Coagulation Study on Extracted Algal Alginate from Red Algae as Natural Coagulant for Remediation of Textile Dye Congo Red

In the present study, extracted algal alginate from red algae as natural coagulant was used for removal of textile dye congo red (CR) from water. In developing countries like India, only about 10% of the wastewater being generated is treated, whereas the remaining 90% is discharged into the water bodies as it stands. Color and turbidity are the most common problems in the disposal of wastewater. The removal of color is one of the key challenges in wastewater treatment. For the coagulation process, the synthetic textile wastewater samples had CR concentrations of 50, 100, 150, 200, and 250 mg/L and varying initial pH of 4, 5, and 6. Different dosages of calcium and alginate (1, 2, 3, 4, 5, and 6 g/L) were used to perform the experiments. The obtained results exhibited that the effectiveness of color removal was higher at lower pH 4, and the calcium and alginate dosages are dependent on the CR concentration of the synthetic textile wastewater. These investigations demonstrating the higher efficiency of calcium alginate as a coagulant, where maximum color removal achieved over 95.05%. Increasing alginate dosages and residence times can enhance the performance of coagulation. Dye color is often present in real wastewater and needs to be removed before being reused or discharged to the environment.