Abstract
M.Tech. (Chemistry)
This research study focused on the development of sample preparation methods based on the pre-concentration and separation of arsenic(III) and selenium(IV) in water.
A solid phase extraction method (SPE) was used whereby a functionalised nanometre sized alumina adsorbent was prepared and applied for simultaneous pre-concentration and separation of arsenic and selenium in water prior to their ICP-OES determination. The prepared nanoparticles of the adsorbent were characterised with Fourier transformer infrared (FTIR), Scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), Braunuer Emmet and Teller (BET), X-ray diffraction (XRD), Transmission electron microscopy (TEM).
The optimal pH, mass adsorbent, eluent concentration, sample volume, sample flow rate were found to be 6,500 mg, 3 mol.L-1 HNO3, 100mL, 2 mL.min-1 ,respectively. Under these optimal experimental conditions the enrichment factor (EF) was 10, limit of detection (LOD) were 0.60 μg.L-1 and 2.17 μg.L-1 for As(III) and Se(IV), respectively. Limit of quantification were found to be 2.00 μg.L-1 for As(III) and 7.22 μg.L-1 for Se(IV). The precisions expressed in terms of relative standard deviation (RSD) were found to be 3.39% and 2.52% for arsenic and selenium metal ions, respectively. The % recovery of arsenic was greater than 80% and selenium was 90%. The proposed method was applied in the determination trace of arsenic and selenium in real water samples.
In the second method, batch adsorption was applied by using raw sieved avocado seed powder and carbon active material synthesised from raw avocado seed as adsorbents. The synthesized activated carbon material and raw avocado seed were characterised by X-ray Diffraction (XRD), Brunauer–Emmett–Teller (BET) and Scanning Electron Microscope coupled with Energy Dispersive Spectroscopy (SEM-EDS) and Fourier Transformation Infrared Spectroscopy (FTIR). The important parameters that affects adsorption were optimized according to the...