عنوان مقاله [English]
Background and Objectives: The availability of clean and healthy water is one of the most important issues facing humankind, and as water levels increase further, pollutants also contaminate water resources in different ways, and this will become even more critical in the future. Environmental pollution, especially water, which is an important factor in limiting human progress, has become so important that the struggle has been addressed by global and regional seminars. Pollution of groundwater and surface water into nitrate in many parts of the world is a serious problem. Different physical, chemical and biological methods exist for nitrate removal, including reverse osmosis, ion exchange, decomposition of chlorination, electrodialysis, and chemical denitrification. In recent years, much attention has been paid to low-cost materials such as bark, plant nanoadsorbents and other waste materials. The aim of this study was to investigate the possibility of using oak leaf absorbent as an inexpensive and cost effective absorbent for removing nitrate from aqueous solutions.
Materials and Methods: In order to carry out absorption tests, the first pace is to prepare the absorbent. To do this and in order to achieve the desired result, oak leaf absorbent was used as the best option to obtain the best in terms of absorption. After absorbent preparation, absorbent characterization experiments were carried out, including Particle Size and a Absorbent special surface by methylene blue absorption . Then, discontinuous tests were performed and the data analysis method was mentioned. The present study was conducted in a laboratory scale and was performed in a Discontinuous. In this study, oak leaf absorbent was first crushed against a relatively dry sunshine by household grinder and then passed through the sieve 200 to prepare absorbent nanomaterials. After being washed with distilled water in an oven at 70 ° C for 24 hours. In this study, the effects of factors such as pH, adsorbent mass, contact time and initial concentration of nitrate were tested. Experiments were performed in a discontinuous system with three replications. Data analysis and drawing of charts were done by Exel software. The kinetic models of Lagergrne and Ho were used to examine the adsorption process, Also using equilibrium absorption data was analyzed using Freundlich and Langmuir isotherm models.
Results: The results showed that for the absorbent, the equilibrium time after 120min and the maximum nitrate absorption at pH = 5 were obtained. . By increasing the absorbent mass from 0.3 to 0.7 grams, the removal efficiency ranged from 88.93 to 93.82 percent, However, with increasing adsorbent content from 0.7 to 1.6 g, the absorption efficiency Almost reduced. By increasing the concentration of dissolved nitrate (5-120 mg/l), the removal efficiency decreased from 94.41 to 89.35%.
Conclusion: Based on the results, the absorption process was followed by the Ho et al model and the absorption data was more consistent with the Freundlich isotherm. Therefore, it can be stated that oak leaf can be used as a suitable and cost effective absorbent with the least technology in nitrate removal.