2.1 Materials
(A) Collection of Raw Materials
Palm oil and palm kernel oil were sourced from ORIE-AKABO Market in Ikeduru Local Government Area of Imo State. These oils were transported to the laboratory of the Chemical Engineering Department, Federal University of Technology, Owerri, for analysis and processing. All solvents used in this study were of analytical grade and purchased from the university's chemical stores.
(B) Equipment and Instruments
- Reactor vessel
- Thermometer
- Heating mantle
- Stirrer
- Filter paper
- Evaporating dish
- Weighing balance
- pH meter
- Spectrophotometer
(C) Reagents
- Caustic potash (KOH)
- Distilled water
- Ethanol
- Ether
- Phenolphthalein indicato
Here's an explanation of each apparatus and equipment used in the study:
Apparatus/Equipment Used:
1. Weighing Balance: Used to measure the mass of ingredients and materials with precision.
2. Autoclave: A pressure chamber used to sterilize equipment and materials.
3. Incubator: A temperature-controlled environment used to promote microbial growth or chemical reactions.
4. Thermometer: Measures temperature, ensuring accurate control and monitoring.
5. Soap Moulds: Shapes the soap into desired forms.
6. Refrigerator: Stores materials and samples at a controlled temperature.
7. Gas Burner: Provides a heat source for various processes.
8. Beakers: Glass containers for measuring and mixing liquids.
9. Siever: A tool for separating particles of different sizes.
10. Conical Flask: A glass vessel for mixing and heating materials.
11. Nylon (waterproof): Used for covering and protecting equipment or materials.
12. Digital Weighing Balance: Provides precise measurements of mass.
13. Screpper: A tool for scraping and transferring materials.
14. Petri Dishes: Shallow containers for culturing microorganisms or chemical reactions.
15. Measuring Cylinder (1 liter, 100mls): Accurately measures liquid volumes.16. Stirrer:
Mixes and blends materials.
Chemicals/Reagents Used:
1. Palm Oil (red oil): A vegetable oil used as a soap-making ingredient.
2. Palm Kernel Oil (from frying): Another vegetable oil used in soap production.
3. Caustic Potash (KOH): A strong alkaline substance used for saponification.
4. Isopropanol Solvent: A chemical used for dissolving and extracting materials.
5. Phenolphthalein Indicator: A pH indicator used to detect acidic or basic conditions.
6. Ethanolic Potassium Hydroxide: A solution used for titration and analysis.
7. Water (H2O): Used as a solvent and in various chemical reactions.
8. Hydrochloric Acid (HCl): A strong acid used for neutralization and analysis.
These apparatus and chemicals/reagents were used in the soap-making process, analysis, and quality control of the produced soaps.
2.2 RESEARCH METHODOLOGY
Preparation of Caustic Potash (KOH).
The unripe plantain peels were sun-dried for seven days to remove excess moisture. The dried peels were then weighed using an analogue weighing balance, which showed a mass of 2 kg. The peels were subsequently burnt in a controlled environment to produce a caustic potash (KOH) extract. The burnt plantain peels were collected and weighed using a digital weighing balance, which showed a mass of 233.4 g.
To prepare the caustic potash solution, 233.4 g of the burnt plantain peels were soaked in 500 ml of water for 12 hours to allow for complete dissolution of the caustic contents. The resulting solution was then filtered using a net sieve to separate the raffinate (solid residue) from the extract (liquid solution). To maximize caustic extraction, the raffinate was soaked again in an additional 500 ml of water for another 12 hours. The combined solution weighed 1,300 g.
To concentrate the caustic potash solution, it was heated using a gas burner while continuously stirring. This process ensured the removal of excess water and increased the solution's potency. After heating, the solution was weighed to be 700 g, indicating a concentrated caustic potash solution.
This prepared caustic potash solution was then used in the soap-making process, as described in the subsequent sections.
2.3PREPARATION OF BLACK SOAP WITH PALM KERNEL OIL
A batch of black soap was prepared using palm kernel oil and caustic potash. Initially, 410 g of palm kernel oil (obtained from frying) was measured into a reactor, followed by the addition of 205 g of caustic potash. The mixture was then placed on a gas burner and heated under continuous stirring until homogeneity was achieved.
The temperature of the mixture was monitored, and at 170°C, the water in the soap mixture had fully evaporated, indicating the formation of the soap base. The soap mixture was then poured into a plastic mould and allowed to solidify for three days.
After solidification, the black soap was removed from the mould and was ready for use. The physical and chemical properties of this soap were later analyzed and compared with those of the soap produced using palm oil.
Note: The temperature of 170°C is quite high and may affect the quality of the soap. Typically, soap making temperatures range from 100°C to 140°C. Also, the use of a plastic mould may not be ideal, as it may affect the soap's texture and quality. A metal or wooden mould would be a better option.
2.4 PREPARATION OF BLACK SOAP WITH PALM OIL.
A batch of black soap was prepared using palm oil and caustic potash (KOH). Initially, 152 g of caustic potash (KOH) was measured into a reactor, followed by the addition of 313 g of palm oil. The mixture was then placed on a gas burner and heated under continuous stirring until a homogenous mixture formed. The temperature of the mixture was monitored using a thermometer, and at 175°C, the water in the soap had fully evaporated. The soap mixture was then poured into a plastic mould and allowed to solidify for three days.
2.5 QUALITY CONTROL
To ensure the reliability and accuracy of the results, all determinations were carried out in triplicates. All glassware used was thoroughly washed and rinsed with distilled water. Additionally, all reagents used were of analytical grade and sourced from British Drug House, Poole, England.
2.6 PREPARATION OF BLACK SOAP SAMPLES.
Two samples of black soap, labelled BS1 and BS2, were prepared according to the method . Equal quantities of palm oil and palm kernel oil were added to separate containers containing equal portions of caustic potash derived from plantain peels. The mixtures were then manually kneaded using a pestle and mortar. The soap samples were allowed to cure for at least two weeks before they were ready for use. These samples were subsequently analyzed using pH determinations, infrared spectroscopic analyses, and phytochemical screenings.
help determine the optimal conditions for soap production and ensure the final product meets the desired standards.
Free Fatty Acids (Acid Number or Acid Value)The chemical analysis of the oil was conducted to determine its quality and properties. The following chemical parameters were determined using standard procedures outlined by the Association of Official Analytical Chemists (AOAC):
1. pH: This measures the acidity or basicity of the oil.
2. 2. Acid Value (AV): This represents the amount of free fatty acids present in the oil.
3. Free-Fatty Acids (FFA): This measures the amount of unbound fatty acids in the oil.
4. Iodine Value (IV): This indicates the degree of unsaturation in the oil, which affects its stability and shelf life.
5. Saponification Value (SV): This measures the amount of fatty acids present in the oil, which is essential for soap production.
6. Peroxide Value (PV): This indicates the level of oxidation in the oil, which can affect its quality and stability.
These chemical parameters provide valuable information about the oil's quality, stability, and suitability for soap production. The results of these analyses can One gram (1 g) of the oil was dissolved in 50 ml of isopropanol solvent in a 250 ml conical flask. 3-4 drops of phenolphthalein indicator were added to the mixture, and the content was titrated against 0.1M KOH until a pink color that persisted for 15 seconds was obtained .
The acid value (mgKOH/g) was calculated using the following formula:
Acid Value (mgKOH/g) = (Volume of KOH used (ml) x Molarity of KOH (0.1M) x 56.1) / Weight of oil sample (g)
Where 56.1 is the molecular weight of KOH.
The free fatty acid (FFA) content was calculated as a percentage using the following formula:
Free Fatty Acid (FFA) (%) = (Acid Value (mgKOH/g) x 100) / 1.99
Where 1.99 is the factor used to convert acid value to FFA percentage.
Note: The factor 1.99 is specific to oleic acid, which is the most common fatty acid in oils. If the oil contains other fatty acids, a different factor may be required.
2.7 Determination of Iodine Value
The iodine value (IV) of the oil sample was determined using the Wijs' iodine method. The procedure involved the following steps:
1. Weighing: 0.4 g of the oil sample was accurately weighed into a conical flask.
2. Addition of carbon tetrachloride: 20 ml of carbon tetrachloride was added to the flask.
3. Addition of Dam's reagent (Wijs' iodine): 25 ml of Dam's reagent was added to the flask using a safety pipette in a fume chamber.
4. Mixing and waiting: The content of the flask was vigorously swirled and then placed in the dark for 150 minutes (2.5 hours).
5. Addition of potassium iodide and water: 20 ml of 10% aqueous potassium iodide and 125 ml of distilled water were added to the flask using a measuring cylinder.
6. Titration: The content was then titrated with 0.1 M sodium thiosulfate solution until the yellow color almost disappeared.
7. Addition of starch indicator: A few drops of 15% starch indicator were added, and the titration was resumed until the color disappeared after vigorously shaking.
8. Blank test: The same procedure was repeated for the blank test.
The iodine value (IV) was calculated using the following expression:
IV = (Volume of sodium thiosulfate used (ml) x Molarity of sodium thiosulfate (0.1M) x 12.69) / Weight of oil sample (g)
Where 12.69 is the factor used to convert the titration result to iodine value.
Note: The iodine value represents the amount of iodine (in grams) that reacts with 100 grams of oil. It is an indicator of the oil's unsaturation level and its tendency to oxidize.
Iodine Value (IV)
- IV = (C x (V1 - V2)) / M
- Where:
- C = Concentration of Sodium thiosulfate solution
- V1 = Volume of Sodium thiosulfate solution used for blank titration
- V2 = Volume of Sodium thiosulfate solution used for sample titration
- M = Mass of the sample
Saponification Value (SV)
- SV = (N x (V1 - V2)) / W
- Where:
- N = Normality of hydrochloric acid used
- V1 = Volume of hydrochloric acid used to titrate sample
- V2 = Volume of hydrochloric acid used to titrate blank
- W = Weight of oil in grams
Peroxide Value (PV)
- PV = (S - B) / M
- Where:
- S = Volume of sodium thiosulfate solution used to titrate sample
- B = Volume of sodium thiosulfate solution used to titrate blank
- M = Mass of the sample
The units for the Iodine Value, Saponification Value, and Peroxide Value are typically expressed in terms of grams per 100 grams of oil (g/100g).
PV = (S - B) x N x 200 / W
Where:
- PV = Peroxide Value
- S = Titre value for the sample
- B = Titre value for the blank
- N = Normality of the acid (0.1N)
- W = Weight of the sample
This formula calculates the Peroxide Value, which is a measure of the amount of peroxides present in the oil sample. The units of Peroxide Value are typically expressed in terms of milliequivalents per kilogram of oil (meq/kg).
2.8 Physical Characterization of Soap:
Hardness Test:
- The hardness of the soap was determined using a modified penetrometer method.
- A needle (6.4 cm in length; 1 mm in diameter) with a lead fishing weight (130g) attached was lowered into the soap.
- The distance the needle penetrates the soap after 30 seconds was recorded as a measure of its hardness.
- This was repeated three times for each soap sample, and the mean and standard deviation were computed.
Determination of pH:
- 5 g of the oil sample was poured into a clean, dry 25 ml beaker.
- 13 ml of distilled water was added to the sample and mixed for 5 minutes.
- The mixture was then cooled to 25°C in a cold water bath.
- A pH meter was standardized with a buffer solution, and the electrode was immersed into the sample.
- The pH value was read and recorded..
The pH meter was likely standardized with a buffer solution of known pH, such as pH 4 or pH 7, to ensure accuracy and reliability of the pH readings.
Plantain Peel Extract
- Mass of dried plantain peel: 2000g
- This indicates the initial amount of plantain peel used for extraction.
- Mass of burnt plantain peel: 233.4g
- This suggests that some of the plantain peel was burnt or degraded during the extraction process, resulting in a loss of mass.
- Initial and final mass of H2O: 1000ml (1 liter)
- This indicates that 1 liter of water was used for extraction, and the initial and final masses are the same, suggesting no significant water loss or gain.
Black Soap with Palm Kernel Oil and Caustic Potash (KOH)
- Weight of KOH: 205g
- This is the amount of caustic potash (KOH) used in the soap production.
- Weight of palm kernel oil (P.K.O4): 410g
- This is the amount of palm kernel oil used in the soap production.
- Temperature at which H2O evaporated: 170°C
- This is the temperature at which water evaporated during the soap production process.
- Specific gravity of water: 0.93g/cm3
- This is the density of water used in the soap production.
- Density of water: 0.93g/cm3
- This is the same as the specific gravity of water, indicating the density of water.
- Weight of water: 93g (144g - 51g)
- This is the weight of water used in the soap production, calculated by subtracting the weight of the empty beaker (51g) from the weight of the beaker with water (144g).
- Weight of sample (KOH): 127g (178g - 51g)
- This is the weight of the KOH sample, calculated by subtracting the weight of the empty beaker (51g) from the weight of the beaker with the KOH sample (178g).
- Density of sample: 1.27g/cm3
- This is the density of the KOH sample, calculated by dividing the weight of the sample (127g) by its volume (100cm3).
- Specific gravity of sample: 1.366 (1.27/0.93)
- This is the specific gravity of the KOH sample, calculated by dividing the density of the sample (1.27g/cm3) by the density of water (0.93g/cm3).
- Weight of whole sample (KOH): 700g
- This is the total weight of the KOH sample used in the soap production.
- Concentration of sample (KOH): not explicitly stated, but can be calculated based on the weight of KOH and the volume of water used.
Black Soap with Palm Oil and Caustic Potash (KOH)
- Mass of caustic potash: 152g
- This is the amount of caustic potash (KOH) used in the soap production.
- Mass of oil used: 304g (152g x 2)
- This is the amount of palm oil used in the soap production, calculated by multiplying the mass of caustic potash (152g) by 2.
- Temperature at which H2O evaporated: 170°C
- This is the temperature at which water evaporated during the soap production process.