Assessment of cationic dye biosorption onto anaerobic digested sludge: Spectroscopic characterization

The main purpose of this research was to assess sludge binding properties as a bioadsorbent towards cationic dyes. Digested sludge was used to adsorb a cationic dye (methylene blue) from aqueous solution. A complete spectroscopic analysis (FTIR, 1H NMR, and 13C NMR) was carried out on sludge before and after the adsorption of methylene blue and after two months of storage. Results showed the presence of important binding sites to cationic dyes. FTIR, 1H NMR, and 13C NMR analysis reflected the presence of carboxyl and amino groups, which play an important role in the adsorption of methylene blue due to chemical interactions. In addition, these techniques showed the accumulation of methylene blue after storage of samples for a two month period. The sludge matrix was modified by biological activity resulting in the preferential degradation of carbohydrate-type materials. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1330–1337, 2016