Four types of biochars were prepared out of chicken droppings or wheat straw through pyrolysis at 350 or 650 ℃separately and analyzed for physic-chemical properties. Batch sorption tests were conducted to explore Cd~(2+)adsorption characteristics of the biochars relative to duration of the adsorption,pH of the solution,and Cd~(2+)concentration in the solution. Results show that the higher the temperature of pyrolysis,the higher the pH,ash content,aromaticity and hydrophobicity and the lower the polarity of ...