Zn(2+) removal from the aqueous environment using a polydopamine/hydroxyapatite/Fe(3)O(4) magnetic composite under ultrasonic waves

In this study, an easily magnetically recoverable polydopamine (PDA)-modified hydroxyapatite (HAp)/Fe(3)O(4) magnetic composite (HAp/Fe(3)O(4)/PDA) was suitably synthesized to exploit its adsorption capacity to remove Zn(2+) from aqueous solution, and its structural properties were thoroughly examined using different analytical techniques. The effect of multiple parameters like pH, ultrasonic power, ultrasonic time, adsorbent dose, and initial Zn(2+) concentration on the adsorption efficiency was assessed using RSM-CCD. According to the acquired results, by increasing the adsorbent quantity, ultrasonic power, ultrasonic time, and pH, the Zn(2+) adsorption efficiency increased and the interaction between the variables of ultrasonic power/Zn(2+) concentration, pH/Zn(2+) concentration, pH/absorbent dose, and ultrasonic time/adsorbent dose has a vital role in the Zn(2+) adsorption. The uptake process of Zn(2+) onto PDA/HAp/Fe(3)O(4) followed Freundlich and pseudo-second order kinetic models. The maximum capacity of Zn(2+) adsorption (q(m)) obtained by PDA/HAp/Fe(3)O(4), HAp/Fe(3)O(4), and HAp was determined as 46.37 mg g(−1), 40.07 mg g(−1), and 37.57 mg g(−1), respectively. Due to its good performance and recoverability (ten times), the HAp/Fe(3)O(4)/PDA magnetic composite can be proposed as a good candidate to eliminate Zn(2+) ions from a water solution.