**6. Conclusion**

This chapter described the promising development of utilizing chitosan and its derivatives with the focus on separation processes, and overviewed principal investigations. Reactive molecular chains of chitosan derived from hydroxyl and amino groups serve to form an attractive polymeric gel structure. In the filtration process, dense chitosan membranes separate small molecules of solvents, organic dyes, and toxic ions. The deacetylation degree is found to be the most notable factor for water permeation through membranes and its antibacterial ability. The complexity of chitosan-immobilizing systems with functional materials are found to be available in water purification processes. In recent years, adsorption combined with filtration is being developed for various types of water treatment. In this new type process, both the equilibrium adsorption capability and diffusivity in the absorbent matrix should be mentioned as describe in Section 4.1. Due to the easy operation, high selectivity, and low operational costs, adsorption process with chitosan gel is widely studied. As advanced separation media, highly porous chitosan aerogels and nanofibers, which possess large surface area that contribute to improved separation ability, have been developed recently.

Great demands of a novel biocompatible material and environmentally-friendly processes will continue to increase in future. Innovative separation technology utilizing chitosan obtained from bioresources is promising. The multifaceted development of chitosan-based system will lead to environmentally-friendly processes.

**Author details**

Keita Kashima1,2\*, Tomoki Takahashi3

*DOI: http://dx.doi.org/10.5772/intechopen.95839*

Nihon University, Narashino, Chiba, Japan

provided the original work is properly cited.

**219**

, Ryo-ichi Nakayama2,4 and Masanao Imai<sup>2</sup>

1 Department of Materials Chemistry and Bioengineering, National Institute of

*Innovative Separation Technology Utilizing Marine Bioresources: Multifaceted Development…*

2 Course in Bioresource Utilization Sciences, Graduate School of Bioresource

3 Department of Liberal Arts and Basic Sciences, College of Industrial Technology,

4 Department of Environmental Chemistry and Chemical Engineering, School of

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Advanced Engineering, Kogakukuin University, Hachioji, Tokyo, Japan

\*Address all correspondence to: keitakashima@oyama-ct.ac.jp

Technology, Oyama College (Oyama KOSEN), Oyama, Tochigi, Japan

Sciences, Nihon University, Fujisawa, Kanagawa, Japan

## **Acknowledgements**

The authors sincerely appreciate the financial support from Mukai Science and Technology Foundation (Japan). Prussian Blue used in this study was kindly provided from Dainichiseika Color & Chemicals Mfg. Co., Ltd. (Japan). Authors are also grateful for laboratory students in National Institute of Technology, Oyama College and their great efforts on the studies presented in this chapter: Mr. Tomoyuki Fujisaki for the study on chitosan membrane immobilizing Prussian Blue particles and Mr. Haruki Koya for preparation of chitosan aerogel.

The authors sincerely thank Prof. Norikazu Namiki of Kogakuin University, who provide the experimental set up for evaluating particle collection performance of test filter media. Ms. Yuki Suto of laboratory student in Kogakuin University, who for the study on chitosan nanofibers filter media.

*Innovative Separation Technology Utilizing Marine Bioresources: Multifaceted Development… DOI: http://dx.doi.org/10.5772/intechopen.95839*
