Response Surface Optimization of Chromium (IV) Removal with Teff Straw-Based Activated Carbon
This study examined the use of activated carbon made from teff (Eragrostis tef) straw to adsorptively remove hexavalent chromium (Cr (VI)) from aqueous solution. Activated carbon (TSAC) from teff straw was synthesized using phosphoric acid (H₃PO₄) followed by calcination at high temperature. Then, i...
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Elsevier
2025-05-01
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| Series: | Results in Chemistry |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2211715625001511 |
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| author | Sintayehu Shewatatek Girma Gonfa Sintayehu Mekuria Hailegiorgis Belete Tessema |
| author_facet | Sintayehu Shewatatek Girma Gonfa Sintayehu Mekuria Hailegiorgis Belete Tessema |
| author_sort | Sintayehu Shewatatek |
| collection | DOAJ |
| description | This study examined the use of activated carbon made from teff (Eragrostis tef) straw to adsorptively remove hexavalent chromium (Cr (VI)) from aqueous solution. Activated carbon (TSAC) from teff straw was synthesized using phosphoric acid (H₃PO₄) followed by calcination at high temperature. Then, it was characterized using FTIR, SEM, XRD, BET, and pHpzc analysis. The BET surface area of TSDAC was obtained as 823.63 m2/g. The adsorption parameters used in this study were an activation temperature of 400–600 °C, an impregnation ratio of 1:4–1:6, and an H₃PO₄ concentration of 1–3 M. The adsorption parameters were then optimized using the Response Surface Methodology (RSM) of Central Composite Design (CCD). Based on the CCD, the quadratic regression model was obtained with an R2 of 0.9819. Furthermore, this study examined the relationship between the removal effectiveness and the initial concentration of Cr (VI), contact time, adsorbent dose, and solution of pH. As a result, the optimal parameters of the study were an H₃PO₄ concentration of 3 M, activation temperatures of 502.87 °C, and impregnation ratios of 6 g of H₃PO₄ per 1 g of TS, and the result was 94.21 % of chromium (VI) ion removal. This result was shown as an efficient adsorption of Chromium (VI) ion. Different models such as Langmuir, Freundlich, Redlich-Peterson, and isotherm models were shown to be appropriate with the adsorption data and suggested that both the monolayer and heterogeneous surface adsorption. The dynamics of the adsorption study were best represented by the pseudo-second-order kinetic model. The thermodynamic studies verified that the adsorption process is endothermic and spontaneous. Based on the findings in this study, the TSDAC adsorbent synthesis from a raw material of teff straw is promising. |
| format | Article |
| id | doaj-art-6eb83077d57349929e1670f7fb46ae8d |
| institution | Kabale University |
| issn | 2211-7156 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Elsevier |
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| series | Results in Chemistry |
| spelling | doaj-art-6eb83077d57349929e1670f7fb46ae8d2025-08-20T03:46:50ZengElsevierResults in Chemistry2211-71562025-05-011510216810.1016/j.rechem.2025.102168Response Surface Optimization of Chromium (IV) Removal with Teff Straw-Based Activated CarbonSintayehu Shewatatek0Girma Gonfa1Sintayehu Mekuria Hailegiorgis2Belete Tessema3Department of Chemical Engineering, Addis Ababa Science and Technology University, 16417, Addis Ababa, EthiopiaDepartment of Chemical Engineering, Addis Ababa Science and Technology University, 16417, Addis Ababa, Ethiopia; Biotechnology and Bioprocess Center of Excellence, Addis Ababa Science and Technology University, 16417, Addis Ababa, Ethiopia; Nanotechnology Center of Excellence, Addis Ababa Science and Technology University, 16417 Addis Ababa, Ethiopia; Corresponding author at: Department of Chemical Engineering, Addis Ababa Science and Technology University, 16417 Addis Ababa, EthiopiaDepartment of Chemical Engineering, Addis Ababa Science and Technology University, 16417, Addis Ababa, Ethiopia; Biotechnology and Bioprocess Center of Excellence, Addis Ababa Science and Technology University, 16417, Addis Ababa, EthiopiaDepartment of Chemical Engineering, Addis Ababa Science and Technology University, 16417, Addis Ababa, EthiopiaThis study examined the use of activated carbon made from teff (Eragrostis tef) straw to adsorptively remove hexavalent chromium (Cr (VI)) from aqueous solution. Activated carbon (TSAC) from teff straw was synthesized using phosphoric acid (H₃PO₄) followed by calcination at high temperature. Then, it was characterized using FTIR, SEM, XRD, BET, and pHpzc analysis. The BET surface area of TSDAC was obtained as 823.63 m2/g. The adsorption parameters used in this study were an activation temperature of 400–600 °C, an impregnation ratio of 1:4–1:6, and an H₃PO₄ concentration of 1–3 M. The adsorption parameters were then optimized using the Response Surface Methodology (RSM) of Central Composite Design (CCD). Based on the CCD, the quadratic regression model was obtained with an R2 of 0.9819. Furthermore, this study examined the relationship between the removal effectiveness and the initial concentration of Cr (VI), contact time, adsorbent dose, and solution of pH. As a result, the optimal parameters of the study were an H₃PO₄ concentration of 3 M, activation temperatures of 502.87 °C, and impregnation ratios of 6 g of H₃PO₄ per 1 g of TS, and the result was 94.21 % of chromium (VI) ion removal. This result was shown as an efficient adsorption of Chromium (VI) ion. Different models such as Langmuir, Freundlich, Redlich-Peterson, and isotherm models were shown to be appropriate with the adsorption data and suggested that both the monolayer and heterogeneous surface adsorption. The dynamics of the adsorption study were best represented by the pseudo-second-order kinetic model. The thermodynamic studies verified that the adsorption process is endothermic and spontaneous. Based on the findings in this study, the TSDAC adsorbent synthesis from a raw material of teff straw is promising.http://www.sciencedirect.com/science/article/pii/S2211715625001511Teff strawActivated carbonPhosphoric acidAdsorption kineticsThermodynamics |
| spellingShingle | Sintayehu Shewatatek Girma Gonfa Sintayehu Mekuria Hailegiorgis Belete Tessema Response Surface Optimization of Chromium (IV) Removal with Teff Straw-Based Activated Carbon Results in Chemistry Teff straw Activated carbon Phosphoric acid Adsorption kinetics Thermodynamics |
| title | Response Surface Optimization of Chromium (IV) Removal with Teff Straw-Based Activated Carbon |
| title_full | Response Surface Optimization of Chromium (IV) Removal with Teff Straw-Based Activated Carbon |
| title_fullStr | Response Surface Optimization of Chromium (IV) Removal with Teff Straw-Based Activated Carbon |
| title_full_unstemmed | Response Surface Optimization of Chromium (IV) Removal with Teff Straw-Based Activated Carbon |
| title_short | Response Surface Optimization of Chromium (IV) Removal with Teff Straw-Based Activated Carbon |
| title_sort | response surface optimization of chromium iv removal with teff straw based activated carbon |
| topic | Teff straw Activated carbon Phosphoric acid Adsorption kinetics Thermodynamics |
| url | http://www.sciencedirect.com/science/article/pii/S2211715625001511 |
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