Authors: Lanyan Peng Chunping Yang Guangming Zeng Lu Wang Chuanhua Dai Zhiyong Long Hongyu Liu Yuanyuan Zhong
Publish Date: 2014/04/30
Volume: 98, Issue: 15, Pages: 6847-6858
Abstract
A new bioflocculant was produced by culturing Rhodococcus erythropolis in a cheap medium When culture pH was 70 inoculum size was 2 v/v Na2HPO4 concentration was 05 g L−1 and the ratio of sludge/livestock wastewater was 71 v/v a maximum flocculating rate of 876 could be achieved Among 13 different kinds of pretreatments for sludge the optimal one was the thermalalkaline pretreatment Different from a bioflocculant produced in a standard medium this bioflocculant was effective over a wide pH range from 2 to 12 with flocculating rates higher than 98 Approximately 16 g L−1 of crude bioflocculant could be harvested using cold ethanol for extraction This bioflocculant showed color removal rates up to 80 when applied to direct and disperse dye solutions but only 230 for reactive dye solutions Infrared spectrum showed that the bioflocculant contained functional groups such as –OH –NH2 and –CONH2 Components in the bioflocculant consisted of 912 of polysaccharides 76 of proteins and 12 of DNA When the bioflocculant and copper sulfate CuSO4 were used together for decolorization in actual dye wastewater the optimum decolorization conditions were specified by the response surface methodology as pH 11 bioflocculant dosage of 40 mg/L and CuSO4 80 mg/L under which a decolorization rate of 939 could be reached
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