Controlling harmful algae blooms using aluminum-modified clay

• Published in: Marine pollution bulletin Vol. 103; no. 1-2; pp. 211 - 219
• Main Authors: Liu, Yang, Cao, Xihua, Yu, Zhiming, Song, Xiuxian, Qiu, Lixia
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.02.2016
• Subjects: algae; algae culture; algal blooms; aluminum; Aluminum - pharmacology; aluminum chloride; Aluminum Hydroxide; Aluminum Silicates; aluminum sulfate; Aluminum-modified clay; Aureococcus anophagefferens; clay; coagulation; Dispersion medium; Flocculation; HABs control; Harmful Algal Bloom - drug effects; Hydrogen-Ion Concentration; hydrolysates; Marine; Phytoplankton - physiology; Removal mechanism; Surface charge; Suspension pH; water pollution; Dispersion medium; Suspension pH; Surface charge; Removal mechanism; HABs control; Aluminum-modified clay
• ISSN: 0025-326X; 1879-3363; 1879-3363
• DOI: 10.1016/j.marpolbul.2015.12.017

The performances of aluminum chloride modified clay (AC-MC), aluminum sulfate modified clay (AS-MC) and polyaluminum chloride modified clay (PAC-MC) in the removal of Aureococcus anophagefferens were compared, and the potential mechanisms were analyzed according to the dispersion medium, suspension pH and clay surface charges. The results showed that AC-MC and AS-MC had better efficiencies in removing A.anophagefferens than PAC-MC. The removal mechanisms of the three modified clays varied. At optimal coagulation conditions, the hydrolysates of AC and AS were mainly monomers, and they transformed into Al(OH)3(am) upon their addition to algae culture, with the primary mechanism being sweep flocculation. The PAC mainly hydrolyzed to the polyaluminum compounds, which remained stable when added to the algae culture, and the flocculation mainly occurred through polyaluminum compounds. The suspension pH significantly influenced the aluminum hydrolysate and affected the flocculation between the modified clay and algae cells. •AC-MC and AS-MC showed better efficiencies in removing Aureococcus anophagefferens than PAC-MC.•The effects of clay suspension pH and dispersion medium on the removal ability depended on the type of modified clay.•The suspension pH significantly influenced the alum hydrolysate and thus the flocculation was affected.•Different removal mechanisms were observed for the three modified clays on the algae cells.•The removal ability of modified clay was related to its surface charge at the pH of the algae culture after clay addition.