Graft copolymerization of methyl methacrylate on Meizotropis Pellita fibres and their applications in oil absorbency

Abstract

This research paper deals with the graft copolymerisation of methyl methacrylate (MMA) on the backbone of Meizotropis Pellita fibres (MPF), which was successfully carried out under aqueous medium using Fenton's reagent [ferrous ammonium sulphate (FAS) (8.0 × 10–3 M) and H2O2 (0.12 M)] as a redox initiator to impart hydrophobic properties. Grafting was optimized under different conditions concerning time, temperature, monomer ratio, material to liquor ratio and initiator concentration. Maximum graft yield percentage obtained was 120%. The grafted MPF was characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) studies. The FTIR spectroscopic data showed a peak at 1728 cm−1 of C=O (ester), and another peak at 1650 cm−1 of adsorbed water, which was absent in the grafted fibre. The grafted fibre showed excellent thermal stability with an overall weight loss of 56.5% with a char residue of 33.5%. In addition, X-ray diffraction of MMA-grafted MPF showed 21% crystallinity and crystallinity index of 0.16. These raw and grafted fibres were also subjected to physico-chemical properties like moisture absorbance, swelling behaviour and chemical resistance, which they showed that MMA-grafted MPF exhibited hydrophobic properties. Therefore, due to this hydrophobic behaviour, the oil absorbency of MMA-grafted MPF was studied towards four emulsions: crude oil–saline, engine oil–saline, diesel oil–saline and used engine oil–saline. An MMA-grafted MPF by 120% absorbed 23.60 g of crude oil in the first cycle, 17. 41 g in the second cycle and 14.21 g in the third cycle, whereas 13.14 g of diesel oil was absorbed in the first cycle, 8.24 g in the second cycle and 5.25 g in the third cycle. Similarly, 20.14 g of engine oil was absorbed in the first cycle, 10.00 g in the second cycle and 7.51 g in the third cycle. Lastly, 19.80 g of the engine oil was absorbed in the first cycle, 12.25 g in the second cycle and 7.98 g in the third cycle. These results showed that the oil removal efficiency of the grafted MPF was intact by oil fraction type and they can be applied for all kinds of oil fraction spillage.