PREPARATION AND CHARACTERIZATION OF POLYMERIC FOAMS FOR REMOVAL OF FREE OIL FROM WATER

Abstract

Development of polymeric foams for removal of oily pollutants (spills) from water is a key target of this thesis. Pollutants occur in the form of free oil (floating on the water surface) or oil/water macroscopic, non-stabilized mixtures. The foams designed for an efficient oil removal should have a high sorption capacity for oil but low affinity to water. This is insured by either chemical composition of polymeric materials themselves (e.g. polyolefines), or by post chemical and physical treatment of suitable materials (polyurethane and melamine foams) reducing their hydrophilicity and thus water sorption capability. In this thesis, two different strategies have been chosen. Firstly, low molecular oligomer (paraffinic) material was used for synthesis of foamy structures through crosslinking and foaming of an original material. This material, arbitrarily marked as Qwax is the waste material formed during polyethylene synthesis, and it was offered by QAPCO. The foamy, elastic structures were prepared through crosslinking by dicumyl peroxide and foaming by 1,1?-azobiscarbamide. The target of this research was a preparation of porous, hydrophobic and hydrophilic material with an appropriately high sorption ability for oil and low sorption of water, suitable for removal of free oil from water surfaces. The porosity of foam determined by computer micro-tomography was found of 58.9 %, and the bulk density of 0.42 g.cm-3. The hydrophobic character of foam was observed under both air and oil as the contact angle values of water are 114° and 128°, respectively. On the other hand, super oleophilicity was observed for Qwax foam under both air and water as the contact angle values where 0°. The foams are thermally stable up to 360oC. Secondly, commercial melamine foam, commonly used for cleaning was modified by graphene oxide to enhance oleophilicity of material and, particularly reduce its hydrophilicity. Sorption ability as well as reuse of both foams for different type of oil (crude oil, diesel oil, and motor/engine oil) was studied.