MS2 coliphage inactivation by Al/Fe PILC-activated Catalytic Wet Peroxide Oxidation: multiresponse statistical optimization

The optimization of the Catalytic Wet Peroxide Oxidation (CWPO) assisted by an Al/Fe-pillared clay (Al/Fe-PILC) was assessed in the inactivation of the MS2 coliphage in the presence of a synthetic surrogate of natural organic matter (NOM). The simultaneous effect of two experimental factors (i) H(2)O(2) dose - (H(2)O(2))(d) (3.00–25.50 % of the H(2)O(2) theoretically required for full mineralization) and (ii) catalyst concentration (0.33–2.60 g/L), and four non-controllable variables (covariates) (a) circumneutral pH (6.00–9.00), (b) temperature (5.00–25.0 °C), (c) synthetic NOM concentration (2.0–20.0 mg C/L) and (d) MS2 titer (10(4), 10(5) and 10(6) PFU/mL) was investigated by Response Surface Methodology (RSM). Every response was modeled and maximized: (1) MS2 inactivation, (2) fraction of reacted H(2)O(2), (3) decolourization and (4) NOM mineralization. Multi-response optimization via desirability function based on responses (1) to (3) achieved excellent fitting (0.94 out of 1.0) and following set of optimal experimental conditions: 0.33 g Al/Fe-PILC/L, 3.36 % (H(2)O(2))(d) ​(Fe(active)/H(2)O(2)) = 0.46, giving rise to 92.9 % of MS2 inactivation and 100 % of reacted H(2)O(2) at pH 7.07, 25.0 +/- 0.1 °C, 16.06 mg C/L as starting NOM concentration, and MS2 titer of 10(6) PFU/mL after just 70 min ​of reaction.