Facile synthesis and characterization of multi-walled carbon nanotubes decorated with hydroxyapatite from cattle horns for adsorptive removal of fluoride.

dc.contributor.authorOjok, Walter
dc.contributor.authorBolender, James P.
dc.contributor.authorWasswa, John
dc.contributor.authorNtambi, Emmanuel
dc.contributor.authorWanasolo, William
dc.contributor.authorMoodley, Brenda
dc.date.accessioned2023-07-31T10:53:00Z
dc.date.available2023-07-31T10:53:00Z
dc.date.issued2023-03-09
dc.description.abstractDeveloping a new adsorbent for fluoride removal from cattle horn waste materials by a facile chemical method has shown great potential for fluoride removal. This paper reports the synthesis of multi-walled carbon nanotubes decorated with hydroxyapatite from cattle horns (MWCNT-CH) using a facile chemical method. Characterization studies using standard techniques showed that the composite is mesoporous with a rough morphology and contained MWCNTs uniformly encapsulated by the hydroxyapatite forming a crystalline MWCNT-CH composite. Optimization of fluoride adsorption by the as-synthesized composite using Response Surface Methodology (RSM) showed that a maximum fluoride removal efficiency of 80.21% can be attained at initial fluoride concentration = 10 mg/L, pH = 5.25, adsorbent dose = 0.5 g and a contact time of 78 min. ANOVA indicates contribution of the process variables in descending order as pH > contact time > adsorbent dose > initial fluoride concentration. Langmuir isotherm (R2 = 0.9991) best described the process, and the maximum adsorption capacity of fluoride onto the as-synthesized MWCNT-CH composite was 41.7 mg/g. Adsorption kinetics data were best fitted in the pseudo-second-order kinetic model (R2 = 0.9969), indicating chemisorption. The thermodynamic parameter ( H = 13.95 J/mol and S = 65.76 J/mol/K) showed that fluoride adsorption onto the MWCNT-CH composite was a spontaneous, endothermic, and entropy-driving process. Moreover, the adsorption mechanism involves ion exchange, electrostatic interaction, and hydrogen bonding. Fluoride was successfully desorbed (using 0.1 M NaOH) from the composite in four cycles, retaining fluoride removal efficiency in the fourth cycle of 57.3%.en_US
dc.description.sponsorshipGerman Academic Exchange Service (DAAD) (Grant No. 91672385)en_US
dc.identifier.citationOjok, W., Bolender, J. P., Wasswa, J., Ntambi, E., Wanasolo, W., & Moodley, B. (2023). Facile synthesis and characterization of multi-walled carbon nanotubes decorated with hydroxyapatite from cattle horns for adsorptive removal of fluoride. Heliyon, 9(3).en_US
dc.identifier.issn2405-8440
dc.identifier.urihttps://dir.muni.ac.ug/handle/20.500.12260/549
dc.language.isoenen_US
dc.publisherElsevier Ltd.en_US
dc.subjectCattle hornen_US
dc.subjectFluoride adsorptionen_US
dc.subjectHydroxyapatiteen_US
dc.subjectKineticsen_US
dc.subjectMulti-walled carbon nanotubesen_US
dc.subjectResponse surface methodologyen_US
dc.titleFacile synthesis and characterization of multi-walled carbon nanotubes decorated with hydroxyapatite from cattle horns for adsorptive removal of fluoride.en_US
dc.typeArticleen_US

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