Simultaneous removal of organic and heavy metal contaminants by granular activated carbon (GAC) columns

摘要

A series of pilot-scale granular activated carbon (GAC) column experiments were performed to determine the feasibility of simultaneously removing heavy metal and organic contaminants from waste streams. The following synthetic waste streams were examined: (1) 1 mg/L lead (Pb) only, (2) process water containing diverse anions and cations spiked with 1 mg/L Pb, (3) 1 mg/L Pb and 10 mg/L phenol, and (4) 1 mg/L Pb and 1 mg/L trichloroethylene (TCE). Column breakthrough curves were determined and column performance parameters were calculated. For the Pb-only wastewater, column effectiveness was not strongly dependent on the empty bed contact time (EBCT) or on upstream Pb desorption/resolubilization from the first column in serial column operation. Pb removal decreased by about 50% in the presence of other cations and anions (complex matrix) and was attributed to the column pH being about 1 pH unit lower than the Pb-only experiments. Pb removal was not significantly affected by the presence of phenol; however, due to its amphoteric nature, phenol desorbed at the high pHs encountered during the base rinse portion of the regeneration step and during the initial portion of the treatment run. GAC columns were most effective for treating the Pb-TCE wastewater because TCE did not desorb at high pH values. Four treatment runs with Pb-TCE wastewater were conducted and the base rinse portion of the regeneration scheme was recovered and reused. TCE breakthrough did not occur during any portion of the column experiment. [References: 15]