Degree of Pb stabilization in MSWI fly ash using size-fractionated natural fishbone hydroxyapatite

Authors : Mitali NAG, Amirhomayoun SAFFARZADEH, Takayuki SHİMAOKA, Hirofumi NAKAYAMA

Pages : 137-147

Doi:10.35208/ert.998326

View : 15 | Download : 14

Publication Date : 2022-06-30

Article Type : Research Paper

Abstract :Incineration is a common technique worldwide for treating Municipal Solid Waste insert ignore into journalissuearticles values(MSW);. However, incineration residues insert ignore into journalissuearticles values(e.g., bottom and fly ash); require special treatment to prevent environmental risks due to the high content of heavy metals. The present study evaluated the stabilization degree of Pb, a toxic heavy metal in MSW incineration fly ash insert ignore into journalissuearticles values(IFA); treating by size-fractionated natural fishbone insert ignore into journalissuearticles values(FB); hydroxyapatite insert ignore into journalissuearticles values(HA);. Bones from various fish species were used at different size fractions insert ignore into journalissuearticles values(<600 µm, 600 µm–2 mm, and 0–2 mm);. The effect of different fishbone hydroxyapatite insert ignore into journalissuearticles values(FB-HA); sizes was studied by batch tests under the FB/IFA ratios of 0.0 and 1:10 insert ignore into journalissuearticles values(wt.);, the contact or settling time of 6, 12, 24, and 672 hours, and the fixed W/S ratio of 1.5 mL/g. Using only 10% FB, Pb stabilization efficiency after 672 hours obtained 95.55% and 94.24% for FB sizes <600 µm and 600 µm–2 mm, respectively, and about 86.1% for non-fractionated FB insert ignore into journalissuearticles values(0–2 mm);. The results indicated that contact time was the most critical factor for enhanced Pb stabilization. The FB particle size of 0–2 mm was deemed appropriate for Pb immobilization in short and long time settling periods. The adsorption isotherms were fitted well with the Langmuir and Freundlich models. The R L values of the Langmuir model were less than one and the n values of the Freundlich isotherm lie between 3 and 5, conferring the favorable adsorption of Pb to FB-HA for all size fractions.
Keywords : Fishbone hydroxyapatite, fly ash, heavy metal, size fractionation, stabilization