Ca/Al layered double hydroxide (LDH) was successfully synthesized by co-precipitation method at pH 11 under room temperature condition then followed by calcination at 800 o C. The synthesized Ca/Al LDH was further intercalated with Keggin ion [α-SiW12O40] 4-in order to prepare the intercalated form of Ca/Al LDH. The synthesized materials were characterized by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) and used as an adsorbent for iron(II) removal from the aqueous medium. The adsorption performance was investigated by studying the kinetics and thermodynamic properties of the adsorption process. The results showed that pristine Ca/Al LDH exhibited diffraction peak at 2θ about 20 o which corresponds to the layer structure of the LDH material. For the intercalated Ca/Al LDH, the diffraction observed at 2θ around 30-40 o indicated that the [α-SiW12O40] 4-was successfully intercalated into the interlayer space of Ca/Al LDH. Furthermore, the intercalated Ca/Al LDH showed higher adsorption capacity toward iron(II) than the pristine form of Ca/Al LDH.
This study successfully synthesized a core-shell-shell in the form of CoFe 2 O 4 -SiO 2 -TiO 2 catalyst magnetic and recyclable. The catalyst was employed for the photocatalytic degradation of methyl orange (MO) dye. Subsequently, the catalyst was subjected to XRD, FTIR, SEM-EDS, VSM, as well as UV-DRS characterizations. The photocatalytic degradation was studied as a function of the solution pH, MO concentration, and irradiation time, while the kinetics of photocatalytic degradation and the catalyst reusability were also evaluated. On the basis of the XRD, FTIR, and SEM-EDS characterizations, the CoFe 2 O 4 coating was successfully carried out using SiO 2 and TiO 2 . CoFe 2 O 4 -SiO 2 -TiO 2 was discovered to possess magnetic properties with a saturation magnetization of 17.59 emu/g and a bandgap value of 2.4 eV. The photocatalytic degradation of MO followed the Langmuir-Hishelwood model. The optimum degradation was obtained at the MO concentration of 25 mg/L, solution pH of 4, catalyst dose of 0.05 g/L, irradiation time of 160 minutes, MO removal efficiency achieved 93.46%. The regeneration study showed CoFe 2 O 4 -SiO 2 -TiO 2 after 5 cycles were able to catalyze the photocatalytic degradation with an MO removal efficiency of 89.96%.
Nano-hydroxyapatite was synthesized by coprecipitation method and tested its antibacterial properties. Nano-hydroxyapatite was synthesized using CaO precursors from snakehead (Channa striata) fish bones and (NH4)2HPO4. The synthesis was carried out with temperature variations of 30, 60, 80, and 100 °C. Antibacterial activity was determined using two types of bacteria, namely gram-positive and gram-negative. The XRD spectra show that the highest peak is hydroxyapatite synthesized at a temperature of 100 °C. Hydroxyapatite produced from various synthesis temperatures has the size of nanoparticles in the range 37.32-49.27 nm. The nano-hydroxyapatite functional groups are characterized using FTIR, the analysis indicate the presence of OH, CO32‒ and PO43‒. The molar ratio Ca/P is obtained of 1.71 approaching theoretical hydroxyapatite of 1.67. The resulted nano-hydroxyapatite has significant antibacterial properties to Escherichia coli and Staphylococcus aureus.
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