Application of Fe3O4@THAM-CH2CH2Cl magnetic nanoparticle as a new adsorbent in ultrasonically assisted removal of Congo red from aqueous solutions

The objective of this work was to evaluate the efficiency of a promising ultrasonically assisted adsorption with the Fe3O4@THAM-CH2CH2Cl magnetic nanoparticle (MNPS) as a new adsorbent for the elimination of Congo red from water samples. The FE-SEM images show that Fe3O4@THAM-CH2CH2Cl MNPs adsorbent is spherical. Due to the presence of pores on the Fe3O4@THAM-CH2CH2Cl MNPs adsorbent surface, the proposed adsorbent can remove Congo red from the aqueous environment by trapping the pollutant in its pores. Different parameters influencing the ultrasonically assisted adsorption (UAA) by the Fe3O4@THAM-CH2CH2Cl MNPs adsorbent, including the dye concentration and adsorbent mass, ultrasonic time, and pH, were studied and optimized by multivariate methods. The best adsorption efficiency was obtained at 0.04 g of adsorbent, 17 mg.L-1 of dye, pH = 6.6, and ultrasonic treatment for 7.2 min. The results indicated that the efficiency of dye adsorption ranged from 97.85 to 99.65 %. The kinetic, isotherm, and thermodynamic for the proposed method were assayed. The larger R2 for the pseudo-second kinetic model indicates that this model is more suitable to describe the adsorption process of Congo red on the Fe3O4@THAM-CH2CH2Cl MNPs adsorbent. The Langmuir adsorption isotherm had a larger correlation coefficient (R2 = 0.9987), which indicates it fits best with the experimental data and is more suitable for the Congo red adsorption process. Analysis of actual samples showed that Congo red removal values (R %, mean ± standard deviation, n = 3) in tap water and wastewater were 98.48 ± 1.52 % and 98.05 ± 2.11 %, respectively.