Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China.
Chinese National Engineering Research Center for Control and Treatment of Heavy Metals Pollution, Changsha, 410083, China.
Environ Sci Pollut Res Int. 2019 Oct;26(30):31099-31110. doi: 10.1007/s11356-019-06175-x. Epub 2019 Aug 27.
To improve the mass transfer efficiency of poly(m-phenylenediamine) for the effective removal of hexavalent chromium (Cr (VI)) from aqueous solution, a facile and one-step method to prepare two-dimensional poly(m-phenylenediamine) functionalized reduction graphene oxide (rGO-PmPD) by dilution polymerization is developed. The structure and morphology of rGO-PmPD as well as rGO and PmPD were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), Brunauer-Emmett-Teller (BET), Fourier-transformed infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Raman, and X-ray diffraction (XRD). The preparation mechanism, adsorption performance, and mechanism of rGO-PmPD were then investigated in detail. The obtained rGO-PmPD exhibited thin 2D nanosheet morphology with much improved specific surface area and pore volume (18 and 25 times higher than that of PmPD, respectively). The Cr (VI) adsorption of rGO-PmPD was fitted well with the pseudo-second-order kinetic model and Langmuir isotherm model, and the maximum adsorption capacity of rGO-PmPD reached 588.26 mg g, higher than that of PmPD (400 mg g) and rGO (156.25 mg g). Moreover, the regeneration efficiency of the rGO-PmPD nanosheet is also promising that the adsorption performance after five times of adsorption-desorption cycles still maintains more than 530 mg g. The removal mechanism involved reduction coupled with adsorption and electrostatic interaction between rGO-PmPD and Cr (VI), and ~ 65% of Cr (VI) removal was attributed to reduction and ~ 35% was ascribed to adsorption and electrostatic interaction. This study thus provides a simple and effective route to achieve high accessible surface area of adsorbent materials with enhanced mass transfer efficiency and thereafter improved adsorption performance.
为了提高聚间苯二胺（PmPD）的传质效率，从而有效去除水溶液中的六价铬（Cr(VI)），本研究开发了一种简便的一步稀释聚合法制备二维聚间苯二胺功能化还原氧化石墨烯（rGO-PmPD）的方法。通过扫描电子显微镜（SEM）、透射电子显微镜（TEM）、Brunauer-Emmett-Teller（BET）、傅里叶变换红外光谱（FT-IR）、X 射线光电子能谱（XPS）、拉曼和 X 射线衍射（XRD）对 rGO-PmPD 以及 rGO 和 PmPD 的结构和形态进行了表征。然后详细研究了 rGO-PmPD 的制备机制、吸附性能和机制。所得到的 rGO-PmPD 呈现出薄的 2D 纳米片形态，比 PmPD 的比表面积和孔体积分别提高了 18 倍和 25 倍。rGO-PmPD 的 Cr(VI)吸附符合准二级动力学模型和 Langmuir 等温模型，rGO-PmPD 的最大吸附容量达到 588.26mg/g，高于 PmPD（400mg/g）和 rGO（156.25mg/g）。此外，rGO-PmPD 纳米片的再生效率也很有前景，吸附-解吸 5 次后，其吸附性能仍保持在 530mg/g 以上。去除机制涉及还原偶联和 rGO-PmPD 与 Cr(VI)之间的静电相互作用，65%的 Cr(VI)去除归因于还原，35%归因于吸附和静电相互作用。因此，本研究为实现高比表面积吸附剂材料提供了一种简单有效的途径，从而提高传质效率和吸附性能。
