Ghazy Nada M, Ghaith Eslam A, Abou El-Reash Y G, Zaky Rania R, Abou El-Maaty Weam M, Awad Fathi S
Chemistry Department, Faculty of Science, Mansoura University Mansoura 35516 Egypt
Chemistry Department, Faculty of Science, Imam Mohammad Ibn Saud Islamic University P.O. Box, 90950 Riyadh 11623 Saudi Arabia.
RSC Adv. 2022 Dec 12;12(55):35587-35597. doi: 10.1039/d2ra07032d.
This work reports the synthesis of an innovative multifunctional carbon nitride based adsorbent and its successful application for the removal of crystal violet (CV) and methylene blue (MB) from wastewater. The functionalized graphitic carbon nitride (f/g-CN) adsorbent was produced by the pyrolysis of melamine followed by thermal alkali treatment to introduce OH, NH , and CN groups onto the graphitic carbon nitride (g-CN) surface. Experimental data obtained from batch tests revealed that the maximum adsorption capacities of g-CN and f/g-CN were found to be 28.9 and 239.0 mg g for MB, and 163.0 and 532.0 mg g for CV, respectively, at pH 8, 25 °C and after 90 min. This increase in adsorption capacity of f/g-CN can be explained by the presence of multiple functional groups in its structure. f/g-CN showed 100% removal for MB and CV with concentrations lower than 100 ppm and the equilibrium time required for the 100% removal of 500 ppb dye is 60 seconds. Additionally, the experimental data fitted well with the Langmuir isotherm model ( = 0.992) and pseudo second order kinetic model ( = 0.999) suggesting that the mechanism of adsorption is based on π-π stacking and electrostatic interactions between the NH and OH groups of f/g-CN and dye molecules with monolayer formation. Moreover, a reusability test showed that the adsorption capacity remained at around 90% after 7 cycles. This work highlights the merits of the prepared adsorbent f/g-CN which is an eco-friendly, stable, efficient, and reusable adsorbent for removing cationic dyes from wastewater.
本工作报道了一种创新的多功能氮化碳基吸附剂的合成及其在去除废水中结晶紫（CV）和亚甲基蓝（MB）方面的成功应用。功能化石墨相氮化碳（f/g-CN）吸附剂通过三聚氰胺热解，随后进行热碱处理制备而成，以便将OH、NH 和CN基团引入到石墨相氮化碳（g-CN）表面。批次试验获得的实验数据表明，在pH值为8、25℃且90分钟后，g-CN和f/g-CN对MB的最大吸附容量分别为28.9和239.0 mg/g，对CV的最大吸附容量分别为163.0和532.0 mg/g。f/g-CN吸附容量的增加可归因于其结构中存在多个官能团。f/g-CN对浓度低于100 ppm的MB和CV的去除率为100%，去除500 ppb染料达到100%去除率所需的平衡时间为60秒。此外，实验数据与Langmuir等温线模型（ = 0.992）和伪二级动力学模型（ = 0.999）拟合良好，表明吸附机制基于f/g-CN的NH 和OH基团与染料分子之间的π-π堆积和静电相互作用，并形成单分子层。此外，可重复使用性测试表明，经过7个循环后，吸附容量仍保持在90%左右。这项工作突出了制备的吸附剂f/g-CN的优点，它是一种用于从废水中去除阳离子染料的环保、稳定、高效且可重复使用的吸附剂。
