Kinetic Analysis of the Adsorption of Chromium onto Calcium Alginate Nanoparticles

Abstract

The widespread use of chromium in industrial applications such as leather tanning, metallurgy, electroplating, and refractory materials has resulted in it being one of the most harmful trace elements to be introduced into surface and ground waters. The sorption isotherm of chromium sorption onto calcium alginate nanoparticles were analyzed using three models—pseudo-1st, pseudo-2nd and Elovich, and fitted using non-linear regression. The Elovich model was the poorest in fitting the curve based on visual observation followed by the pseudo-1st order. Statistical analysis based on root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), accuracy factor (AF), corrected AICc (Akaike Information Criterion), Bayesian Information Criterion (BIC) and Hannan–Quinn information criterion (HQC) that showed that the pseudo-1ST order model is the best model. Kinetic analysis using the pseudo-1st order model at 400 mg/L 4-BDE gave a value of equilibrium sorption capacity qe of 31.89 mg g-1 (95% confidence interval from 30.37 to 33.42) and a value of the pseudo-1st-order rate constant, k1 of 0.22 (95% confidence interval from 0.019 to 0.025). Further analysis is needed to provide proof for the chemisorption mechanism usually tied to this kinetic.