Thioether-functionalized corn oil biosorbents for the removal of mercury and silver ions from aqueous solutions

Authors: Dunn, Robert - Bob; Bantchev, Grigor; Doll, Kenneth - Ken; Ascherl, Kim; LANSING, JAMES - Orise Fellow; Murray, Rex

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2018
Publication Date: 7/17/2018
Citation: Dunn, R.O., Bantchev, G.B., Doll, K.M., Ascherl, K.L., Lansing, J.C., Murray, R.E. 2018. Thioether-functionalized corn oil biosorbents for the removal of mercury and silver ions from aqueous solutions. Journal of the American Oil Chemists' Society. 95:1189-1200. https://onlinelibrary.wiley.com/doi/abs/10.1002/aocs.12089.
DOI: https://doi.org/10.1002/aocs.12089

Interpretive Summary: The availability of pure water is an essential part of agriculture, industry, and life. Unfortunately, it is these very things that have left much of the world without clean water. Toxic metals and elements currently flow through rivers and streams contaminating the environment. Recently, ARS developed a material which offers hope. Starting with ordinary corn oil, a slight modification has allowed only a single drop of oil to purify a large volume of water. The oil can then be removed for safe disposal or recovery of the metal. This report explores the science as to how the invention actually works. Using a combination of different metals, silver and mercury, an accurate and predictive mathematic model was developed. Using this knowledge, further work can be done to make the corn oil work more effectively and realize its promise of an inexpensive and convenient way to utilize agricultural products to solve the serious problem of water pollution.

Technical Abstract: Heavy-metal contamination is one of the most important environmental problems faced in the world, particularly in developing countries. Metals such as silver and mercury from drinking water, food, and air sources can accumulate in living organisms and present significant health concerns. Meanwhile, the demand for these metals in many industries continues to increase. In the present study, thioether-functionalized corn oil (TFCO) from a photoinitiated thiol-ene synthesis was utilized to remove Ag+ and Hg2+ ions from an aqueous solution. An aqueous solution containing AgNO3 and Hg[NO3]2 was prepared and contacted directly with TFCO. After vortex mixing for 60 s, the experiment ran for 351 min with the aqueous phase being periodically sampled for the analysis of metal ions (Mn+). Results showed that 88.9% of Ag+ and 99.6% of Hg2+ ions were removed from the aqueous phase by the TFCO. Mass balances indicated that the total Mn+ concentration in the oil phase was 13.890 g kg-1 under the conditions studied. TFCO exhibited higher selectivity for removing Hg2+ than for Ag+ ions. Analysis of the adsorption kinetics showed that a pseudosecond-order model may be used to determine the rate of Ag+ ion sorption by the oil phase. The presence of the Hg2+ ions interfered with the adsorption of Ag+ ions from the aqueous solution.