Enhanced ibuprofen removal from wastewater using Ni-doped ZIF-67 MOF: Synthesis, characterization, and impact of doping on adsorption performance
Muhammad Qamer Abbas, Huma Javeria, Afaq Nazir, Zhenxia Du, Basem E. Keshta
Abstract
The purification of wastewater from pharmaceutical contaminants like ibuprofen (IBP) has become a critical issue due to its widespread usage, making the removal of such pollutants essential for the health and well-being of humans and aquatic life. Herein, we synthesized ZIF-67 with high BET surface area (1743 m 2 /g) and porosity along with Nickel doped ZIF-67 (Ni@ZIF-67 IBP) by using two different strategies to investigate their impact on synthesis and IBP removal efficiency. The synthesized highly porous adsorbents were employed for the removal of IBP molecules from wastewater. Different characterization techniques, including XPS, XRD, SEM, TEM, BET, FTIR, and TGA/DTG analysis, were studied to check the properties and characteristics of the synthesized materials. The Ni@ZIF-67 synthesized via method B has a higher surface area and porosity than the materials synthesized by method A and ultimately possesses a higher IBP uptake capacity (225 ± 5 mg/g). In contrast, the ZIF-67 adsorbent has 187 ± 5 mg/g adsorption efficiency. The adsorption study was conducted under optimum conditions, i.e., adsorbent = Ni@ZIF-67-10%B, m = 2 mg, V = 50 mL, pH = 2, C o = 50 mg/L, and 25 °C. The IBP adsorption process followed the pseudo-second-order kinetics and the Redlich-Peterson and Langmuir isotherm models. Due to the high BET surface area and porosity of adsorbents, the removal of IBP mainly follows the electrostatic, host-guest, and π-π interactions as the primary adsorption mechanism. The thermodynamic study indicated that the IBP adsorption is thermodynamically favorable and spontaneous. After the 5 th cycle, the overall IBP uptake was almost 72% of the pristine material, which means the adsorbent is effective for the removal of IBP from wastewater.