Practical performance and its efficiency of arsenic removal from groundwater using Fe-Mn binary oxide

Area of Science:

• Environmental Science
• Water Treatment Technologies
• Materials Science

Background:

• Groundwater contamination by arsenic is a significant global health concern.
• Arsenic (III) often predominates in anaerobic groundwater, posing treatment challenges.
• Existing methods may require pre-treatment or generate secondary waste.

Purpose of the Study:

• To evaluate the efficacy of a granular Fe-Mn binary oxide incorporated into diatomite (FMBO(1:1)-diatomite) adsorbent.
• To assess arsenic removal from raw anaerobic groundwater without pre- or post-treatment.
• To investigate the adsorbent's performance, regeneration, and removal of co-contaminants like iron and manganese.

Main Methods:

• Utilized a treatment unit packed with FMBO(1:1)-diatomite.
• Treated raw anaerobic groundwater (35-45 µg/L arsenic, 60-80% As(III)) from Beijing.
• Conducted continuous operation for four months, including 15 regeneration cycles.
• Monitored arsenic, iron, and manganese concentrations in the effluent.

Main Results:

• Achieved over 7,000 bed volumes of treated water with arsenic below 10 µg/L.
• Demonstrated efficient oxidation and adsorptive filtration of iron and manganese, with near-zero effluent concentrations.
• Regeneration significantly improved adsorption capacity, though higher Fe-Mn loading decreased capacity by 20-40%.

Conclusions:

• FMBO(1:1)-diatomite is a highly effective adsorbent for arsenic removal from anaerobic groundwater.
• The adsorbent exhibits strong oxidation and adsorptive filtration capabilities for iron and manganese.
• The material offers a sustainable solution for arsenic remediation with proven long-term performance and regenerability.