Malaysian Journal of Analytical Sciences Vol 23 No 1 (2019): 31 - 39

DOI: 10.17576/mjas-2019-2301-04






(Mitigasi Alexandrium tamiyavanichii Bertoksik Menggunakan Komposit Kitosan-Silika)


Anwar Iqbal1*, Najwa Ahmad2, Normawaty Mohammad Noor2, Lee D. Wilson3, Nur Hanisah Ibrahim1


1School of Chemical Sciences,

Universiti Sains Malaysia, 11800 USM  Penang, Malaysia

2 Department of Marine Science, Kulliyyah of Science,

International Islamic University Malaysia, Jalan Sultan Ahmad Shah, Bandar Indera Mahkota, 25200 Kuantan, Pahang, Malaysia

3Department of Chemistry, 110 Science Place, Room 156 Thorvaldson Building,

University of Saskatchewan, Saskatoon, S7N 5C9 Canada


*Corresponding author:



Received: 24 January 2018; Accepted: 13 September 2018




The harmful algal bloom (HABs) phenomena affects human health, ecosystems, fishing, and tourism industries. In a single occasion, the loss due to HABs can reach thousands of Ringgit Malaysia. In this study, a chitosan-silica composite (RHA-CHi) was synthesized via sol-gel technique for the mitigation of Alexandrium tamiyavanichii, a toxic HAB species isolated from Malaysian waters. Rice husk ash silica was used as the silica precursor in the composite synthesis. The FT-IR spectroscopy suggests that the chitosan was covalently bonded with the surface silanol groups. Light microscope analysis showed that the algal cells were stuck on the surface of the composite and underwent lysis.  The incorporation of chitosan decreased the surface negative charge of the silica, hence, increasing the electrostatic attraction between the cells and RHA-Chi. The removal efficiency of A. tamiyavanichii was 75% using 0.1 mg/mL of RHA-Chi in 2 hours, increasing to 85% after 24 hours. Reduced removal efficiency (16%) was observed using silica alone. The findings show that the chitosan-silica composite has high potential to be used in the mitigation of A. tamiyavanichii. 


Keywords:  toxic algae, flocculate, silica, chitosan, rice husk



Fenomena ledakan alga-bahaya mengancam kesihatan manusia, industri perikanan dan pelancongan. Dalam satu kejadian, kerugian boleh mencecah ribuan Ringgit Malaysia. Dalam kajian ini, komposit kitosan-silika (RHA-CHi) telah disintesis melalui kaedah sol-gel untuk mitigasi Alexandrium tamiyavanichii, spesis bertoksik HAB yang dipencilkan dari perairan Malaysia. Abu sekam padi telah digunakan sebagai pelopor silika dalam sintesis komposit. Spektroskopi FT-IR menunjukkan kitosan terikat secara kovalen dengan kumpulan silanol permukaan. Analisis mikroskopi cahaya menunjukkan sel alga melekat pada permukaan komposit dan mengalami lisis. Penggabungan kitosan telah mengurangkan cas negatif permukaan silika lalu meningkatkan tarikan elektrostatik antara sel dan RHA-Chi. Kecekapan penyingkiran A. tamiyavanichii dalam masa 2 jam  apabila 0.1 mg/ml RHA-Chi digunakan adalah 75% dan meningkat ke 85% selepas 24 jam manakala pengurangan kecekapan penyingkiran (16%) diperhatikan bagi silika sahaja. Penemuan ini menunjukan komposit kitosan-silika mempunyai potensi yang tinggi untuk digunakan dalam mitigasi ledakan alga-bahaya terutamanya A. tamiyavanichii. 


Kata kunci:  alga beracun, mengumpal, silika, kitosan, sekam padi



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