Figure 1: Removal Rate vs CuO:SA Ratio
1. Objective
The purpose of this experiment is to determine the optimal ratio of copper oxide (CuO) and sodium alginate for the highest efficiency in removing chromium ions (Cr3+) from water containing chromium chloride (CrCl3).
2. Background
Heavy metal ions, such as chromium, are toxic pollutants often found in industrial wastewater. Effective removal of these ions is crucial for environmental safety. Copper oxide (CuO) is known for its adsorption properties, and sodium alginate, a natural biopolymer, can enhance stability and facilitate removal in water purification processes. Understanding the synergistic effects of these materials can lead to an efficient and cost-effective solution for water treatment.
3. Materials
Copper oxide (CuO), Sodium alginate, Chromium chloride solution (CrCl3), Deionized water
Beakers (100 mL), Magnetic stirrer and stir bars, pH meter, Filtration apparatus, UV-Vis spectrophotometer, Standard Cr3+ calibration solution
4. Methods
4.1 Experimental Setup: Preparation of CuO and Sodium Alginate Mixtures
- Prepare sodium alginate solutions at a fixed concentration (e.g., 2% w/v).
- Prepare mixtures of CuO and sodium alginate at varying weight ratios (e.g., 1:1, 2:1, 1:2, 3:1, 1:3)
4.2 Experimental Procedure:
- Add 50 mL of a 10 ppm CrCl3 solution to separate beakers.
- Introduce the CuO-sodium alginate mixtures into the beakers at fixed dosages (e.g., 1 g of total material).
- Stir the solution using a magnetic stirrer for 30 minutes to ensure proper interaction between the pollutants and the adsorbent.
- Measure the pH before and after the reaction to ensure stability.
- Filter the solution to remove solid residues.
4.3 Measurement of Cr3+ Concentration:
- Measure the initial and final Cr3+ concentrations using a UV-Vis spectrophotometer calibrated with standard solutions.
- Record absorbance values at the characteristic wavelength for Cr3+ (e.g., ~400 nm).
5. Diagrams
Table 1: Chromium Ion Removal Results
| CuO:Alginate Ratio |
Initial Cr3+ Concentration (ppm) |
Final Cr3+ Concentration (ppm) |
Removal Efficiency (%) |
| 1:1 |
10 |
4.5 |
55.0 |
| 2:1 |
10 |
2.3 |
77.0 |
| 1:2 |
10 |
5.2 |
48.0 |
| 3:1 |
10 |
1.8 |
82.0 |
| 1:3 |
10 |
6.1 |
39.0 |
6. Discussion
- The 3:1 ratio of CuO:SA showed the highest removal efficiency at 75%, indicating optimal performance.
- Higher CuO content generally improved removal efficiency, likely due to increased adsorption sites.
- Excess sodium alginate (ratios 1:2 and 1:3) resulted in reduced efficiency, possibly due to blocked active sites.
- The results suggest that balancing CuO content with structural stability is crucial for optimal performance.
7. Conclusion
The optimal ratio of CuO to sodium alginate for chromium ion removal was determined to be 3:1, achieving a removal efficiency of 75%. This ratio provides the best balance between active site availability and structural integrity.