Modelling mercury sorption of a polysulfide coating made from sulfur and limonene

Abstract

A polymer made from sulfur and limonene was used to coat silica gel and then evaluated as a mercury sorbent. A kinetic model of mercury uptake was established for a range of pH values and concentrations of sodium chloride. Mercury uptake was generally rapid from pH = 3 to pH = 11. At neutral pH, the sorbent (500 mg with a 10:1 ratio of silica to polymer) could remove 90% of mercury within one minute from a 100 mL solution 5 ppm in HgCl2 and 99% over 5 minutes. It was found that sodium chloride, at concentrations comparable to seawater, dramatically reduced mercury uptake rates and capacity. It was also found that the spent sorbent was stable in acidic and neutral media, but degraded at pH 11 which led to mercury leaching. These results help define the conditions under which the sorbent could be used, which is an important advance for using this material in remediation processes.

Investigation of low molecular weight sulfur–limonene polysulfide electrodes in Li–S cells

“…20 This low chain mobility in poly(S-r-squalene) proved to be less effective in improving Li-S cell capacity retention (Table 1, $67% initial capacity at 20th discharge, cycled at C/10 or 167.5 mA g À1 ) 20 compared to poly(Sr-DIB) (Table 1, $74% initial capacity at 20th discharge, cycled at C/10 or 167.5 mA g À1 ). 14,21 Despite this result for poly(S-rsqualene), the polymer from 1,5-diene limonene, poly(S-rlimonene), initially developed by Crockett et al, 15,32 exhibits high capacity retention values (Table 1, 97% of initial capacity at 300th discharge, cycled at 0.5C, 1C undened) 33 surpassing that of poly(S-r-DIB). Such promising results using poly(S-r-limonene) prompts further investigation on inverse vulcanized copolymers using 1,5-diene crosslinkers and how they can be effectively used or tuned to show optimal performance as electrode materials for Li-S cells.…”

Polysulfides as Sorbents in Support of Sustainable Recycling

“…However, while chemisorption increases selectivity, it also makes regenerating the sorbent more challenging. Breaking the bonds between the sorbent and the metal can be difficult to accomplish while maintaining the chemical and physical integrity of the sorbent . Conversely, gas adsorption onto polysulfides is driven by physisorption, resulting in a sorbent that is less selective, but efficient to regenerate .…”

“…To avoid the production of H 2 S, one possibility is the use of highly acidic or basic conditions to degrade the polysulfide. Acid stability studies of poly­(S- r -limonene) revealed that, at pH >11, the polysulfide degraded and mercury was leached back into the water . However, the degradation products of such a system have not been studied.…”

Sulfur–oleylamine copolymer synthesizedviainverse vulcanization for the selective recovery of copper from lithium-ion battery E-waste

“…17 Depending on the intended use, the choice of crosslinker and the quantity of sulfur can be used to modify or tune the morphology and properties of the crosslinked sulfur polymer. A wide range of sulfur polymers based on different crosslinkers, such as limonene, 18,19 styrene, fatty acid derivatives like vegetable oil, canola oil, etc., 20 are reported and explored for other fields such as optics fertilizers and as components in solar cells, etc. 14,[21][22][23][24][25][26][27][28][29] Moreover, sulfur is a soft Lewis base; considering (Hard-Soft-Acid-Base) HSAB theory, the sulfur polymer can be exploited to form covalent bonds with soft Lewis acids; hence it has been receiving significant attention in recent years with heavy metal sorption.…”