Equilibrium and Kinetic Studies of Direct Red Biosorption onto Modified Silk Maze as an Economical Biosorbent

Abstract

In this study, the potential of biosorbent obtained from silk maze, was investigatedfor the batch biosorption of Direct red (DR ) in aqueous solution. The effects of temperature,biosorbent amount, contact time, initial dye concentration and ultrasonic irradiation were alsoevaluated. Furthermore, experimental equilibrium and kinetics data were fitted by Langmuir andFreundlich isotherms and pseudo-first-order and pseudo-second-order kinetic models, respectively.Kinetic experiments revealed that the biosorption of DR onto modified silk maze can bedescribed with a pseudo second-order model while the equilibrium isotherm data were welldescribed by the Freundlich model. The negative thermodynamic values of ΔHoand ΔGoshowed thatthe biosorption is an endothermic process and occurs spontaneously in the nature.The resultspresented that this waste material may be a suitable biosorbent for removal of industrial effluentsdue to its low cost and high efficiency.