Predicting the capability of diatomite magnano composite boosted with polymer extracted from brown seaweeds for the adsorption of cyanide from water solutions using the response surface methodology: modelling and optimisation

Abstract

The rate of cyanide reduction in the aqueous solutions by adsorption onto the diatomite magnano composite boosted with alginate polymer beads (DMBA) was evaluated. The R software using RSM was used as an experimental technique to design a statistical equation. Based on statistical results obtained, second order model due to insignificant lack of fit (0.12) and the higher value of correlation coefficient (0.92) was selected as a suitable model to design of the adsorption process. Based on the stationary points, the maximum adsorption of cyanide (98.11%) was achieved under selected conditions (initial cyanide concentration, 4.88 mg L−1; contact time, 91.06 min and DMBA dosage, 2.05 g L−1). The Sips nonlinear model indicated the best compatibility with the experimental data. It was found to be a successful model for predicting the heterogeneity of surfaces. The maximum adsorption capacity of cyanide onto DMBA was determined 208.55 mg g−1. The pseudo-first-order model was found to agree well with the adsorption experimental data obtained for cyanide. The thermodynamic data revealed the spontaneous sorption and endothermic for the adsorption of cyanide onto DMBA.