Amorphous carbon nanotubes as potent sorbents for removal of a phenolic derivative compound and arsenic: theoretical support of experimental findings

Abstract

This work depicts the adsorptive removal efficiency of the carcinogenic phenolic derivative compound, resorcinol and highly toxic arsenic(III) from water by low temperature, chemically synthesized amorphous carbon nanotubes (a-CNTs). The as prepared a-CNTs were characterized by X-ray diffraction, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy; Raman spectroscopy and Fourier transform infrared spectroscopy. The a-CNTs were used in order to remove both an organic pollutant as well as a heavy metal like arsenic(III) by the process of adsorption. The quantification has been made with the help of UV-Vis spectroscopy. The removal efficiency of a-CNTs for both resorcinol and arsenic(III) was analysed by kinetic spectrophotometric study. It is seen that for resorcinol, the maximum possible removal efficiency was 76% within a time period of about 5 hours. Several sorption parameters like contact time, adsorbent dosage and pH were investigated for adsorption of resorcinol. For arsenic(III), the removal efficiency was 42%. Also a first principles study has been done and the adsorption of As adatoms on 5–8–5 type double vacancy defects is computationally investigated as a simplified case for As(III) atom trapping by a-CNTs. It is seen that the native point defects of a-CNTs bond strongly with As adatoms.