FABRICATION AND CHARACTERIZATION OF POLYANILINE-GRAPHENE COMPOSITE AS ELECTRODE IN ELECTROCHEMICAL CAPACITOR

In this study, polyaniline-graphene composites with different nano-structures are synthesized and the behaviour of the obtained composites serving as electrode materials in electrochemical capacitors is studied. The morphology, crystal structure, and thermal stability of the composites are examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Thermal gravimetric analysis (TGA). Electrochemical properties are characterized by cyclic voltammetry (CV). According to the results, the obtained composites show different crystal structures and different thermal stabilities, and consequently different electrochemical capacities, when used as electrodes in electrochemical capacitors. A nano-fibre composite is shown to have a good degree of crystallization, 5.17% water content, 637oC degradation onset temperature, and 379 Fg-1 electrochemical capacity

Safranin-O removal from aqueous solutions using lignin nanoparticle-g-polyacrylic acid adsorbent: Synthesis, properties, and application

In this study, alkali lignin modified by ethylene glycol and lignin nanoparticles was prepared through acid precipitation technology. Lignin nanoparticle-g-polyacrylic acid adsorbent was prepared using copolymerization reactions between lignin nanoparticle and polyacrylic acid in the presence of potassium persulfate as the radical initiator. Then, lignin nanoparticle-g-polyacrylic acid adsorbent was used to remove Safranin-O from an aqueous environment. The adsorbent structures and morphologies of lignin nanoparticle and lignin nanoparticle-g-polyacrylic acid adsorbent were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Nanoparticle sizes were assessed using dynamic light scattering. Equilibrium isotherms were compared using the Langmuir, Freundlich, and Temkin adsorption models. Both adsorbent lignin nanoparticle and lignin nanoparticle-g-polyacrylic acid adsorbent showed good agreement with the Langmuir isotherm. The maximum adsorption capacities of lignin nanoparticle and lignin nanoparticle-g-polyacrylic acid adsorbent reached 99 and 138.88 mg g −1 using model-like, pseudo-second-order, and intraparticle diffusion, respectively. Experimental results showed that adsorbent lignin nanoparticle and lignin nanoparticle-g-polyacrylic acid adsorbent followed the pseudo-second order kinetic model