Modelling the coag-flocculation kinetics of cashew nut testa tannins in an industrial effluent

N.J.N. Nnaji; J.U. Ani; L.E. Aneke; O.D. Onukwuli; U.C. Okoro; J.I. Ume

Journal of Industrial and Engineering Chemistry, Vol.20, No.4, 1930-1935, July, 2014

DOI10.1016/j.jiec.2013.09.013 Export Citation

Modelling the coag-flocculation kinetics of cashew nut testa tannins in an industrial effluent

N.J.N. Nnaji^†, J.U. Ani^{1, †}, L.E. Aneke¹, O.D. Onukwuli², U.C. Okoro¹, and J.I. Ume³

Department of Industrial Chemistry, Caritas University, Amorji-Nike, Enugu State, Nigeria
¹Department of Pure and Industrial Chemistry, University of Nigeria, 410001 Nsukka, Enugu State, Nigeria
²Department of Chemical Engineering, Nnamdi Azikiwe University, Anambra State, Nigeria
³Materials and Energy Technology Division, Projects Development Institute, Enugu State, Nigeria

E-mail:,

The coagulant behaviour of tannins of Anacardium occidentale (CANTETA) testa was assessed for the removal of suspended solids from a fibre-cement industry effluent. A series of flocculation experiments were conducted to examine the optimal concentration of the coagulant together with the pH of the effluent needed to obtain the best results. The results showed that CANTETA have significant flocculation properties particularly at lower doses and in alkaline medium. Optimum efficiency for TSS removal was 84% with 100 mg/L CANTETA at initial effluent pH of 12. The kinetics of the coagulation process suitably fits the second order kinetic model.

Keywords:Tannins;Anacardium occidentale;Total suspended solids;Coagulation;Chemical kinetics

[References]

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[1] World Health Organization, Guidelines for Drinking Water Quality: Health Criteria and Other Supporting Information, vol. 2, World Health Organization, Geneva, 2010.

[2] Menkiti MC, Nwoye CI, Onyechi CA, Onukwuli OD, Adv. Chem. Eng. Sci., 1, 125 (2011)

[3] Anastasakis K, Kalderis D, Diamadopoulos E, Desalination, 249(2), 786 (2009)

[4] Ozacar M, Soykan C, Sengil IA, J. Appl. Polym. Sci., 102(1), 786 (2006)

[5] Yurtsever M, Sengil IA, J. Hazard. Mater., 163(1), 58 (2009)

[6] Chatterjee T, Chatterjee S, Woo SH, Chem. Eng. J., 148(2-3), 414 (2009)

[7] Ukoha PO, Ejikeme PM, Maju CC, J. Am, Leather Chem. Assoc., 105, 242 (2010)

[8] Greenberg AE, Standard Method for the Examination of Water and Wastewater, 18th ed., APHA and AWWA, Washington, DC, 1992.

[9] Menkiti MC, Nnaji PC, Onukwuli OD, Nat. Sci., 7(6), 1 (2009)

[10] Zanten JHV, Elimelech M, J. Colloid Interface Sci., 154(1), 1 (1992)

[11] Ani JU, Nnaji NJN, Onukwuli OD, Okoye COB, J. Hazard. Mater., 243, 59 (2012)

[12] Abel JS, Stangle GC, Schilling, Aksay IA, J. Mater. Res., 9(2), 451 (1994)

[13] Atkins PW, Physical Chemistry, 4th ed., Oxford University Press, Oxford, 1990.

[14] da Costa FP, J. Math. Anal. Appl., 192, 892 (1995)

[15] Thomas DN, Judd SJ, Fawcett N, Water Res., 33(7), 1579 (1999)

[16] Tchobanoglous G, Burton FL, Stensel HD, Wastewater Engineering, Treatment and Reuse, Metcaf and Eddy Inc Tata Mc Graw-Hill, New Delhi, 2003.