Immobilization conditions of iminodiacetic acid onto methacrylate resins containing glycidyl groups

The conditions for immobilization of iminodiacetic acid onto a methacrylate resin consisting of a copolymer of glycidyl methacrylate and ethylene glycol dimethacrylate, the pH of the iminodiacetic acid aqueous solution, the concentration of iminodiacetic acid, the reaction time, the amount of solution, and the resin/solution ratio were investigated. Based on the Cu(II) capture capacity and the amount of iminodiacetic acid immobilized determined by elemental analysis, a pH of 11.0 was found to be suitable for immobilization. A resin with a maximum Cu(II) capture capacity (0.54 mmol g ⁻¹) and iminodiacetic acid immobilization amount (0.48 mmol g ⁻¹) could be prepared by reacting the resin for 20 hours at a concentration of 37 wt% iminodiacetic acid while heating and stirring at 50°C and 120 rpm . The rapidity of Cu(II) capture of resins with different iminodiacetic acid immobilization amounts was evaluated based on the pseudo-second-order reaction rate constant in a batch-type solid-phase extraction operation. The resin with the smallest iminodiacetic acid immobilization amount (0.27 mmol g ⁻¹) showed the largest rate constant. This result suggests that resins with a small iminodiacetic acid immobilization amount, i.e., a small immobilization density, may be superior in rapid element capture.