Total petroleum hydrocarbon removal from oil-sand by injecting charged nanobubbles

The objective of this study is to demonstrate oil-sand separation in the injection of positively charged nanobubbles (NBs) with respect to the effects of the NB/oil-sand ratio, treatment time, and NB injection regimes. Utilizing total petroleum hydrocarbon (TPH) removal, an assessment of the oil-sand separation efficiency is presented. The resulting injection of NBs was shown to be an effective treatment process with a TPH removal ≥85%. A greater TPH removal was obtained with the intermittent injection of positively charged NBs for an NB/oil-sand ratio ≥2/1 (v/v) and separation times from 5 to 20 min. The buoyancy force played a major role in detaching the oil. The larger external contact angle between the bubble and oil layer and the creation of micro- and macro-bubbles via NB coalescence in the oil-sand reactor attached to the oil layer were fundamental in producing a stronger buoyancy force for enhanced TPH removal.