“…The use of adequate concentration of reagents in the heterogeneous Fenton-like process is essential in order to improve the reaction efficiency and then, to reduce the operational cost of the CWPO. As explained, an excess of solid catalyst loading could lead to excessive adsorption effect preventing proper activation of the oxidizing agent, whereas an excess of H 2 O 2 could either increase the possibility of recombination of the oxidizing radicals, make more likely the loss of them by scavenging species in the liquid phase or promote production of less active ROS such as HO 2 · ; besides, H 2 O 2 can also deactivate HO · radicals to H 2 O and O 2 (Tehrani-Bagha and Balchi, 2018), reaction more significant as the pH increases.Fig. 6Experimental evaluation of the multi-response optimal conditions of the CWPO reaction in terms of MS2 inactivation, fraction of reacted H 2 O 2 and decolourization: 0.33 g cat/L; 3.36 % (H 2 O 2 ) d , 25.0 °C, pH 0 = 7.07, DOC 0 = 16.06 mg C/L and 10 6 PFU/mL.…”
Section: Resultsmentioning
confidence: 99%
“…6). Some studies have proven that under an optimum (Fe active /H 2 O 2 ) ratio , the amounts of Fe and H 2 O 2 can be considerably reduced preventing extra-costs of operation by excess of reagents (Mirzaei et al., 2017; Tehrani-Bagha and Balchi, 2018). Furthermore, it could also reduce environmental impacts referring to processes at higher scales (Yamal-Turbay et al., 2013).…”
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.
“…The use of adequate concentration of reagents in the heterogeneous Fenton-like process is essential in order to improve the reaction efficiency and then, to reduce the operational cost of the CWPO. As explained, an excess of solid catalyst loading could lead to excessive adsorption effect preventing proper activation of the oxidizing agent, whereas an excess of H 2 O 2 could either increase the possibility of recombination of the oxidizing radicals, make more likely the loss of them by scavenging species in the liquid phase or promote production of less active ROS such as HO 2 · ; besides, H 2 O 2 can also deactivate HO · radicals to H 2 O and O 2 (Tehrani-Bagha and Balchi, 2018), reaction more significant as the pH increases.Fig. 6Experimental evaluation of the multi-response optimal conditions of the CWPO reaction in terms of MS2 inactivation, fraction of reacted H 2 O 2 and decolourization: 0.33 g cat/L; 3.36 % (H 2 O 2 ) d , 25.0 °C, pH 0 = 7.07, DOC 0 = 16.06 mg C/L and 10 6 PFU/mL.…”
Section: Resultsmentioning
confidence: 99%
“…6). Some studies have proven that under an optimum (Fe active /H 2 O 2 ) ratio , the amounts of Fe and H 2 O 2 can be considerably reduced preventing extra-costs of operation by excess of reagents (Mirzaei et al., 2017; Tehrani-Bagha and Balchi, 2018). Furthermore, it could also reduce environmental impacts referring to processes at higher scales (Yamal-Turbay et al., 2013).…”
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.
“…To solve the previous drawback, a water-insoluble solid catalyst can be used. This heterogeneous Fenton process is called catalytic wet peroxide oxidation (CWPO) [19][20][21]. The CWPO has been mainly used to oxidize phenols and their derivatives [20,22].…”
“…Wet air oxidation (WAO) and wet peroxide oxidation (WPO) are two wastewater treatment methods used to effectively remove (mineralize) high concentrations of persistent, toxic, and nonbiodegradable organic pollutants [1]. WAO takes place at elevated temperatures and pressures using gaseous oxygen or air as oxidant [2].…”
Section: Introductionmentioning
confidence: 99%
“…Classic WPO, homogeneous Fenton, uses Fe 2+ and H 2 O 2 to efficiently reduce the organic load of wastewaters. Although the process is very efficient and fast, it has a few disadvantages: It is only efficient at 2-4 pH, iron salt will remain in solution upon process completion, and a high amount of Fe 2+ and H 2 O 2 is required [1]. All these disadvantages can be overcome by using the heterogeneous process, in which Fe 2+ is supported on a porous matrix.…”
Iron-doped carbon xerogels were prepared using sol-gel synthesis, with potassium-2,4-dihydroxybenzoate and formaldehyde as starting materials, followed by an ion exchange step. The obtained samples were characterized (XRD, FTIR, SED-EDX, TEM) and investigated as catalysts in heterogeneous Fenton and catalytic wet air oxidation (CWAO) processes. Experiments were conducted in the same conditions (0.1 g catalysts, 25 mL of 100 mg/L dye solution, 25 °C, initial solution pH, 3 h) in thermostated batch reaction tubes (shaking water bath, 50 rpm) at atmospheric pressure. A series of three cationic dyes were considered: Brilliant green (BG), crystal violet (CV), and methyl green (MG). Dyes and TOC removal efficiencies up to 99% and 92%, respectively, were obtained, in strong correlation with the iron content of the catalyst. Iron content measured in solution at the end of the reaction, indicated that its amount was less than 2 ppm for all tested catalysts.
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