Biosorption of bisphenol A and sulfamethoxazole from water using sulfonated coffee waste: Isotherm, kinetic and thermodynamic studies

Herein, we report a facile method for the synthesis of sulfonated coffee waste (CW-SO3H). The biosorbent was characterized using Scanning Electron Microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), Fourier-transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, Thermogravimetric analysis (TGA) and Zeta potential measurements. The biosorbent was used for the biosorption of endocrine disrupting chemicals such as bisphenol A (BPA) and antibiotics such as sulfamethoxazole (SMX) from water. The calculated biosorption capacifies of CW-SO3H were 271 mg/g and 256 mg/g towards the removal of BPA and SMX, respectively. The as synthesized biosorbent is capable to form pi-pi interaction and electrostatic interaction that allow the efficient biosorption of BPA and SMX. The Temkin isotherm model fits the experimental data better for BPA biosorption process, whereas the Temkin and Langmuir models explain the experimental data better for SMX biosorption process. The kinetic studies showed that the biosorption of BPA and SMX by CW-SO3H follows pseudo-second order kinetic model. The thermodynamic studies showed that the biosorption processes were spontaneous as well as exothermic in both cases. Therefore, CW-SO3H could be used as a promising biosorbent for the rapid removal of BPA and SMX from the wastewater.