Adsorptive Removal of Oxygenated Organosulfur Compounds from Peroxymonosulfate-Treated Waters Using Micron-Sized Amorphous ZrOx

Oxygenated organosulfur compounds are oxygen-containing organic sulfur species, including organosulfates, sulfonates, and other sulfur-containing oxidation products. These compounds can persist after peroxymonosulfate (PMS) oxidation, yet their subsequent removal remains poorly understood. Here, micron-sized amorphous ZrOx (MA-ZrOx) was evaluated as an adsorbent for post-PMS treatment. In model-compound experiments at an initial concentration of 100 ng/L, five of seven representative compounds achieved removal efficiencies of at least 98% within 10 min. Density functional theory (DFT) calculations suggested that multiple hydrogen-bonding contacts and steric accessibility contributed to compound-dependent adsorption. In natural organic matter (NOM)-simulated water and two natural waters, MA-ZrOx adsorption after PMS oxidation removed 37.8–54.3% of residual total organic carbon, accompanied by a decrease in the number of detected oxygenated organosulfur formulas. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) revealed that O-rich N-free formulas showed higher apparent capture than the reference group (O = 4, N = 0), while N-containing groups showed higher pooled capture across the three waters. Exact formula-pair comparisons further indicated that CH2 increments were associated with an initial decrease in apparent capture followed by a recovery. These findings support MA-ZrOx adsorption as a complementary treatment step for controlling residual oxygenated organosulfur compounds after PMS oxidation.