0Removing lead ions from contaminated water using EDTA (Ethylenediaminetetraacetic acid) is a common method in analytical chemistry. Here's a step-by-step procedure:
Preparation
1. EDTA solution preparation: Prepare a 0.01 M EDTA solution by dissolving 3.72 g of EDTA disodium salt in 1 liter of distilled water.
2. pH adjustment: Adjust the pH of the EDTA solution to 9-10 using a strong base like sodium hydroxide (NaOH).
3. Standardization of EDTA solution: Standardize the EDTA solution by titrating it against a standard lead solution (e.g., Pb(NO3)2).
Removal of Lead Ions
1. Sample preparation: Take a known volume of the contaminated water sample (e.g., 100 mL) and transfer it to a clean beaker.
2. pH adjustment: Adjust the pH of the sample to 9-10 using a strong base like NaOH.
3. Addition of EDTA: Add a known volume of the standardized EDTA solution to the sample, ensuring that the EDTA concentration is in excess of the lead ion concentration.
4. Mixing and reaction: Mix the sample and EDTA solution thoroughly and allow the reaction to proceed for 10-15 minutes.
5. Precipitation and filtration: Allow the mixture to stand for a few hours or overnight. The lead-EDTA complex will precipitate out. Filter the mixture using a 0.45 μm membrane filter.
Determination of Lead Removal
1. Atomic Absorption Spectroscopy (AAS): Measure the lead concentration in the filtered sample using AAS or another suitable analytical technique.
2. Calculation of lead removal: Calculate the percentage of lead removal using the initial and final lead concentrations.
The lead-EDTA complex is stable and water-soluble, allowing for effective removal of lead ions from the contaminated water sample.
