Cost-effective degradation of ultra-high concentration polyvinyl alcohol through peroxymonosulfate based oxidation using nano spinel CoFe2O4 deposited acidified diatomite as the catalyst

To degrade the ultra-high concentration polyvinyl alcohol present in the disposable nuclear protective clothing, nano spinel CoFe2O4 was successfully deposited on acidified diatomite, serving as a catalyst to activate peroxymonosulfate. CF@Dt consists of a base layer with high mechanical strength, which was wrapped by a dense catalytic layer. CF@Dt/PMS reduced the molecular weight of PVA from over 100,000-1380 Da in 300 min, with a total organic carbon removal of 76.3 %. This proves the superiority of CF@Dt/PMS system in degrading ultrahigh concentrations of PVA. The performance of CF@Dt/PMS process in PVA degradation was well maintained under a wide range of pH conditions. Although CoFe2O4/PMS process also achieved decent degradation of PVA, CF@Dt exhibited better stability and longer reusability than CoFe2O4. The low metal dissolution rate of CF@Dt was attributed to the chemical interaction between the hydroxyl groups of diatomite and CoFe2O4, as well as the pore confinement effect of diatomite. center dot OH was found to be crucial in the degradation of PVA by CF@Dt/PMS, with minimal impact from the electron transfer mechanism. The mechanisms of PMS activation by CoFe2O4 and CF@Dt were investigated by density functional theory. Furthermore, an economic evaluation of various PVA degradation processes revealed that the CF@Dt/PMS system is the most cost-effective option.