Evaluation of hyper-cross-linked polymeric sorbents (Macronet MN200 and MN300) on dye (Acid red 14) removal process

Abstract

Polymeric supports are presented as an alternative to granular activated carbon (GAC) for organic contaminants removal from waste waters from industrial processes. The present work describes the sorption of an azo dye (Acid red 14) from aqueous solution onto Macronet polymeric sorbent MN200 and MN300. Batch experiments were performed to determine loading isotherms and loading rates at different pH. The behaviour of a non-functionalized Macronet support MN200 was compared with Macronet MN300 containing tertiary amine groups. The loadings achieved were 65 g kg 1 for MN200 and 108 g kg 1 for MN300. The influence of the acidity on dye removal was notable; the decrease of pH provides an increase on the loading around 100% of the value reported at neutral pH. Equilibrium data were modelled with Langmuir, Freundlich and Redlich–Peterson isotherms. The hyper-cross-linked polymers extract Acid red 14, via a complex sorption process depending on the aqueous feed composition and depending on the nature of the sorbent evaluated. The Redlich–Peterson isotherm provides a better description of sorption data for both resins. Kinetic experiments were carried out for both sorbents at different pH and azo dye concentrations. Three theoretical models (pseudo-first, pseudo-second-order reaction and the Elovich model) were used to describe the Acid red 14 sorption kinetics, and to determine the sorption rate constants by graphical and numerical analysis of the experimental data by using the proposed models. The study showed that sorption systems followed a pseudo-first-order reaction model although the pseudo-second-order reaction model provides a good description of the sorption process.