Demulsification and recycling of spent oil based drilling fluid as nanofiller for polyamide 6 nanocomposites.
Adegbotolu, Urenna V.
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ADEGBOTOLU, U.V. 2016. Demulsification and recycling of spent oil based drilling fluid as nanofiller for polyamide 6 nanocomposites. Robert Gordon University, PhD thesis.
Spent oil based drilling fluid and cutting wastes are global liabilities due to their hazardous hydrocarbon content which impacts negatively on flora, fauna, and global carbon footprint. The formulation of two demulsifiers to ensure chemically enhanced phase separation of this waste into oil, water and solid components was successfully carried out in addition to recycling the solid phase into PA6 nanocomposite materials. Initial characterisation of the untreated waste was carried out by Fourier Transform Infra Red (FTIR) for total petroleum hydrocarbon (TPH) analysis, Inductively coupled plasma optical emission spectrometry (ICPOES) for quantitative elemental analysis and Energy dispersive xray analysis (EDXA) for qualitative elemental composition amongst other characterisation methods. The analysis showed that the sample had a high hydrocarbon load of 662,500mg/kg and a high heavy metal load for Pb of 122mg/kg. No As, Cd, Hg were detected. The demulsifier formulations were composed of isopropanol, sodium dodecyl sulphate, poloxamer, sodium chloride, chitosan in 0.2M acetic acid and deionised water for demulsifier S4 and addition of phosphoric acid for demulsifier S3. Hydrocarbon reduction on the extracted solid phase nanofiller S3 and nanofiller S4 was 98.6% and 98.5% respectively after demulsification. The demulsified spent oil based drilling fluid solid extracts were below OSPAR regulation of <1% oil on cutting by weight. However, recycling of the recovered solid was carried out in order to achieve environmentally sustainable management of the waste in Polyamide 6 (PA6) nanocomposite manufacture/fabrication. The formulation of different blends of PA6 nanocomposite materials from untreated, demulsifier treated and thermally treated drilling fluid and cuttings was successfully achieved. Nanocomposite leaching test showed Pb immobilisation. The flexural and compressive - modulus and strength of the PA6 were markedly improved in the presence of the nanofillers and glass fibre. This was attributed to the reinforcement, exfoliating, stiffening, rigidity effect of the nanofillers. S6 (untreated drilling fluid) nanofillers significantly improved the mechanical properties of PA6. This was attributed to the increased interfacial bonding between the fillers and the polymer matrix as a result of the petroleum hydrocarbon present in the sample. The Thermogravemetric analysis (TGA) results showed that nanocomposites PA6/S3 and PA6/S3/GF30 had improved the thermal stability of PA6 by 13.6% and 38.8% respectively compared to PA6/S2 and PA6/S2/GF30 (simulated commercial nanocomposite materials) that improved PA6 by 9.7% and 35.8% respectively.