Plackett–Burman experimental design of modified wood ceramics for ammonia nitrogen removal from water and response optimization of the modified wood ceramic's comprehensive performance

Abstract

Modified wood ceramic is a carbon-carbon composite material obtained by calcining pine wood in a nitrogen atmosphere by using montmorillonite and magnesium chloride as modifiers. The Plackett–Burman fractional factorial design was used to analyze 11 parameters in the experimental preparation of modified wood ceramics and to determine the factors that significantly affected the ammonia-nitrogen adsorption capacity and apparent porosity of the modified wood ceramics while optimizing the composite properties of the modified wood ceramics. Experimental results of the Plackett–Burman fractional factorial design showed that the filling weight, the mass ratio of wood fiber to wood powder, the mass ratio of montmorillonite to anhydrous ethanol, and the heating rate significantly influenced the comprehensive performance of the modified wood ceramics. The structure and properties of the modified wood ceramics were determined using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and the Brunauer–Emmett–Teller (BET) method. For ammonia nitrogen as the target pollutant (initial concentration: 100 mg/L), results of isotherm model fitting showed that the Freundlich isotherm model parameter fitted the adsorption process of ammonia nitrogen well. The results show that the pseudo-second-order model was better fitted to describe the experimental data than the pseudo-first-order kinetic, intraparticle diffusion, Elovich, and double–constant models. The filling weight, the mass ratio of wood fiber to wood powder, the mass ratio of montmorillonite to anhydrous ethanol, and the heating rate had a stronger impact on the comprehensive performance of the modified wood ceramics.