Modification of granular activated carbons for enhanced adsorption of dissolved organic matter. Adsorption isotherms

The effect of activated carbon pore structure and surface chemistry on the adsorption of dissolved organic matter (DOM) from natural water was studied. High temperature ammonia treatment of F400, He (F400,He,8N2H) did not have a significant impact on both physical and chemical characteristics of the precursor, thus on the DOM uptake. High temperature ammonia treatment of oxidized carbons would be a promising method to enhance DOM uptake of granular activate carbon (GAC), since it is possible to simultaneously develop a more mesoporous and basic (with some nitrogen functionalities) carbon. The isotherm results showed that this treatment is effective for both raw and treated (through conventional treatment processes) waters. The isotherms for both F400,He,16NO and F400,He,16NO,Fe3E showed the least DOM uptake among all carbons tested. To decrease surface acidity, F400,He,16NO,Fe3E carbon was treated with ammonia at 800°C. After ammonia treatment, a basic and more mesoporous carbon (F400,He,16NO,Fe3E,8N2H) was produced. The isotherm results showed that this carbon had significantly higher DOM capacity than virgin F400 for both raw and treated waters.