Micropollutant elimination from complex water matrices by microporous covalent triazine frameworks

Abstract

Organic micropollutants (OMPs), such as pharmaceuticals and endocrine disruptors, have been recognized as threats to both ecosystems and human health. Several advanced polymeric adsorbents have been developed over the last decade to address the issue of OMP pollution. However, their efficacy in complex mixtures is rarely assessed to evaluate their applicability. This study presents the technical feasibility of an emerging covalent triazine framework (CTF) adsorbent with a high surface area (1226 m2 g−1) and nitrogen-rich triazine cores for OMP removal from water. The CTF adsorbent demonstrated ultrafast adsorption kinetics, with 85% removal of bisphenol A within 10 s, and was superior to activated carbon (AC) based on mass transfer and effective diffusion coefficients. It also exhibited remarkable durability by maintaining performance for 10 cycles without pore collapse and versatility by achieving above 99% removal of individual OMPs. However, in mixed OMP systems, the CTF exhibited a significant decline in adsorption kinetics, with the pseudo-second-order rate constant (k2) decreasing by up to 62.4-fold as compared to individual OMPs. Importantly, the presence of co-existing impurities in real water matrices inhibited both the instant and overall removal of mixed OMPs due to competitive adsorption and steric hindrance. This study is a concrete example of the significance of examining advanced polymeric adsorbents under environmentally relevant conditions.