P. vittata is one of the hyperaccumulators of arsenic(As)

the combustion experiments were conducted in a horizontal tube furnace to investigate the transformation behavior of As during the combustion of P. vittata.Results show that the release of As in P. vittata increased first then decreased

reaching the highest at 500℃.With increasing temperature from 400℃ to 500℃

the higher release rate is due to the volatility of the inorganic As at lower temperature.With further increase the temperature from 500℃ to 900℃

As release decreased which may be attributed to the fast oxidation of As and the formation of some inorganic compounds.Moreover

the soluble As in the solid residue mainly presents as As5+

and the content varies largely with the temperature with a peak value of 81% of total As at 800℃.The content of soluble As5+ decreases before 500℃ due to the volatility of the inorganic As.The physical adsorption of some compounds plays an important role for the As fixation at the temperature from 500℃ to 700℃

while the As fixation is mainly conducted by the chemical oxidation at 800℃.The content of soluble As5+ decreases a little

possibly because of the sintering of the ash.Considering the As recycling process

800℃ is recommended as the optimum combustion temperature for the P. vittata.