An Eco-friendly and Economical Approach for Removal of Remazol Blue, Malachite Green and Rhodamine B Dyes from Wastewater using Bio-char Derived from Chlorella Vulgaris Biomass

Background: Rapid urbanization and industrialization have led to the depletion of water resources and the generation of an enormous amount of wastewater. One among them is the textile industry, which discharges a huge amount of dye wastewater into the aquatic environment. Methods: This study deals with adsorption of Remazol blue, Malachite green and Rhodamine B dyes into bio-char derived from Chlorella Vulgaris biomass cultivated from municipal wastewater. Column studies were performed to depict the industrial usage of bio-char for the treatment of a large quantity of wastewater. The effect of temperature, time, pH, dye concentration and adsorbent dosage on dye removal was studied in a batch process. Results: The best batch adsorption conditions are temperature (25°C), time (60min), pH (7), dye concentration (100ppm) and adsorbent dosage (1g) with ± 5% for all three dyes. Dye removal percentage of bio-char increased with increase in adsorbent dosage to 94.5%, 88.2% and 90.1% for Remazol blue, Malachite green and Rhodamine B dyes at 1g/L adsorbent dosage. Freundlich isotherm exhibited correlation coefficient (R2) values of 0.99, 0.98 and 0.99 for Remazol blue, Malachite green and Rhodamine B dyes, respectively. Kinetic studies revealed that all three dyes followed the pseudo first-order model. An increase in column bed height resulted in increased dye removal percentage since the increase in bed height resulted in an increase in bio-char quantity with more number of surface area Conclusion: From the study, it can be concluded that Bio-char was the economical and ecofriendly alternative adsorbent for the wastewater treatment process. Bio-char reusability study revealed that it could be used for 3-4 consecutive cycles.