New Flocculants based on Technical Vegetable Oil–A Residue of Sunflower Oil Production
Abstract
A mixture of fatty carboxylic acids (FCA) was derived from technical vegetable oil - a residue of sunflower oil production. Chromatographic-mass spectrometric analysis revealed that the mixture primarily consists of nine types of fatty carboxylic acids. Nonionic surfactants (NIS), specifically FCA-PEG esters, were synthesized via esterification of the FCA mixture with polyethylene glycol (PEG) of molecular weights 300, 600, and 1000. The reaction yield was 93–94%. The functional composition of the resulting NIS was determined using IR and NMR spectroscopy. The critical micelle concentration (CMC), surface activity (ability to reduce the surface tension of water), maximum adsorption at the water/air interface, and other parameters of the obtained NIS particles were determined by measuring the surface tension of aqueous solutions. Among the synthesized NIS, FCA-PEG-600 exhibited the highest surface activity (ПСМС = 28.8 mN/m) and maximal adsorption (Гmax = 3.0´10-6 mol/m2) compared to FCA-PEG-300 and FCA-PEG-1000. This “anomalous” variation in surface activity across the synthesized NIS series can be attributed to the optimal composition (i.e., the optimal hydrophilic-lipophilic balance, HLB) of the FCA-PEG-600 macromolecules. It was found that the obtained FCA-PEG NIS possess flocculating properties. Among them, the macromolecules of FCA-PEG-600 NIS demonstrated the best flocculating ability for bentonite clay suspension particles. Its optimal dosage for flocculation of suspension particles is 0.2 mg/g (200 g/t of dry solids)