Magnetizing Calixarene: Azo Dye Removal from Aqueous Media by Fe₃O₄ Nanoparticles Fabricated with Carboxylic-Substituted Calix[4]arene

Abstract

Calix­[4]­arene was reacted with isonipecotic acid to synthesize the Mannich base derivative, and Fe3O4 magnetic nanoparticles were bonded to the lower rim of the calix[4]­arene derivative through ether linkage to obtain carboxylic calix[4]­arene magnetic nanoparticles (CCMN). After characterization with transmission electron microscopy and Fourier transform infrared spectroscopy, adsorption studies were carried out for the removal of azo dyes (Evans Blue and Chicago Sky Blue 6 B). Adsorption parameters such as effects of pH, dosage, concentration, temperature, and time were optimized. Results showed that adsorption equilibrium was achieved within 15 min, and maximum % adsorption was calculated as 95% for both dyes at pH 2.5. An equilibrium isotherm study suggests that the adsorption mechanism follows a chemical ion exchange process with an adsorption capacity value of 13.9 and 17.5 mmol g–1 for Evans Blue and Chicago Sky Blue 6 B, respectively. The adsorption kinetic follows pseudo-second-order kinetics as anticipated from R 2 values, whereas thermodynamic parameters suggest an endothermic reaction that can also be evident from ΔG° values, which decreased with an increase in temperature suggesting a spontaneous reaction. In addition, the dye removal efficiency of CCMN was hardly effected after 10 consecutive cycles. The study suggests that the magnetically retrievable calix[4]­arene is a promising adsorbent for removal of azo dyes from aqueous solution.

Effective Removal of the Direct Black-38 Dye from Wastewater Using a New Silica-Modified Resin: Equilibrium and Thermodynamics Modeling Studies

“…It is clear in Figure that 99.1% of the DB-38 dye was removed using only 60 mg of DIS resin; increasing further the dosage was found to have no significant effect on the % removal of the DB-38 dye. In the literature, a similar phenomenon has been observed for the adsorption of RB-19, , MB, Evans blue, and Chicago sky blue B6 …”

“…In the literature, a similar phenomenon has been observed for the adsorption of RB-19, 23,30 MB, 31 Evans blue, and Chicago sky blue B6. 32 4.2. Optimization of pH.…”

“…Similarly, OH groups in the DIS resin become active and attract the negative part of the DB-38 dye and the overall net charges tightly bind the dye molecule to the DIS resin. Previously, different studies were performed using other dyes such as Evans blue and Chicago sky blue B6, which were removed successfully using carboxylic calix[4]­arene magnetic (CCM) nanoparticles at pH 2.5 . Another study was performed using 25,26,27,28-tetrakis-( N , N -diethy-l,2-aminoethylamidomethoxy)-calix­[4]­arene-based Amberlite XAD-4 resin for the effective removal of MO and MR dyes from water at pH 3 .…”

Adsorption of Methylene Blue Dye by Calix[6]Arene-Modified Lead Sulphide (Pbs): Optimisation Using Response Surface Methodology

“…On the other side, aromatic functions and aliphatic side groups that surround a hollow cavity with many dimensions depend on the specific phenolic units incorporated, which form a hydrophobic upper rim [ 25 ]. Calix[n]arene’s unique confirmations and complexation properties lend well in studies of synthetic, natural hosts, and the water treatment industry [ 26 , 27 ].…”

Removal of Acid Red 88 Using Activated Carbon Produced from Pomelo Peels by KOH Activation: Orthogonal Experiment, Isotherm, and Kinetic Studies

“…Many removal methods have been reported, such as advanced oxidation process [7][8][9], membrane filtration [10], ion exchange [11], electrochemical process [12,13], biological treatment process [14], and adsorption [15,16]. However, only few are accepted by industries.…”