 245 F g-1 to 346 Fg-1 at 1 A g−1 current density. Using the redox additive, we observe an increment of almost 41% in ZIF-67_rGO composite than its pristine counterpart. The composite also delivered good cycling stability with excellent coulombic efficiency of 89% and 95% after 1000 cycles, at 5 A g-1 current density, respectively.

Synthesis of eco-friendly bio-based coconut shell magnetic biochar for efficient bisphenol S sequestration in aqueous environment: green technology breakthrough

Water pollution has emerged as a critical global challenge, particularly the contamination of water bodies with persistent organic pollutants such as Bisphenol S (BPS), a known endocrine disruptor. This study presents the synthesis and application of eco-friendly bio-based coconut shell magnetic biochar (CSMB) for efficient sequestration of BPS from aqueous environments. Utilizing pyrolysis and co-precipitation techniques, the magnetic biochar was characterized through various methods including surface chemistry (pHpzc), electron dispersive X-ray analysis (EDX), Brunauer-Emmett-Teller (BET) N2 adsorption-desorption, scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR). SEM revealed a porous structure with a high surface area, while FTIR confirmed the presence of functional groups essential for adsorption. X-ray diffraction (XRD) and VSM successfully incorporated magnetic nanoparticles, enhancing the separation process post-adsorption. The CSMB demonstrated a significant surface area of 373 m2 g−1, outperforming regular coconut shell biochar (CSB), with a BPS adsorption capacity of 43.5 mg/g compared to 26.7 mg/g for CSB. Batch adsorption tests assessed the impact of operational factors such as initial BPS concentration (8–150 ppm), contact time (30–150 min), temperature (298.15, 318.15, and 338.15 K), pH (3–11), and CSMB dosage (0.1–0.9 g). The results indicated optimal adsorption at pH 6 with a maximum capacity of 52.3 mg/g. Kinetic studies revealed that the pseudo-second-order model best described the adsorption process, while the Langmuir isotherm model provided an excellent fit for the adsorption data. The reusability of CSMB was validated over five cycles, with adsorption capacity decreasing slightly from 43.5 mg/g to approximately 41 mg/g, making it a sustainable and effective adsorbent for water treatment.

The impact of ammonium hydroxide flow rate on iron oxide nanoparticle hydrodynamic size and colloidal stability

Precise control over the synthesis of iron oxide nanoparticles is essential to achieving optimal particle characteristics such as size, hydrodynamic size, polydispersity index, and zeta potential, all of which significantly influence colloidal stability. The commonly used co-precipitation technique often leads to high polydispersity and variable particle sizes, resulting in poor colloidal stability. This study demonstrates that varying the ammonium hydroxide flow rate during co-precipitation significantly affects particle size, hydrodynamic size, aggregation, and colloidal stability. An optimal flow rate of 4.25 mmol/min produced smaller, more uniform, and colloidally stable nanoparticles. Nanoparticle tracking analysis showed that this flow rate resulted in the smallest and most consistent hydrodynamic size of 123.3 ± 0.7 nm, while both higher and lower flow rates yielded larger and more polydisperse particles, up to 155.8 ± 20 nm. Dynamic light scattering confirmed that the 4.25 mmol/min rate produced the lowest polydispersity index of 0.21 ± 0.04, indicating the highest uniformity. Additionally, UV-Vis measurements demonstrated that nanoparticles synthesized at this optimal flow rate exhibited minimal changes in absorbance over 24 h, indicating superior colloidal stability. This study highlights the importance of optimizing the flow rate during the co-precipitation synthesis of IONPs to control particle hydrodynamic size and polydispersity, which are crucial parameters for numerous biomedical, chemical, and environmental applications.

Mechanistic insights into the reaction pathway for efficient cationic dye photocatalytic degradation and the importance of the enhanced charge isolation over dual Z-scheme CeO2/BiOCl/Ag2WO4 photocatalyst

Fabricating a multi-component heterojunction system with enhanced charge isolation efficacy remains challenging. A photoactive CeO2/BiOCl/Ag2WO4 heterojunction was successfully constructed using a co-precipitation technique to degrade crystal violet and methylene blue dyes. It was found through a combination of characterization and experiments that the dual Z-scheme system not only augmented the charge isolation and migration efficiency but also maintained superior redox ability with extended visible light absorption capacity. In the CeO2/BiOCl/Ag2WO4 system, 97 % of methylene blue and 98 % of crystal violet were degraded in 75 min using 50 mg/L of ternary photocatalyst. The rate of reaction of CeO2/BiOCl/Ag2WO4 for methylene blue (0.0445 min−1) and crystal violet (0.05053 min−1) exhibited a multi-fold increase in comparison to the bare photocatalysts. The electron spin resonance (ESR) analysis has remarkably identified hydroxyl and superoxide radicals (•OH, •O2−) as the primary reactive species in the photodegradation process. Liquid chromatography-mass spectrometry analysis was utilized to obtain potential degradation pathways for methylene blue and crystal violet, respectively. The dual charge transferal mechanism by the ternary photocatalyst resulted in a significant increase in photocatalytic activity. It provided new perspectives on the principles guiding the rational development of a multicomponent system for environmental remediation.

Synthesis and Characterisation of Nanocrystalline CoxFe1-xGDC Powders as a Functional Anode Material for the Solid Oxide Fuel Cell.

The necessity for high operational temperatures presents a considerable obstacle to the commercial viability of solid oxide fuel cells (SOFCs). The introduction of active co-dopant ions to polycrystalline solid structures can directly impact the physiochemical and electrical properties of the resulting composites including crystallite size, lattice parameters, ionic and electronic conductivity, sinterability, and mechanical strength. This study proposes cobalt-iron-substituted gadolinium-doped ceria (CoxFe1-xGDC) as an innovative, nickel-free anode composite for developing ceramic fuel cells. A new co-precipitation technique using ammonium tartrate as the precipitant in a multi-cationic solution with Co2+, Gd3+, Fe3+, and Ce3+ ions was utilized. The physicochemical and morphological characteristics of the synthesized samples were systematically analysed using a comprehensive set of techniques, including DSC/TGA for a thermal analysis, XRD for a crystallographic analysis, SEM/EDX for a morphological and elemental analysis, FT-IR for a chemical bonding analysis, and Raman spectroscopy for a vibrational analysis. The morphological analysis, SEM, showed the formation of nanoparticles (≤15 nm), which corresponded well with the crystal size determined by the XRD analysis, which was within the range of ≤10 nm. The fabrication of single SOFC bilayers occurred within an electrolyte-supported structure, with the use of the GDC as the electrolyte layer and the CoO-Fe2O3/GDC composite as the anode. SEM imaging and the EIS analysis were utilized to examine the fabricated symmetrical cells.