[Extinguishment of harmful algae by organo-clay modified by alkyl glucoside quaternary ammonium compound]

Systematic study of the sorption behavior of alkyl glucoside quaternary ammonium compound (AGQAC) on kaolin and bentonite showed that the isotherms of its sorption can be described very well by the Langmuir isotherm. The rate of alkyl glucoside quaternary ammonium compound sorption on kaolin and bentonite was very fast, it could reach equilibration in one or two minutes, and its saturate sorption amount was much enough to be used to modify clays. Then the influence of alkyl glucoside quaternary ammonium compound on the growth of Prorocentrum donghaiense, Amphidinium carterae, Scrippsiella trochoidea were studied, it was found that when its concentration was below 0.4 mg/L, 0.5 mg/L, 0.8 mg/L it just restrained the growth of the algae, but when the concentration was above 0.6 mg/L, 0.75 mg/L, 1.2 mg/L it could cumber the algae's growth and even made them die after three days. When it was used combined with clays the concentration below 5 mg/L could enhance the algal removal efficiency of 50 mg/L clay from about 20% to above 90%, so it could decrease the concentration of crude clays in removing algal blooms. Meanwhile, the kinetics of red tide organism coagulation with clay was studied, the effects of different kinds and concentrations of clays, the second component added in clays were examined. Results showed that adding the second component in clay was the most efficient method to improve the algal removal efficiency.