Kumar Rajeev, Barakat M A, Alseroury F A
Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
Central Metallurgical R & D Institute, Helwan, 11421, Cairo, Egypt.
Sci Rep. 2017 Oct 9;7(1):12850. doi: 10.1038/s41598-017-12850-1.
Nanomaterials with selective adsorption properties are in demand for environmental applications. Herein, acid etching and oxidative decomposition of melon units of graphitic carbon nitride (g-CN) was performed to obtain the oxidized graphitic carbon nitride (Ox-g-CN) nanosheets. Ox- g-CN nanosheets were further decorated on the polyaniline nanofiber (Ox-g-CN/Pani-NF). Ox-g-CN/Pani-NF was well characterized and further applied for a selective removal of hexavalent chromium (Cr(VI)) form aqueous solution. The zeta potential analysis indicate that the surface of Ox-g-CN/Pani-NF was positively charged which could be beneficial to bind anionic Cr(VI) ions electrostatically. In addition, nitrogen and oxygen containing functional groups exist on the Ox-g-CN/Pani-NF were mainly responsible for adsorption of Cr(VI) ions from aqueous solution. Moreover, the adsorption of Cr(VI) ions was also dependent on solution pH, reaction temperature and initial concentration of Cr(VI) ions. The maximum monolayer adsorption capacity of Ox-g-CN/Pani-NF for Cr(VI), calculated from Langmuir isotherm was 178.57 mg/g at pH = 2 and 30 °C. The activation energy (Ea = -20.66 kJ/mol) and the enthalpy change (ΔH° = -22.055 kJ/mol) validate the role of physical forces in adsorption of Cr(VI). These results demonstrate that Ox-g-CN/Pani-NF can be used as a potential adsorbent for environmental remediation applications.
具有选择性吸附特性的纳米材料在环境应用中具有需求。在此，对石墨相氮化碳（g-CN）的瓜环单元进行酸蚀刻和氧化分解，以获得氧化石墨相氮化碳（Ox-g-CN）纳米片。将Ox-g-CN纳米片进一步修饰在聚苯胺纳米纤维上（Ox-g-CN/Pani-NF）。对Ox-g-CN/Pani-NF进行了充分表征，并进一步用于从水溶液中选择性去除六价铬（Cr(VI)）。zeta电位分析表明，Ox-g-CN/Pani-NF的表面带正电，这有利于通过静电作用结合阴离子Cr(VI)离子。此外，Ox-g-CN/Pani-NF上存在的含氮和含氧官能团主要负责从水溶液中吸附Cr(VI)离子。此外，Cr(VI)离子的吸附还取决于溶液pH值、反应温度和Cr(VI)离子的初始浓度。根据朗缪尔等温线计算，Ox-g-CN/Pani-NF在pH = 2和30°C时对Cr(VI)的最大单层吸附容量为178.57 mg/g。活化能（Ea = -20.66 kJ/mol）和焓变（ΔH° = -22.055 kJ/mol）证实了物理力在Cr(VI)吸附中的作用。这些结果表明，Ox-g-CN/Pani-NF可作为一种潜在的吸附剂用于环境修复应用。
