Heavy Metal Removal and Leaching from Pervious Concrete Filter: Influence of Operating Water Head and Reduced Graphene Oxide Addition

Abstract

The effects of an operating water head (OWH) and reduced graphene oxide (RGO) addition on the pervious concrete filter (PCF) and heavy metals interaction were investigated in the present study. Five simulated wastewaters containing Cd, Zn, Cu, Pb, and these four ions mixed together were filtered by PCF monoliths, considering the influence of three OWHs, viz. 30 cm, 7.5 cm, and trickling water head. The metal ions fixation degree increased with decreasing levels of OWH, which indicates that empty bed contact time influences PCF performance. Additionally, heavy metals removal and leaching from 0.06 wt% RGO modified PCF (G-PCF) and plain PCF were examined by first passing the five wastewater samples, immediately followed with strong acidic water, while maintaining the same flow and time. As a consequence of acid water passage, the fixated ions were seen to leach out from PCFs, but the RGO’s strong reinforcement substantially reduced such leaching degree and additionally improved the simultaneous removal of four heavy metals. Although the estimated cost of G-PCF was relatively higher than plain PCF, both these filters appear highly efficient and inexpensive, unlike treatment units that are currently used by the electroplating industry for heavy metals removal.