Synthesis, Characterization, and Analytical Applications of a New Chelating Resin Containing p‐Bromophenylhydroxamic Acid

Synthesis, Characterization, and Metal Adsorption Properties of Formaldehyde-Based Terpolymeric Resins Derived from Anthranilic Acid, Salicylic Acid, and Catechol

Two formaldehyde-based terpolymeric resins (anthranilic acid-catechol-formaldehyde (ACF) and salicylic acid-catechol-formaldehyde (SCF)) have been synthesized by condensing anthranilic acid with catechol and salicylic acid with catechol at 80 ± 5°C using dimethylformamide as a solvent. The resins were characterized by spectral analysis using Fourier-transform infrared (FTIR) spectroscopy. The physical-chemical properties of the resins have been studied. The exchange behavior of various metal ions, namely, Cd2+, Cr3+, Ca2+, and Mg2+, towards the synthesized resins has been studied depending on contact time and pH. Chelating properties of two resins were pH dependent, and with an increase in pH value from 1 to 5, the exchange capacity of metal ions was increased. The increasing rate of ion-exchange capacity was greater in ACF than that in SCF. Cd2+ showed higher rate of exchange at different time intervals in both cases, ACF and SCF. Cr3+ had higher exchange capacity with pH variation in both resins.

Characterization of hydroxybenzoic acid chelating resins: Equilibrium, kinetics, and isotherm profiles for Cd(II) and Pb(II) uptake

Chelating ion-exchange resins were synthesized by polycondensation of ortho/para hydroxybenzoic acid with resorcinol/catechol employing formaldehyde as cross-linking agent at 80?5?C in DMF. The resins were characterized by FTIR and XRD. The uptake behaviour of synthesized resins for Cd(II) and Pb(II) ions have been studied depending on contact time, pH, metal ion concentration and temperature. The sorption data obtained at optimized conditions were analyzed by the Langmuir and Freundlich isotherms. Experimental data of all metal-resin system were best represented by the Freundlich isotherm. The maximum obtained sorption capacity for cadmium was 69.53 mg g-1 and 169.32 mg g-1 for Lead. The adsorption process follows first order kinetics and the specific rate constant Kr was obtained by the application of the Lagergan equation. Thermodynamic parameters ?Gads, ?Sads and ?Hads were calculated for the metal-resin systems. The external diffusion rate constant (Ks) and the intra-particle diffusion rate constant (Kid) were calculated by the Spahn-Schlunder and Weber-Morris models, respectively. The sorption process was found to follow an intra-particle diffusion phenomenon.