Methods are provided for using a combination of nanomaterials and oil-degrading bacteria to detoxify a multiphasic liquid (e.g., an oil-water mixture) and to ameliorate the toxicity of oil to local organisms, e.g., meiobenthos, in or near the area of the multiphasic liquid. The methods can be utilized for oil recovery and environmental clean-up and detoxification after spills and discharges. Through synergistic combination of the nanomaterials with oil degrading bacteria, methods can ameliorate environmental damage due to the presence of oil in an area through increased activation of the bacteria as well as through removal of the oil.