Application of biochar in advanced oxidation processes: supportive, adsorptive, and catalytic role

Study of polarized activated carbon filters as simultaneous adsorbent and 3D-type electrode materials for electro-Fenton reactors

“…The acidic treatment of AC further modifies the surface characteristics of the adsorbent, such as the type and concentration of functional groups [ 10 , 42 ]. Fang et al for example, reported an increase in the number of oxygen-containing functional groups (such as OH, HCO, R (CO) R’, COOH, and phenolic O-H) on the surface of AC upon HNO 3 treatment.…”

“…In this way, acid activation of AC results in a significant aliphatic AC oxidation that derives in oxygen containing functionalities on its surface [ 49 ]. Typically, carboxylic, ketonic and amine groups as well as other oxygen-containing moieties are expected to increase the polar and hydrophilic character of the surface; thus modifying adsorptive and electrocatalytic properties [ 10 , 42 , 49 ] that in turn, should influence the performance of AC materials in an EF reactor. In this way, in addition to the AC source, the application of an acid pre-treatment was defined a second variable for the study.…”

“…These source materials are activated either with HNO 3 , H 2 SO 4 , HCl, H 3 PO 4 , NaOH or KOH and then thermally treated by pyrolysis, carbonization or hydrothermal treatment, to obtain activated carbon (AC). In addition to their excellent adsorbent properties, AC substrates are characterized by reasonable electric conductivity and a high density of polar, oxygenated surface chemical units such as carboxylic (—COOH), hydroxide (-OH) and carbonyl (-CO-) functional groups [ 10 , 11 ].…”

Electro-Fenton degradation of a ternary pharmaceutical mixture and its application in the regeneration of spent biochar

“…It is essential to consider that hydrogen peroxide and hydroxyl radicals were in the same setting in the pores and on the surface of the carbonaceous material, favouring the fast initial cracking reactions [34]. Faheem et al [35] also reported that the biochar could also act as an "electron shuttle" due to its electron-accepting nature which assists in regulating the electron transfer reactions and favouring the degradation reactions [35]. Concerning the structure, mesoporous biochar plays a key role in its regeneration, it being the most appropriate for such goal, which is in agreement with a previous report [36].…”

Characterization and Sodium Cations Sorption Capacity of Chemically Modified Biochars Produced from Agricultural and Forestry Wastes

“…The presence of mineral (ash) components (e.g. carbonates, phosphates, or oxides) can pose both positive and negative effects on the supportive removal of contaminants where different sorption properties can be obtained during biochar deashing [17,18]. In terms of biochars derived from crop residues, e.g., straw or husk, the chemical pre-treatment might be necessary to remove excess amounts of Na + [19], as part of the Na that exists in chlorides, carboxylates, or carbonates in biochar can be easily leachable, contributing to the salinization process [20].…”