Cu(II) and methylene blue dyestuff removal from aqueous solutions by using peganum harmala l. and chitosan biocomposite

One of the biggest problem of today threatening the environment is the pollution of wastewater with heavy metals and dyestuffs. In this study, the biosorption efficiency and ability of Peganum harmala L. and chitosan (PHLC) biocomposite were investigated to remove copper(II) metal and methylene blue (MB) dyestuff from aqueous media in a batch system. The effects of pH, temperature, biosorbent amount, initial Cu(II) and MB concentration and contact time on the biosorption process were investigated. While the optimum pH was found to be 5 for Cu(II) biosorption, it was 10 for MB. At the optimum pH values obtained, the effect of biosorbent amount on the biosorption was investigated and 10 g/L for Cu(II) and 4 g/L for MB were determined respectively as the highest removal rates. Equilibrium was reached at the contact times of 60 minutes for Cu(II) and 30 minutes for MB. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models were used to explain the biosorption mechanism, and it was found that both Cu(II) and MB biosorption of the biocomposite best fitted to the Langmuir model. The maximum biosorption capacity for Cu(II) and MB was determined as 16,428 mg/g and 58,139 mg/g at 45 °C, respectively. Pseudo-first-order kinetic, pseudo-second-order kinetic and intraparticle diffusion models were examined; it was observed that the experimental data conformed the pseudo-second-order kinetic model better. In order to see the biosorption ability of PHLC in the presence of many other ions, a wastewater sample was prepared and the results were compared with the results obtained from synthetic solutions and the usability of the biocomposite in real environments was discussed.