relation: https://khub.utp.edu.my/scholars/13520/ title: Flocculation of Chlorella vulgaris by shell waste-derived bioflocculants for biodiesel production: Process optimization, characterization and kinetic studies creator: Suparmaniam, U. creator: Lam, M.K. creator: Uemura, Y. creator: Shuit, S.H. creator: Lim, J.W. creator: Show, P.L. creator: Lee, K.T. creator: Matsumura, Y. creator: Le, P.T.K. description: Flocculants are foreign particles that aggregate suspended microalgae cells and due to cost factor and toxicity, harvesting of microalgae biomass has shifted towards the use of bioflocculants. In this study, mild acid-extracted bioflocculants from waste chicken's eggshell and clam shell were used to harvest Chlorella vulgaris that was cultivated using chicken compost as nutrient source. It was found that a maximum of 99 flocculation efficiency can be attained at pH medium of 9.8 using 60 mg/L of hydrochloric acid-extracted chicken's eggshell bioflocculant at 50 °C of reaction temperature. On the other hand, 80 mg/L of hydrochloric acid-extracted clam shell bioflocculant was sufficient to recover C. vulgaris biomass at pH 9.8 and optimum temperature of 40 °C. The bioflocculants and bioflocs were characterized using microscopic, zeta potential, XRD, AAS and FT-IR analysis. The result revealed that calcium ions in the bioflocculants are the main contributor towards the flocculation of C. vulgaris, employing charge neutralization and sweeping as possible flocculation mechanisms. The kinetic parameters were best fitted pseudo-second order which resulted in R2 of 0.99 under optimal flocculation temperature. The results herein, disclosed the applicability of shell waste-derived bioflocculants for up-scaled microalgae harvesting for biodiesel production. © 2019 Elsevier B.V. publisher: Elsevier B.V. date: 2020 type: Article type: PeerReviewed identifier: Suparmaniam, U. and Lam, M.K. and Uemura, Y. and Shuit, S.H. and Lim, J.W. and Show, P.L. and Lee, K.T. and Matsumura, Y. and Le, P.T.K. (2020) Flocculation of Chlorella vulgaris by shell waste-derived bioflocculants for biodiesel production: Process optimization, characterization and kinetic studies. Science of the Total Environment, 702. ISSN 00489697 relation: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074634580&doi=10.1016%2fj.scitotenv.2019.134995&partnerID=40&md5=e3fcef581140ddc5ac54c0c11889dd81 relation: 10.1016/j.scitotenv.2019.134995 identifier: 10.1016/j.scitotenv.2019.134995