Performance of phosphorus adsorption by acid-activated iron-based waterworks sludge adsorbent

Abstract

Iron-based waterworks sludge was activated using 0.5-3 mol/L H2SO4 acid to obtain the acid-activated iron-based waterworks sludge (AAIBWS). The sludge treated with 1 mol/L H2SO4 acid was best for phosphorus adsorption and used to carry out batch phosphorus adsorption experiments. The influencing factors including solution pH, contact time and reaction temperature were investigated. The results indicated that the acid environment was favourable for P adsorption. The phosphorus adsorption increased with the rising reaction time and temperature. The pseudo-second-order equation was best to describe the adsorption process among the three kinetic models. The Langmuir isotherm provided a better fit of the data than the Freundlich model. Thermodynamic parameters showed that the phosphorus adsorption on AAIBWS-1 had a spontaneous and endothermic nature.