Synthesis of chitosan-nTiO2 nanocomposite, application in adsorptive removal of Cu(II)-Adsorption and desorption study, mechanism, scale-up design, statistical, and genetic algorithm modeling

The present study comprises the preparation of chitosan-nTiO(2) nanocomposites and their characterization with the help of scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Various adsorbent samples are prepared with different weight ratios of chitosan to nTiO(2). The adsorption capacity of the prepared adsorbents towards Cu(II) in an aqueous solution is also tested. The adsorption experiment is performed in batch mode under varying experimental conditions. Several isotherm and kinetic models are analyzed with the experimental data, and thermodynamic conditions required for adsorption are also determined. The highest elimination of Cu(II) was 39.19% with the adsorbent chitosan without nTiO(2) (CWT) with 20 mg L-1 initial Cu (II) concentration at adsorbent dosage 3 gL(-1) and 98.5% with the adsorbent CTNC1-1 (chitosan/nTiO(2) nanocomposite with the mass proportions of chitosan:nTiO(2) = 1:1) and 93% with CTNC2-1 (chitosan/nTiO(2) nanocomposite with the mass proportions of chitosan:nTiO(2) = 2:1) with 10 mg L-1 initial Cu(II) concentration at adsorbent dosage 5 g L-1. The isotherm model confirmed the monolayer adsorption. Maximum Langmuir adsorption capacities (q(L)) of the adsorbents for Cu(II) were given as CTNC1-1 > CTNC2-1 > CWT. The pseudo-second-order model excellently depicted the kinetic process with good correlation for all adsorbents. The statistical (R-square is more than 0.99) and genetic algorithm (GA) model (R-square is more than 0.99) effectively predicted the percentage removal of Cu(II).