The degradation of phenolic compounds through persulfate (PS) activation is a valuable approach for soil/groundwater remediation. Several reports have been made related to PS activation and contaminant degradation using carbo-catalysts; however, there is no detailed study on soil remediation by colloidal activated carbon. This study demonstrates the phenol (PhOH) degradation efficiency in spiked and field-contaminated soils by a novel and low-cost ball-milled colloidal activated carbon (CACBM) catalyst. The CACBM/PS system exhibited outstanding degradation performance for PhOH in both spiked and field-contaminated soils. Optimum condition for degradation of 5.63 mmol PhOH kg soil-1 was achieved at 2.5 mg CACBM g soil-1, 5 mM PS, and a solid-liquid ratio of 1:5 at 25 °C in the wide pH range of 3-11. Radical scavenger experiments and electron spin resonance (ESR) spectroscopy revealed that both radical (•OH and SO4•-) and non-radical (1O2) species were involved in the CACBM/PS system. PhOH degradation in soil phase followed several degradation pathways, resulting in various intermediate byproducts such as acetic acid, maleic acid, p-benzoquinone, fumaric acid, and ferulic acid as analyzed by ultra-high-performance liquid chromatography with mass spectroscopy (UPLC-MS). The CACBM/PS system showed a promising potential in the remediation of organic-contaminated soil.
Keywords: Advanced oxidation process; Colloidal activated carbon; Non-radical mechanism; Oxidation kinetics; Soil remediation.
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