Preparation of sodium alginate-activated carbon immobilized algal-bacteria and its effect on basic orange Ⅱ degradation
The adsorption-embedding method was used to prepare immobilized algal-bacteria spheres,in which sodium alginate and activated carbon were used as embedding agents,along with CaCl2 as the cross-linking agent for treating azo dye basic orange l1.The extemal and intemal structures of these spheres were examined via scanning electron microscopy and their reusability was investigated.Results indicate that the optimal preparation conditions were as follows:sodium alginate,activated carbon and CaCl2 concentrations(w/w)of 2.58%,0.838%and 2%,respectively,an immobilized biomass concentration of 1.139%,a sludge-to-algae mass ratio of 2∶1 and an immobilization period of 14h.Decolorization efficiency exceeded 90%,while TOC removal rates ranged from 74%to 90%at influent dye concentrations between 50 and 250mg/L and influent pH values between 6and 10.5.UV-visible full-wavelength and GC-MS scanning spectra demonstrated the destruction of the nitrogen-nitrogen double bond,conjugated system and benzene ring structure in basic orange Ⅱ,which confirmed the decolorization and degradation reactions,thereby the mineralization of the azo dye.After five cycles of reuse,the algal-bacteria spheres maintained a high efficiency of decolorization and TOC removal.
algal-bacterial symbiotic systemimmobilizedresponse surface methodologybasic orange Ⅱdegradation process