Discarded floral foam as a source for green preparation of sustainable adsorbent for quick and efficient removal of phenoxyacetic acid herbicides from waters

Due to the high toxicity and increasing consumption, efficient removal of phenoxyacetic acid herbicides (PAAHs) from water is imperative. In current study, a new adsorbent was prepared by modifying porous carbon derived from disused floral foam with chitosan (CS) (ACFC). Density functional theory (DFT) calculation uncovered that the amino and hydroxyl groups in the introduced CS played a critical role in the efficient adsorption of ACFC towards PAAHs. Batch experiments were performed to study the adsorption behaviors and removal mechanism. Under the optimal adsorption conditions, the PAAHs residues in various environmental waters were efficiently removed within 20 min by the ACFC, the removal rates varied from 81.9 % to 93.8 %, which remarkably better than that achieved on unmodified carbon (32.5-56.5 %). The maximum adsorption capacities were in the range of 172-221 μg/g. In addition, the prepared adsorbent presented excellent preparation repeatability and acceptable reusability. In comparison with reported adsorbents, the ACFC displayed some merits such as low cost, green, short removal period and high removal rate. The current study not only supplies a cost-effective and sustainable adsorbent for the removal of PAAHs residues from waters, but also opens up a new route for the recycle utilization of disused floral foam.