Preliminary Study on Extraction of Bio-flocculants from Okra and Chinese Yam

Chai Siah Lee; Mei Fong Chong; John Robinson; Eleanor Binner

Chai Siah Lee Centre of Excellence for Green Technologies, Department of Chemical and Environmental Engineering, Faculty of Engineering, The University of Nottingham Malaysia Campus, 43500 Semenyih, Selangor, Malaysia
Mei Fong Chong Centre of Excellence for Green Technologies, Department of Chemical and Environmental Engineering, Faculty of Engineering, The University of Nottingham Malaysia Campus, 43500 Semenyih, Selangor, Malaysia
John Robinson Microwave Process Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD.
Eleanor Binner Microwave Process Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD.

Keywords: Okra, Chinese yam, bio-flocculant, extraction, flocculation, wastewater treatment

Abstract

Natural bio-flocculants were extracted from okra and Chinese yam using water extraction method, and the extract yield and their flocculating abilities were evaluated. Results showed that extraction of okra with seed removal and incubation followed by freeze drying enhanced the extract yield by 91% and improved the flocculating ability greatly by achieving solids removal of above 99% when compared with extraction without incubation and followed by oven drying. The effect of an incubation step was further investigated by using Chinese yam. With incubation, a higher extract yield of 2.95% was obtained compared with the extraction without incubation at 2.13% and high flocculating ability was achieved at 99.5% solids removal. To further investigate the application of bio-flocculants, the samples with the highest extract yield and flocculating ability were selected for a case study focusing on treatment of oleochemical wastewater. Yam bio-flocculant showed its flocculating activity with 80% solids removal when it was coupled with coagulant without pH alteration. However, pH adjustment was required for okra bio-flocculant. In conclusion, highly efficient okra and yam bio-flocculants were successfully extracted and their applicability to wastewater treatment was proven.

References

1. A. Mishra, M. A., M. Bajpai, S. Rajani and R.P. Mishra (2002). Plantago psyllium mucilage for sewage and tannery effluent treatment, Iranian Polymer Journal 11(6), 381-386.
2. Adrianus van Haandel, J. v. d. L. (2012). Handbook Biological Waste Water Treatment - Design and Optimisation of Activated Sludge Systems, IWA Publishing.
3. Ahmad, A. L., S. S. Wong, et al. (2008). Improvement of alum and PACl coagulation by polyacrylamides (PAMs) for the treatment of pulp and paper mill wastewater, Chemical Engineering Journal, 137(3), 510-517.
4. Al-Hamadani, Y. A. J., M. S. Yusoff, et al. (2011). Application of psyllium husk as coagulant and coagulant aid in semi- aerobic landfill leachate treatment, Journal of Hazardous Materials, 190(1–3), 582-587.
5. Ameena, K., C. Dilip, et al. (2010). Isolation of the mucilages from Hibiscus rosasinensis linn. and Okra (Abelmoschus esculentus linn.) and studies of the binding effects of the mucilages, Asian Pacific Journal of Tropical Medicine, 3(7), 539-543.
6. Amid, B. T. and H. Mirhosseini (2012). Optimisation of aqueous extraction of gum from durian (Durio zibethinus) seed: A potential, low cost source of hydrocolloid, Food Chemistry, 132(3), 1258-1268.
7. Anastasakis, K., D. Kalderis, et al. (2009). Flocculation behavior of mallow and okra mucilage in treating wastewater, Desalination, 249(2), 786-791.
8. ASN, A. P. H. (Jan 1999). Standard methods for the examination of water and wastewater, American Public Health Association, Washington.
9. Chong, M. (2012). Direct Flocculation Process for Wastewater Treatment in Advances in Water Treatment and Pollution Prevention, Springer Netherlands, 201-230.
10. Ghasemi Pirbalouti, A., E. Mahdad, et al. (2013). Effects of drying methods on qualitative and quantitative properties of essential oil of two basil landraces, Food Chemistry, 141(3), 2440-2449.
11. Jaya, S. and T. D. Durance (2009). Compressive characteristics of cellular solids produced using vacuum- microwave, freeze, vacuum and hot air dehydration methods, Journal of Porous Materials, 16(1), 47-58.
12. Lee, C. S., J. Robinson, et al. A review on application of flocculants in wastewater treatment, Process Safety and Environmental Protection, Article In Press.
13. Lee, K. E., N. Morad, et al. (2012). Development, characterization and the application of hybrid materials in coagulation/flocculation of wastewater: A review, Chemical Engineering Journal, 203(0), 370-386.
14. Mishra, A., M. Agarwal, et al. (2003). Fenugreek mucilage as a flocculating agent for sewage treatment, Colloid and Polymer Science, 281(2), 164-167.
15. Mishra, A. and M. Bajpai (2005). Flocculation behaviour of model textile wastewater treated with a food grade polysaccharide, Journal of Hazardous Materials, 118(1–3), 213-217.
16. Mishra, A. and M. Bajpai (2006). The flocculation performance of Tamarindus mucilage in relation to removal of vat and direct dyes, Bioresource Technology, 97(8), 1055-1059.
17. Mishra, A., R. Srinivasan, et al. (2002). Flocculation of Textile Wastewater by Plantago psyllium Mucilage, Macromolecular Materials and Engineering, 287(9), 592-596.
18. Mishra, A., A. Yadav, et al. (2004). Fenugreek mucilage for solid removal from tannery effluent, Reactive and Functional Polymers, 59(1), 99-104.
19. Rahimmalek, M. and S. A. H. Goli (2013). Evaluation of six drying treatments with respect to essential oil yield, composition and color characteristics of Thymys daenensis subsp. daenensis. Celak leaves, Industrial Crops and Products, 42(0), 613- 619.
20. Ratti, C. (2001). Hot air and freeze-drying of high-value foods: a review, Journal of Food Engineering, 49(4), 311-319.
21. Renault, F., B. Sancey, et al. (2009). Chitosan for coagulation/flocculation processes – An eco-friendly approach, European Polymer Journal, 45(5), 1337- 1348.
22. Samavati, V. (2013). Polysaccharide extraction from Abelmoschus esculentus: Optimization by response surface methodology, Carbohydrate Polymers, 95(1), 588-597.
23. Sanjeet Kumar, S. D., Adamou Haougui, Alain Ratnadass, Dov Pasternak and Christophe Kouame (2010). Okra (Abelmoschus spp.) in West and Central Africa: Potential and progress on its improvement, African Journal of Agricultural Research, 5, 3590-3598.
24. Suopajärvi, T., H. Liimatainen, et al. (2013). Coagulation–flocculation treatment of municipal wastewater based on anionized nanocelluloses, Chemical Engineering Journal, 231(0), 59-67.
25. USEPA (September 2012). FWPCA Methods for Chemical Analysis of Water and Wastes BiblioGov, Ohio.
26. Wang, J.-P., S.-J. Yuan, et al. (2013). Synthesis, characterization and application of a novel starch-based flocculant with high flocculation and dewatering properties, Water Research, 47(8), 2643-2648.
27. Yang, Z., H. Yan, et al. (2013). Flocculation performance and mechanism of graphene oxide for removal of various contaminants from water, Water Research, 47(9), 3037-3046.
28. Yang, Z., B. Yuan, et al. (2012). Evaluation of the flocculation performance of carboxymethyl chitosan-graft- polyacrylamide, a novel amphoteric chemically bonded composite flocculant, Water Research, 46(1), 107-114.