Role of humic acid in bioleaching of copper from waste computer motherboards

Abstract

In recent years, an increasing attention has been paid to the bioleaching of copper from waste computer motherboards. Here, we investigate the effect of humic acid on the bioleaching of waste computer motherboards using the mixed culture HQ0211. For this, the response surface methodology (RSM) is employed to investigate the effect of pulp density, initial pH and humic acid content on copper recovery. Samples leached at optimized experimental conditions according to RSM were analyzed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The results show that under optimum conditions; the initial pH = 1.53, pulp density = 1.35% (w/v) and humic acid addition = 0.31 g/L, a complete the copper leaching could be achieved. According to the results, the effectiveness of the bacterial and its capability to oxidize humic acid was proved. Overall, the biological leaching was found to be more effective than the chemical leaching. Humic acid can promote the bioleaching of waste computer motherboards, reducing its environmental hazards.