Nitrate removal from groundwater using negatively charged nanofiltration membrane

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Nitrate contamination in groundwater poses a significant environmental and health risk.
• Conventional water treatment methods for nitrate removal can be costly or inefficient.
• Nanofiltration (NF) membranes offer a promising technology for water purification.

Purpose of the Study:

• To enhance the nitrate removal efficiency of a commercial NF membrane.
• To investigate the surface modification of NF membranes using poly(sodium 4-styrenesulfonate) (PSS).
• To evaluate the performance of the modified NF membrane under various conditions.

Main Methods:

• Surface modification of NF membrane with PSS at varying concentrations.
• Characterization of membrane properties using FTIR, TGA, zeta potential, and contact angle.
• Nitrate rejection tests with analysis of permeate flux.
• Investigation of the impact of initial nitrate concentration and pH.

Main Results:

• Successful coating of PSS on the NF membrane, indicated by enhanced negative surface charge density.
• Optimal PSS concentration of 1.5 mg/L yielded an 88.8% nitrate rejection rate.
• Permeate flux of 27.0 L/m²h was maintained, indicating minimal flux loss.
• Effective nitrate removal from actual groundwater with improved performance at specific pH levels.

Conclusions:

• PSS modification significantly improves the nitrate rejection capability of NF membranes.
• The modified NF membrane demonstrates effective nitrate removal from real groundwater sources.
• The developed method offers a viable approach for enhancing NF membrane performance in water treatment applications.