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

Abstract

[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.

Analog and Digital Bipolar Resistive Switching in Co–Al-Layered Double Hydroxide Memristor

“…In hexazinone adsorbed on Co-Al LDHs, two bands at 2975 and 2849 cm −1 disappeared, and a new band of hexazinone appeared at 1349 cm −1 , which indicates symmetric vibrations of hexazinone. The broad strong absorption band centered at 3396 cm −1 originated from the stretching vibrations of surface and interlayer hydroxyl groups [42], as shown in Figure 2b. The weaker band at 1648 cm −1 came from the bending mode of water molecules.…”

“…The broad strong absorption band centered at 3396 cm −1 originated from the stretching vibrations of surface and interlayer hydroxyl groups [ 42 ], as shown in Figure 2 b. The weaker band at 1648 cm −1 came from the bending mode of water molecules.…”

Acid‐Thermally Modified Merremia vitifolia for the Removal of 2,4‐Dichlorophenoxyacetic Acid

“…Three consecutive bands appeared after 2,4-D biosorption at 1144, 1080, and 1017 cm -1 . The newly formed peak at 1080 cm -1 indicates the symmetric vibration of 2,4-D [30].…”

CaFe-Based Layered Double Oxides With Superior Iron Alloy Corrosion Inhibition Behaviors in Aggressive Seawater Environment

“…6) and pseudo-second-order (Eq. 7) models based on experimental data (Calisto et al, 2019;Rathee et al, 2019):…”