The role of graphenized pencil lead/cysteine composite as high efficiency adsorbent for removal of tetracycline drug from wastewater

A novel sorbent consisting of graphenized pencil lead modified with cysteine was synthesized via the coprecipitation method and used an efficient sorbent for the elimination of tetracycline. The morphology, dimensions and structure of as prepared sorbent was characterized using Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). Optimization of important parameters such as initial drug concentration, pH, adsorbent dosage, stirring time effecting the removal efficiency was performed using central composite design. The sorption data were best fitted with the Langmuir isotherm model. A pseudo-second-order kinetic model was suitable for explaining the tetracycline sorption rate on the sorbent. The obtained results reveal that this sorbent is capable for efficient elimination of tetracycline in wastewaters.