Dye wastewater produced by dyestuff, textile, leather, paper
and food industries is one of the most serious environmental problems
[1,2]. Generally, dye pollution is treated by physical–chemical
methods due to its low biological degradability. Coagulation–floc
culation, adsorption, ion-exchange, oxidation and advanced oxidation,
incineration, electrochemical treatment, photo-catalysis
degradation, and membrane filtration are reported to be used in
dispose of dye wastewater pollution [1]. Among them, coagula
tion–flocculation is one of the most commonly used processes in
dye wastewater treatment works, especially dissolvable dyes
wastewater treatment. Additionally, dye molecule removed by coa
gulation–flocculation without degradation will produce less toxic
compounds.
Recent decades, many researchers are engaged in preparing of
new environmental friendly natural polymers as effective flocculants
instead of metal coagulants [3]. Bioflocculant attracts much
attention due to its high flocculant activity and environmental
friendliness [4]. However, low yield and high price impede practical
application of bioflocculant. Hence, in consideration of the
above factors, bioflocculant is more suitable to be used as