Influence of organic load on the defluoridation efficiency of nano-magnesium oxide in groundwater

Schematic representation of sweep coagulation and formation of magnesium humate. [Display omitted] •The rate of HA removal is a function of the sorption capacity of the NMgO.•HA and F− removal were described by different isotherm equations.•The removal of HA was not affected by the interfering effects of F−.•The interfering effects of HA was felt only at low F− concentration.•Simultaneous removal of F− and HA significantly reduced the TIC and CO32− in GW. The study aimed at the determination of the influence of organic load, simulated by the dissolution of appropriate humic acid (HA) concentrations in water, on the defluoridation efficiency of nano magnesium oxide (NMgO), a nascent reactive material for groundwater (GW) defluoridation. The kinetic analysis of the process of sorption of HA and fluoride (F−) by the NMgO showed that the rate of sorbate removal is a function of the sorption capacity of the sorbent and not the solution concentrations of the sorbate. The Frumkin isotherm equation gave the best description of HA sorption while Freundlich isotherm equation gave a better description of the F− sorption. The determination of the efficiency of interfering ions on the removal of HA and F−, from both synthetic feed water and natural GW systems, showed that the removal of HA was not affected, when F− was the interfering ionic specie, but the negative impact of the presence of HA, as the interfering ion, on the defluoridation efficiency of the NMgO was felt only at the initial F− concentration that is