High-efficient removal of phthalate esters from aqueous solution with an easily regenerative magnetic resin: Hydrolytic degradation and simultaneous adsorption

Abstract

Efficient removal of phthalate esters (PAEs) is of considerable concern since they pose serious ecological and human health risks. In this study, a magnetic strong base anion-exchange resin named MAER-OH was prepared and used as a solid basic catalyst and effective adsorbent. The MAER-OH was systematically characterized by scan electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermos-gravimetric analyses and vibrating sample magnetometer. Various factors influencing the removal of dimethyl phthalate (DMP) such as initial DMP concentration, resin dosage and temperature were investigated. The DMP can be completely converted to far less toxic phthalate at the final treatment stage, and more attractively, the potential hydrolysis intermediates were ion-exchanged by the resin simultaneously without obvious change of solution pH. The co-existing chloride was found to obviously enhance the DMP removal efficiency but result in an obvious increase of solution pH and formation of much more hydrolytic intermediates. The exhausted MAER-OH could be regenerated by 8.0% NaOH solution with negligible efficiency loss, and maintain its virgin removal efficiency for 20 successive cycles. Sequencing batch jar tests indicated that more than 5000 bed volumes of DMP solution (10 mg L−1) were efficiently treated by the MAER-OH and the saturated capacity of MAER-OH for DMP removal was 134.9 mg g−1. Taken together, this highly effective and reusable MAER-OH can be easily modularized and separated, promising its huge potential for industrial-scale PAEs wastewater treatment.