Efficient recovery of aromatic compounds from the wastewater of styrene monomer and propylene oxide co-production plant via hypercrosslinked aryl-rich starch-β-cyclodextrin polymeric sorbent

Abstract

• A hydrophilic HSPS-ACD(H) with high porosity was fabricated. • HSPS-ACD(H) is a new benchmark sorbent for uptake of AP and 1-PE. • Competitive or synergetic adsorption of co-existing aromatics was studied. • Efficient recovery of the target aromatics was demonstrated in fixed bed column. • DFT calculations provided insights into mechanism for selective adsorption. Adsorptive recovery of valuable components from industrial wastewater is highly desirable for avoiding resource wastage but remains a challenge. Herein, we develop an efficient continuous adsorption process for recovering aromatic compounds in wastewater from styrene monomer and propylene oxide co-production (SMPO) plant. Based on our insight into the potential of bio-based porous materials for adsorption application, starch-graft-polystyrene (SPS) and aryl-modified β-cyclodextrin (ACD) were prepared, and novel hypercrosslinked porous polymers combined SPS with ACD (HSPS-ACDs) were synthesized through external crosslinking approach. In a binary-component system, the best-performing one HSPS-ACD(H) with high ACD content and large specific surface area possessed superior capacities for the representative aromatic compounds, acetophenone (AP, 2.81 mmol·g −1 ) and 1-phenylethanol (1-PE, 1.35 mmol·g −1 ) compared with the previously reported materials. Further, the adsorption properties of aromatic compounds on HSPS-ACD(H) were investigated in batch mode. For practical application, continuous adsorption experiments were conducted in a HSPS-ACD(H)-packed fixed bed, where the target aromatic components in wastewater were effectively retained and further released by elution. Besides showing the reversible adsorption and efficient enrichment effect, the HSPS-ACD(H)-packed fixed bed also maintained great stability in multiple cycles. Moreover, quantum chemical calculations were performed to elucidate the potential mechanism of adsorption of AP and 1-PE onto HSPS-ACD(H).