Persulfate and hydrogen peroxide-activated degradation of bisphenol a with nano-scale zero-valent iron and aluminum

In the present study, hydrogen peroxide (HP) and persulfate (PS)-activated nanoscale zero-valent iron (nZVI) and zero-valent aluminum (nZVAl) heterogeneous treatment systems (nZVI/HP-PS and nZVAl/HP-PS) were investigated for the removal of 20 mg/L (88 M) aqueous Bisphenol A (BPA). Oxidation with HP and PS in the absence of nanoparticles did not cause BPA degradation, whereas the nZVI/O2/H+ and nZVAl/O2/H+ treatment systems resulted in 33% and 38% BPA removals at an initial reaction pH of 3, respectively. Activation of nZVI and nZVAl with HP or PS improved BPA and TOC removals due to the enhancement of hydroxyl and sulfate radicals generation. Removal efficiencies decreased upon increasing the reaction pH from 3 to 5, while a remarkable enhancement in BPA and TOC removals was evident when nZVI was activated with PS. Complete BPA removal was achieved by using 1 g/L nanoparticle activated with 2.5 mM HP or PS at pH 3 for the nZVI/HP and nZVAl/HP-PS treatment combinations, whereas 84% BPA removal was obtained for nZVI/PS treatment. Highest TOC removal was achieved as 90% for nZVI/PS treatment at pH 5 and nZVAl/PS treatment at pH 3. Treatment performances correlated with the HP/PS consumption and Fe/Al release rates.