Zn(II) removal from wastewater by an alkali-activated material prepared from steel industry slags: optimization and...

Removal of dissolved zinc (Zn) from water by a novel alkali-activated material (AAM) prepared from steel industry slags in a fixed-bed column was investigated. Design of experiments was used to find the optimum operation parameters [flow rate $$, adsorbent mass, ($$), and initial Zn concentration ($$)] for the removal of Zn²⁺ from a ZnCl₂ solution. Regression models for the breakthrough ($$), and saturation ($$) capacities of the bed and three other response parameters as functions of $$, $$ and $$ were fitted with coefficients of determination ($$) ranging from 0.48 to 0.99. Experimental values of $$ and $$ varied within 1.42-7.03 mg Zn/g and 10.57-17.25 mg Zn/g, respectively. The optimum operation parameters were determined to be $$ 1.64 ml/min and $$ 4.5 g, whereas $$ had negligible effect on the response parameters in the range 73-107 mg Zn/l. Finally, three empirical breakthrough curve (BTC) models were employed to describe the individual BTCs of which the modified dose - response model was found to give the best fit (0.960 $$ $$ $$ 0.998). The results of the present work demonstrate that the novel AAM has considerable potential to be utilized in water purification applications.