Eko Sri Kunarti

Adsorption competition of Cu(II) ion in ionic pair and multi-metal solution by ionic imprinted amino-silica hybrid adsorbent

AbstractIt was carried out the synthesis of the Cu(II) ionic imprinted polymer (Cu(II)-IIP) material of amino-silica hybrid via sol-gel process using a tetraethyl-orthosilicate precursor and an active compound 3-aminopropyltrimetoxyslane. Adsorption process of Cu(II) ion on non-imprinted ionic (NIP) material and Cu(II)-IIP follows pseudo-first-order kinetics model with the value of adsorption rate constants (k1) 0.030 and 0.058 L/min and Langmuir adsorption isotherm with the value of adsorption capacity 29.556 and 71.400 mg/g, respectively. Adsorption competition data in ion pair solution of Cu(II)/Ag(I), Cu(II)/Zn(II), Cu(II)/Ni(II), and Cu(II)/Cd(II) showed that the Cu(II)-IIP adsorbent was more selective than NIP with value of selectivity coefficient (α) > 1. A tendency of metal ion adsorbed in multi-metal solution follows this order: Ca(II) < Cd(II) < Ni(II) < Zn(II) < Ag(I) < Cu(II). The Cu(II)-IIP is stable chemically and it can be reused for adsorption of Cu(II) ion in solution without reduction of...

Synthesis of Fe3O4/TiO2-Ni Composite as a Magnetically Recoverable Photocatalyst

The Fe3O4/TiO2-Ni composites have been prepared by incorporating magnetic particles with doped photoactive titania using sono-coprecipitation and sol-gel methods. The composite was characterised by Fourier Transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy with Energy Disperse X-Ray Spectroscopy (SEM-EDX), Vibrating Sample Magnetometry (VSM) and Specular Reflectance Ultraviolet-Visible light spectroscopy (SR-UV). The results indicated that the composite of Fe3O4/TiO2-Ni had been synthesised. XRD and FTIR results showed that the composite had a good anatase phase. SEM-EDX result confirmed the atomic percentage of element presence in the synthesised product and VSM result proved that the composite has an excellent magnetisation moment of 8.76 emus. SR-UV result suggested that the composite had a good bandgap property compared to that of synthesised undoped titania.

Mechanism of the Removal of AuCl-4 Ions from Aqueous Solution by Means of Peat Soil Humin

Peat soil humin, obtained after the removal of fulvic and humic acid fractions according to the recommended procedure of the International Humic Substances Society (IHSS), has the ability to remove AuCl−4 ions from aqueous solution. The removal was greatest at medium acidity, which was equivalent to pH 2.0, and it was governed by two different processes, i.e. attachment onto un-ionized –COOH groups through hydrogen bonding and reduction to Au metal by the action of the –OH group. Purification of humin through repeated immersion and shaking in a mixed solution consisting of 0.1 M HCl and 0.05 M HF led to the abrupt increase in the –COOH contents from 386 mmol/kg to 2510 mmol/kg, while the content of total –OH functional groups remained relatively constant at values slightly higher than 3000 mmol/kg. The increase in –COOH content improved the removal of AuCl−4 ions from 23 mg/g to 27 mg/g, but it was unfortunately accompanied by a diminished reduction ability to Au metal. Hence, the role of the –COOH functional group in removing AuCl−4 ions through hydrogen bonding was more significant for the purified humin, while that of the –OH group in removing AuCl−4 ions through reduction to Au metal was better for the crude (unpurified) humin.

Synthesis of Fe3O4/TiO2-Co Nanocomposite as Model of Photocatalyst with Magnetic Properties

Synthesis and characterization of Fe3O4/TiO2-Co as magnetic photocatalyst had been done. The research was started with the preparation of magnetite through co-precipitation and sonication system, followed by preparation of Co-dopedTiO2 using sol-gel method and then mixed both of them with a ratio of Fe3O4:TiO2 1:3; 1:9; 1:15 (FT3, FT9, FT15) and ended by calcination. The product was characterised by using Fourier transform infrared spectrophotometer (FTIR), X-ray diffractometer (XRD), scanning electron microscope-energy dispersive X-ray spectrophotometer (SEM-EDX), UV-Specular reflectance spectrophotometer (SR-UV) and vibrating sample magnetometer (VSM). The resulting material showed a maximum value of band gap energy at 2.83 eV in FT3. The effect of Fe3O4:TiO2 ratio known can be affected the magnetic moment and showed the optimum result 2.0 emu/g in FT3. The magnetic character of Fe3O4/TiO2-Co also known can be affected by the magnetite crystalline size from the composites composition.

Synthesis of Gold Nanoparticle from Adsorbed Au on Hydrotalcite Using SDS and Sodium Citrate as Capping Agent and its Recovery into Pure Gold

Gold nanoparticles (AuNPs) have been synthesised from adsorbed Au on hydrotalcite (Mg/Al HT-AA-Au) using SDS (sodium dodecyl sulfate) and sodium citrate as capping agent. Then, the nanoparticles were recovered into pure gold by centrifugation. It is shown that sodium citrate has better activity compared to SDS as the capping agent. The electronic spectra of the resulted AuNPs showed that the optimum pH, sodium citrate concentration and time of sonication were 5, 70 mM, and 2 h, respectively. The results showed that the average size of AuNPs was 32 nm at SPR 531 nm. By centrifugation at 13000 rpm for 8 min, gold dust of Au(0) can be obtained from the gold nanoparticles capped sodium citrate. Based on infrared spectra and XRD, it is proven that the gold dust still contains citric and Mg/Al HT.

SINTESIS SILIKA MCM-41 DAN UJI KAPASITAS ADSORPSI TERHADAP METILEN BIRU

Synthesis of MCM-41 with hydrothermal time variation 18, 24, 36, 48 hours using templating agent cetiltrimetilammonium bromide (CTAB) has been done. The results showed that the time of hydrothermal influence the intensity and the index field (ao). Synthesis of MCM-41 with a time of hydrothermal 24 hours produce the highest intensity which indicates that MCM-41 has the best crystallinity. While testing the adsorption capacity of MCM-41 has 37,037 mg/g for adsorption of the methylene blue.