Adsorptive properties of rod-shaped silver nanoparticles-functionalized biogenic hydroxyapatite for remediating methylene blue and congo red

[Display omitted] •Biogenic hudroxyapatite (HAP) was successfully functionalized with Terminalia catappa-mediated silver nanoparticles (AgNPs)•The maximum monolayer adsorption capacities of AgNPs-functionalized HAP for congo red and methylene blue are 159.11 and 1039.07 mgg−1, respectively.•The adso...

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Veröffentlicht in:Inorganic chemistry communications 2022-08, Vol.142, p.109655, Article 109655
Hauptverfasser: Azeez, Luqmon, Adebisi, Segun A., Adejumo, Ayoade L., Busari, Hassan K., Aremu, Harun K., Olabode, Olalekan A., Awolola, Oluwadamilare
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Sprache:eng
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Zusammenfassung:[Display omitted] •Biogenic hudroxyapatite (HAP) was successfully functionalized with Terminalia catappa-mediated silver nanoparticles (AgNPs)•The maximum monolayer adsorption capacities of AgNPs-functionalized HAP for congo red and methylene blue are 159.11 and 1039.07 mgg−1, respectively.•The adsorption processes for both dyes was accurately described by Freundlich isotherm model.•The adsorption kinetics was best fitted to pseudo-second order and the rate-determining step was both controlled by adsorption and intramolecular diffusion.•The adsorption process was exothermic, spontaneous, and physical in nature. Periwinkle shelled-hydroxyapatite (HAP) was functionalized with Terminalia catappa-mediated silver nanoparticles (AgNPs) for effective methylene blue (MB) and congo red (CR) adsorption. The adsorbent, AgNPs-functionalized HAP, was characterized using scanning electron microscopy (SEM), energy dispersive X-ray (XRD) and Fourier Transform Infra-red (FTIR) spectroscopy. The adsorption process was significantly influenced by all batch adsorption parameters. The rod-shaped AgNPs-functionalized HAP with a 1.85 ± 0.84 µm thickness had a pH point of zero charge (pHpzc) of 7.09 and adsorbed congo red (CR) and methylene blue (MB) maximally at pH 2 and 11, respectively. Freundlich isotherm model accurately predicted the adsorption of both dyes. The monolayer adsorption capacities (qmax) ranged from 47.75 to 159.11 mgg−1 for CR and 1039.07 to 205.49 mgg−1 for MB, from 303 to 313 K. The kinetics of adsorption was best fitted to pseudo-second order while the rate-determining step was both controlled by adsorption and intramolecular diffusion. Adsorption process was spontaneous (-ΔG) with decreasing feasibility with increasing temperature, exothermic (-ΔH) with a decreased degree of randomness (-ΔS) and physical in nature. The considerably higher qmax of AgNPs-functionalized HAP implies its superiority over previously reported adsorbents for dyes. Hence, AgNPs-functionalized HAP is a more promising adsorbent for dye wastewater remediation.
ISSN:1387-7003
1879-0259
DOI:10.1016/j.inoche.2022.109655