Modification of disused floral foam with polyethylene diamine for the removal of heavy metal ions

Abstract

Floral foam (FF) based on phenol formaldehyde resin has been used widely for many years, but it is re-used rarely and the discarded FF is harmful to environment. Therefore, recycling of disused FF is interesting and highly required. In current study, a new strategy for reutilization of disused FF was proposed. FF which had been treated with NaOH solution was dipped in polyethyleneimine (PEI) solution to anchor active amino groups on the framework of FF, and then glutaraldehyde was employed to cross-link the anchored PEI to obtain a novel adsorbent based on disused FF (PEI@FF). Due to the abundant amino groups, the prepared adsorbent displayed satisfactory chelating ability towards heavy metal ions. Under the optimal synthesis and adsorption conditions, the PEI@FF was applied to remove Cu(II), Cd(II) and Pb(II) in environmental waters, and the removal rates varied from 91.4% to 95.6%, which were much higher than that achieved on unmodified FF (35–43%). Additionally, the PEI@FF exhibited good batch-to-batch preparation repeatability and acceptable number of cyclic utilization. The satisfactory results well evidence the proposed method is practicable for reutilization of discarded FF, and the present study also supplies a new adsorbent for the high efficient removal of heavy metal ions.