Nitrate removal from synthetic and real groundwater by electrocoagulation: effect of operating parameters and electrolytes

ABSTRACT

The present study elaborates the electrocoagulation process for the removal of nitrates from synthetic and real groundwater. Electrocoagulation treatment has a positive effect on the quality of groundwater in general and the removal of nitrate in particular, which is one of the most potent pollutants found in groundwater. Moreover, it is supposed that nitrate removal mechanisms are likely to be dependent on operational parameters like applied current, electrode material, initial concentration of nitrates, and pH of the solution, etc. Therefore, in the present study various process parameters have been optimised in terms of nitrate removal efficiency. Experiments were performed using batch process at different initial concentration of nitrates (100–500 mg/L), pH (6.0–12), stirring speed (100–500 rpm), inter-electrode distance (0.5–2 cm) and electrolysis time (30–180 min). Further, the effect of co-existing ions using KNO₃, Ca(NO₃)₂ and Mg(NO₃)₂ in the presence of NaCl and Na₂SO₄ was investigated. Maximum 98%, Nitrate removal efficiency was obtained at inter-electrode distance 1 cm, agitation speed 300 rpm, electrolyte concentration of 1.1688 (g/L) NaCl, current 1.5 A and time 180 min for initial nitrate concentration of 100 (mg/L). Isotherm and kinetics models have been studied and it was observed from the present investigation that the process follows pseudo-second-order kinetics. The Freundlich isotherm model simulations match satisfactorily with the experimental observations. Further, optimised parameters were used to remove nitrates from real groundwater and 92.5% removal efficiency was attained.

KEYWORDS:

• Nitrates
• electrocoagulation
• removal efficiency
• aluminium electrodes

Acknowledgments

The authors are thankful to GGSIPU, Dwarka, New Delhi, India, for providing facilities to carry out the research work in the concerned area.

The authors are thankful to Guru Gobind Singh Indraprastha University (GGSIPU), Dwarka, New Delhi, India, for financial support (FRGS/2019-20/42) to carry out the research work in the concerned area.

Disclosure statement

No potential conflict of interest was reported by the author(s).

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Funding

This work was supported by the GGSIPU/FRGS 2019-20/42