Effective Dye Adsorption with Cross-linked Hexagonal Boron Nitride Spheres

Abstract

In this study, cross-linked spheres (CS) were synthesized with chitosan and hexagonal boron nitride (h-BN) to be used in Reactive Blue 3R (RB3R) and Red P4BN (RP4BN) dye adsorption from wastewater. Surface characteristics of the CS were investigated by Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) analysis. The behavior of the adsorption processes with varying effective parameters were investigated. The highest removals were obtained at pH 3 for the RB3R and RP4BN removal processes as 62.8 and 74.2%, respectively. The equilibrium time of the processes was determined as 150 min. The pseudo-first-order kinetic model best explained the adsorption rates of the processes. The Freundlich isotherm model was fitted to define the adsorption mechanisms for both dyes. The positive ΔH values obtained as 24.27 and 16.59 kJ mol−1 for the RB3R and RP4BN adsorption processes, respectively, showed that the processes were endothermic. For the RB3R and RP4BN dye removal processes, ΔS values were calculated as 93.38 and 72.23 J mol−1K−1, respectively. Positive ΔS value indicates the processes that occur with an increase in disorder at the interface. The results described that the CS can be used in the adsorption of RB3R and RP4BN dyes from wastewater.