Nitrate Removal From Groundwater By Ion Exchange

Groundwater is the most important drinking water source in North China, especially in some rural areas of North China the groundwater may be the only drinking water source. But unfortunately the groundwater has badly been contaminated by nitrate in North China. To research and develop an appropriate nitrate removal process which would fit in with the needs of the rural area water supply has great significance for guaranteeing drinking water safety of peasants.Thus, the ion exchange process with characteristics of simple, efficient, and relatively low investment and operating cost was applied to remove nitrate from simulated groundwater. The performances of the nitrate removal from groundwater by a strongly basic gel anion exchange resin (Purolite A 300E) and a nitrate selectivity macroporous strong base anion resin (Purolite A 520E) were evaluated in the batch and the continuous experiment.The results showed that the nitrate in groundwater could be effectively removed by both Purolite A 300E and Purolite A 520E resins. The batch experiment result showed that the adsorption process between the resin and the nitrate obeyed the Langmuir isotherm and the saturation capacity of Purolite A 300E and Purolite A 520E were 49.02 and 48.54 mg NO3-N/g, respectively. The continuous experiment result showed that Purolite A 300E and Purolite A 520E resins could produce water of 145 and 230BV respectively; as the sulfate or chloride concentration in the groundwater was high, the performance of Purolite A 520E resin was better than that of Purolite A 300E; the regeneration efficiency using NaCl solution was more than twice of that using NaHCO3 solution and the appropriate NaCl concentration in the regenerating solution was 3%; part of regeneration was more economical than complete regeneration and the nitrate removal performance through ion exchange was not affected by the resins'regeneration times.