Feasibility Study of UV Activated Persulfate Oxidation of Glutaraldehyde

Abstract

Glutaraldehyde (GA) is widely used as a broad-spectrum biocide for medical instrument disinfection; however, residual GA may inhibit biological treatment processes and adversely affect receiving environments. This study evaluated the ultraviolet-activated persulfate (UV/S2O82–) process for generating sulfate radical (SO4•–) to degrade GA and examined the effects of persulfate (PS) dosage and UV intensity on degradation, mineralization, reaction kinetics, and oxidant consumption. Batch experiments were conducted using a 254 nm low-pressure mercury lamp, and treatment performance was assessed by measuring GA concentration, total organic carbon (TOC), and residual PS. GA remained largely stable under pH adjustment, PS alone, and UV alone, demonstrating that direct photolysis and unactivated PS were ineffective. In contrast, UV/S2O82– rapidly degraded GA and caused initial solution acidification. Increasing PS dosage and UV intensity enhanced GA removal and TOC mineralization; however, excessive PS produced diminishing improvements, likely because of radical self-consumption and competing side reactions. Kinetic analysis at 8 W UV and 0.5–1.0 mM PS indicated an SO4•–-dominated mechanism, with steady-state radical concentrations of approximately 10–8 M. These findings support UV/S2O82– as a promising pretreatment technology for GA-containing wastewater and provide guidance for process optimization and scale-up.