Dual functional cobalt-yttrium binary oxide activation of peroxymonosulfate for degradation of phenylphosphonic acid and simultaneous adsorption of phosphate product

Cobalt-yttrium binary oxide (CYBO) was successfully fabricated, which exhibited excellent catalytic performance in the activation of peroxymonosulfate (PMS) and superior adsorption capacity towards phosphate (116.3 mg-P/g). The results demonstrated that a complete degradation of phenylphosphonic acid (PPOA) within 30 min and a thorough removal of phosphate product within 60 min could be realized in the system of CYBO/PMS. CYBO also possessed superb reusability and stability, and no decline of the PPOA degradation and phosphate removal was observed during 5 cycles at initial pH 7. The decomposition of PPOA and the adsorption of phosphate were strongly dependent on solution pH. In an initial pH range of 3 to 7, both PPOA and phosphate product could be efficiently removed. However, almost no PPOA was degraded at initial pH 11. SO4 center dot-, (OH)-O-center dot, and O-1(2) (especially SO4 center dot- and (OH)-O-center dot) were identified as main reactive oxygen species responsible for the PPOA degradation and the formation of phosphate product. The produced phosphate was simultaneously eliminated via anion/ligand exchange. Combined with identification of PPOA degradation intermediates via HPLC-QTOF-MS2, the calculation of frontier electron densities based on Density Functional Theory was used for proposing reasonable degradation pathways. In addition, the toxicity assessment via Toxicity Estimation Software Tool was utilized to appraise eco-environmental effect. Our findings may shed some light towards the application of CYBO in the control of organophosphorus pollution and the reduction of water eutrophication.

Automated summary

Cobalt-yttrium binary oxide (CYBO) showed excellent catalytic performance in activating peroxymonosulfate (PMS) and had superior adsorption capacity for phosphate removal. The degradation of phenylphosphonic acid (PPOA) and the removal of phosphate by CYBO were pH-dependent, with efficient removal at pH 3-7 and minimal degradation at pH 11. Reactive oxygen species such as SO4 center dot-, (OH)-O-center dot were identified as responsible for the degradation of PPOA and formation of phosphate product.