Acid Blue 113 removal from aqueous solution using novel biosorbent based on NaOH treated and surfactant modified fallen leaves of Prunus Dulcis

In the present work, the fallen leaves of Prunus Dulcis (almond) have been used for obtaining biosorbent with activation based on NaOH and surfactant treatment. Characterization of biosorbent was performed using Fourier transform infrared spectroscopy, scanning electron microscopy, elemental analysis and Brunauer-Emmett-Teller analysis techniques. The obtained biosorbent was subsequently applied for removal of azo dye, Acid Blue 113, from aqueous solution. The effects of biosorbent dose, contact time, initial dye concentration, salt concentration and temperature on the extent of adsorption of AB 113 were investigated in batch mode. The optimum conditions obtained for maximum dye removal were biosorbent dose of 10 g L−1 for NaOH treated biosorbent and 3 g L−1 for surfactant modified biosorbent, contact time of 2.5 h and temperature of 293 K. Better results were obtained for surfactant modified biosorbent (almost 100% removal) as compared to the NaOH activated biosorbent. The adsorption kinetics data were found to be well described by pseudo-second order equation whereas Langmuir and Temkin isotherm models were observed to be best fitted to the obtained equilibrium data. The adsorption was found to be exothermic and spontaneous in nature. Maximum biosorption capacity obtained under optimized conditions were 10.87, 25.51 and 97.09 mg g−1 for conventionally obtained biosorbent, NaOH treated biosorbent and surfactant modified biosorbent respectively. Regeneration studies and subsequent application demonstrated potential of the biosorbent for dye removal in more than one cycle. The present study conclusively established the potential of surfactant modified biosorbent for effective removal of Acid Blue 113 dye with significantly higher biosorption capacity of 97.09 mg g−1 in comparison with other commonly used adsorbents.