Surface chemistry of wood‐based phosphoric acid‐activated carbons and its effects on adsorptivity

Abstract

The surface oxygen content of selected wood-based phosphoric acid-activated carbons was quantified using X-ray photoelectron spectroscopy (XPS) and correlated with the residual bulk phosphate levels of the carbons and their adsorptivity in solution. The adsorption of Al 3+ , Cu 2+ , and parachlorophenol, respectively, from water decreased as a function of increasing surface oxygen content of the carbons. When the carbon of lowest surface oxygen content was oxidized with ozone to impart a surface oxygen content comparable to that of a carbon with a much higher phosphate level, adsorption of Al 3+ , Cu 2+ , and para-chlorophenol from water decreased proportionally. The increase in polarity of the carbon surface was accompanied by a decrease in pH and appeared to be the dominant factor with respect to the adsorption of the target species from water.

Effects of Ozone Dissolved in Water on the Physicochemical Properties of Activated Carbons Applied in Drinking Water Treatment

“…As shown by the plots depicted in Figure 4 and by the data listed in Table 1, increasing surface oxygen content had a negative effect on the adsorption of p-chlorophenol. Similar decreases in the extent of adsorption of p-chlorophenol with increasing carbon surface acidity after ozone oxidation have been observed and reported previously (Álvárez et al 2005;Baker et al 2005).…”

Selection and evaluation of adsorbents for the removal of anionic surfactants from laundry rinsing water

“…This is most likely the result of the different activation method for Norit C Gran, which was activated with phosphoric acid instead of steam. Activation with phosphoric acid results in more oxygen groups at the surface and will give a weakly negatively charged, acidic surface (Baker et al, 2005). Wu and Pendleton (2001) stated that an inverse linear relationship exists between the amount of anionic surfactant adsorbed and the oxygen content of the adsorbent surface.…”