Figure 6.

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Variation of pHf versus pHi for oils containing 5 wt% C5 asphaltenes (red triangles) and for C7 asphaltenes (black squares), without (solid symbols) and with (open symbols) SDBS. The lines are fits with the model of reference [17]: pKaA = 5; TAN = 0.4; pKaB = 9; TBN = 0.5 and Xw = 0.95.