The use of chelating agents to modify the Fenton reaction is well-documented in the literature. Polymeric chelates (such as poly(acrylic acid), PAA) provide multiple binding sites and can complex iron ion (ferrous/ ferric ion) and prevent ferric hydroxideprecipitation even at neutral pH environment. In this study, it was proven that poly(acrylic acid) could act as a polychelate in the modified Fenton reaction for the oxidation of chlorinated organic compounds (such as 2,2'-dichlorobiphenyl and biphenyl) at neutral pH environment. Numerical simulation based on the kinetic model developed from the well-known Fenton reaction and iron-chelate chemistry fits the experimental data well for both standard and chelate-based modified Fenton reactions without pollutant. This is the first reported confirmation of the dechlorination of carbon tetrachloride from the aqueous phase by superoxide radical anion using both monomeric (citrate) and polymeric (PAA) chelate-based modified Fenton reactions. The main purpose of this research is to understand and model a chelate-based modified Fenton reaction in a homogeneous phase. The oxidation reactions involving immobilized iron on PAA-functionalized solid support (silica particles and PVDF membrane) were also explored.