Biorremoção de cromo por biossurfactantes produzidos a partir de melaço de soja em sistema de flotação por ar dissolvido
Bibliographic record
Abstract
The industrial branch has as characteristic the use of great volumes of water and, often, of heavy metals, generating liquid effluents with preoccupying concentrations of these metals, among which stands the chrome. Such element in its hexavalent state presents high toxicity and carcinogenic properties, thus requiring treatment for its removal. There are several techniques used for this purpose, and dissolved air flotation (DAF) has been widely used because it presents several advantages. Therefore, the present work studied the use of dissolved air flotation in chromium bioremediation, using as binder the biosurfactant produced by Pseudomonas aeruginosa from soybean molasses. The biosurfactant, rhamnolipid, was evaluated for surface tension, emulsification index and biosurfactant concentration, whose values were 34.16 mN/m, 100% and 9.02 g/L, respectively. In addition, several preliminary tests were carried out to evaluate the influence of saturated water volume, pH, biosurfactant concentration, presence of coagulant (ferrous sulphate) and stirring speed in the chromium removal process. The results of these tests showed that pH and iron concentration were determining factors in reducing the content of hexavalent chromium. Thereby, a central composite design (CCD) with two variables and three replicates at the central point was proposed to optimize the removal of chromium from aqueous solutions. The independent variables analyzed were pH (3,17 – 8,83) and iron concentration (0 – 225 mg/L) in the medium, while the studied responses were the percentages of removal of chromium (VI) and total. To execute the CCD, all experiments were performed in duplicate with initial Cr (VI) concentration of 100 mg/L, 500 mL of solution volume, 200 mL of saturated water, 6 minute fast mixing step at 120 rpm and concentration of biosurfactant equal to 9 g/L. The results showed that in acidic pH and high concentrations of iron the percentage of Cr (VI) removal increased, whereas for total chromium the best result was for higher iron concentration and pH near neutral. Thus, in order to validate the experiments, the values of 3.5 for pH and 180 mg/L for the iron concentration were used. The percentages of Cr (VI) and total Cr removal obtained in the validation were 100 and 57.55%, respectively, and those predicted by the model were 100 and 57.79%, respectively. From the analysis of the results achieved, it became evident that the DAF and the biosurfactant produced were efficient in the removal of chromium from aqueous solutions.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".