Nitrate reduction by electrochemical processes using copper electrode: evaluating operational parameters aiming low nitrite formation

Nitrates Removal from Simulated Groundwater Using Nano Zerovalent Iron Supported by Polystyrenic Gel

The main objectives of this present paper were to indicate the immobilization of nano zerovalent iron (nZVI) onto a polymeric material (Purolite A400) and the synthesis of the polymeric material (A400-nZVI) through sodium borohydride (NaBH4) reduction. The obtained polymeric material (A400-nZVI) was used for the nitrate ions removal from a simulated groundwater at different conditions. The polymeric materials, without and with nano zerovalent iron (A400 and A400-nZVI), were characterized trough the FTIR, SEM-EDAX, XRD, and TGA analysis. The analysis confirmed the presence of nano zerovalent iron (nZVI) onto the polymeric material (A400). The adsorption capacity of A400-nZVI, used as polymeric adsorbent, was evaluated by kinetic and thermodynamic studies. The obtained experimental results indicated that the nitrate ions reduction was fitted well by models: pseudo-second-order kinetic and Freundlich isotherm. According to the kinetic model results, a reaction mechanism could exist in the stage of reactions. The higher value of removal nitrate (>80%) was obtained under acidic condition. The results indicated that the obtained polymeric material (A400-nZVI) can be considered as a potential polymeric adsorbent for different pollutants from groundwater and wastewater.

Comparing the effects of Cu-Ti/RuO2-IrO2 electrode configuration on the electro-reduction of nitrate

Nitrate pollution is a global problem as it affects both the environment and human health. The objective of this research was to study the effect of electrode configuration on the electro-reduction of nitrate. Coaxial cylindrical (inner rod and outer tube copper cathodes) and vertical plate parallel copper cathodes paired with Ti/RuO₂-IrO₂ (rod, tube, and plate) configurations were studied under various current densities and initial nitrate concentrations. The efficiency of each configuration was determined based on the removal efficiency of nitrate, specific energy consumption, mass transfer coefficients, and first order rate constants. Additionally, the overall systems' resistance and geometric factors are discussed. It was found that the performances of the inner rod and outer tube copper cathodes were similar. The vertical plate parallel configuration was superior to the coaxial cylindrical electrode setup, as evident from a higher maximum nitrate removal of 74 and 56% at a current density of 7 mA/cm² and lower energy consumption of 46.7 × 10^-3 and 54.3 × 10^-3 kWh/mmol NO₃^- at 36.4 mA/cm², respectively. In addition, the mass transfer coefficients and first order rate constants were higher in all conditions tested for the vertical plate parallel configuration.