Biochar enhanced the degradation of organic pollutants through a Fenton process using trace aqueous iron

Co-catalysis of trace dissolved Fe(iii) with biochar in hydrogen peroxide activation for enhanced oxidation of pollutants

“…For example, Wang et al 29 and Hong et al 34 have proposed that PFRs in the biochar prepared at 500 °C were the dominant electron donors to reduce Fe( iii ) for activation of persulfates. However, our previous study has shown that the biochar prepared at 700 °C was more reactive on facilitating the Fe( iii )/Fe( ii ) cycle in Fenton process, 20 although Yang et al 58 and Zeng et al 30 have reported that there are few PFRs in the biochar prepared at 700 °C. Therefore, PFRs are not likely to be the major electron donors for reduction of Fe( iii ) in this study.…”

“…The H 2 O 2 or Fe( ii ) concentration was measured using UV-vis spectrophotometry (Spectrum 1920, Shanghai, China). 20 The total aqueous iron was measured by inductively coupled plasma-atomic emission spectrometry (ICP-AES) (Prodigy XP, Leeman, USA), and the TOC was determined on a total carbon analyzer (Elementar vario, German).…”

“…The biochar samples were derived from two different feedstock: one labeled as LB from a cereal waste aer making liquor, and another labeled as WB from a pinewood sawdust, according to the method reported in our previous study. 20 The temperature of 700 C for pyrolysis was selected for producing the biochar that has both relatively stable properties 40,41 and high reactivity in catalyzing Fenton process. 20 The carbon contents, ash contents and surface areas (Brunauer-Emmet-Teller (BET) method) were 66.0% AE 0.3% and 93.9% AE 0.4%, 23.4% AE 0.1% and 0.89% AE 0.03%, and 6.66 and 409 m 2 g À1 , respectively for LB and WB.…”

“…20 The temperature of 700 C for pyrolysis was selected for producing the biochar that has both relatively stable properties 40,41 and high reactivity in catalyzing Fenton process. 20 The carbon contents, ash contents and surface areas (Brunauer-Emmet-Teller (BET) method) were 66.0% AE 0.3% and 93.9% AE 0.4%, 23.4% AE 0.1% and 0.89% AE 0.03%, and 6.66 and 409 m 2 g À1 , respectively for LB and WB. More details regarding the compositions of these two biochars are provided in the ESI (Table S1 and Fig.…”

“…Biochar, being an electron-rich and conductive carbon material, can act as a reductant of Fe(III) for persulfate activation to enhance the degradation of organic pollutants, 29,30 and can also accelerate Fe(III)/Fe(II) cycle that is the rate-limiting step in Fenton and Fenton-like processes. 31,32 Thereby, the required dosage of Fe(II) in Fenton process can be diminished substantially by biochar, 20 which is benecial for minimizing the production of iron sludge that is still a challenge in Fenton process. 33,34 In this context, it is interesting to reduce further the iron concentration to a trace level that is close to natural environment, and to explore the interactions between trace iron and biochar on co-catalyzing the oxidation of pollutant by H 2 O 2 .…”