Synthesis of nanoscale zerovalent iron (nZVI) derived from lignin containing wastewater for arsenic removal

Abstract

Nanoscale zerovalent iron (nZVI) plays a significant role in environmental remediation including the removal of arsenic from groundwater and drinking water. This study synthesized modified nZVI particles in order to remove arsenic in drinking water. Reductive precipitation under various conditions was used to produce non-modified nZVI (B-nZVI) and lignin-modified nZVI using either 1 g/L lignin solution (L-nZVI) or pulp and paper wastewater (P-nZVI) as the substrate. Ferrous to borohydride molar ratio of 1:1 was found to be the most appropriate ratio for L-nZVI and P-nZVI production since lignin was incorporated into the nZVI structure the most. According to TEM analysis, the particle sizes of B-nZVI, L-nZVI, and P-nZVI were 52.72±17.58, 4.77±3.51, and 2.04±1.09 nm, respectively. The specific surface areas of P-nZVI (49.36 m²/g) were much greater than those of L-nZVI (13.32 m²/g), presumably because of the co-existence of other polymers such as carbohydrates, tannin, organic acids, sulfur compounds, and resin. For arsenic study, it was found that the B-nZVI, L-nZVI, and P-nZVI at 1 g/L could remove 88.79%, 88.66%, and 90.79%, respectively, of 1 mg/L total arsenic in 5 minutes.