Single- and double-walled boron nitride nanotubes: Controlled synthesis and application for water purification

Hyunjin Cho,Cheol Park,Cheol Sang Kim,Hunsu Lee,Jun Hee Kim,Myung Jong Kim,Se Gyu Jang,Jae Hun Hwang

doi:10.1038/s41598-020-64096-z

Abstract

Research interest in boron nitride nanotubes (BNNTs) has increased after the recent success of large-scale BNNT syntheses using high-temperature-pressure laser ablation or high-temperature plasma methods. Nonetheless, there are limits to the application and commercialization of these materials because of the difficulties associated with their fine structural control. Herein, the growth kinetics of BNNTs were systemically studied for this purpose. The growth pressure of the nitrogen feed gas was varied while the growth temperature remained constant, which was confirmed by black body radiation measurements and calculations based on a heat loss model. Changing from the diffusion-limited regime to the supply-limited regime of growth kinetics based on the optimized BNNT synthesis condition afforded the control of the number of BNNT walls. The total amount of BNNTs possessing single and double walls was over 70%, and the BNNT surface area increased to 278.2 m2/g corresponding to small wall numbers and diameters. Taking advantage of the large surface area and high-temperature durability of the material, BNNTs utilized as a recyclable adsorbent for water purification. The efficiency of the BNNTs for capturing methylene blue particles in water was approximately 94%, even after three repetition cycles, showing the potential of the material for application in the filter industry.

Highlights

Research interest in boron nitride nanotubes (BNNTs) has increased after the recent success of largescale BNNT syntheses using high-temperature-pressure laser ablation or high-temperature plasma methods
single-walled CNTs (SWCNTs) are preferred for various applications, and the developed synthesis techniques for high SWCNT yields have expanded their applicability to various research and industrial fields beyond composite materials
Researchers in the BNNT field are interested in the selective synthesis of single-walled BNNTs (SWBNNTs) and double-walled BNNTs (DWBNNTs) because they have superior properties to those of multi-walled BNNTs (MWBNNTs) due to structural perfection and quantum confinement effects

Summary

Introduction

Research interest in boron nitride nanotubes (BNNTs) has increased after the recent success of largescale BNNT syntheses using high-temperature-pressure laser ablation or high-temperature plasma methods. The growth pressure of the nitrogen feed gas was varied while the growth temperature remained constant confirmed by black body radiation measurements and calculations based on a heat loss model including thermal conduction, convection, and radiation.

Results

Conclusion