This study investigated, modelled and simulated the influence of multi-chlorohalogenation in hetero-geneous photocatalytic degradation of substituted phenols (pentachlorophenol (PCP), trichlorophenol(TCP), dichlorophenol (DCP), and monochlorophenol (CP)). The Langmuir–Hinshelwood approach wasapplied to determine oxidation kinetics. Aquasim 2.0 computational software was used to model, sim-ulate and estimate model parameters of the different chlorophenols. Chemical adsorption equilibriumisotherms for the four chlorophenols and phenol were studied and modelled for adsorption onto tita-nium dioxide (TiO2) semiconductor catalyst. Langmuir adsorption parameters were determined and usedto calculate adsorption constant and maximum adsorption capacity. The adsorption of chloride pheno-lics onto titanium dioxide catalyst increased in the order of 4-CP < DCP < Ph < TCP < PCP. Photocatalyticstudies analysed the efficiency of oxidation and found improved degradation with higher chloride sub-stituted phenolics in the order of PCP > TCP > DCP ≥ 4-CP. Photocatalytic parameters were calculated andestimated along with sensitivity and uncertainty analyses.