Eco-friendly Recovery and Utilization of Innovative Industrial Adsorbents for Multi-metal Ion Removal in Aqueous Solutions

This study investigates the ability of recovered industrial bentonite waste (RIBW) as a Nano, low-cost, and new adsorbent to remove the Pb, Cd, Cr, Zn, and Ni that have different electrochemical properties in the form of multi-metal ions from aqueous solution. The investigated doses of (RIBW) were (0.1, 0.2, and 0.3) g/100 mL for each system, and the initial concentration of each metal ion in the binary, ternary, quaternary, and quinary system was 50, 33.3, 25, and 20 ppm, respectively, where the total concentration of ions remained constant and equivalent to 100 ppm. The maximum removal efficiency of Pb, Cd, Cr, Zn, and Ni was in the binary system with a dose of 0.3 gm of (RIBW) and equaled 99.7, 95.7, 99.5, 99.2, and 97.3. The minimum in the quinary system with an adsorbent mass of 0.1 g equaled 80.8, 51.1, 72.7, 71.1, and 36.6, respectively. The correlation coefficient values of R-2 for all experiments ranged from 0.91 to 1.00. The adsorption capacity on the level of the single or multi decreases with increasing the number of partaken metal ions in an aqueous solution where the adsorption capacity order of metal ions in binary > ternary > quaternary > quinary. It was evident that the electrochemical properties such as atomic weight, ionic radius, hydrated ionic radius, and softness value have essential effects on the adsorption capacity where the ion metal having high values of these properties was more adsorbed on the surface of RIBW adsorbent.