Removal of some chemical and microbial pollutants from wastewater via biochar/iron oxide nano-composite

Abstract

In this study we mixed prepared nano-magnetite with two kinds of biochars forming two nanocomposites so as to improve their surface properties in pollutants removal. The present study examined the ability of rice husk and sugarcane bagasse biochars in removal Fe and Zn ions from domestic wastewater released from a municipal waste oxidation ditch plant in (Quhafa, ezbet Henin Fayuom city, Egypt). Rice husk and sugarcane bagasse biochars were prepared by burning at two different pyrolysis temperatures 300 °C and 600 °C. The two biochars were used to remove Fe, and Zn ions in a batch experiments and showed low removal efficiencies. As a result, 1. Individual separate phase of magnetite (Fe3O4) was successfully synthesized in nano-scale 16-30 nm and by co-precipitation method at room temperature. 2. Nano-particulate composite of biochar / magnetite, (x) biochar / (1 − x) Fe3O4, was successfully prepared with different weight ratios (x = 0.0, 0.2, 0.3, 0.5, 0.7, 0.8, 1.0). 5. The composite of weight ratio of x = 0.5 and (1 − x) = 0.5 has the most effective ratio. To obtain two composites;

One is 50% Sugarcane bagasse biochar (SCB-BC) : 50% nano-magnetite (Fe3O4) And the other is 50% Rise Husk biochar (RH-BC) : 50% nano-magnetite (Fe3O4) The FTIR confirmed the presence of the main characteristic bands of Fe-O bonds that characterize the formation of iron oxides. HR-TEM confirms the FTIR spectra results by confirming the formation of nano-particulate composite with spherical particle shape. The two composites used for this study indicated maximum removal efficiencies in the first 15 min, higher efficiencies at shorter contact times are desirable. Finally, the two composites were of the same efficiency in Fe ions removal while the sugarcane bagasse biochar / magnetite composite were more efficient in Zn ions removal than the rice husk biochar/ magnetite. This was probably attributable to high intensities of carboxylic groups as evidenced by the FT-IR characterization results.