Fraction Distribution Changes of Heavy Metals in Co-pyrolysis of Sewage Sludge and Corn Straw

Maiz's short sequential extraction procedure was used to extract the heavy metals in the carbon residues made from sewage sludge by co-pyrolysis with corn straw. The content of heavy metals in the residues was determined by ICP-MS to study the fraction distribution changes of heavy metals. It is concluded that the content of mobile and mobilization heavy metals exsisted in the residue decrease and the content of residual heavy metals increase due to the co-pyrolysis. The co-pyrolysis temperature has great effect on the fraction distribution changes of heavy metals. The content of residual fraction for Cr, Ni, Pb is up to the top at 700 degrees C and for Cd,Cu,Zn is at 500 degrees C. The carbon residues are unhazardous and safe.