Sorption and degradation of phthalate esters by a novel functional hyper-cross-linked polymer

Abstract

A novel functional hyper-cross-linked polymer (NFHP) modified with trimethylamine was prepared. NFHP was characterized by FTIR, XPS, XRD, SEM and Micromeritics ASAP-2010 automatic surface area analysis instrument. Adsorption and hydrolysis degradation of phthalate acid esters (PAEs) by NFHP were also investigated as a function of temperature, equilibrium concentration and PAEs types. Results indicated that NFHP could adsorb and catalyze hydrolysis of PAEs simultaneously. There was a positive relationship between the removal capacity and temperature, equilibrium concentration, and PAEs hydrophobicity. However, the increase of PAEs equilibrium concentration and hydrophobicity resulted in the decreased level of their hydrolysis, while high temperature promoted the hydrolysis of PAEs. Film diffusion was the rate controlling step of the removal process. The apparent removal rate of PAEs increased as temperature increased due to the higher diffusion coefficient at higher temperature. The results of continuous fixed-bed runs demonstrated that NFHP was capable of synchronously removing PAEs and their hydrolysis products from tap water. In the effluent solution, the PAEs concentration was below the detection limit (0.01 mg/L) of HPLC within 1400 BVs. Moreover, the exhausted NFHP beads can be completely regenerated for repeated use. Physical adsorption, hydrolysis degradation and ion-exchange played significant roles in removing of PAEs and their hydrolysis products. The analysis of hydrolysis products, FTIR and XPS spectra proved that physical adsorption, hydrolysis and ion-exchange were the main removal mechanism. The results reported herein suggested that this novel material has a great potential in efficient removal of PAEs from wastewater.