Removal Properties, Mechanisms, and Performance of Methyl Green from Aqueous Solution Using Raw and Purified Sejnane Clay Type

Abstract

Adsorption of cationic methyl green (MG) on nontreated (AB) and purified (AP) natural Sejnane clay type was studied in an equilibrium batch process. This work reported the application of kaolinite-rich heterogeneous clay for the removal of a cationic dye. Effects of contact time, initial dye concentration, mass adsorbent, pH, and temperature on the MG removal were checked. The adsorbent before and after adsorption processes was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and atomic adsorption spectrophotometer. Equilibrium data were mathematically modeled using the Freundlich, Langmuir, and intraparticle diffusion models. Kinetic of adsorption was determined by pseudo-first-order and pseudo-second-order models. The free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°) were calculated. A fast increase in the equilibrium removal of the cationic dye was obtained at a pH ranging between 3 and 11 and moderate temperature. This rapid MG adsorption proved the efficiency of kaolinite clay in cationic dye removal. Decolorizing yields were 73.3% for AB and 99.8% for AP. Thus, the adsorption capacity of purified clay was clearly higher than of H2SO4 and thermic activated clays. The data more closely resembled a pseudo-second-order model process, and the clay had reasonable Freundlich adsorption capacity. Adsorption process was endothermic and spontaneous chemisorption. SEM analysis showed that the adsorbed MG had remarkably changed the morphology of raw and purified clay surface. The low desorption rates confirmed effectiveness of this type of material for the retention of methyl green molecules. Thus, tested clays have no environmental impact.

Green Synthesis of pH-Responsive, Self-Assembled, Novel Polysaccharide Composite Hydrogel and Its Application in Selective Capture of Cationic/Anionic Dyes

“…Similarly, composites containing CH, a positively charged biopolymer, exhibited higher adsorption potential for anionic dye, MO. Previously, clays ( Satlaoui et al, 2019 ) and carbon nanotubes ( Bahgat et al, 2012 ) have been utilized for MG dye adsorption with adsorption efficiencies of nearly 150 and 181.2 mg g −1 , respectively. Recently, Wu et al (2021) utilized halloysite nanotubes (HNTs) and chrysotile nanotubes (ChNTs) for MO dye adsorption with efficiency of 13.56 and 31.46 mg/g, respectively.…”

Study on the Adsorption of Cr3+ by Peanut Shell: Adsorption Kinetics, Thermodynamics, and Isotherm Properties

“…The kinetic study of the adsorption process focuses on describing the residence time of the adsorbate at the solid‐liquid interface. The adsorption kinetic model can be described by the Lagergren first‐order rate equation: [31–34] $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr {\rm dq}/{\rm dt}={\rm k}{_{1}}({\rm q}{_{{\rm e}}}- {\rm q})\hfill\cr}}$$$ …”

“…The kinetic study of the adsorption process focuses on describing the residence time of the adsorbate at the solid-liquid interface. The adsorption kinetic model can be described by the Lagergren first-order rate equation: [31][32][33][34] dq=dt ¼ k 1 ðq e À qÞ (7) Where q is the adsorption amount (mg/g) at a certain time t, t is the reaction time (min), k 1 is the adsorption kinetic rate constant (min À 1 ), and q e is the equilibrium adsorption amount (mg/g).…”

Facile Synthesis of ZIF-67 for the Adsorption of Methyl Green from Wastewater: Integrating Molecular Models and Experimental Evidence to Comprehend the Removal Mechanism

“…The test solution was conducted at room temperature (27 °C), pH 11, with varying initial concentrations of ZIF-67 (0.5 to 2.5 g L −1 ). This shows that the adsorption efficiency of ZIF 67 increased from 0.5 to 2.0 g/L (MG concentration 100 mg/L) and then decreased when adsorbate concentration was increased to 2.5 g/L in the starting solution [ 32 ].…”