Intrinsic Activity of SBA-like Silica in the Catalytic Ozonation of Organic Pollutants

Catalytic ozonation of Orange-G through highly interactive contributions of hematite and SBA-16 – To better understand azo-dye oxidation in nature

“…This explains the higher acidic character of SBA-16 as compared to SBA-15 which has parallel channels and almost no catalytic activity in ozonation (Ouargli et al, 2016). TPD measurements revealed lower CO 2 retention capacities (CRC) between 20 and 80 C of only 9.3e19.5 mmol g À1 for SBA-16 versus 14.5e52.3 mmol g À1 for SBA-15 (Table S1).…”

“…After 5 min of ozonation, clear A/A 0 decreases were reported at 259 nm and 478 nm till total disappearance after 10 min even without catalyst (Ouargli et al, 2016). This was attributed to changes around the azo bond and complete degradation of common chromophoric groups of both OG and its first derivatives (Xu and Li, 2010;Deng et al, 2008).…”

“…The corresponding depletion of A/A 0 at 421 nm ( Fig. 1) must be due to cleavage of the phenyl and naphtyl rings (Ouargli et al, 2016). The low A/A o values registered without catalyst indicate that this ratio is not necessarily proportional to the residual OG amount.…”

“…Initial OG concentration ¼ 10 À4 M in water. Ozone (600 mg h À1 ) was injected at 25 C. Fe 3þ -silanol and oxalate interactions, as reported earlier (Ouargli et al, 2016;Shahidi et al, 2015aShahidi et al, , 2015b.…”

“…Pure silicas have scarcely been investigated (Ouargli et al, 2016), because of their limited catalytic activity due to the lack of permanent surface charge and cation exchange capacity (CEC). In highly crystalline frameworks like SBA-16 that belongs to the Santa-Barbara Amorphous family, the lack of lattice defects may also contribute to the limited catalytic activity .…”