Ntakirutimana Samuel, Tan Wei, Wang Yang
School of Chemical Engineering and Technology, Tianjin University No. 135 Yaguan Road Tianjin 300350 PR China
Tianjin Key Laboratory of Membrane Science and Desalination Technology Tianjin 300072 PR China.
RSC Adv. 2019 Aug 23;9(45):26519-26531. doi: 10.1039/c9ra04521j. eCollection 2019 Aug 19.
Activated carbon (AC) modification has been intensively studied in order to design carbon electrodes with enhanced electrochemical performance. Hexadecyltrimethylammonium bromide (HDTMA) and Tween 80 were employed for enhancing the surface activity of AC synergism. The synergistic effects of the mixed surfactants on AC surface activity in the light of interface behaviors were studied. Both field emission scanning electron micrographs and FTIR spectra indicated a successful adsorption of loaded surfactants. AC gained a good wettability originated from the surfactants, especially in the binary mixture (T80-HDTMA). The zeta potential results unveiled the positive charge density enhancement in the mixed surfactants system. Isoelectric point and point of zero charge implicate heterogeneous distribution of charges and the extent of surfactants treatment. Tween 80 displayed a significant size control dependence on AC particles. Electrochemical characterization revealed a higher specific capacitance and a decaying resistance of specific capacitance in AC-T80-HDTMA than AC-HDTMA at high concentration. In 5 g L of NaCl, AC-T80-HDTMA (0.01 : 0.01 mM) exhibits the specific capacitance of 209.79 F g, at 0.8 V whereas AC-HDTMA (0.01 mM) and AC exhibited 186.5 F g, 178.9 F g, respectively. Moreover, the stability testing reveals a strong attachment of HDTMA in AC-T80-HDTMA than AC-HDTMA with the loss of 0.32% and 1.32%, respectively. The hypothetical synergistic mechanism of surfactants adsorption on the surface of AC was depicted as hydrophobic interaction and steric stabilization being the main keys for the synergy between cationic and nonionic surfactants. This study demonstrates the beneficial effects of mixed surfactants on AC electrode properties and discloses the impact on electrochemical performance.
为了设计具有增强电化学性能的碳电极，人们对活性炭（AC）改性进行了深入研究。采用十六烷基三甲基溴化铵（HDTMA）和吐温80来增强AC的表面活性，以实现协同作用。从界面行为的角度研究了混合表面活性剂对AC表面活性的协同效应。场发射扫描电子显微镜图像和傅里叶变换红外光谱均表明负载的表面活性剂成功吸附。AC由于表面活性剂而获得了良好的润湿性，尤其是在二元混合物（T80-HDTMA）中。zeta电位结果揭示了混合表面活性剂体系中正电荷密度的增强。等电点和零电荷点暗示了电荷的不均匀分布以及表面活性剂处理的程度。吐温80对AC颗粒显示出显著的尺寸控制依赖性。电化学表征表明，在高浓度下，AC-T80-HDTMA比AC-HDTMA具有更高的比电容和比电容衰减电阻。在5 g/L的NaCl中，AC-T80-HDTMA（0.01∶0.01 mM）在0.8 V时的比电容为209.79 F/g，而AC-HDTMA（0.01 mM）和AC分别为186.5 F/g、178.9 F/g。此外，稳定性测试表明，HDTMA在AC-T80-HDTMA中的附着比在AC-HDTMA中更强，损失率分别为0.32%和1.32%。表面活性剂在AC表面吸附的假设协同机制被描述为疏水相互作用和空间稳定作用是阳离子和非离子表面活性剂之间协同作用的主要关键。本研究证明了混合表面活性剂对AC电极性能的有益影响，并揭示了其对电化学性能的影响。
