Conference Dates

September 15-20, 2019


Magnetic modified hemp biochar with an aim of high adsorption capacity and rapid adsorption rate was prepared by two simple steps using microwave pyrolyzed biochar. This was investigated as a potential green adsorbent for lead remediation from wastewater in a batch-mode experiment. The 150 – 300 µm biochar particles obtained from microwave-assisted pyrolysis of 1.5 kg hemp biomass batch at an average temperature of 600˚C were first impregnated with H2O2 and then magnetized by mixing aqueous biochar suspensions with aqueous Fe3+/Fe2+ solutions. The composition, morphology and surface chemistries of this magnetic biochar was examined by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM) and BET surface area (SBET). The SBET of the magnetic hemp biochar is 83.76 m2 g-1.

Batch sorption studies were performed for a 50 mg L-1 lead solution at room temperature and pH 5.5 using 0.02 g of the magnetic adsorbent in 20 ml solution for 2 hours. The experimental results have shown that the adsorption capacity of this magnetic adsorbent for Pb2+ is 43.97 mg g-1, about 87.94% removal within the 2 hours. Both pseudo-second-order and pseudo-first-order kinetic model could predict the adsorption and desorption kinetic process on the modified sorbent. EDX analysis are used to show the mechanisms for the adsorption of Pb2+ onto the adsorbent via mainly ion exchange. The Freundlich, Temkin and Langmuir models are used to predict the sorption isotherm in the system. The as-prepared magnetic hemp sorbent demonstrated a potential in heavy metal wastewater treatment.

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