Effective Chemical Coagulation Treatment Process for Cationic and Anionic Dyes Degradation

Throughout the industrial activities, water consumption is increased, resulting in large amounts of wastewater that must be treated before being discharged into the water streams. Coagulation/flocculation and sedimentation processes are considered as one of the most used chemical treatment methods for removing the majority of water contaminants Cationic dye of methylene blue (MB) and anionic dye of methyl orange (MO) are common hazardous organic wastewater contaminants that mostly degraded by different chemical coagulants processes. Chemical coagulants act as an auxiliary agent in the coagulation/flocculation-sedimentation process. This study aimed to investigate the effectiveness of combined chemical coagulants of FeCl3/lime in the degradation of cationic and anionic dyes. In this work, kinetics, effect of adsorption parameters such as pH, initial concentration of dyes and the chemicals coagulants doses was studied. At an optimum coagulant dosage of (200/70) mg/L and (70/100) mg/L, and optimum pH ranged from (6.0 - 8.0) for MO and MB, repectively . The achieved removal values for both anionic and cationic dyes using the combined coagulant (FeCl3/lime) were 97.78% and 95.54% for MO and MB, respectively. The maximum adsorption capacity of FeCl3/lime was calculated from the isotherm at 500 mg/g. This technique was successfully conducted for the treatment of tannery and laundry wastewaters for improving the quality of pollution parameters and investigating the efficiency of the applied treatment technique. The achieved removal efficiencies for tannery and laundary wastewater ranged from 93.9 to 94.4 % for COD, 92.9 to 92.5% for BOD5, 93.7 to 92.8% for TSS, and 96.7 to 99.2% for turbidity, respectively.