Factorial experimental design for Remazol Yellow dye sorption using apple pulp/apple pulp carbon–titanium dioxide co-sorbent

Abstract

Dye containing effluents can cause severe organic and color pollution in the water environment, thus removal of reactive dyes by sorption is an important circumstance. The aim of this study was to identify the operating conditions which influence Remazol Yellow dye sorption from aqueous solutions. There are limited numbers of literature studies about Remazol Yellow dye sorption. Despite that the sorption of Remazol Yellow dye by co-sorbent system and optimization of such process have not yet been studied. Thus, apple pulp and carbonized apple pulp at 550 °C were used as sorbents, also apple pulp–titanium dioxide and apple pulp carbon–titanium dioxide mixtures were used as co-sorbents. Elemental analysis, X-ray fluorescence spectroscopy, scanning electron microscopy, zeta potential, particle size distribution, and Fourier transform infrared spectroscopy analysis were conducted to analyze apple pulp and apple pulp carbon. The effects of pH, initial dye concentration and contact time were investigated by 33 full factorial experimental design method and analysis of variance statistical approach to optimize the operating conditions. The maximum percentage dye removal was obtained as 86.97% (sorbent type = apple pulp–titanium dioxide, pH = 2, initial dye concentration = 10 mg/L and contact time = 120 min). pH, initial dye concentration and contact time were found as significant within a 95% confidence level for all type of sorbents. Equilibrium isotherm data were fitted to Langmuir and Freundlich equations and the Langmuir model showed the best fit with equilibrium isotherm data. Furthermore, pseudo-first and second-order kinetic models were also used to analyze sorption kinetics. Since apple pulp was low-cost and easily available material, and also application of co-sorbent was influential for dye sorption; it could be successfully applied for the removal of Remazol Yellow dye from aqueous solutions.