Degradation of trichloroethylene (TCE) by a modified Fenton reaction was investigated in aqueous solution. Fenton reaction can be significantly enhanced in the presence of Fe(II) chelated by cross-linked chitosan (CS) with glutaraldehyde (GLA) at neutral pH. A remarkable oxidative degradation of TCE (1.838 h(-1)) was observed in the modified Fenton system with Fe(II)-CS/GLA (10 mM and 2 g L(-1), respectively) and H(2)O(2) (318 mM), while no significant degradation (0.005 h(-1)) was observed in the classic Fenton reaction system with Fe(II) (10 mM) and H(2)O(2) (318 mM) at pH 7 in 5 h. The kinetic rate constants for the degradation of TCE in the modified Fenton system was dependent on the initial suspension pH, Fe(II) loading, CS/GLA dosage, and concentration of H(2)O(2). We observed the formation of surface Fe(II)-CS/GLA complex using microscopic analyses and identified Fe oxidation (Fe(II) to Fe(III)) coupled with H(2)O(2) reduction on the Fe(II)-CS/GLA surfaces during the modified Fenton reaction. Copyright 2010 Elsevier B.V. All rights reserved.