Surface acidity of carbons characterized by their continuous pK distribution and Boehm titration

A study of ignition of metal impregnated carbons: the influence of oxygen content in the activated carbon matrix

“…The peat-based carbon seems to have more species with pK a in the acidic range than the coconut-based material. This is also reflected in its low surface pH [16][17][18][19]. After oxidation, the surface of coconut-based carbon becomes very heterogeneous form a chemical point of view.…”

Surface Chemistry of Activated Carbons: Combining the Results of Temperature-Programmed Desorption, Boehm, and Potentiometric Titrations

“…For all carbons, except the C-CN sample, the number of basic sites significantly decreased as a result of oxidation. Another "wet" chemistry method used to determine the surface chemistry of carbons is potentiometric titration (10)(11)(12). In this method it is assumed that the system under study consists of acidic sites characterized by their acidity constants, K a .…”

“…The "wet" techniques involve titrations such as Boehm (3) and potentiometric titrations (10)(11)(12). "Dry" methods include diffuse reflectance FTIR (DRIFTS) (9, 13), X-ray photoelectron spectroscopy (XPS) (14,15), thermal analysis (TA) (16), and thermal programmed desorption (TPD) (17,18).…”

Preparation and characterization of trihydroxamic acid functionalized carbon materials for the removal of Cu(II) ions from aqueous solution

“…Thus this is maintained up to a much higher pH value than in the case of F (pH pzcMerck = 8.3) [24]. The accumulation of negative surface charge on both ACs surfaces at pH > pH pzc is likely due to the deprotonation of weak acid oxygen functions on the surfaces of the sorbents (mainly phenol, anhydride and lactone types) [52][53][54]. Furthermore, the deprotonation of water molecules coordinated to alkaline metal ions (at pH > 9) on C centers of the sorbents also contributes to the increase of negative surface charge [55][56][57].…”