Experimental design approach for ultra-fast nickel removal by novel bio-nanocomposite material

In the present study, novel chitosan coated magnetic magnetite (Fe₃O₄) nanoparticles were successfully biosynthesized from mushroom, <i>Agaricus campestris</i>, extract. The obtained bio-nanocomposite material was used to investigate ultra-fast and highly efficient for removal of Ni²⁺ ions in a fixed-bed column. Chitosan was treated as polyelectrolyte complex with Fe₃O₄ nanoparticles and a Fungal Bio-Nanocomposite Material (FBNM) was derived. The FBNM was characterized by using X-Ray Diffractometer (XRD), Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS), Fourier Transform Infrared spectra (FTIR) and Thermogravimetric Analysis (TGA) techniques and under varied experimental conditions. The influence of some important operating conditions including pH, flow rate and initial Ni²⁺ concentration on the uptake of Ni²⁺ solution was also optimized using a synthetic water sample. A Central Composite Design (CCD) combined with Response Surface Modeling (RSM) was carried out to maximize Ni²⁺ removal using FBNM for adsorption process. A regression model was derived using CCD to predict the responses and analysis of variance (ANOVA) and lack of fit test was used to check model adequacy. It was observed that the quadratic model, which was controlled and proposed, was originated from experimental design data. The FBNM maximum adsorption capacity was determined as 59.8 mg g^&#8722;1. Finally, developed method was applied to soft drinks to determine Ni²⁺ levels. Reusability of FBNM was tested, and the adsorption and desorption capacities were not affected after eight cycles. The paper suggests that the FBNM is a promising recyclable nanoadsorbent for the removal of Ni²⁺ from various soft drinks.