Optimization of nitrate, urea, and ammonium removal from agricultural wastewater using selected modified organic and inorganic adsorbents

Document Type : Research Paper

Authors

1 Ph. D Student, Sari Agricultural Sciences and Natural Resources

2 Faculty member, Sari Agricultural Sciences and Natural Resources University

3 Faculty member, Sari Agricultural Sciences and and Natural Resources

4 Faculty member, Sari Agricultural Sciences and Natural Resources

10.22059/jwim.2026.404969.1271

Abstract

In order to investigate the efficiency of organic and inorganic adsorbents in removing nitrogenous compounds, some available organic adsorbents (including 7 treatments: rice straw and husk, biochar-rice straw and husk prepared at two temperatures of 300 and 600 °C, and Leonardite) and inorganic adsorbents (including 3 treatments: bentonite, pumice, and zeolite) were used to remove nitrogenous compounds (nitrate, urea and ammonium). To increase efficiency and comparison, the adsorbents were used in simple form, modified with acid, and with iron at two different acidity levels (pH=2 and pH=6). The results showed that biochar prepared from rice straw at a temperature of 600 °C and modified with iron at pH=2, with an absorption of about 79% of nitrate from water, was the best adsorbent for removing nitrate from water among all organic and inorganic adsorbents studied in this study. Rice straw biochar prepared at 600°C and modified with iron at pH=6 removed the highest amount of urea, and acid-modified zeolite showed the best performance with 92% ammonium absorption. Overall, this study indicates the effective and efficient removal of nitrogen compounds by these adsorbents, and modification with acid and iron improved the removal capability of these adsorbents. As a result, they can be used as a cheap and accessible method for removing pollutants from water sources.

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