First-Principles Density Functional Theory Calculations for Formic Acid Adsorption onto Hydro-Garnet Compounds

Masanobu Nakayama; Kunihiro Ishida; Kentaro Watanabe; Naoto Tanibata; Hayami Takeda; Hirotaka Maeda; Toshihiro Kasuga

doi:10.1021/acsomega.9b03746

First-Principles Density Functional Theory Calculations for Formic Acid Adsorption onto Hydro-Garnet Compounds

ACS Omega. 2020 Feb 19;5(8):4083-4089. doi: 10.1021/acsomega.9b03746. eCollection 2020 Mar 3.

Authors

Masanobu Nakayama^{1

2

3

4}, Kunihiro Ishida¹, Kentaro Watanabe¹, Naoto Tanibata^{1

3}, Hayami Takeda^{1

3}, Hirotaka Maeda¹, Toshihiro Kasuga¹

Affiliations

¹ Department of Advanced Ceramics, Nagoya Institute of Technology, Gokiso, Showa, Nagoya, Aichi 466-8555, Japan.
² MaDiS/CMi2, National Institute for Materials Science (NIMS), 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047, Japan.
³ Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Katsura, Saikyo-ku, Kyoto 615-8520, Japan.
⁴ Frontier Research Institute for Materials Science (FRIMS), Nagoya Institute of Technology, Gokiso, Showa, Nagoya, Aichi 466-8555, Japan.

Abstract

Efficient and large-scale removal of humic acid (HA) from aqueous environments is required since HA causes human health and esthetic issues. Hydro-garnet compounds, Ca₃Al₂(SiO₄)_3-x (OH)_4x , have recently been suggested as HA adsorbents not only due to their superior adsorption behaviors but also because they are ubiquitous element-derived compounds. In this study, the adsorption behavior of formic acid to hydro-garnets was investigated by means of first-principles density functional theory (DFT) computations. Formic acid was chosen owing to its reasonable computational cost and inclusion of carboxylic acid as HA. Comparisons of adsorption energies for formic acid among various compounds (including platinum and kaolinite) indicate that hydro-garnet compounds are promising due to their lower (more stable) adsorption energies. Also, the optimization of composition x enables selective adsorption of formic acid against solvent water molecules. Relationships between surface electronic/atomistic structures and adsorption properties are discussed.