The raw syngas generated in a partial oxidation gasifier (2) also includes carbon soot which is removed and recovered from the syngas by scrubbing with water. The scrubbing water (4) contains one or more high temperature surfactants (6) which allow greater soot concentrations in the water-scrubbing quench zone of the gasifier (2). The carbon soot is separated from the scrubbing water (10) with the aid of a scrubbing oil. The separation of the carbon soot from the scrubbing water (10) is enhanced with the aid of one or more surfactants (6) that render the soot particles hydrophobic and oleophilic. The recovered carbon soot is ultimately recycled to the gasifier (2) to recover the energy value of the carbon during the partial oxidation reaction. The overall energy efficiency of the gasification process can be increased by removing all or a significant portion of the water from the soot mixture before recycling the soot. Separating the soot from the water allows for independent regulation of the soot and water recycle streams, depending on the reaction conditions in the gasifier (2).