Removal of mercury(II) from aqueous solutions via Box–Behnken experimental design by synthesized hierarchical nanoporous ZSM-5 zeolite

In this study, hierarchical nanoporous ZSM-5 zeolite is synthesized from bagasse ash as silica source (grows in the south of the Caspian Sea, Mazandaran province, Iran) and used as adsorbent for removal of the Hg(II) from aqueous solutions. Synthesized zeolite is characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electronic microscopy, and energy dispersive X-ray, Brunauer–Emmett–Teller and Barrett–Joyner–Halenda methods. Four important parameters in three levels including: adsorbent dosage (10, 25 and 50 mg), pH of solution (3, 7 and 10), contact time (20, 180 and 320 min), temperature (25, 55 and 75 °C), are optimized to obtain the best response of Hg(II) removal % using the Box–Behnken design. A second-order quadratic model suggested the optimum conditions to be as follows: adsorbent dosage 50 mg, pH of solution 7, contact time of 180 min and temperature 75 °C. Graphical abstract