Papers by Keyword: Co-Precipitation

Abstract: The main purpose of this study is to synthesize nano-hydroxyapatite/cellulose (nHAP/Cel) and nano-hydroxyapatite/chitosan (nHAP/CS) scaffolds via co-precipitation method for bone tissue engineering due to their suitable biocompatibility, cytotoxicity and mechanical properties. The characterizations of these scaffolds were investigated by Infrared absorption spectra (FT-IR), X-ray Diffraction (XRD), and Scanning Electron Microscope (SEM). The cytotoxicity of these nanoparticles was evaluated with bone marrow cell using the 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazoliumbromide) (MTT) assay. The porosity of scaffolds was estimated 87%. The results indicate that the nano composite scaffolds have good morphology, tissue biocompatibility and biodegradability to be used for tissue engineering.

Abstract: At room temperature, zinc oxide (ZnO) nanoparticles co-doped with praseodymium (Pr) and copper (Cu) using a low-cost chemical co-precipitation method. As a capping agent, polyvinylpyrrolidone (PVP) was used for synthesizing the nanosamples, and a pH of 9 was maintained. The synthesis of nanosamples was then characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and photoluminescence (PL). X-ray diffraction studies revealed the wurtzite hexagonal structure of ZnO, and no impurity peaks were found. The particle size obtained from XRD studies was 32 to 46 nm and is well supported by TEM. SEM micrographs demonstrated the surface morphology of the samples. With Cu dopant concentration, Pr-doped ZnO nanosamples exhibited enhanced luminescence properties.

Abstract: Lanthanum-substituted cobalt ferrite nanoparticles (CoLa_0.1Fe_1.9O₄) with different Fe³⁺ cation sources i.e., using standard chemical lab (sample A) and a Bengawan Solo River fine sediment (sample B), were synthesized using the co-precipitation method. FTIR analysis showed that the absorption of the two nanoparticles sample appeared at a peak of v₁=586.39 cm^-1, whereas the v₂ appear at 461.97/cm and 435.93/cm respectively. It is suggested that the La³⁺ cation has succeeded in replacing the original structure of the cobalt ferrite. X-ray diffraction analysis showed that nanoparticles produce using a standard chemical lab (sample A) have smaller crystallite sizes, D=18.16 nm than the natural source of fine sediment (sample B), D=24.56 nm, respectively. Furthermore, the VSM results showed that the magnitude coercive field of Hc = 3100 Oe and Hc = 100 Oe for samples A and B, respectively. Meanwhile, the obtained saturated magnetization Ms of 15.55 emu/g for sample A and the Ms is 58.40 emu/g for sample B. This result informs that if a hard magnetic material is desired then the use of lab raw materials is more promising, while if soft magnetic is desired then a natural source of fine sediment is more appropriate to use.

Abstract: Bismuth ferrite nanoparticles were successfully synthesized by the co-precipitation method and modified by polyethylene glycol (PEG) 4000. X-ray diffraction patterns showed a sillenite structure of bismuth ferrite (Bi₂₅FeO₄₀) with a crystallite size of 35.0 nm and the new phase appeared after surface modification. The new phase was Bi₂Fe₄O₉. Crystallite size increased after surface modification of nanoparticles with PEG. The highest increase of crystallite size after surface modification with PEG was 40.1 nm. Transmission electron microscopy images showed that samples before and after surface modification were polycrystalline and still agglomerated. Spectra of Fourier transform infrared showed the presence of C-O stretching at 1080 cm^-1 and C-H bending vibration at 1342 cm^-1 in the bismuth ferrite/PEG sample, which did not appear in bismuth ferrite sample. The magnetic measurement indicated the weak ferromagnetic properties of the samples. Saturation magnetization did not appear after a maximum external magnetic field (15 kOe) was applied. The maximum magnetization of nanoparticles was 0.5 emu/g and tended to decrease to 0.2 emu/g after surface modification with PEG. Optical properties analysis showed a shift in the maximum absorption peak of bismuth ferrite nanoparticles towards a lower wavelength (blue shift) after surface modification of the nanoparticles. The specific absorption rate (SAR) value of nanoparticles increased by increasing an alternating magnetic field (AMF) strength. The SAR values of bismuth ferrite nanoparticles were 48.8, 61.4, and 84.4 mW/g and decreased to 32.0, 45.2, and 83.3 mW/g after surface modification at the AMF strength of 150, 200, and 250 Oe, respectively.

Abstract: The magnetic photocatalyst of CoZnFe₂O₄/SiO₂ nanoparticles has been synthesised to degrade methylene blue (MB) dye. The CoZnFe₂O₄ nanoparticles were prepared by co-precipitation method under mechanical stirring and coated with SiO₂ by stöber method using Na₂SiO₂ with various concentrations of 5%, 10%, 15%, 20%, 30%, and 50%. The properties of CoZnFe₂O₄/SiO₂ was confirmed by x-ray diffraction (XRD), Fourier transforms infrared (FTIR), vibrating sample magnetometer (VSM), and UV-Visible spectroscopy. XRD analysis revealed that CoZnFe₂O₄ had the spinel ferrite phase structure with crystalite size of 17.0 nm, and then after coating with SiO₂, the size became 17.1 nm. FTIR clearly show an M-O octahedral vibrational bond found with a wavelength of 378 cm^-1, O-Si-O, Si-OH, and Si-O-Fe at 1087, 794, and 570 cm^-1, respectively. The saturation magnetization (Ms) and coercivity of CoZnFe₂O₄/SiO₂ was 29.0 emu/g and 251.9 Oe, respectively. Furthermore, the results of UV-Visible data presented that the absorption edges CoZnFe₂O₄/SiO₂ in the range of 190 - 600 nm. The percentage of CoZnFe₂O₄ degradation is 88.4%, while after coted SiO₂ 50%, the degradation becomes 98.9%.

Abstract: Abstract: In the present studies, gadolinium doped cobalt oxide nanostructures (1 wt. %, 5 wt. % and 10 wt. %) were synthesized by co-precipitation method. The samples were characterized by SEM (scanning electron microscopy), XRD (X-ray diffraction spectroscopy), UV-Visible spectroscopy. UV-Visible exhibited maximum absorption at 440.81 nm for Gd_{(10% wt)}Co₃O₄ Band gap energy was calculated using Tauc plots and it was observed that band gap energy decreased from 7.74 eV to 2.64 eV upon increasing the doping percentage of Gd to Co₃O_4. The crystallinity of the Gd_{(10% wt)} Co₃O₄ NS increased as compared with Gd_{(1% wt)}Co₃O₄ NS. SEM morphology revealed average particle size were between 95 nm to 78 nm uniformly distributed over Co₃O₄ NS.

Abstract: The storage of electrical energy is an important thing today because it is influenced by the increasing human energy needs. Batteries are one of the energy storage that continues to be explored. Sodium-ion batteries are batteries that are planned to replace lithium-ion batteries. The abundance of sodium elements and their more economical price than lithium are the main attractions. The main constituent components of sodium batteries are anodes and cathodes. Both have a significant influence on the performance of sodium batteries. Currently, several cathodes have been developed but have some challenges especially their instability to air exposure. NaNi_0.5Ti_0.5O₂ is a transition metal oxide-based cathode that has been known to have good structural stability. In this study, NaNi_0.5Ti_0.5O₂ has successfully developed using a combination method of co-precipitation and solid-state. The precipitant is oxalic acid, while the chelating agent is ammonia. The obtained oxalate precursor was sintered in the airstream. Characterization of NaNi_0.5Ti_0.5O₂ is carried out. XRD patterns demonstrate a hexagonal-layered material structure. The material was achieved after the sintering process, according to FTIR analysis. XRF analysis confirmed the composition of the final product in the form of Ni 54.7% and Ti 45.26%. The SEM test showed uniform particles with an average size of 3 microns. Small particle size, which allows greater diffusion of Na ions thereby improving electrochemical performance. This structure characterization result shown that the used method has been succeed. The obtained EIS graph is a semi-circle and slope that shows the process of charge transfer of lithium ions on the surface of the material and electrolyte.

Abstract: Modification of nanometer size order in anode material of hematite nanoparticles is believed to be one of the keys to increasing the specific capacity of Li-ion batteries application. So that, the synthesis temperature dependence of nanocrystallite size properties in co-precipitated hematite nanoparticles is studied. Sample of Hematite nanoparticles is modified the physical properties by synthesis temperature and then annealed of 700°C for 4 hours. The crystallite size increase with the increase of the synthesis temperature i.e., 23.06 to 29.64 nm. It is indicated that the synthesis temperature affects crystallite formation. Furthermore, the magnetic properties show that the coercive field decrease from 869 to 211 Oe with the increase of the temperature synthesis. It is related to the change in the nanosize-order of the sample crystallite.

Abstract: A high-quality Lithium Nickel Manganese Oxide (LiNi_0.7Mn_0.3O₂) material is successfully synthesized via co-precipitation. The precursors for lithium rechargeable batteries have been prepared using starting materials (NiCl₂.6H₂O and MnSO₄.H₂O) with precipitating agents of oxalic acid and sodium hydroxide, Ethylene diamine tetra acetic (EDTA) and sodium hydroxide, and sodium carbonate for oxalate co-precipitation, hydroxide co-precipitation, and carbonate co-precipitation, respectively. Then, the precursors were calcined at 500°C for 5 hours, mixed with Li₂CO₃, and sintered at 850°C for 15 hours under oxygen. X-ray Diffraction (XRD) analysis results show that the particles obtained by oxalate co-precipitation (LiNi_0.7Mn_0.3O₂-C₂O₄) have higher crystallinity and more uniform particle shape than hydroxide co-precipitation and carbonate co-precipitation. The Fourier Transform Infrared (FTIR) spectroscopy characterization shows no carbonate group peak in the LiNi_0.7Mn_0.3O₂-C₂O₄. Furthermore, electrochemical tests were analyzed by evaluating the charge/discharge curves and cycling performance. The highest specific discharge capacity of 122 mAh/g was achieved by the LiNi_0.7Mn_0.3O₂-C₂O₄ sample, which also had a low capacity loss (22.7%), retaining 89.9% of its initial specific capacity at 0.5C between 2.5 and 4.25 V after 45 cycles. Based on these results, a cheap cobalt-free cathode material is promising for a new commercialized Li-ion battery.

Abstract: Sustainable green new and renewable energy is continuously developed along with the development of cheap and commercially available secondary energy storage such as Li-ion batteries (LIBs). Nickel-rich cathode material obtained from cheap raw materials can significantly reduce the overall LIBs production cost and improve the overall process feasibility. For the first time, Ni-rich cathode material precursor was synthesized from mixed hydroxide precipitate (MHP). Based on MHP characterization test, the nickel content is high but have slight Mn and Mg level. NCM precursors was prepared in three facile steps, i.e., acid leaching using cheap and environmentally friendly organic acids, coprecipitation using oxalic acid, and thermal decomposition of as-prepared oxalate precipitate. Based on FTIR and XRD analysis, high crystalline oxalate dihydrate precipitates were successfully obtained. The morphological feature of the precipitate is significantly affected by the type of leaching solution. Fine metal oxides precursor powders also were successfully prepared which is confirmed by XRD, FTIR, and SEM analysis and can be readily used for Ni-rich cathode material preparation. In this study, NCM-Ox-LA have the best characteristic properties.