Reuse of waste activated sludge for textile dyeing wastewater treatment by biosorption: performance optimization and comparison

The aim of this study is to assess the ability of local low-cost biomaterials to remove reactive dyes from aqueous solutions. Granules prepared from dried activated sludge (DAS) were used as a sorbent for the removal of red bimacid dye (E5R) chosen as model dye. The study involves batch type experiments to investigate the effects of initial dye concentration, adsorbent dose, contact time, temperature and pH of solution on biosorption process. Optimal experimental conditions were ascertained. The pseudo-second-order kinetic model fits very well with the experimental results. The thermodynamic parameters for the biosorption process have also been calculated and found the sorption process as exothermic. The sorption performance of this DAS is finally compared with that of different reference sorbents and of other low-cost materials.