Synthesis ratios of Mg-Al and Zn-Al layered double hydroxides efficiency and selectivity in nitrate removal from solution
Four diverse chlorides layered double hydroxides with diverse ratios, i.e. Mg-Al (3:1), Mg-Al (4:1), Zn-Al (4:1), and Zn-Al (3:1) LDHs, were prepared to evaluate their efficiency and selectivity towards nitrate removal from aquatic solutions. A batch experiment was done at the initial nitrate concen...
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2019-10-01
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| Series: | Global Journal of Environmental Science and Management |
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| author | M. Mohammadi A. Mohammadi Torkashvand P. Biparva M. Esfandiari |
| author_facet | M. Mohammadi A. Mohammadi Torkashvand P. Biparva M. Esfandiari |
| author_sort | M. Mohammadi |
| collection | DOAJ |
| description | Four diverse chlorides layered double hydroxides with diverse ratios, i.e. Mg-Al (3:1), Mg-Al (4:1), Zn-Al (4:1), and Zn-Al (3:1) LDHs, were prepared to evaluate their efficiency and selectivity towards nitrate removal from aquatic solutions. A batch experiment was done at the initial nitrate concentration of 5-1000 mg/L, pH 5 to 12, and contact time of 5-180 min. Isotherms of nitrate adsorption on LDHs, soil and soil-LDH mixtures were studied. Kinetics of adsorption, temperature effect, nitrate adsorption in nitrate adsorption, simulated soil solution and desorption on Mg-Al-LDH (4:1) were measured. At an optimum speed of 250 rpm, pH value of 7 and adsorbent dosage of 2 g/L, the amounts of nitrate adsorption on Mg-Al- LDH (3:1) and Mg-Zn-LDH (3:1) and also on Mg-Al- LDH (4:1) and Mg-Zn-LDH (4:1) were obtained after 30 and 60 min, respectively. Isotherm studies indicated that nitrate adsorption on soil, soil-LDH mixture, and LDH fitted Langmuir linear isotherm. The highest nitrate adsorption on Mg-Al-LDH (4:1) and a mixture of soil-Mg-Al-LDH (4:1) were 188.67 and 107.52 mg/g, respectively. Among the studied kinetic equations for nitrate adsorption on Mg-Al-LDH (4:1), the pseudo-second-order with R<sup>2</sup>=0.998 had the best fitness. Negative values of ∆H in different nitrate concentrations indicated the exothermic process of nitrate adsorption on Mg-Al-LDH (4:1). In the presence of other anions, Mg-Al-LDH (4:1) removed nitrate preferentially. Moreover, Mg-Al-LDH (4:1) could exchange nitrate 20 times in different concentrations with no reduction in its adsorption capacity. |
| format | Article |
| id | doaj-art-ca3759aa6f5841eca708c28f34beeff2 |
| institution | Kabale University |
| issn | 2383-3572 2383-3866 |
| language | English |
| publishDate | 2019-10-01 |
| publisher | GJESM Publisher |
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| series | Global Journal of Environmental Science and Management |
| spelling | doaj-art-ca3759aa6f5841eca708c28f34beeff22025-02-02T01:51:48ZengGJESM PublisherGlobal Journal of Environmental Science and Management2383-35722383-38662019-10-015448550010.22034/GJESM.2019.04.0835751Synthesis ratios of Mg-Al and Zn-Al layered double hydroxides efficiency and selectivity in nitrate removal from solutionM. Mohammadi0A. Mohammadi Torkashvand1P. Biparva2M. Esfandiari3Department of Soil Science, Science and Research Branch, Islamic Azad University, Tehran, IranDepartment of Soil Science, Science and Research Branch, Islamic Azad University, Tehran, IranDepartment of Basic Science, Sari University of Agricultural Sciences and Natural Resources, Sari, IranDepartment of Soil Science, Science and Research Branch, Islamic Azad University, Tehran, IranFour diverse chlorides layered double hydroxides with diverse ratios, i.e. Mg-Al (3:1), Mg-Al (4:1), Zn-Al (4:1), and Zn-Al (3:1) LDHs, were prepared to evaluate their efficiency and selectivity towards nitrate removal from aquatic solutions. A batch experiment was done at the initial nitrate concentration of 5-1000 mg/L, pH 5 to 12, and contact time of 5-180 min. Isotherms of nitrate adsorption on LDHs, soil and soil-LDH mixtures were studied. Kinetics of adsorption, temperature effect, nitrate adsorption in nitrate adsorption, simulated soil solution and desorption on Mg-Al-LDH (4:1) were measured. At an optimum speed of 250 rpm, pH value of 7 and adsorbent dosage of 2 g/L, the amounts of nitrate adsorption on Mg-Al- LDH (3:1) and Mg-Zn-LDH (3:1) and also on Mg-Al- LDH (4:1) and Mg-Zn-LDH (4:1) were obtained after 30 and 60 min, respectively. Isotherm studies indicated that nitrate adsorption on soil, soil-LDH mixture, and LDH fitted Langmuir linear isotherm. The highest nitrate adsorption on Mg-Al-LDH (4:1) and a mixture of soil-Mg-Al-LDH (4:1) were 188.67 and 107.52 mg/g, respectively. Among the studied kinetic equations for nitrate adsorption on Mg-Al-LDH (4:1), the pseudo-second-order with R<sup>2</sup>=0.998 had the best fitness. Negative values of ∆H in different nitrate concentrations indicated the exothermic process of nitrate adsorption on Mg-Al-LDH (4:1). In the presence of other anions, Mg-Al-LDH (4:1) removed nitrate preferentially. Moreover, Mg-Al-LDH (4:1) could exchange nitrate 20 times in different concentrations with no reduction in its adsorption capacity.https://www.gjesm.net/article_35751_bdf07da28733f9fb68f66733442c5192.pdfadsorption and desorptionContaminationIsothermKineticsLayered double hydroxides (LDHs)pHTemperature |
| spellingShingle | M. Mohammadi A. Mohammadi Torkashvand P. Biparva M. Esfandiari Synthesis ratios of Mg-Al and Zn-Al layered double hydroxides efficiency and selectivity in nitrate removal from solution Global Journal of Environmental Science and Management adsorption and desorption Contamination Isotherm Kinetics Layered double hydroxides (LDHs) pH Temperature |
| title | Synthesis ratios of Mg-Al and Zn-Al layered double hydroxides efficiency and selectivity in nitrate removal from solution |
| title_full | Synthesis ratios of Mg-Al and Zn-Al layered double hydroxides efficiency and selectivity in nitrate removal from solution |
| title_fullStr | Synthesis ratios of Mg-Al and Zn-Al layered double hydroxides efficiency and selectivity in nitrate removal from solution |
| title_full_unstemmed | Synthesis ratios of Mg-Al and Zn-Al layered double hydroxides efficiency and selectivity in nitrate removal from solution |
| title_short | Synthesis ratios of Mg-Al and Zn-Al layered double hydroxides efficiency and selectivity in nitrate removal from solution |
| title_sort | synthesis ratios of mg al and zn al layered double hydroxides efficiency and selectivity in nitrate removal from solution |
| topic | adsorption and desorption Contamination Isotherm Kinetics Layered double hydroxides (LDHs) pH Temperature |
| url | https://www.gjesm.net/article_35751_bdf07da28733f9fb68f66733442c5192.pdf |
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