Application of volume retarded osmosis – Low pressure membrane hybrid process for recovery of heavy metals in acid mine drainage

• Published in: Chemosphere (Oxford) Vol. 232; pp. 264 - 272
• Main Authors: Choi, Jungwon, Im, Sung-Ju, Jang, Am
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2019
• Subjects: Acid mine drainage treatment; Forward osmosis; Low pressure membrane process; Membranes, Artificial; Metals, Heavy - analysis; Osmosis; Osmotic Pressure; Pressure; Recovery heavy metals; Ultrafiltration; Volume retarded osmosis; Water; Water Pollutants, Chemical - analysis; Water Purification - methods; Acid mine drainage treatment; Recovery heavy metals; Low pressure membrane process; Volume retarded osmosis; Forward osmosis
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2019.05.209

Recovery of heavy metals in acid mine drainage (AMD) such as Mn, Fe, Cu, Zn, As, Cd and Pb was evaluated using volume retarded osmosis and low-pressure membrane (VRO-LPM) process. In VRO-LPM process, the draw solution (DS) is regenerated by the naturally generated pressure, giving its economic value. Ethylenediaminetetraacetic acid tetrasodium salt (EDTA-4Na) and Poly (sodium-4-styrenesulfonate, PSS-Na) were used and compared to determine more suitable DS in heavy metal recovery from the AMD. Forward osmosis (FO) and nanofiltration (NF) membrane were employed in VRO-LPM process, due to the low EDTA-4Na rejection (about 50%) in ultrafiltration (UF) process. For the FO part in the VRO-LPM process, PSS-Na had flux values of 0.12, 0.11 and 0.05 L m−2 h−1 and at osmotic pressure of 8.9, 12 and 13 bar, respectively. Unlike the flux values, the RSF of PSS remained at 0.01 mmol h−1 at all osmotic pressures. For EDTA-4Na, the flux values were 0.10, 0.06 and 0.04 L m−2 h−1, which are relatively higher than those of PSS-Na; and the RSF values were 0.1, 1.2, 2.2 mmol h−1, which are higher compared to those of PSS-Na. Unlike PSS-Na, RSF for EDTA-4Na increased as the concentration increases. In the NF part of the VRO-LPM process, PSS-Na had higher water flux and rejection than EDTA-4Na, and the flux and rejection both decreased with concentration for both PSS-Na and EDTA-4Na. The overall rejection in VRO-LPM process was over 95% for all heavy metal ions. Therefore, VRO-LPM process has proven its ability to be used in AMD treatment for heavy metal removal. [Display omitted] •Single FO experiment was done using PSS-Na and EDTA-4Na as the DSs.•Single UF and NF experiments were done using PSS-Na and EDTA-4Na as the FSs.•Applicability of PSS-Na and EDTA-4Na as DS in VRO-LPM process was tested.•Heavy metal rejection in FO was tested using model mine-impacted water as FS.•Heavy metal rejection in VRO-LPM process using model mine-impacted water as FS, and PSS-Na and EDTA-4Na ad DSs.