Removal of reactive dyes from aqueous solution by different bacterial genera

The use of biomass for the removal of reactive dyes from an aqueous solution with different bacterial genera has been investigated. Three Gram-negative bacteria: Aeromonas sp., P. luteola and E. coli, and two Gram-positive bacteria: B. subtilis and S. aureus and a mixed biomass of activated sludge are the tested biosorbents. Dead cells of Gram-negative bacteria have a higher specific adsorption capacity than the living cells. The dye removal is in the order of Aeromonoas sp. > P. luteola > E. coli. The adsorption equilibrium can be reached within one hour. Due to the positively charged cells at acidic pH, the removal of reactive dyes increases with decreasing pH. Evaluating the adsorption parameters, bacterial biomass exhibits stable adsorption characteristics, which makes it a suitable adsorbent for different dye compounds.