Rapid Removal of Dyes by Carbonized Sludge: Process,Effects of Environmental Factors,and Mechanism

The disposal of sewage sludge is one of the most pressing environmental issues with increasing amount of sewage sludge. Among these methods, carbonized sludge is thought to be a potential approach for resource utilization and becomes one of the most widely used adsorbent for wastewater treatment. However, effects of environmental factors and its relative mechanism for pollutant removal have not been thoroughly studied. In this study, carbonized sludge derived from sewage sludge was investigated. The adsorption of C. I. Acid Red 73 (AR 73) on the carbonized sludge was a rapid process and fit well to the Langmuir model with a maximum adsorption capacity of 137.95 mg g^?1 at pH 6.8. In addition, the common coexisting ions had a negligible negative impact on dye adsorption on the carbonized sludge. The magnetic carbonized sludge also exhibited high adsorption efficiency for other anionic dyes. Furthermore, the adsorption mechanism was proposed by analysis Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), high surface area, and proper porous structure as well as the π-π interaction between dye molecules and the graphene carbon surface were likely be the mechanisms of dye adsorption. Overall, the results reported herein indicated that carbonized sludge is very attractive and implies a potential of practical application for dyeing effluent treatment.