Mercury Sorbents Made By Inverse Vulcanization of Sustainable Triglycerides: The Plant Oil Structure Influences the Rate of Mercury Removal from Water

High sulfur content polymers are prepared through the copolymerization of sustainable triglycerides and sulfur. These products of “inverse vulcanization” contain 50% sulfur by mass and are evaluated in the removal of mercury from water. The structurally distinct triglycerides found in canola oil, castor oil, and rice bran oil are examined as co-monomers to determine how each influences the rate and capacity of mercury uptake. An important discovery is that the high percentage of hydroxylated ricinoleic acid in castor oil improves both wetting and the rate of uptake of mercury(II) chloride into the polymer, in comparison with the polymers made from canola oil and rice bran oil. Detailed kinetic and isotherm modeling is carried out for all polymers for both inorganic and organic mercury sorption. All of the polymers are superior to elemental sulfur in their mercury capture ability. In terms of sustainability, this work advances the use of renewable monomers such as triglycerides sourced from plants and inexpensive industrial byproducts such as sulfur to make affordable mercury-binding materials.