Study on the removal of RR4 in aqueous solution by protonated sewage sludge
质子化剩余污泥作为生物吸附剂去除水溶液中活性红4的研究

The protonated sewage sludge biomass discharged from a sewage treatment plant was used as a new type of biosorbent for the removal of anionic dye Reactive Red 4. Various experimental parameters (e.g. pH, contact time, salt concentration, dye concentration etc.) were investigated. Adsorption reached equilibrium after 22 hours. The dye uptakes increased with the declining of solution pH, and under alkaline conditions desorption was dominating. The desorption efficiencies were higher than 87% at pH8. The isothermal data of biosorption followed the Langmuir and Freundich models well, and the maximum sorption capacities of the biosorbent, activated carbon and diatomite were 35.66,20.48 and 1.82 mg·g-1 respectively. The uptake of RR4 was not significantly affected by a high concentration of salt when RR4 concentration was lower, and salt promoted sorption when RR4 concentration was higher. The results indicated that protonated sewage sludge was an attractive substance for removing dyes from wastewater, and it was a new way to resource reutilize sewage sludge.