Integrated ultrafiltration-nanofiltration membrane processes applied to the treatment of gold mining effluent: Influence of feed pH and temperature

ABSTRACT

This study aimed to evaluate the effect of feed pH (2.2 - original effluent pH – up to 6.0) and temperature (20 up to 40°C) on the performance of integrated ultrafiltration (UF) and nanofiltration (NF) applied to gold mining effluent. pH increase led to a significant decrease in UF permeate flux. NF showed high retention efficiencies of ions when temperature was below 30°C. Retention of high-valence counter-ions to balance the charge of retained co-ions seemed to be the strongest NF mechanisms. Process performance at feed pH of 5.0 was superior in terms of fouling, retention efficiency, and investment cost.

KEYWORDS:

• Feed pH and temperature
• gold mining acid effluent
• nanofiltration
• ultrafiltration
• zeta potential

Acknowledgements

The authors thank the Coordination of Improvement of Higher Education Personnel (CAPES) and Foundation for Research Support of Minas Gerais (FAPEMIG) for scholarships provided.