Removal Of Chlorophenolic Compounds From Aqueous Solution By Adsorption Onto Various Activated Carbons Produced From Oil Palm Shell

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dc.contributor.authorHamad, Bakhtiar Kakil
dc.date.accessioned2018-08-03T07:31:59Z
dc.date.available2018-08-03T07:31:59Z
dc.date.issued2011-02
dc.description.abstractThis study seeks to explore the possibility of preparing mesoporous activated carbons from the oil palm shell agricultural by-product abundantly available in Malaysia. Physiochemical activation processes using sodium hydroxide, potassium hydroxide and potassium carbonate and impregnated with nitrogen and carbon dioxide gases were used to prepare the activated carbons. The experimental results showed that the activation temperature and time and the impregnation ratio of the chemical agents were significant factors affecting the yield of the activated carbons and adsorption efficiency for chlorophenolic compounds. All the activated carbons derived from oil palm shell were mesoporous with high surface areas (1571-2247 m2/g) and with the average pore diameters 2.2 - 2.7 nm. SEM micrographs demonstrated many orderly and developed homogeneous pores of the activated carbons. FTIR analyses illustrated the presence of different functional groups on the activated carbon surfaces. The adsorption rates of the chlorophenols increased with increasing contact time and initial concentrations (30-225 mg/L). The highest removal efficiency of the chlorophenols (CPs) onto the activated carbons was at pH 2 while the lowest removal efficiency was at pH 12. Adsorption of 4-chloro-2-methoxyphenol on all activated carbons was best fitted by the Langmuir isotherm model while adsorption of 2-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol were better fitted by the Freundlich and Temkin models. Adsorption of all chlorophenols was best described by the pseudo-second-order kinetic model. In general, the values of the activation energies were lower than 40 kJ /mol of all the adsorption processes, which represented physisorption mechanism. The negative values of ΔG° (0.01-5.29 kJ/mol) and ΔH° (0.77-12.14 kJ/mol) were obtained in all cases for all chlorophenols, indicating the spontaneous and exothermic nature of the adsorption process whereas the positive values of ΔS° (0.03-17.44 J/mol K) obtained demonstrated the affinity of the activated carbon for CPs and the enhancement of randomness at the solid–solution interface. Ethanol desorption was a feasible technique for regenerating the exhausted activated carbons.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/6171
dc.language.isoenen_US
dc.publisherUniversiti Sains Malaysiaen_US
dc.subjectPossibility of preparing mesoporous activated carbonsen_US
dc.subjectfrom the oil palm shell agriculturalen_US
dc.titleRemoval Of Chlorophenolic Compounds From Aqueous Solution By Adsorption Onto Various Activated Carbons Produced From Oil Palm Shellen_US
dc.typeThesisen_US
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