In this study, shea residues (<em>Vitellaria paradoxa</em>) dumped in the wild by the units processing almonds into butter were used in the production of activated carbons. Shea nut shells harvested in the...In this study, shea residues (<em>Vitellaria paradoxa</em>) dumped in the wild by the units processing almonds into butter were used in the production of activated carbons. Shea nut shells harvested in the locality of Baktchoro, West Tandjile Division of Chad were used as a precursor for the preparation of activated carbons by chemical activation with phosphoric acid (H<sub>3</sub>PO<sub>4</sub>) and sulphuric acid (H<sub>2</sub>SO<sub>4</sub>). Central Composite Design (CCD) was used to optimize the preparation conditions, and the factors used were concentration of activating agent (1 - 5 M), carbonization temperature (400<span style="white-space:nowrap;"><span style="white-space:nowrap;">°</span></span>C - 700<span style="white-space:nowrap;"><span style="white-space:nowrap;">°</span></span>C) and residence time (30 - 120 min). The studies showed that at optimal conditions the yield was 51.45% and 42.35%, while the iodine number (IN) was 709.45 and 817.36 mg/g for CAK-P (phosphoric acid activated carbon) and CAK-S (sulphuric acid activated carbon) respectively. These two activated carbons (ACs) which were distinguished by their considerable iodine number, were variously characterized by elementary analysis, pH at the point of zero charge (pHpzc), bulk density, moisture content, Boehm titration, Fourier transform infrared spectroscopy, BET adsorption and scanning electron microscopy. These analyses revealed the acidic and microporous nature of CAK-P and CAK-S carbons, which have a specific microporous surface area of 522.55 and 570.65 m<sup>2</sup>·g<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> respectively.展开更多
The experiment was conducted in the laboratories of the Departments of Chemistry and Animal Health and Production Technology, Adamawa State University, Mubi, Nigeria. The experiment was replicated three times in a Ran...The experiment was conducted in the laboratories of the Departments of Chemistry and Animal Health and Production Technology, Adamawa State University, Mubi, Nigeria. The experiment was replicated three times in a Randomized Complete Block Design (RCBD) and consisted of six heating time 30, 60 and 120 minutes boiling, 30, 60 and 120 minutes roasting and one control. Data were collected on acid value, free fatty acid, iodine value, peroxide value, saponification value and unsaponifiable matter. The data collected were analyzed statistically using Generalized Linear Model (GLM) procedure of statistical analysis system (SAS). The means that were significantly different were separated using Least Significant Difference (LSD). The results showed that there were highly significant differences (P ≤ 0.01) among the treatments. The highest Acid Value (AV) of 3.53 and 3.64 were recorded by heating time at 120 minutes of boiling and 120 minutes of roasting. Heating time at 30 minutes of boiling, 30 minutes roasting, 60 minutes boiling and 60 minutes roasting recorded lower Free Fatty Acid (FFA) values of 1.52, 1.55, 1.57 and 1.58, respectively. Heating time at 60 minutes of roasting and 60 minutes of boiling recorded the highest Iodine value (IV) of 43.80 and 43.53, respectively. Based on the results of this study, it can be concluded that heating time of 30 or 60 minutes by boiling or roasting are better than longer heating times for Shea butter extraction.展开更多
文摘In this study, shea residues (<em>Vitellaria paradoxa</em>) dumped in the wild by the units processing almonds into butter were used in the production of activated carbons. Shea nut shells harvested in the locality of Baktchoro, West Tandjile Division of Chad were used as a precursor for the preparation of activated carbons by chemical activation with phosphoric acid (H<sub>3</sub>PO<sub>4</sub>) and sulphuric acid (H<sub>2</sub>SO<sub>4</sub>). Central Composite Design (CCD) was used to optimize the preparation conditions, and the factors used were concentration of activating agent (1 - 5 M), carbonization temperature (400<span style="white-space:nowrap;"><span style="white-space:nowrap;">°</span></span>C - 700<span style="white-space:nowrap;"><span style="white-space:nowrap;">°</span></span>C) and residence time (30 - 120 min). The studies showed that at optimal conditions the yield was 51.45% and 42.35%, while the iodine number (IN) was 709.45 and 817.36 mg/g for CAK-P (phosphoric acid activated carbon) and CAK-S (sulphuric acid activated carbon) respectively. These two activated carbons (ACs) which were distinguished by their considerable iodine number, were variously characterized by elementary analysis, pH at the point of zero charge (pHpzc), bulk density, moisture content, Boehm titration, Fourier transform infrared spectroscopy, BET adsorption and scanning electron microscopy. These analyses revealed the acidic and microporous nature of CAK-P and CAK-S carbons, which have a specific microporous surface area of 522.55 and 570.65 m<sup>2</sup>·g<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> respectively.
文摘The experiment was conducted in the laboratories of the Departments of Chemistry and Animal Health and Production Technology, Adamawa State University, Mubi, Nigeria. The experiment was replicated three times in a Randomized Complete Block Design (RCBD) and consisted of six heating time 30, 60 and 120 minutes boiling, 30, 60 and 120 minutes roasting and one control. Data were collected on acid value, free fatty acid, iodine value, peroxide value, saponification value and unsaponifiable matter. The data collected were analyzed statistically using Generalized Linear Model (GLM) procedure of statistical analysis system (SAS). The means that were significantly different were separated using Least Significant Difference (LSD). The results showed that there were highly significant differences (P ≤ 0.01) among the treatments. The highest Acid Value (AV) of 3.53 and 3.64 were recorded by heating time at 120 minutes of boiling and 120 minutes of roasting. Heating time at 30 minutes of boiling, 30 minutes roasting, 60 minutes boiling and 60 minutes roasting recorded lower Free Fatty Acid (FFA) values of 1.52, 1.55, 1.57 and 1.58, respectively. Heating time at 60 minutes of roasting and 60 minutes of boiling recorded the highest Iodine value (IV) of 43.80 and 43.53, respectively. Based on the results of this study, it can be concluded that heating time of 30 or 60 minutes by boiling or roasting are better than longer heating times for Shea butter extraction.
