GRANULAR ACTIVATED CARBON - IMPORTANCE OF SURFACE-PROPERTIES IN THE ADSORPTION OF NATURALLY-OCCURRING ORGANICS

The presence of dissolved organic matter (humic material in particular ) in source water decreases the effectiveness of granular activated ca rbon filters in the treatment of drinking water. Results from potentio metric titrations. electrophoretic mobility measurements and BET surfa ce area analyses suggest that this may be due to an increase in the ne gative charge on the carbon surface and a decrease in available surfac e area after adsorption. An increase in pH and the application of heat causes organics to desorb. After a subsequent acid treatment the carb on exhibits an increased ability to adsorb dissolved organic material. X-ray photoelectron spectroscopy was used to examine the carbon surfa ce before adsorption, after adsorption and after regeneration treatmen t.