Optimizing the process conditions for the biosorption of chromium (VI) by Bacillus subtilis in artificial wastewater
Background: The contamination by heavy metals, particularly hexavalent chromium Cr (VI), is a pressing environmental concern. Cr(VI) is highly toxic, non-biodegradable and carcinogenic. Traditional remediation methods are often costly, energy-intensive, or generate secondary waste. This study explor...
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Elsevier
2025-07-01
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| Series: | Electronic Journal of Biotechnology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S071734582500017X |
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| author | Khawla E. Alsamhary |
| author_facet | Khawla E. Alsamhary |
| author_sort | Khawla E. Alsamhary |
| collection | DOAJ |
| description | Background: The contamination by heavy metals, particularly hexavalent chromium Cr (VI), is a pressing environmental concern. Cr(VI) is highly toxic, non-biodegradable and carcinogenic. Traditional remediation methods are often costly, energy-intensive, or generate secondary waste. This study explores the optimal conditions for the bacterium Bacillus subtilis in reducing Cr(VI) from synthetic wastewater. Results: The research employed batch experiments to simulate wastewater treatment. The removal of Cr(VI) was measured spectrophotometrically. The active functional groups were studied using Fourier Transform Infrared Spectroscopy that showed an incremental shift for alkyl halides (500.75 cm−1) and OH-groups (3347 cm−1) were observed. Scanning Electron Microscopy images demonstrated that the surface morphology of the biosorbent was more homogenous before than after adsorption. The biosorbent’s structure was confirmed by a prominent peak in X-ray Diffraction at 290.04°. The highest adsorption was observed at the adsorbent dose of 0.5 g/L, the contact time 60 min, pH 6 and temperature of 40°C. The thermodynamic parameters validated the process’s feasibility and spontaneity. Several models for biosorption kinetics and isotherm were tested. The pseudo-second-order was more suitable than the pseudo-first-order model. Langmuir isotherm model had the best fit compared to Freundlich, Dubinin–Radushkevich, and Temkin models. Conclusions: B. subtilis appeared to be resistant to chromium and reduce Cr(VI) efficiently. This study shows the potential of B. subtilis as a viable bioremediation agent for Cr(VI) contamination in wastewater and should be studied further using real wastewater with different pollutants.How to cite: Alsamhary KE. Optimizing the process conditions for the biosorption of chromium (VI) by Bacillus subtilis in artificial wastewater. Electron J Biotechnol 2025;76. https://doi.org/10.1016/j.ejbt.2025.03.005. |
| format | Article |
| id | doaj-art-08b5dc5ef8d441868820dae15cb35503 |
| institution | Kabale University |
| issn | 0717-3458 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Electronic Journal of Biotechnology |
| spelling | doaj-art-08b5dc5ef8d441868820dae15cb355032025-08-20T03:34:05ZengElsevierElectronic Journal of Biotechnology0717-34582025-07-0176223810.1016/j.ejbt.2025.03.005Optimizing the process conditions for the biosorption of chromium (VI) by Bacillus subtilis in artificial wastewaterKhawla E. Alsamhary0Department of Biology, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi ArabiaBackground: The contamination by heavy metals, particularly hexavalent chromium Cr (VI), is a pressing environmental concern. Cr(VI) is highly toxic, non-biodegradable and carcinogenic. Traditional remediation methods are often costly, energy-intensive, or generate secondary waste. This study explores the optimal conditions for the bacterium Bacillus subtilis in reducing Cr(VI) from synthetic wastewater. Results: The research employed batch experiments to simulate wastewater treatment. The removal of Cr(VI) was measured spectrophotometrically. The active functional groups were studied using Fourier Transform Infrared Spectroscopy that showed an incremental shift for alkyl halides (500.75 cm−1) and OH-groups (3347 cm−1) were observed. Scanning Electron Microscopy images demonstrated that the surface morphology of the biosorbent was more homogenous before than after adsorption. The biosorbent’s structure was confirmed by a prominent peak in X-ray Diffraction at 290.04°. The highest adsorption was observed at the adsorbent dose of 0.5 g/L, the contact time 60 min, pH 6 and temperature of 40°C. The thermodynamic parameters validated the process’s feasibility and spontaneity. Several models for biosorption kinetics and isotherm were tested. The pseudo-second-order was more suitable than the pseudo-first-order model. Langmuir isotherm model had the best fit compared to Freundlich, Dubinin–Radushkevich, and Temkin models. Conclusions: B. subtilis appeared to be resistant to chromium and reduce Cr(VI) efficiently. This study shows the potential of B. subtilis as a viable bioremediation agent for Cr(VI) contamination in wastewater and should be studied further using real wastewater with different pollutants.How to cite: Alsamhary KE. Optimizing the process conditions for the biosorption of chromium (VI) by Bacillus subtilis in artificial wastewater. Electron J Biotechnol 2025;76. https://doi.org/10.1016/j.ejbt.2025.03.005.http://www.sciencedirect.com/science/article/pii/S071734582500017XAdsorptionAdsorption–desorptionArtificial wastewaterBacillus subtilisBioremediationBiosorption |
| spellingShingle | Khawla E. Alsamhary Optimizing the process conditions for the biosorption of chromium (VI) by Bacillus subtilis in artificial wastewater Electronic Journal of Biotechnology Adsorption Adsorption–desorption Artificial wastewater Bacillus subtilis Bioremediation Biosorption |
| title | Optimizing the process conditions for the biosorption of chromium (VI) by Bacillus subtilis in artificial wastewater |
| title_full | Optimizing the process conditions for the biosorption of chromium (VI) by Bacillus subtilis in artificial wastewater |
| title_fullStr | Optimizing the process conditions for the biosorption of chromium (VI) by Bacillus subtilis in artificial wastewater |
| title_full_unstemmed | Optimizing the process conditions for the biosorption of chromium (VI) by Bacillus subtilis in artificial wastewater |
| title_short | Optimizing the process conditions for the biosorption of chromium (VI) by Bacillus subtilis in artificial wastewater |
| title_sort | optimizing the process conditions for the biosorption of chromium vi by bacillus subtilis in artificial wastewater |
| topic | Adsorption Adsorption–desorption Artificial wastewater Bacillus subtilis Bioremediation Biosorption |
| url | http://www.sciencedirect.com/science/article/pii/S071734582500017X |
| work_keys_str_mv | AT khawlaealsamhary optimizingtheprocessconditionsforthebiosorptionofchromiumvibybacillussubtilisinartificialwastewater |