Macroporous rubber gels as reusable sorbents for the removal of oil from surface waters

Macroporous organogels were prepared by solution crosslinking various rubbers in benzene at −18 °C. Butyl rubber (PIB), cis-polybutadiene (CBR) and styrene-butadiene rubber (SBR) were used as the rubber components, while sulfur monochloride was the crosslinker in the gel preparation. The organogel networks consist of large pores of 101-102 μm in size caused by the benzene crystals acting as a template during gelation. The networks formed by CBR and SBR showed an aligned porous structure consisting of regular pores, whereas those derived from PIB had irregular pores with a broad pore size distribution due to the phase separation of PIB chains at low temperatures. All organogels were very tough and could be completely compressed without any crack development. Sorption tests showed that the organogels were efficient at removing crude oil, gasoline, diesel, fuel oil and olive oil. The organogels are reusable once they are squeezed, leading to continuous sorption capacities of CBR or SBR gels for crude oil and olive oil of 33-38 g/g and 24-27 g/g, respectively. These sorption capacities are two to three times the capacity of the gels derived from PIB.