Adsorption-reduction of Fe(III) by different biochars and their co-activation of H2O2 for oxidation of refractory pollutants

Long Cycle Life Rechargeable Moisture‐Enabled Electricity Cell

“…f) XPS fitting curves for elemental Fe in rMEC after the workng phase. [ 23 ] g,h) Schematic representations of the working phase of rMEC. i) Prolonged working of rMEC leading to depletion of the Fe ion concentration gradient and subsequent performance degradation.…”

“…Simultaneously, electrons are transferred to O 2 on the Au electrode, generating a concentration gradient of OH − in the PDDA layer near the Au electrode, as shown in Figure 4b,c. The redox reactions accompanying the above process are as follows: [ 23 ] $$$$\begin{equation}{\mathrm{Fe}}\left( {\mathrm{s}} \right) + 2{{\mathrm{H}}_2}{{\mathrm{O}}_2}\left( {{\mathrm{aq}}} \right) \leftrightarrow {\mathrm{F}}{{\mathrm{e}}^{2 + }}\left( {{\mathrm{aq}}} \right) + 2{{\mathrm{H}}_2}{\mathrm{O}} + {{\mathrm{O}}_2}\left( {\mathrm{g}} \right) + 2{\mathrm{e}}\end{equation}$$$$ $$$$\begin{equation}2{\mathrm{F}}{{\mathrm{e}}^{2 + }}\left( {{\mathrm{aq}}} \right) + {{\mathrm{H}}_2}{{\mathrm{O}}_2}\left( {{\mathrm{aq}}} \right) + 2{{\mathrm{H}}^ + }\left( {{\mathrm{aq}}} \right) \leftrightarrow 2{\mathrm{F}}{{\mathrm{e}}^{3 + }}\left( {{\mathrm{aq}}} \right) + 2{{\mathrm{H}}_2}{\mathrm{O}}\end{equation}$$$$ $$$$\begin{equation}{{\mathrm{O}}_2}\left( {\mathrm{g}} \right) + 2{{\mathrm{H}}_2}{\mathrm{O}}\left( {{\mathrm{aq}}} \right) + 4{\mathrm{e}} \leftrightarrow 4{\mathrm{O}}{{\mathrm{H}}^ - }\left( {{\mathrm{aq}}} \right)\end{equation}$$$$…”

“…Simultaneously, electrons are transferred to O 2 on the Au electrode, generating a concentration gradient of OH − in the PDDA layer near the Au electrode, as shown in Figure 4b,c. The redox reactions accompanying the above process are as follows: [23] Fe (s)…”

Coactivation of Hydrogen Peroxide Using Pyrogenic Carbon and Magnetite for Sustainable Oxidation of Organic Pollutants

“…In addition to being a capable adsorbent of pollutant, , pyrogenic carbon can mediate electron transfer in redox reactions. − For example, biochar alone can activate H 2 O 2 , and persulfates , to produce ROS for oxidation of pollutants. However, the yield of • OH from H 2 O 2 decomposition in the biochar-activated system was less than 10% while H 2 O and O 2 are the dominant products. , Thus, pyrogenic carbon was more often used as the supporting material of other active ingredients (e.g., iron nanoparticles) to enhance the performance of AOPs. − The supporting effect of carbon, such as dispersion of magnetic nanoparticles and/or enriching pollutants to the interfacial reaction sites, has been focused in the previous studies. , Co-activation of H 2 O 2 using pyrogenic carbon and iron sources together provides a novel solution for the sustainable oxidation of organic pollutants, because pyrogenic carbon can mediate microbial reduction of Fe­(III) − and may facilitate the regeneration of Fe­(II) in Fenton reaction (eq ). Thus, the enhanced oxidation efficiency of pollutants by coactivation of H 2 O 2 using biochar and aqueous iron (Fe­(III) or Fe­(II)) has been observed in our previous studies. , However, little is known about the performance of pyrogenic carbon on coactivation of H 2 O 2 with magnetite, although magnetite has been reported to be a reactive iron mineral to catalyze Fenton reaction.…”

Unveiling the Potential of Corn Cob Biochar: Analysis of Microstructure and Composition with Emphasis on Interaction with NO2

“…Secondly, it has a highly porous structure offering a large surface area, thereby supplying numerous sites that can enhance its adsorption capacity for NO 2 molecules [ 27 ]. Thirdly, it is comprised of carbonaceous materials from biomass, such as agricultural waste or forest residues [ 29 ]. Such biomass sources are plentiful and renewable, making biochar a sustainable option for NO 2 adsorption when compared with conventional adsorbents.…”