High-efficient recovery of chromium (VI) with lead sulfate

Lead sulfate was chose to precipitate chromium (VI) based on the difference of the solubility between lead sulfate and lead chromate. The effects of parameters on the precipitation efficiency of chromium including reaction temperature, reaction time, and initial pH of solution and dosage of lead sulfate were investigated. Results showed that the initial pH of solution and dosage of lead sulfate had big influence while reaction time and reaction temperature had little. The concentration of chromium (VI) could reduce from 0.2 mol/L to 0.0015 mmol/L (0.08 mg/L) at pH value of 13.90 and the dosage of lead sulfate as n (PbSO4)/n (K2CrO4) = 4. The XRD result of precipitation was consistent with the result predicted by Visual MINTEQ software and the precipitation was composed of PbCrO4, PbSO4 and other oxides containing lead. Otherwise, XRF and ICP were used to analyze the residual lead (II) in the filtrate and results indicated that the concentration of Pb (II) in the filtrate was acceptable. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.