Wax-wetting sponges for oil droplets recovery from frigid waters

Abstract

Energy-efficient recovery of oil droplets from ice-cold water, such as oil sands tailings, marine, and arctic oil spills, is challenging. In particular, due to paraffin wax crystallization at low temperatures, the crude oil exhibits high viscosity, making it difficult to collect using simple solutions like sponges. Here, we report a wax-wetting sponge designed by conforming to the thermoresponsive microstructure of crude oil droplets. To address paraffin wax crystallization, we designed the sponge by coating a polyester polyurethane substrate with nanosilicon functionalized with paraffin-like octadecyl ligands. The wax-wetting sponge can adsorb oil droplets from wastewater between 5° and 40°C with 90 to 99% removal efficacy for 10 cycles. Also, upon rinsing with heptol, the adsorbed oil is released within seconds. The proposed approach of sponges designed to conform with the temperature-dependent microstructure of the crude oils could enable cold water technologies and improve circular economy metrics in the oil industry.

Ultrafast reclamation of fracking effluents using surface-engineered nanosilicon sponges

“…Figure 2a shows the scanning electron microscopy (SEM) images of the SEnS fabricated by coating a polyester polyurethane (PESPU) thermoset sponge with decyl capped nanosilicon (ncSi-C10) coating using previously reported methods. 6,13,14 Due to crosslinking between polyester and polyurethane, and PESPU-ncSi-C10 coating, the SEnS was expected to exhibit surface chemical and thermomechanical stability at desired high temperatures.…”

“…Previously, we reported PESPU and SEnS performance to remove oil droplets from saline and freshwater at variable pH levels. 6,13,14,23 In this work, the SEnS was evaluated for oil/water emulsions separation at high temperatures (30-100 °C) and pressure (40 psi). As shown in Figure 4a, the SEnS demonstrated oil uptakes between 1155 and 1236 mg g -1 for tested temperatures, but the speed of removal varied (Figure 4b).…”

“…SEnS fabrication. Detailed protocols on the nanocoating synthesis and SEnS fabrication are reported elsewhere 13,14,25 . Briefly, a commercial PESPU thermosetting porous sponge was used as the substrate.…”

“…[10][11][12] Furthermore, the adsorbed crude oil from the SEnS can be collected by simply rinsing with safe, crude oil miscible diluents, such as heptane, hexane, and toluene. 13,14 Thus, thermoset-based SEnS can emerge as a techno-economic-environmentally feasible solution for ultrafast fracking water reclamation as well as residual oil recovery to improve environmental sustainability at a critical time for the oil industry (Figure 1b). The remaining hot water is difficult to recycle due to presence of emulsified crude oil.…”

Bio‐based polydimethylsiloxane porous sponge materials with programmable hydrophobicity and porosity for efficient separation of hydrophobic liquids from water

“…Environmental concerns related to spilling of oils, 1,2 organic liquids and contaminated oily waste water produced from petroleum industry 3 in water domain are serious and possess a major threat to biodiversity 4–6 and habitat 7 . Spilled oil, due to different weathering processes 8 forms micro droplets 9 and deeply harms the marine ecosystems 10,11 innumerably 12–16 . The species in local vicinity face the death fate with in short duration of the spill accidents 17–19 .…”