Hydroxyapatite-PEG/Fe3O4 Composite for Adsorption of Phenol from Aqueous Solution
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Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Sriwijaya
Poedji Loekitowati Hariani   

Department of Chemistry, Sriwijaya University Jl Palembang Prabumulih Km 32 Ogan Ilir 30662 Indonesia, Jl Palembang Prabumulih Km 32 Ogan Ilir 30662, 30662, Ogan Ilir, Indonesia
Submission date: 2020-05-12
Final revision date: 2020-07-26
Acceptance date: 2020-07-27
Online publication date: 2020-12-02
Publication date: 2021-02-05
Pol. J. Environ. Stud. 2021;30(2):1621–1629
Hydroxyapatite-PEG/Fe3O4 composites were prepared using the co-precipitation method and applied for phenol removal from the solution. The composites synthesized within ratios of hydroxyapatite to Fe3O4 of 3:1, 2:1, and 1:1 at a fixed amount of polyethylene glycol. The properties of resulting materials were evaluated using XRD, FTIR, SEM-EDS, and VSM while the surface areas were calculated using the BET method. The effectiveness of the composites on phenol removal was studied, including contact time, solution pH, and initial concentration. Hydroxyapatite surface area decreased by the addition of Fe3O4 on the composites with ratios of 3:1, 2:1 and 1:1 from its initial value of 264.6 to 245.2, 237.3 and 201.4 m2 g-1, respectively. As the amount of the Fe3O4 impregnated increased, the magnetic properties increased to 44.1, 57.8, and 65.5 emu g-1. A composite having a ratio of 2:1 was chosen for phenol adsorption due to its optimum combined properties, namely the surface area and magnetism. The Langmuir isotherm model best described the phenol adsorption by hydroxyapatite and the chosen composite resulting in adsorption capacities of 88.49 and 95.24 mg g-1, respectively. The composite was found to be more effective, can be separated and easily regain using a permanent magnet. The pseudosecond order kinetics shows a higher correlation on describing the mechanism of phenol adsorption by both materials. The negative value of ΔG0and ΔH0 shows that the adsorption process is spontaneous and exothermic.