Physicochemical characterisation of unmodified oil palm mill fly ash and its adsorption of copper (II) and lead (II) ions from aqueous solutions
This study was conducted to test the capability of locally abundant oil palm mill fly ash (OPMFA) in its ability to adsorb copper(II) and lead(II) ions from aqueous solutions. The OPMFA sample was collected from a local palm oil mill. Sample characterisation was carried out in order to understand it...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2017
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/38958/1/24%20PAGES.pdf https://eprints.ums.edu.my/id/eprint/38958/2/FULLTEXT.pdf |
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| Summary: | This study was conducted to test the capability of locally abundant oil palm mill fly ash (OPMFA) in its ability to adsorb copper(II) and lead(II) ions from aqueous solutions. The OPMFA sample was collected from a local palm oil mill. Sample characterisation was carried out in order to understand its physicochemical properties. Different experiments related to characterisation including, particle size distribution analysis, leaching test, surface area and pore distribution, elemental analysis, Fourier transform infrared analysis, surface morphology, point of zero charge, adsorbent pH in distilled water and thermogravimetric analysis were conducted to understand its behaviour as an adsorbent. The OPMFA was observed to be fine in nature from grey to black in colour with highly porous irregular structure with BET specific surface area of 24.04 m2/g and average pore diameter of 2.37 nm. The OPMFA was found to be safe for use, as an adsorbent, as no heavy metal leach out was detected upon Atomic Absorption Spectrometry analysis. The point of zero charge of OPMFA found in this study was 8.9, which favours the adsorption of copper(II) and lead(II) ions, and specific functional groups responsible for adsorption were found upon FT-IR analysis. Batch adsorption experiments were conducted to test the ability of OPMFA to adsorb copper(II) and lead(II) ions from aqueous solutions. The effects of particle size, contact time, agitation rate, adsorbent dosage, initial concentration, pH and accompanying anions were experimented. The particle size fraction of 0.150 < x ≤ 0.200 mm with 60 min of contact time at agitation speed of 150 rpm were the optimum conditions observed in this study. Additionally the adsorbent dosage of 0.1 g per 100 mL with the initial concentration of metal ions of 10 mg/L at the natural pH 5.5 are the suitable conditions for effective adsorption. Nitrate ions were selected in this study as the counter ion effect was the lowest compared to sulphate, acetate and chloride ions. The isotherm studies revealed that the adsorption of copper(II) and lead(II) ions followed the monolayer adsorption pattern with maximum adsorption capacity of 153.85 and 181.82 mg/g, respectively. The kinetic studies illustrated that the pseudo-second order model better fitted the kinetic data compared to other kinetic models suggesting that chemisorption is the rate limiting step. |
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