Heavy metal ions removal from industrial wastewater using magnetic nanoparticles (MNP)

Abstract

A novel iron oxide magnetic nanoparticles (MNPs) grafted on hyperbranched polyglycerol (HPG) polymer were synthesized, characterized and tested for heavy metals (Ni, Cu and AL) removals from secondary effluent industrial wastewater (SEIWW). The effect of water matrix (organic matter, nutrient and pH) on removal efficiencies were evaluated. The heavy metal adsorption mechanism was investigated from adsorption isotherm and kinetic point-of-view. HPG-MNPs was successfully applied adsorbent for heavy metal removal from SEIWW. The adsorption process is spontaneous, pH dependence and showed high Ni, Cu and AL removal efficiency from water solutions. The magnetic separation process was very fast and took only 35 s. Adsorption isotherms were successfully fitted to Langmuir and Frindluich isotherms with a maximum equilibrium capacity (qmax) of 0.700, 0.451 and 0.790 mg mg−1 for Cu, Ni and Al, respectively. The pseudo-second-order model described well the adsorption kinetic data suggesting the sorbent connects to adsorbent by two or more steps including intra-particle diffusion. Through characterization tests, it is evident HPG-MNPs are uniformly dispersed in the solution, have a size in the nanometer range and have a spherical morphology. The removal efficiencies were not affected by the organic matter and phosphorous content of the wastewater but increasing the concentration of nitrogen reduced the percentage of heavy metal removals. The excellent reproducibility of the HPG-MNPs indicate they can be a promising adsorption material for the removal and separation of different heavy metals from aqueous solutions.