Investigation on Potential of Nitrate Removal in the Aqueous Solution by using plant adsorbants(Rice husk, sawdust and wheat straw)in laboratory condition

Agricultural waste water are one of the most significant environmental pollutant sources. Nitrate ion in the wastewater is the most important pollutants that arise from using of nitrogen fertilizers. Increasing concentration of Nitrate can lead to various diseases in humans and animals. Lots of methods use for removing nitrate from water that are expensive. Hence, this study aimed at evaluating of nitrate removal by using low-cost agricultural waste. Also this survey is done with a discontinuing system in irrigation laboratory at Sari Agricultural Sciences and Natural Resources University. In this experiment some factors, such as balance time, optimum pH, optimum mass of adsorbent and Langmuier and Freundlich models were investigated. The results showed that the equilibrium time for rice husk, sawdust and wheat straw are 60, 30 and 60 minutes respectively and for each 3 absorbents decreasing PH lead to increase of nitrate removal efficiency and optimum value for pH occurred at 3. Also, by increasing mass of adsorbent, initial adsorption increased and then decreased and for two optimized absorbents calculated 2.5mg/lit. Finally investigations showed that for each three absorbents include; rice husk, sawdust and wheat straw, adsorption amount is matched with Langmuir model rather than Freundlich model and maximum absorption calculated 7.43, 10.73 and 6.52mg/lit respectively.