A bench study on lead removal from battery manufacturing wastewater by carbonate precipitation

A residual soluble Pb ≤ 0.2 mg/l has been measured after hydrocerussite precipitation in the range of pH 9–10 and filtration with 0.45 μm filter, at a total carbonate concentration (CT) of about 1.5 × 10−4 M. Filterability and sedimentation were optimized by minimizing the “relative supersaturation” coefficient during precipitation. Pb abatement was implemented in the pH range 9–9.5, following a preliminary precipitation step consisting of a slow, gradual change of pH from 6.8 to 7.8 with 0.1 M NaOH solution. The crystals formed may settle within 24 h, allowing Pb to be recovered as Pb3(CO3)2(OH)2.