In order to develop a new process for lowering harmful heavy metals from anaerobically digested sewage sludge, the adsorption and recovery of heavy metals from acidified sewage sludge were investigated using a fibrous chelating agent enwrapped with a nylon mesh bag. First, heavy metals in simulated wastewater were adsorbed to the chelating fiber through the nylon mesh with opening of 30 μm. Heavy metals adsorbed to the fiber were successfully desorbed with dilute sulfuric acid at a pH of 1. Next, the leaching of heavy metals from anaerobically digested sewage sludge was conducted by adjusting the pH of the sludge to 2 with sulfuric acid for 48 hours. And then, the pH of the acidified sludge was adjusted to 2.5, 3 and 4 after the addition of nylon mesh bag including the fiber. The optimum pH values in the adsorption with the fiber were 2.5 for Cu, 3 for Pb, and 4 for Cd, Cr, Ni and Zn, respectively. The application of the fibrous chelating agent would be useful for the recovery of soluble heavy metals from acidified sludge without using an acid tolerant solid-liquid separator.
繊維状キレート剤を用いた酸性化汚泥からの重金属類の吸着除去および回収
dgrg-v77n7pIII_375-Ⅲ_383
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