Preparation of ammoniated tobacco leave powder residue biochar and its adsorption behavior on Cr(VI)

Using the waste cigarette leave powder residue as raw materials, after carbonization, the amino functional group was introduced to prepare the ammoniated tobacco leave powder residue biochar (NH2/TPB), and the effects of pH, dosage, temperature and adsorption time on NH2/TPB adsorption of Cr(Ⅵ) were studied. The mechanism was analyzed by scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and other techniques. The results show that when the initial concentration is 210 mg/L, pH=4, dosage is 0.8 g/L, temperature is 45℃, and adsorption time is 120 min, the maximum adsorption capacity of NH2/TPB for Cr(Ⅵ) is 103.627 mg/g. The adsorption process conforms the quasi-second-order kinetic model and Langmuir adsorption isotherm model. The adsorption and removal mechanism of Cr(Ⅵ) mainly include electrostatic interaction, reduction reaction, coordination and complexation with —NH2, —OH, —COOH, and “π-π” interaction with Si—O—Si. Through five times about adsorption-desorption tests, the Cr(Ⅵ) removal rate is more than 82.88%. This research presents that the ammoniated tobacco leave powder residue biochar has the potential to treat and repair acidic Cr(Ⅵ)-containing wastewater pollution.