Flocculation of cyanobacterial cells using coal fly ash modified chitosan

Yuan, Y, Zhang, H and Pan, G ORCID: https://orcid.org/0000-0003-0920-3018, 2016. Flocculation of cyanobacterial cells using coal fly ash modified chitosan. Water Research, 97, pp. 11-18. ISSN 0043-1354

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Abstract

Harmful algal blooms (HABs) have increasingly occurred worldwide, which pose serious threats to water environment safety. In this study, a compound flocculant (CFAL-Chitosan) was developed for HABs mitigation where chitosan was modified by coal fly ash leachate (CFAL). When using optimized dosage of CFAL-Chitosan flocculant, the zeta potential of Microcystis aeruginosa (M.A.) flocs stayed close to zero and the algal removal efficiency plateaued over 95 % in a wide dosage range from 3 to 6 mg/L. For chitosan without CFAL, the removal efficiency peaked at 3 mg/L with a maximum removal efficiency of 81% , which quickly decreased as the dosage increased (> 3 mg/L) due to the fast reversal of zeta potential. This indicated that CFAL-chitosan could maintain better removal efficiency over a wide dosage range due to improved property on charge neutralization than that of chitosan alone. The flocs of CFAL-Chitosan were larger and denser than that of chitosan without CFAL. However, excessive CFAL beyond the optimized dose inhibited M.A. removal due to the hydrolysis and declining of molecular weight of chitosan that weakened the bridging-netting property, where the surface charge reversal happened within a narrow dosage range and the removal-dosage curve became parabola. The pH and environmentally sensitive metal residuals in the algal solution were not significantly affected by the adding of optimized dosage of CAFL-chitosan. The study provides a possible way for HABs control using the cheap material of CFA. Further studies are needed to check the potential influence of leachable metals and persistent organic pollutants (pops) in CFA under a wide range of environmental condition.

Item Type:	Journal article
Publication Title:	Water Research
Creators:	Yuan, Y., Zhang, H. and Pan, G.
Publisher:	Elsevier
Date:	15 June 2016
Volume:	97
ISSN:	0043-1354
Identifiers:	Number Type 10.1016/j.watres.2015.12.003 DOI
Divisions:	Schools > School of Animal, Rural and Environmental Sciences
Record created by:	Linda Sullivan
Date Added:	11 May 2016 14:37
Last Modified:	09 Jun 2017 14:02
URI:	https://irep.ntu.ac.uk/id/eprint/27769

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