Adsorption of strontium from aqueous solution using activated carbon produced from textile sewage sludges

► All the binary variables were considered statistically significant. ► The adsorption reactions were calculated as endothermic and spontaneous. ► 5 min shaking time was selected as an optimum parameter. ► Prepared activated carbon was described by Freundlich isotherm. ► The correlation coefficient value (R2) was calculated as 95%.