Abstrakt

Studies on reduction and removal of hexavalent chromium in industrial waste water by Alternanthera sessilis and Tagetes erecta

G.Hemalatha, S.Sujitha, G.S.Pavithra

Background: This study was taken up to remediate Cr6+ that is usually present in waste water of Industries that employs Chromium. This is a new venture in remediating Cr6+ using natural antioxidants which are usually overlooked.Also, it is an effort to both reduce and remove the Cr 6+ from the waste water that gives an extra edge over other technologies. Antioxidant activity and sorption ability of the leaves of Alternanthera sessilis and Tagetes erecta were studied for reduction and removal of Cr 6+ fromIndustrial waste water. FRAP and DPC assays were conducted for determining, Antioxidant Activity and Cr6+ concentration respectively. Results: Antioxidant activity of the aqueous (A.sessilis: 2657 AOU, T. erecta: 3071AOU) and methanol (A. sessilis: 2932AOU, T. erecta: 3127 AOU) extracts of both the plantswas found to be almost similar. Untreated industrialwaste water (106.07 ppmof hexavalent chromium) was collected froman electroplating unit and tests were conducted on the same. Extracts obtained by Ultra-Sonication for 5min showed the highest reduction efficiency (60%until 100ppm) when compared to other time intervals of sonication and conventional shaking, while Cake obtained by Ultrasonication for 10min was found to have the highest adsorption efficiency (approximately 80%) for waste water. In the view of combining both reduction & removal, Synthetic and Industrial waste water were directly incubated with 2g of plant sample for various incubation periods and concentration levels. 1hr incubation for all the concentration levels proved to be the optimum incubation time for both plant samples with approximately 98% remediation efficiency. Conclusion: Current studies indicate that the plant samples adopted for our studies prove to be both cost effective and environment friendly alternative to the conventional techniques.