Electro-migration of nitrate in sandy soil.
Migration of nitrate to groundwater has become a serious threat in many agricultural areas. This paper presents the results of experimental laboratory tests studying the nitrate gradient developed in response to an electrical potential. Two systems were tested; the first had no flow (closed system) and the second had flow opposite to the direction of the electrical current. A solution of sodium nitrate in sandy soil was used in both systems. The tests showed that the electro-kinetic process effectively concentrated and retained nitrate close to the anode. The movement of NO(3)(-) through the soil column was significantly influenced by the development of a pH gradient. Statistical analysis was performed to determine best-fit equations relating the nitrate gradient to the electrical input and pH gradient. A simple one-dimensional finite difference model was used to predict the pH gradient developed during the electro-kinetic process. The experimental measurements closely agreed with the predicted spatial and temporal distribution of the nitrate gradient for both closed and open system configurations.
Eid
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National Water Research Center, Cairo, Egypt.
Elshorbagy
W
W
Larson
D
D
Slack
D
D
D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009566:Nitrates / Q000493:pharmacokinetics*; D012989:Soil Pollutants / Q000493:pharmacokinetics*; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics*
D009566:Nitrates; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical