Simultaneous removal of binary mixture dyes using mn - Fe layered double hydroxide coated chitosan fibers prepared by wet spinning

Abstract

In this study, the carbohydrate polymer chitosan (CS) fibers were prepared successfully by a simple wet spinning process and subsequently coated by manganese iron layered double hydroxide (Mn-Fe LDH) through hydrothermal technique. The properties of the Mn-Fe LDH/CS composite were identified by various techniques such as FESEM, EDS, FT-IR, BET and element mapping analyses. The simultaneous removal of indigo carmine (IC) and sunset yellow (SY) as anionic dyes from aqueous solutions using an as-prepared composite were studied. In binary solutions, the first order derivative spectrophotometric approach was used for the simultaneous measurement of IC and SY. Four operational variables, concluding initial concentration of IC and SY, adsorbent amount and contact time were selected to investigate by central composite design (CCD) coupled with response surface methodology (RSM). In the optimum conditions, kinetic study was performed and the pseudo second order model for both IC and SY were found the well fitted model compared to other models, whereas the adsorption isotherm of dyes followed the Langmuir isotherm model with a maximum adsorption capacity of 17.85 and 11.37 mg g −1 for IC and SY, respectively. The thermodynamic analysis highlighted that the adsorption process of dyes onto the Mn-Fe LDH/CS fibers was an endothermic process.