The photocatalytic reduction of NO3− to N2 with ilmenite (FeTiO3): Effects of groundwater matrix

This work analyzes the role of natural groundwater, as well effect HCO3−, Ca2+, Mg2+, K+, SO42- and Cl− concentrations, upon photocatalytic nitrate reduction using ilmenite catalyst oxalic acid hole scavenger. The removal selectivity towards N2 are significantly limited compared to previous experiments ultrapure water matrix. Calcium (Ca2+), bicarbonate (HCO3−) pH claimed major controlling factors related process yield. Thus, Ca2+ promotes formation insoluble oxalate microcrystals, reducing amount scavenger available. presence HCO3− leads a steeply increase in value, favoring adsorption onto surface ions OH−instead NO3−, NO2− C2O42. aforementioned issues overcome by working with C2O42−/NO3− ratio above stoichiometric one, that also maintains value an range. A completed depletion starting no detection either or NH4+ aqueous phase, 95% were achieved two times dose.