The Use of Sugarcane Bagasse to Remove the Organic Dyes from Wastewater

In the present study, the potential of sugarcane bagasse (SCB) was evaluated by methylene blue (MB) retention. The selected low-cost adsorbent was characterized by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), BET method, and determination of the point of zero charge (pHzpc). Batch kinetic and isothermal studies were performed to examine the effects of contact time, initial dye concentration, adsorbent dose, pH, and temperature. The results show that the kinetic study of MB adsorption on sugarcane bagasse is very fast; the equilibrium is reached after only 20 minutes. The kinetic model of pseudo-second-order and the Langmuir isotherm model perfectly explain the adsorption process of MB with a monolayer adsorption capacity equal to 49.261 mg·g−1 activation parameters’ values such as free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) also determined as −4.35 kJ·mol−1, −31.062 kJ·mol−1, and −0.084 J·mol−1·K−1, respectively. Besides, the thermodynamic parameters of the methylene blue sugarcane bagasse system indicate that the exothermic adsorption process is spontaneous.