Enhanced adsorption performance of methylene blue from aqueous solutions onto modified adsorbents prepared from sewage sludge

Abstract In the present work, an attractive and creative adsorbent derived from sewage sludge was freshly fabricated via pyrolysis technology, followed by modification for improving the absorptive ability. First, the (NH4)2S2O8 modified pyrolytic sludge (MSAP) was selected from 19 modified pyrolytic sludges for the highest removal efficiency and adsorption capacity for methylene blue (MB). Then, the adsorption performance for MB of MSAP was compared systematically with the pristine adsorbent (MSDW) by batch adsorption experiments. The main conclusions were that the adsorption process was better fitted with the Langmuir model, and the maximum adsorption capacity (qmax) of MSAP was observed to be 149.05 mg g−1. Moreover, the adsorption kinetics data showed a good fit with the pseudo second order model; when the addition of MSAP was 1.0 g·L−1, the rate constant was 0.05 g·mg−1·min−1, which was far greater than that of the other modified adsorbents.