Effects of operating parameters and coexisting ions on the efficiency of heavy metal ions removal by nano-fibrous metal-organic framework membrane filtration process

Johnson E Efome; Dipak Rana; Takeshi Matsuura; Christopher Q Lan

doi:10.1016/j.scitotenv.2019.04.187

Effects of operating parameters and coexisting ions on the efficiency of heavy metal ions removal by nano-fibrous metal-organic framework membrane filtration process

Sci Total Environ. 2019 Jul 15:674:355-362. doi: 10.1016/j.scitotenv.2019.04.187. Epub 2019 Apr 14.

Authors

Johnson E Efome¹, Dipak Rana², Takeshi Matsuura¹, Christopher Q Lan¹

Affiliations

¹ Industrial Membrane Research Institute, Department of Chemical and Biochemical Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, ON K1N 6N5, Canada.
² Industrial Membrane Research Institute, Department of Chemical and Biochemical Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, ON K1N 6N5, Canada. Electronic address: rana@uottawa.ca.

PMID: 31005837
DOI: 10.1016/j.scitotenv.2019.04.187

Abstract

The purification process of wastewater containing heavy metal ions (HMIs) using nano-fibrous metal-organic frameworks, MOF-808, embedded polyacrylonitrile membrane has been studied. The process parameters that were evaluated included feed concentration, transmembrane pressure (TMP), and membrane thickness. The effect of coexisting cations in the solution upon the removal efficiencies of Zn²⁺, Cd²⁺, Pb²⁺ and Hg²⁺ ions was also investigated. Results from the filtration experiments indicate a substantial variation in the feed volume that the membrane can treat before the permeate lead concentration reaches the allowable limit of 10 ppb, depending on the process parameter. An increase in the membrane thickness showed a significant improvement (26%) with 440 L of the treated feed volume after doubling the membrane layer. An increase in TMP could reduce the treated feed volume by 38% while a decrease in feed concentration led to a 21% increase in the treated feed volume. In the presence of other common background cations in the solution, the removal efficiency of HMIs by adsorption onto MOF-808 dropped by 18 to 37%. This result was dependent upon the HMIs, in the presence of up to three other cations but was minimal in the presence of a single cation indicative of good selectivity.

Keywords: Coexisting ions; Heavy metal ions; Membrane adsorption; Metal-organic frameworks; Nano-fibrous membrane.