Potential application of SDSO-layered double hydroxide in wastewater treatment: Synergy between hydrophobicity and activation activity

Abstract

The hydrophobic surface properties of catalysts, generally overlooked in the field of sulfate radical-based advanced oxidation processes (SR-AOPs), have significant potential in enhancing the applicability of catalysts in realistic wastewater treatment. The conflicting nature of hydrophobicity and activation activity presents considerable challenges in developing heterogeneous oxidation. To overcome such limitation, herein, different surfactants were employed to regulate the surface properties of CoCu-layered double hydroxides (LDH) for the activation of peroxymonosulfate (PMS). Our results demonstrated that by comparison with sodium dodecyl sulfate (SDS) and sodium laurate (SLA), sodium dodecyl sulfonate (SDSO) regulated LDH (SDSO-LDH) exhibited the most effective interpolation of organic anions into the interlayer space, simultaneously showing efficient ability for PMS activation and hydrophobicity. The SDSO-LDH/PMS system exhibited excellent degradation performance of various emerging contaminants (ECs), with Co(IV) = O and SO₄^•- species identified as the dominant oxidative intermediates. Density functional theory (DFT) calculations further confirmed the thermodynamic feasibility of these reactions. Moreover, the effective degradation of intrinsic organic substances in realistic wastewater and sustained hydrophobicity establishes SDSO-LDH a competitive candidate catalyst for SR-AOPs. The synergy between activation activity and hydrophobicity offers a novel perspective for the application of SR-AOPs in wastewater treatment.