Simultaneous Removal of Nitrate and Typical Antibiotics Using Fe/MS/C Composite: Performance, Mechanism, Ecological...

Area of Science:

• Environmental Chemistry
• Materials Science
• Water Treatment Technologies

Background:

• Nitrate and antibiotic co-contamination poses complex water treatment challenges.
• Existing treatment methods struggle with simultaneous removal of these diverse pollutants.
• Integration of iron-carbon (Fe/C) micro-electrolysis and manganese materials for synergistic contaminant transformation is underexplored.

Purpose of the Study:

• To develop and evaluate a novel Fe/MS/C composite for the simultaneous removal of nitrate (NO₃⁻-N) and antibiotics.
• To investigate the underlying mechanisms of contaminant degradation by the composite material.
• To assess the performance and feasibility of the Fe/MS/C system in pilot-scale and continuous-flow applications.

Main Methods:

• Synthesis of a novel Fe/MS/C composite using metallurgical manganese slag (MS), iron, cement, and activated carbon.
• Optimization of composite formulation (Fe:MS = 3:1, 30% cement, 5% activated carbon).
• Evaluation of removal efficiency for NO₃⁻-N and four antibiotics (SMX, ENR, OFX, FLO) under varying conditions using batch and pilot-scale reactors.
• Analysis of degradation mechanisms involving micro-electrolysis, redox cycling, and reactive oxygen species generation.
• Assessment of microbial community changes and metal leaching.

Main Results:

• The optimized Fe/MS/C composite efficiently removed both NO₃⁻-N and antibiotics simultaneously under acidic and neutral conditions without mutual inhibition.
• The composite demonstrated high resistance to interference from coexisting anions and humic acid.
• Mechanistic studies revealed synergistic effects of in situ micro-electrolysis, redox cycling (Mn³⁺/Mn²⁺, Fe²⁺/Fe³⁺), and reactive oxygen species (•OH, ¹O₂) production.
• Pilot-scale tests achieved >90% NO₃⁻-N removal and ~100% antibiotic degradation, with selective enrichment of key bacteria.
• Continuous-flow tests over 60 days maintained >95% NO₃⁻-N and >70% antibiotic removal, with 30-40% lower operational costs than conventional Fe/C materials.
• Metal release remained below detection limits.

Conclusions:

• The Fe/MS/C composite presents a highly efficient, stable, and cost-effective solution for simultaneous nitrate and antibiotic removal.
• The material exhibits excellent ecological adaptability and engineering feasibility for treating complex waterborne pollutants.
• This technology offers a promising strategy for sustainable water purification, minimizing ecological risks and operational expenses.