Adsorption kinetic and thermodynamic studies of the 2, 4 – dichlorophenoxyacetate (2,4-D) by the [Co–Al–Cl] layered double hydroxide

Heliyon

Sheila C. Canobre¹  Leonardo L. Freitas²  Ingrid S. Pacheco²  Josiane S. Calisto²  Wélique S. Fagundes²  Laiane K. Santana²  Fábio A. Amaral² 

[1] Corresponding author.;LAETE - Laboratório de Armazenamento de Energia e Tratamento de Efluentes, Institute of Chemistry, UFU- Uberlândia Federal University, João Naves de Ávila Avenue, 2121, 38400-902, Uberlândia- Minas Gerais, Brazil;

关键词: Inorganic chemistry;    Environmental science;    Layered double hydroxides;    Adsorption;    Herbicide;    dichlorophenoxyacetate;   

DOI  :  

来源: DOAJ

【 摘 要 】

[Co–Al–Cl] layered double hydroxide (LDH) obtained by co-precipitation at constant pH 8 presented a single phase in a hexagonal unit cell parameters similar to the hydrotalcite (JCPDS 14-191) belonging to the rhombohedral crystal system and space group R(-3)m. The adsorption kinetics of 2,4-D onto [Co–Al–Cl] LDH was better described by the Pseudo Second-Order (best adjust R2 = 0.9998 for 60 mg L−1 2,4-D adsorption). Intra-particle diffusion model was not the sole rate-controlling factor, indicating the adsorption of 2,4-D by the [Co–Al–Cl] LDH is a complex process for the experimental conditions performed, involving both boundary layer and intra-particle diffusion. The adsorption isotherm adjusted better to the Freundlich model (R2 = 0.9845) and the ΔH° value of - 51.18 kJ mol−1 indicated the predominance of the physical adsorption. The FT-IR spectrum of LDH after adsorption presented 2,4-D bands together with those of LDH and XRD showed an increase in the interlamellar distance (d003) due to the intercalation of 2,4-D in the interlayer structure of the [Co–Al–Cl] LDH, corroborating inter and intra-particle adsorption data. Thus, [Co–Al–Cl] LDH, commonly used as electrodes in supercapacitors, can be effectively used as an adsorbent for the removal of 2,4-D from contaminated waters.

【 授权许可】

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