Tetrahydrofuran

Functionalized CNTs were prepared by the use of acylation reactions.22 (link),23 (link) For carboxylation of MWCNTs, 1.5 g of MWCNTs was combined with 20 mL of sulfuric acid and nitric acid at a ratio of 3:1 for 30 min in the ultrasonic device and was replaced in reflux system for 24 h at 45 ° C. Subsequently, 100 mL of and were added to the previous phase at a ratio of 4:1, and again, placed to the ultrasonic device for 30 min.24 (link) The reaction mixture was centrifuged, the precipitate was separated, and the supernatant was centrifuged again by adding deionized water. After several steps of washing with the solvents at the pH up to 6, the sample was washed with methanol. The solution was filtered through a 0.2 μm polytetrafluoroethylene filter, and the black solid was dried under vacuum at room temperature. For acylation of carboxylated MWCNTs, 1 g of MWCNTs with 20 mL of thionyl chloride (Merk, Germany) was mixed at 60 °C for 14 h in the reflux system. The final product was washed and separated with tetrahydrofuran (Merk, Germany) and acetone; then, it was dried in an oven at 70 °C.

Commercial melamine sponges
were purchased from commercial sources but were manufactured by BASF. p-Dichloroxylene (DCX) was purchased from Alfa Aesar; iron(III)
chloride (anhydrous FeCl₃, 97%), Sylgard 184 (polydimethylsiloxane),
kerosene, and hexane (95%) were purchased from Sigma-Aldrich; 1,2-dichloroethane
(DCE, 99.8%), diethyl ether (99.7%, RCI Labscan), ethanol (99.5%),
acetone (99.5%), and silicone fluid (350 cSt) were purchased from
Chem-Supply; methanol (99.8%), tetrahydrofuran (99.9%), toluene (99.9%),
and chloroform (99.8%) were purchased from Merk; Tellus S2 M 32 was
obtained from Shell & Turcas Petrol AS; and conventional heavy
crude oil was obtained from the department of Fisheries and Oceans
Canada.