Use of surfactant-modified zeolite as fertilizer carriers to control nitrate release
✍ Scribed by Z. Li
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 398 KB
- Volume
- 61
- Category
- Article
- ISSN
- 1387-1811
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✦ Synopsis
Use of soluble N fertilizers is one of the major causes for groundwater contamination in agricultural farmland. Thus, research producing inexpensive slow-releasing fertilizers has drawn great attention recently. In this study, the feasibility of using surfactant-modified zeolite (SMZ) as fertilizer carriers to control nitrate release was investigated. The zeolite was first modified by hexadecyltrimethylammonium, a cationic surfactant, to increase its capacity of nitrate retention. Batch studies revealed that nitrate sorption onto SMZ increased as the surfactant loading on SMZ increased. Nitrate desorption from nitrate-loaded SMZ was almost instantaneous and partially reversible. After desorbed with 100 pore volumes of water, 30-40% of sorbed nitrate still remained on SMZ. Column leaching experiments showed a 20-fold reduction in initial effluent nitrate concentration when nitrate-loaded SMZ was used compared to that when soluble nitrate was mixed with zeolite at the same nitrate loading. The effluent nitrate concentration was quickly reduced to <0.2 mM when a mixture of soluble nitrate and zeolite was leached with less than 2 pore volumes of water. In contrast, the effluent nitrate concentration remained >0.3 mM when nitrate-loaded SMZ was flushed with more than 50 pore volumes of water. Greenhouse tests showed the same growth rate for corns when nitrate-loaded SMZ and water soluble nitrate were used. The results indicate that SMZ is a good sorbent for nitrate, while slow release of nitrate is achievable. These dual properties suggest that SMZ has a great potential as fertilizer carriers to control the release of nitrate and other anions.