Investigating the effect of modified zeolite on redaction of nitrate in potable water well in Karaj Suger Factory

Pollution and high level of nitrogen in underground water resources are the major agricultural and environmental contemporary concerns. Inappropriate use and management of nitrogen fertilizers in the last decades exacerbated the environmental pollution. Nitrogen fertilizers appear in the environment in three ion forms of nitrate, nitrite, and ammonium. Nitrate itself is non-toxic, but its reduction to nitrite by gastric bacteria can endanger human health and cause cancer, intensified cardiovascular diseases, methemoglobinemia, and eutrophication. Hence, presenting solutions to remove nitrogen concentration, which is one of the major environmental pollutants, from polluted waters is necessary. There are many physical and chemical methods to remove nitrogen; however, because of high costs and limited application of some methods, recently the use of natural methods and application of cheap absorbents such as zeolite have been tried recently.
In this study, zeolites from Khorasan-e-Razavi mines were used to remove nitrate ion from laboratory solutions. The zeolites were modified using Hexadecyltrimethylammonium bromide organic surfactant to improve their absorbing efficiency. Absorbent dosage, equilibrium time, pH effect, optimum nitrate concentration to be absorbed by zeolite were investigated.
Findings and Increase of absorbent dosage has a good effect on nitrate removal, and showed a 22.3% absorbing capacity in 2 g/L concentration. Increase of treatment time had no effect on absorption and a 15-m treatment caused a removal of 52%. Change of pH led to significant nitrate removal of 100%. For nitrate concentrations in the range of 5 to 50 mg/L, increase of nitrate concentration leads to reduction in absorption, and nitrate absorption by zeolite resulted in nitrate removal of about 20% .