Groundwater is the most important source of drinking water in the Republic
of Moldova, especially in rural regions. Because of pollution, groundwaters
do not meet the requirements of standards for drinking water, being
detected high concentrations of hydrogen sulphide, fluoride ions,
ammonium and nitrite ions, iron, manganese, strontium etc.
This work deals with experimental investigation related to the removal of
nitrite ions from water by adsorption/oxidation processes using laboratory
installation (semi-pilot installation) provided with an air bubbler and
recovery flask. A broad spectrum of carbonaceous adsorbents has been
tested in order to choose the most efficient one for nitrite ions removal from
water. Tests have been done on the model solutions as well as on natural
underground water from the village Isacova, district Orhei, Republic of
Moldova. Underground water had initial concentration of nitrite ions of 7.3
mg/L, nitrate ions of 5.9 mg/L and pH value 8.3. The efficiency of
adsorbents was estimated by studying the kinetics of the process, being
monitored the concentration of nitrite and nitrate ions, as well as pH value.
Comparative studies of efficiency of carbonaceous adsorbents highlight the
adsorbent AG-5ox modified by oxidation with nitric acid. The results
showed that the recommended process, by using carbonaceous adsorbent
AG-5ox, ensures 100% efficiency for the removal of nitrite ions from model
solution and 75% from underground water.