Functions of phosphorus additives on immobilizing heavy metal cadmium in the char through pyrolysis of contaminated biomass

Abstract Pyrolysis was applied for post treatment of two crop residues contaminated by heavy metal cadmium (Cd) after biosorption, with phosphorus additives used for enhancing the recovery and stability of Cd in the char. The results indicate that phosphoric acid (PA) can increase the Cd recovery in char to a level of > 90% at the PA dosage of 71-143 mg/g biomass, when the plant residues were pyrolyzed at 350 °C. The pyrolysis with phosphorus additives reduced the bioavailable Cd to