Intracellular and extracellular organic matter removal by BT/C heterogeneous interface under visible light photodriven

Abstract

Algae-derived organic matter (AOM) limits the effectiveness of conventional water treatment processes, affects the normal operation of water treatment plants, and causes water quality deterioration. Efficient elimination of AOM is an urgent issue in the advanced treatment of drinking water. In this study, A heterogeneous interface for AOM removal was established based on BT/C, which can be driven by visible light. The removal efficiencies of extracellular organic matter (EOM), intracellular organic matter (IOM), and AOM by BT/C reached the optimal levels at 30 min, 60 min, and 90 min, respectively, reaching 48.5 %, 81.8 %, and 74.0 %. BT/C can oxidize and break down a large amount of high-molecular-weight organic matter in EOM into medium- and low-molecular-weight organic substances, and effectively remove the low-molecular-weight organic matter in EOM. In addition, BT/C can efficiently remove humic acids(HS) and aromatic protein organic matter in IOM, directly mineralize or decompose high-molecular-weight biopolymers into small-molecular-weight acidic and neutral organic matter; electron paramagnetic resonance spectroscopy and reactive oxygen species trapping experiments verified that hydroxyl radical (·OH) have play most important role on the degradation of various molecular weight organic matters. Superoxide radical (·O2–) plays a dominant role in the oxidation process of soluble microbial metabolites and HS, and ·OH plays a significant role in the oxidation process of amino acid-like proteins. This study provides new ideas and technical support for the complete removal of algae-derived organic matter and the protection of drinking water safety.