Application for Reprocessing Cattle, Chicken, and Fish Bones in the Removal of Zn (II) and Cr (VI) from Wastewater Using Batch Adsorption System

To reduce the daily heaps of bone waste which causes environmental contamination and disposal site constraints, three different types of animal bone waste including (Cattle, Fish, and Chicken) were utilized as adsorbents to remove zinc and chromium metal ions from wastewater. Maximum sorption was found to occur at an initial pH of 5 and 3 h of equilibrium contact time. The maximum uptake of Zn (II) ions onto each adsorbent bone was found favorably 36.25, 25.65, and 30.75 mg g−1 compared to 56.5, 32.7, and 38 mg g−1 for Cr (VI) ions. Results proved that the Freundlich expression model described the isothermal equilibrium process. Thermodynamic analysis revealed that interaction of both Zn (II) and Cr (VI) ions with bone adsorbents progressed physically and spontaneously with an exothermic nature, and exhibited randomness increased during the adsorption process with increasing temperature. In isothermal equilibrium adsorption, chromium ions had an excessive affinity to stay with all adsorbents instead of zinc ions. The removal performance followed the trend Cr (VI)> Zn (II). The kinetic model result data showed that adsorption followed the pseudo-second-order kinetic model with the highest determinant coefficient of 0.9888.