Introduction
Water contamination by synthetic dyes and organic pollutants is a major concern, especially in industrial regions. Dyes from textile industries are non-biodegradable and toxic, causing environmental pollution and health risks. Sawdust, a byproduct of the timber industry, is an abundant and inexpensive material. It contains lignocellulose, which has a natural affinity for adsorbing dyes and organic pollutants. This project explores the use of chemically treated sawdust as an eco-friendly biosorbent for water purification.
Statement of the Problem
The discharge of dye-laden wastewater from industries into water bodies causes ecological damage and health hazards. Current methods for dye removal, such as chemical coagulation and filtration, are expensive and generate secondary pollutants. This study investigates the potential of sawdust as a low-cost and sustainable alternative for removing dyes from contaminated water.
Objective
- To evaluate the adsorption efficiency of untreated and chemically treated sawdust in removing synthetic dyes from water.
- To determine the optimal conditions for maximum dye adsorption (e.g., pH, contact time, and adsorbent dose).
- To assess the feasibility of using sawdust for large-scale water treatment applications.
Apparatus and Materials
- Sawdust (from untreated wood)
- Mild acid (e.g., acetic acid) or base (e.g., sodium hydroxide)
- Contaminated water samples with synthetic dyes (e.g., methylene blue or Congo red)
- Beakers and glass jars
- Stirring rods
- Measuring cylinders
- Filter paper or cheesecloth
- pH meter
- Spectrophotometer
Procedure
1. Preparation of Chemically Treated Sawdust
- Collect sawdust from untreated wood and sieve it to obtain uniform particle size.
- Wash the sawdust thoroughly with distilled water to remove impurities.
- Prepare two chemical treatments:
- Mild acidic solution (e.g., 5% acetic acid).
- Mild basic solution (e.g., 0.1 M sodium hydroxide).
- Soak equal portions of sawdust in each solution for 24 hours.
- Rinse the treated sawdust with distilled water until neutral pH is achieved.
- Dry the treated sawdust in an oven at 60°C or under sunlight.
2. Adsorption Experiment
- Prepare contaminated water samples by dissolving synthetic dye (e.g., methylene blue) in distilled water to create a concentration of 50 ppm.
- Set up three beakers:
- Beaker A: Untreated water (control).
- Beaker B: Water treated with untreated sawdust (2 g).
- Beaker C: Water treated with chemically treated sawdust (2 g).
- Stir the mixtures gently for 10 minutes and let them sit for 1 hour.
- Filter the solutions using filter paper or cheesecloth to separate the sawdust.
3. Analysis
- Test the dye concentration in each sample before and after treatment using a spectrophotometer.
- Measure pH levels of the water before and after treatment.
Observation
- Untreated sawdust showed moderate dye adsorption, with a visible reduction in color intensity.
- Chemically treated sawdust (acidic and basic) demonstrated significantly higher dye removal efficiency.
- Basic treatment yielded better results, likely due to improved surface functional groups for dye binding.
Data Table
| Parameter | Untreated Water (A) | Untreated Sawdust (B) | Treated Sawdust (C) |
|---|---|---|---|
| Dye Concentration (ppm) | 50 | 25 | 5 |
| pH | 7.5 | 7 | 6.8 |
| Turbidity (NTU) | High | Moderate | Low |
Conclusion
Sawdust is an effective biosorbent for removing synthetic dyes from contaminated water. Chemically treated sawdust, especially with a mild base, enhances adsorption capacity due to improved interaction between functional groups and dye molecules. This method provides a sustainable, low-cost solution for wastewater treatment.
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