Scalable and sustainable remediation of OPD-contaminated aquifer via amphipathic multi-component covalent organic polymers

Abstract

In-situ injection technology provides a sustainable approach for decontaminating o-phenylenediamine (OPD). However, existing agents often exhibit either exclusive hydrophilicity or hydrophobicity, posing challenges in achieving both effective interception and transport within the aquifer. Herein, a facilely and massively synthesized amphipathic multi-component covalent-organic polymer (SLEL-4) demonstrates appreciable transportability (L_max > 182.81 cm) and exceptional competitive adsorption ability (four times that of TWEEN 80) for OPD removal. Meanwhile, quantitative analysis expounds the underlying mechanisms. Column and sandbox experiments co-unravel that SLEL-4 effectively remediates actual groundwater contaminated with OPD, achieving sustained efficacy up to 48 h. Impressively, the constructed SLEL-4 deserves recognition as an eco-responsible and cost-optimal option for groundwater treatment according to Life Cycle Assessment (LCA). Overall, this work offers a refreshing perspective on fabricating amphipathic COPs as promising replacements for surfactants in the decontamination of non-aqueous phase liquids (NAPLs), while underscoring the environmental burdens associated with scalable implementation.