Synthesis of Modified TiO₂ Nanocomposite using Fe₃O₄ and Nickel as Photocatalyst in Reduction of Silver Ions

Nanomagnetite was synthesized using water extract of bilimbi (Averrhoa bilimbi). The high citric acid content has the potential as a reducing agent in the synthesis of magnetite using the hydrothermal method. The synthesis was conducted using different sizes of hydrothermal reactors, 50, 150, and 1700 mL. The results showed that a reactor with a volume of 150 mL and a synthesis time of 12 h was the best condition for synthesis. The results obtained from X-ray diffraction analysis showed that in the best conditions, the crystallinity level was 74.4%, the ratio of product to volume was 3.7×10–2 g/mL, the Fe content in magnetite was 22.0%, the Fe content in the remaining liquid was 0.02%, the Fe ratio was 96.9%, and the ammonium content in the solution was 1.24% w/v. The best conditions were 150 mL reactor and 12 hours synthesis.

“…The results of the X-ray diffractograms were compared with the magnetite standard JCPDS No. 19-0629 [16] (Fig. 5).…”

Section: Characterization Results With Xrdmentioning

confidence: 99%

Hydrothermal Method to Synthesize Nanomagnetite by Water Extract of Averrhoa bilimbi : Effect of Time and Reactor Size

Arif,

Ismawati,

Hikmah

et al. 2023

“…Carica Dieng coffee bean extract was characterized using FTIR to confirm the functional groups of MPRs in the sample. This technique is beneficial in identifying the functional groups of organic and organometallic compounds [18]. The IR spectra were measured in the mid-infrared region at a wavelength of 2.5−50 m or a wave number of 4000−200 cm -1 .…”

Section: Characterization Of Mprs In Carica Coffee Bean Extractmentioning

confidence: 99%

Effect of Roasting Process on Antioxidant Activity of Carica Seeds Coffee (Carica pubescens)

Sukowati¹,

Arif²,

Heryanto³

2022

Carica seeds (Carica pubescens), one of the diversification of coffee drinks, served as antioxidants. The roasting process generated degradation of secondary metabolic compounds but produced Maillard reactions products (MRPs). The study aimed to determine the effect of the roasting process on the antioxidant activity of Carica coffee beans and its correlation to the Maillard reaction. The samples roasting temperatures were 100–115, 150–165, and 200–215 °C. The samples were analyzed for proximate, total phenolic, antioxidant, and FTIR. The moisture and ash content of dry seeds were according to SNI 01-2907-2008. The total phenolic content was 3.21–8.99 µgGAE/g, with the highest contents at 200–215 °C. The antioxidant activity was 83–459.67 ppm AEAC. The high phenolic content and antioxidant at 200–215 °C were thought to come from MRPs compounds. The FTIR spectra showed stretching of OH, C=C (aromatic), C=N, C=O, and C-OH (phenol). The spectrum intensity weakened at higher temperatures. However, only the nC–H stretching at 200–215 °C became stronger. The Cluster Ward analysis showed resemblance spectra at roasting temperature levels of 100–115 and 150–165 °C. The roasting process affected the antioxidant activity of Carica coffee beans, thereby increasing the roasting temperature level. This condition resulted in higher levels of antioxidants.

“…An alternative for adsorbent separation is magnetic separation, utilizing magnetic materials in the adsorbent system. This method is more effective, environmentally friendly, and does not incur high operational costs [14].…”

Section: Introductionmentioning

confidence: 99%

Magnetically Chitosan-Silica-Based Biosorbent as Efficient Removal of Au(III) in Artificial Wastewater

Pradipta,

Putri,

Khairani

et al. 2024

The synthesis of chitosan-modified silica-coated iron oxide magnetic material (Fe3O4/SiO2/Chitosan) via the sol-gel process addresses the need for enhanced stability and functionality in various applications. Coating iron oxide magnetic material with chitosan-modified silica is a common strategy to improve biocompatibility and performance. This study investigates the synthesis of Fe3O4/SiO2/Chitosan using sodium silicate as the silica precursor. The synthesis involved sonication of Fe3O4 and sodium silicate for 5 min, followed by adding chitosan in 4% acetic acid with continuous stirring. The mass ratio of Fe3O4:SiO2 was fixed at 0.5:0.73, with varying chitosan masses (0.025, 0.050, and 0.075 g). Characterization techniques used included Fourier-Transform Infrared Spectroscopy (FTIR), X-ray powder Diffraction (XRD), Thermogravimetric analysis, and Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX). The product with the highest mass yield was further analyzed. The variation in the amount of chitosan in the conducted research aimed to determine the optimum chitosan mass that could still bind to the silica framework. Magnetite was confirmed as the primary composition, with the addition of chitosan and silica functional groups observed through vibration absorption characteristics. SEM imaging revealed larger particles after coating. Thermogravimetric analysis showed differences in decomposition patterns between samples. The optimal chitosan content for characterization was determined at 0.050 g. Future applications might include enhanced adsorption processes owing to the optimized structure and composition of Fe3O4/SiO2/Chitosan nanoparticles.