Investigation of the adsorption efficiency of methylene blue on Iranian Luffa Cylindrica: Effects of temperature and pH

Industrial wastewater containing synthetic dyes is an important factor in environmental pollution. Among the numerous methods that have been investigated to remove dyes, adsorption process using biosorbents is a good option for the removal of dyes from wastewater due to low cost, availability and lack of environmental risk. The aim of this study is to investigate the adsorption of cationic dye methylene blue using Iranian Luffa Cylindrica in a batch system. The effect of operational parameters including: contact time, pH and temperature on removal of methylene blue with Iranian Luffa in same condition, i.e, initial dye concentration 25 mg/L and adsorbent dose 0/5 g was investigated. Finally, data was analyzed using four kinetic and thermodynamic parameters. Results showed that equilibrium was reached at 100 min. Solution with the lowest pH has the low setup take. The maximum absorption was achieved at pH 7 and 8. That due to the insignificant difference of absorption efficiency in the two pH, by considering the economical aspect especially in large scales, pH=7 was chosen as the optimum condition. Also, adsorption efficiency increases with increasing temperature. Results from studying the kinetics of adsorption indicated that adsorption process follows kinetic model of pseudo second-order. the calculated values from thermodynamic parameters showed that the adsorption of methylene blue on Luffa Cylindrica is spontaneous, endothermic and Physical. According to this study Iranian Luffa is proposed as a natural, environmental friendly adsorbent with high efficiency, low cost for effective removal of Methylene Blue from industrial wastewaters (without any pretreatment on Luffa).