Physicochemical Properties of African Black Soap Prepared with Alkali Derived from (Empty) Oil Palm Fruit Bunches

Abstract

The use of oil palm biomass in black soap production was carried out. The soap was prepared using different oils; Palm kernel oil (PKO), Tallow oil (TO), Palm oil (PO), Palm fatty acid distillate (PFAD) and their blends (PKO:PFAD:TO:PO) at 0.5 ratio each. The physiochemical properties of the different oils and their blends were studied. The moisture content, bulk density, foaming stability, pH, solubility of metallic salts and surface tension of the different black soaps produced were analyzed. The results of the oils and their blends had free fatty acid values between (2.56 - 49.48) %, saponification values of (231.4 - 450.20) KOH/g and relative densities of (0.97-1.008) g/ml. The results indicated that the moisture content ranged from (6.0 -7.4) % for all soaps, with the lowest (6.0%) observed in PKO, the highest (7.4%) observed in soaps made with PO and PKO:PFAD:TO:PO blends. The bulk density of the soaps ranged from (0.55 - 0.94) g/cm3. The PKO: PFAD soap had the highest foam stability of 7.4cm and PKO soap (2.08cm) the lowest. The soap produced with various oils and their blends showed a neutral pH in the range of 7.25 -7.38. The metallic salts NaCl, KCl and HgCl2 were soluble in the soap solution with no precipitate formed while MnCl2, PbCl3, and CuCl2 salts precipitated out of the soap solution. The surface tension of water was lowered at different rates by the soaps. The black soap produced with the oils and their blends met the standard quality specification for commercial soaps within the geographical area of manufacture.