Three porous shapeable three-component hydrogen-bonded covalent-organic aerogels as backfill materials in a simulated permeable reactive barrier (PRB) for trapping levofloxacin

Levofloxacin (LEV) infiltrated in groundwater has threatened the safety of drinking water. For in-situ remediation of LEV-contaminated groundwater, there exists a main challenge of exploiting proper high efficient backfill medium in utilizing charming permeable reactive barriers (PRBs). Herein, three porous shapeable three-component hydrogen-bonded covalent organic aerogels (H_COA-1, H_COA-2 and H_COA-3) were fabricated based on a multiple-linking-site strategy to evaluate for adsorptive removal of LEV. The three H_COAs exhibited satisfactory performance in LEV adsorption that could integrate high adsorption capacity, good antiion interference, excellent recyclability and wide pH tolerance. The different regularity of kinetics and isotherms of three H_COAs signified that electrostatic effect, pore preservation, hydrogen bonding probably govern the adsorption process in combination, coupling with π-π electron-donor-acceptor (EDA), dipole-dipole and hydrophobic-hydrophobic interaction besides. In addition, the response surface methodology (RSM) was employed for studying the single and synergetic effects of selected variables and optimizing operation conditions. Furthermore, a laboratory PRB column packed with processable H_COA-2 was set up to investigate the LEV removal, and the breakthrough data was explained by Adams-Bohart, Thomas, BDST and Yoon-Nelson models. We believe could hopefully bring H_COAs into the real in-situ remediation of such challenging and persistent LEV-polluted groundwater with further massive-scale efficiently.