Comparative Evaluation of Lead Removal from Contaminated Water by Chemical Precipitation Using Different Reagents under Varying pH and Dosage Conditions

Lead (Pb) contamination in water is a major environmental problem and necessitates efficient and economical treatment techniques. This study was designed to investigate the removal of Pb by chemical precipitation at different pH and precipitant dosage using sodium carbonate (Na₂CO₃), sodium sulphate (Na₂SO₄) and sodium hydroxide (NaOH). Experiments were conducted at pH 5, 7, and 9, with dosages of 0.10, 0.25, and 0.50 g/50 mL, using an initial Pb concentration of 53.58 mg L⁻¹. The removal efficiency was found to be quite different for various precipitants and operating conditions. The overall performance of Na₂CO₃ was the best, with a mean of 92.77% removal of lead, followed by Na₂SO₄ with 88.75% and NaOH with 43.55% removal of lead. The best Pb removal was 99.58% (residual concentration of 0.226 mg L⁻¹) for Na₂CO₃ at pH 7 and 0.10 g/50 mL. For Na₂SO₄, the highest observed removal was 98.97% at pH 9 and 0.25 g/50 mL, while NaOH showed comparatively lower removal under the tested conditions. Chemical precipitation was found to be effective in removing lead from contaminated water, and Na₂CO₃ showed the highest observed removal among the tested conditions .