The Study Of Granular Activated Carbon Loaded With Silver For The Adsorption Of Haloacetic Acids In Drinking Water

In this article, DCAA and TCAA of the carcinogenic organic compound are as adsorbates, the granular activated carbon as adsorbent, and then loaded silver ions on granular activated carbon. Exploring the optimal amount of silver, comparing the removal of DCAA and TCAA between unmodified GAC and silver modified GAC, the adsorption kinetics of unmodified GAC and silver modified GAC, the effect of adsorption and the influence of pH on the adsorption, providing theory basis for preparation of new and effective adsorbents.These are main conclusions:(1) When the concentration of Ag+ is lOmg/L, the adsorption capacity of DCAA and TCAA reached the maximum. When the quantity of silver modified GAC add to 600mg/L, the removal of DCAA and TCAA almost reach the equilibrium, and the removal efficiency of DCAA is 90 percentage, the removal efficiency of TCAA is 94 percentage. For silver modified GAC, it's beneficial to the adsorption of DCAA and TCAA in acid condition.(2) In mono-base condition, Langmuir, Freundlich and amendatory Freundlich equation all match the experimental results well. So when the concentration is less than 250μg/L, the HAAs removed by unmodified GAC and silver modified GAC are both showed mono-layer adsorption. In different equilibrium concentration, both unmodified GAC and silver modified GAC have high affinity of DCAA and TCAA.(3) In multi-base condition, the competitive adsorption exist in HAAs. The adsorption capacity of TCAA is less influenced than DCAA by GAC, the adsorption capacity of TCAA is slightly reduced than mono-base condition, while the adsorption capacity of DCAA is significantly reduced than mono-base condition.