Initial naphthalene  concentration                    (mg/l)                                                          RL values                                              Particle sizes (mm)   0.125                   0.178                    0.422                                10   0.8744  0.8905  0.9020                    20                                   0.6989  0.7770 0.8072                    30   0.5372  0.6698 0.7189                    40   0.4105  0.5750 0.6390                    50   0.3171  0.4933 0.5682

Table 4: Langmuir isotherm with separation factor (RL) for simultaneous adsorption-biodegradation at different particle size.