[12a-PA2-1~77] 17 Nanocarbon Technology

▲ [12a-PA2-2] Liquid-Phase Plasma-Assisted in Situ Synthesis of Amino-Rich nanocarbon: Innovative Adsorbent Preparation for Transition Metal Ion Adsorption

〇(D)Mongkol TIPPLOOK¹, Nagahiro SAITO^1,2,3,4 (1.Nagoya Univ., 2.Institute for Materials Innovation, 3.Conjoint Research Labo. in Nagoya Uni. And Shinshu Uni., 4.JST)

Keywords:solution plasma process, amino-modified carbon, adsorption

Amino-modified nanocarbon (NH₂-C) has been widely used as an adsorbent for transition metal ion adsorption due to its high specific surface area, high electrical charge and ability to form a coordinate linkage to a transition metal ion. In this work, NH₂-C was successfully synthesized from a mixture of phenol and 3-Aminopropyltriethoxysilane (APTES) through solution plasma processing, which performs both carbonization and amination simultaneously. This synthesis method eliminates the need to functionalize carbon with amino groups, as is required in the conventional process. Our NH₂-C shows a better dispersion and a higher number of amino groups on both the external surface and inner pores, which enhances the adsorption capacity. The maximum capacities for Cu²⁺, Zn²⁺, and Cd²⁺ adsorption were 144.9, 115.4, and 102.0 mg·g^–1, respectively. These values were higher than those of five typical NH₂-Cs synthesized by a conventional process. Based on the adsorption mechanism derived from adsorption kinetic, isotherm, and thermodynamic studies, the transition metal ions were chemisorbed to the surface in a monolayer endothermically and spontaneously. Moreover, it was found that NH₂-C was suitable for use in ten consecutive adsorption-desorption cycles without significant loss of adsorption capacity.