Impact of micelles on the biocidal efficiency in a diesel–water interface

Biodegradation occurs in the diesel/water interface in petroleum product pipelines. The microbial contamination can result in inhibitor/fuel degradation, leading to unacceptable levels of turbidity, filter plugging, storage tank corrosion and stored product souring. Therefore, selection of the biocide/inhibitor plays an important role in the transportation of petroleum products through pipelines. Three biocides (cationic and nonionic)were employed to study the biodegradation in a diesel-water interface. The biocidal efficiency against degradation of diesel was examined by employing Fourier-transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and gas chromatography mass spectrometry (GC-MS) techniques. Bronopol (2-bromo-2-nitro-propane-1, 3-diol) was found to have higher bactericidal efficiency than N-cetyl-N,N, N-trimethyl ammonium bromide (CTAB) and cetyl pyridinum bromide (CPB). But the cationic biocides (CTAB and CPB) showed good biocidal efficiency at the interface. The data are explained in terms of a model that postulates the formation of a ‘micelle’ at the diesel-water interface