The removal of heavy-metal ions from aqueous solutions by using dried activated sludge has been investigated in batch systems. Effect of solution pH, initial metal ion concentration, and temperature were determined. The results of the kinetic studies showed that the uptake processes of the two metal ions(Cd(II) and Pb(II)) followed the pseudo-second-order rate expression. The equi- librium data fitted very well to both the Langmuir and Freundlich adsorption models. The FT-IR analysis showed that the main mechanism of Cd(II) and Pb(II) biosorption onto dried activated sludge was their binding with amide I group.
WANG Xue-jiangXIA Si-qingCHEN LingZHAO Jian-fuCHOVELON Jean-marcNICOLE Jaffrezic-renault
The flocculating activity of a novel bioflocculant MMF1 produced by multiple-microorganism consortia MM1 was investigated.MM1 was composed of strain BAFRT4 identified as Staphylococcus sp.and strain CYGS1 identified as Pseudomonas sp.Theflocculating activity of MMF1 isolated from the screening medium was 82.9%,which is remarkably higher than that of the bioflocculantproduced by either of the strains under the same condition.Brewery wastewater was also used as the carbon source for MM1,and thecost-effective production medium for MM1 mainly comprised 1.0 L brewery water(chemical oxygen demand(COD)5000 mg/L),0.5 g/L urea,0.5 g/L yeast extract,and 0.2 g/L(NH4)2SO4.The optimal conditions for the production of MMF1 was inoculum size2%,initial pH 6.0,cultivating temperature 30°C,and shaking speed 160 r/min,under which the flocculating activity of the MMF1reached 96.8%.Fifteen grams of purified bioflocculant could be recovered from 1.0 L of fermentation broth.MMF1 was identified asa macromolecular substance containing both protein and polysaccharide.It showed good flocculating performance in treating indigotinprinting and dyeing wastewater,and the maximal removal effciencies of COD and chroma were 79.2%and 86.5%,respectively.
