Design and Synthesis of Magnetic Immobilized Pineapple Cellulose/EDTA for Removal of Copper(II) and Zinc(II) by Coordination

Abstract

In recent decades, treatment of polluted water has shifted towards the enhancement of environmentally friendly adsorbents. In this regard, a biosorbent originated from pineapple peel cellulose was synthesized and used for the adsorption of Cu2+ and Zn2+. The magnetic (3-aminopropyl)triethoxysilane was designated to immobilize modified cellulose and ethylenediaminetetraacetic acid. The biosorbent was characterized by FE-SEM, TEM, EDX, XRD, FT-IR, BET, VSM and TGA techniques. The influence of pH, temperature and biosorbent dosage on the cation removal was investigated by Central Composite Design. The maximum uptake% was 93.18 and 96.30% for Cu2+ and Zn2+, respectively. Coordination and electrostatic attraction were proposed as the main reasons for the removal of heavy metal cations. The adsorption of Zn2+ was ultrafast and completed within 40 s and it took 420 s for totally removal of Cu2+. External surface biosorption, the intra-particle diffusion and the diffusion through the smaller pores and slits, in sequence, were the dominant steps in the adsorption of each cation. Modified pseudo-n-order and modified Langmuir-Freundlich were the best models to describe kinetics and equilibrium results. The maximum adsorption capacity of biosorbent for Zn2+ was higher than one for Cu2+ (153.9 versus 149.4 mg·g-1). The regenerating of biosorbent was successfully accomplished for five cycles using a solution of EDTA in the presence of ultrasonic waves.