Preparation of Calcium Cross-linked Nano-Fe 3 O 4 Modified Zeolite Microspheres for Cu 2+ Adsorption from Wastewater

Artificial zeolite was modified by nano-Fe 3 O 4 for development of functional adsorbents. Subsequently, adsorbents such as calcium cross-linked nano-Fe 3 O 4 microspheres (Ca-MS), calcium cross-linked nano-Fe 3 O 4 modified zeolite microspheres (Ca-MZS) and iron cross-linked nano-Fe 3 O 4 modified zeolite microspheres (Fe-MZS) were prepared and compared for their adsorption performance. The effects of adsorbent dosage, solution pH, initial concentration and ion content on the removal of Cu 2+ from wastewater are investigated, and the adsorption kinetics and isotherms for the adsorbent materials were analyzed. The experimental results indicate that for the initial concentration of Cu 2+ of 30 mg/L, the adsorption is noted to be most stable. The optimal initial pH for adsorbing Cu 2+ is observed to be 5.5. At an optimal dosage of Ca-MZS of 900 mg/L, the adsorption capacity is measured to be 28.25 mg/g, along with the removal rate of 72.49%. The addition of Na + and K + affects the adsorption of Cu 2+ . For the Na + and K + concentration of 0.2 mmol/L, the Cu 2+ removal rate by Ca-MZS drops to 11.94% and 22.12%, respectively. As compared with the adsorbents such as Natural Zeolite (NZ), Ca-MS and Fe-MZS, Ca-MZS demonstrates the best removal effect in solution, where the removal rate reaches 84.27%, with the maximum adsorption capacity of 28.09 mg/g. The Cu 2+ adsorption kinetics of Ca-MZS is observed to follow the Elovich kinetic model, with the adsorption isotherm data fitting the Freundlich isotherm model by using the non-linear method.