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Effect of pH, empty bed contact time and hydraulic loading rate on lead removal by granular activated carbon columns
Author(s) -
Reed Brian E.,
Jamil Maqbul,
Thomas Bob
Publication year - 1996
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143096x127875
Subject(s) - chemistry , adsorption , activated carbon , lead (geology) , carbon fibers , metal , hydraulic retention time , chromatography , nuclear chemistry , wastewater , environmental engineering , materials science , organic chemistry , environmental science , composite material , geomorphology , composite number , geology
Batch and column studies were performed to determine the effect of pH, empty bed contact time (EBCT), and hydraulic loading rate (HLR) on lead removal by granular activated carbon (GAC) columns. Lead removal increased with increasing pH, and for the majority of the adsorbate:adsorbent ratios investigated, was 100 % at pHs < pH prec . Column pH was extremely important to lead removal in GAC columns. A simple acid‐base regeneration procedure was found to be effective in desorbing/resolubilizing the carbon‐bound lead and raising the pH for the subsequent treatment run. Regeneration efficiencies were often less than 100%, but column performance was not adversely affected. For 1 mg/L lead, the optimum EBCT was between 6 and 7 minutes, whereas for 10 mg/L lead it was less than 10 minutes. The effect of HLR (4.9 and 9.8 m/hr) on column performance was minimal for 1 mg/L lead, whereas at 10 mg/L lead column removal was slightly better at the higher HLR. Carbon usage rates were higher than those observed for wastewaters containing organic contaminants, especially at 10 mg/L lead. However, given the relatively simple regeneration scheme, the applicability of GAC columns for metal‐bearing wastewaters appears to be technically feasible.