Investigation of Nitrate Removal from Aqueous Solutions by Nano Adsorbent of Wheat Straw

The availability of safe and clean water is one of the most important issues facing human beings. Groundwater and surface water pollution with nitrate is a serious problem in many parts of the world. The aim of this study was to investigate the possibility of using wheat straw nano adsorbent as an inexpensive and cost-effective adsorbent in the removal of nitrate from aqueous solutions. In this study, the effect of factors such as pH, adsorbent mass, contact time, and initial nitrate concentration was tested. In order to evaluate the efficiency of the adsorbent studied and its application in discontinuous tests, desorption tests were performed. Lagergren Pseudo-first-order kinetics model and Ho Pseudo-second-order kinetics model were used to study the adsorption process. In addition, equilibrium adsorption data were analyzed using Freundlich and Langmuir isotherm models. According to the obtained results, the optimal pH adsorption and the equilibrium time for the studied adsorbent were respectively 5 and 30 minutes. The amount of adsorbent showed a direct relationship with nitrate uptake. Increasing the amount of wheat straw by 0.5 gr had no significant impact on the efficiency of nitrate uptake. With increasing initial nitrate concentration, the removal efficiency of the nitrate ion by wheat adsorbent decreased. Based on the results, the adsorption process followed the Pseudo-second-order kinetics model Ho, and the adsorption data were more consistent with the Freundlich isotherm model. Therefore, it can be stated that wheat straw nano adsorbent can be recommended as a suitable and inexpensive absorbent with the least technology in nitrate removal.