Improving the Quality of Baobab Oil by Filtration on Activated Carbon from the Fruit Capsules

The baobab, Adansonia digitata L., plays an important role in the economy of local populations. Nowadays, baobab seed oil is highly prized for its many cosmetic and therapeutic applications, and for its composition of unsaturated fatty acids, sterols, and tocopherols. However, it undergoes numerous reactions during production, processing, transport, and storage, leading to undesirable products that make it unstable. The aim of this study was to provide local processors with innovative solutions for the treatment of unrefined vegetable oils. To this end, an experimental device for filtering crude oil on activated carbon made from fruit capsules was designed. The results obtained after the treatment show a significant decrease at (p < 5%) in acid value (1.62 to 0.58 mg KOH/g), peroxide value (4.40a to 0.50c mEqO2/Kg), chlorophyll concentration (1.81 to 0.50 mg/Kg) and primary and secondary oxidation products. According to these results, activated carbon’s adsorptive power eliminates oxidation products and certain pro-oxidants such as chlorophyll, resulting in a cleaner, more stable and better storable oil.

Processes for the Clarification of the Crude Oil of Baobab Seeds Extracted by Pressing on Activated Carbon Elaborated from the Capsules of the Fruit (Adansonia digitata L.)

The baobab, Adansonia digitata L. plays an important role in the economy of local populations. The oil from the seeds of the baobab fruit is nowadays highly prized because of its numerous cosmetic and therapeutic applications and its composition of unsaturated fatty acids, sterols and tocopherols. However, unlike refined oils, locally extracted baobab oil has not undergone purification operations to ensure its quality. Only a filtration on special cloths is carried out after decantation. Indeed, the oil obtained after pressing is cloudy because of the presence of various impurities. It therefore requires treatment operations to make it more attractive and of higher quality. Therefore, in order to provide innovative solutions to local companies to improve the quality of vegetable oils, a study of clarification (treatment) of crude oil is necessary. An experimental device has been developed in the laboratory. It includes a glass column and a filter bed of dune sand and activated carbon. This study has shown the efficiency of the experimental device. Indeed, the activated carbon, thanks to its adsorbing power, has allowed a significant decrease in turbidity at the 5% threshold, from 14.61 NTU for the raw oil to 0.08 NTU for the oil filtered on 3% carbon and 0.033 NTU for the oil filtered on 5% carbon. That is to say an abatement higher than 95%. This decrease in turbidity could be correlated with the decrease in brown index from 187.39a for the initial crude oil to 128.53d for the oil treated with 3% activated carbon versus 187.59a for the oil filtered on cloths. The lowest brown index was observed with the filtration using 5% activated carbon (35.99b). Thus, for the yellowness index, only the filtration on 5% charcoal allowed to obtain a significant decrease in yellowness. The yellowing index of the oil with 5% was 44.67b against 79.04a for the oil filtered with 3% activated carbon, 86.33a for the crude oil and 86.46a for the oil filtered on cloths. Finally, the oil sample treated with 5% activated carbon had the clearest clarity than the other samples with a clarity (L) equal to 97.98c against 95.63d for the oil treated with 3% carbon and 94.99b for the oil filtered on filter cloths. According to the results obtained, the experimental device made it possible to obtain a clearer baobab oil with a low brown index, thus improving the sensory quality of the oil.

Removal of Methyl Violet in Aqueous Solution on Activated Carbon Based on Saba senegalensis Shell Residues

Adsorption on activated carbon is one of the most widely used methods for the removal of dyes. The objective of this study is to valorize the shells of Saba senegalensis from local product in Senegal in the form of activated carbon and to test its effectiveness for the removal of methyl violet. The study was carried out in batch mode for a maximum duration of one hour with 100 mL of solution treated at 600 rpm. The results reveal that the granulometry 500 μm gives the best yield with an adsorption rate of 95%, a mass of adsorbent of 0.2 g gives an adsorption capacity of 20 mg/g, the contact time of one hour with a capacity of 5 mg/g. The study also showed that the adsorption process of methyl violet is described by the pseudo-second order kinetic model with correlation coefficient of 0.99. Two adsorption isotherms were studied, and the results revealed that the Freundlich model better describes the adsorption of methyl violet on Saba senegalensis shell residue-based activated carbon (SSSRAC). The results indicate that SSSRAC could be used as a low-cost alternative for the removal of textile dyes such as methyl violet.

Modelling and Response Surface Optimisation of Methyl Violet Removal by a Mixture of Titaniferous Sand and Non-Activated Attapulgite

In recent years, the discharge of dye-laden effluents from the textile industries into the aquatic environment has increased considerably. These industries are among the largest consumers of water. They generate huge amounts of pollutants from their huge discharge of toxic effluents and pose serious public health problems. So, this study focuses on the use of the mixture of titaniferous sand and attapulgite for the removal of methyl violet by adsorption in discontinuous mode. The different adsorbents were characterized by X-ray fluorescence spectroscopy and their different physico-chemical properties such as pH, zero charge potential, bulk and absolute density, porosity and specific surface area were determined. The response surfaces, through the Box-Behnken model, were used to model and optimize the operating conditions. The different factors studied were the ratio of titaniferous sand and attapulgite, the initial concentration of methyl violet and the pH. These vary between 1.25 and 8, 20 and 100 mg/L, 4 and 10 respectively. The results obtained after statistical analysis of the data show that the optimum mixture ratio is 2, the optimum concentration is 99.92 mg/L and the optimum pH is 9.88 corresponding to a maximum capacity of 5.52 mg/g and a maximum removal efficiency of 99.56%. The study of the effects of the different factors showed that the initial concentration of methyl violet and the pH significantly influence the adsorption capacity and the removal efficiency of the dye.

Process for the Biological Removal of Fe (II) from Reconstituted Waters on a Support of Filter Material with Coated Jujube Seeds

Three beakers for removing Fe (II) in reconstituted water (doped with FeSO4) were built and tested. Given the set operating conditions ([O2] > 4 mg·L-1, Patm = 1.013 bar, T = 25°C ± 1°C and [Fe2+]0 = 0.5 to 2 mg·L-1), removal of iron was caused by biological and possibly physical and chemical oxidation because there is a quantity of free oxygen in the medium. The extent of each type of oxidation has not been evaluated as it specifically studies the biological degradation of iron in these beaker tests by setting the operating conditions (pH > 6.5, dissolved oxygen from 0 to 8 mg·L-1, Redox Potential from 100 to 400 mV). The experimental studies focused particularly on the measurements of maximum wavelength, conversion efficiencies from Fe (II) to Fe (III), the effect of the Fe (II) concentration, the influence of pH, the action of the temperature of the prepared solutions and the effect of O2 concentration under specified operating conditions. It noticed precipitated amounts of iron deposited at the bottom of the beakers. Thus, the low concentrations of Fe (II) detected in the influent after the biological oxidation operation could be attributed to microorganisms that consume iron as a substrate.