Application of Thermally Treated Water Treatment Sludge as a Remarkable Adsorbent Towards Emerging Pollutant Removal from Aqueous Solution

In this work, the application of thermally treated water treatment sludge on the adsorptive removal of acid red 97 dye, as well as on the treatment of a synthetic textile mixture, was evaluated. The material properties were obtained by different instrumental techniques. The calcined sludge presented mesoporous texture, and specific surface area of 60.2 m2 g−1. The pseudo-second-order model satisfactorily described the adsorption kinetics, while the Langmuir model was appropriate to describe the equilibrium data. A high adsorptive capacity of 4957 mg g−1 was found at 328 K. The thermodynamic investigation showed that the adsorption process is endothermic and spontaneous. There was a remarkable removal of several dyes contained in the synthetic mixture, corresponding to 74.4%. Therefore, the calcined sludge sample could be applied as a potential adsorbent in the treatment of colored wastewaters.