Enhanced reduction of nitrate by TDER packed with surface-modified plastic particles electrodes

Area of Science:

• Environmental Chemistry
• Electrochemistry
• Materials Science

Background:

• Nitrate contamination in wastewater poses significant environmental risks.
• Iron cathodes can decompose nitrate but efficiencies are limited by synergistic effects.
• Developing efficient and cost-effective nitrate removal methods is crucial.

Purpose of the Study:

• To investigate the use of Ti/RuSn anodes and modified plastic particles in a TDER for enhanced nitrate and total nitrogen removal.
• To evaluate the performance of the TDER system in terms of degradation efficiency, product selectivity, and sludge production.
• To understand the synergistic mechanisms driving nitrate degradation.

Main Methods:

• Utilized Titanium (Ti) metal plates coated with Ru-Sn oxidizing compounds as plate anodes.
• Employed surface-modified plastic particles as conductive electrodes.
• Operated a Three Dimensional Electrode Reactor (TDER) for wastewater treatment.
• Analyzed nitrate, total nitrogen, ammonia, nitrogen gas, and iron ion concentrations.

Main Results:

• Ti/RuSn plate anodes demonstrated high nitrate degradation efficiency, producing predominantly nitrogen gas (83.84%) and minimal ammonia (15.51%).
• The TDER system achieved low residual total nitrogen and iron ion levels (0.02 mg/L) with reduced chemical sludge production (0.20 g/L).
• Surface-modified plastic particles further enhanced nitrate and total nitrogen removal efficiencies.

Conclusions:

• The TDER system with Ti/RuSn anodes and modified plastic particles is highly effective for selective nitrate and total nitrogen removal.
• Synergistic reactions involving hydrogen radicals and hypochlorite on Ru-Sn sites play a key role in enhancing degradation and converting ammonia to nitrogen gas.
• The developed system offers a promising, cost-effective, and environmentally friendly solution for wastewater treatment.