The Role of Carbon Nanotube Pretreatments in the Adsorption of Benzoic Acid

Pierantonio De Luca; Carlo Siciliano; Anastasia Macario; Jànos B Nagy

doi:10.3390/ma14092118

The Role of Carbon Nanotube Pretreatments in the Adsorption of Benzoic Acid

Materials (Basel). 2021 Apr 22;14(9):2118. doi: 10.3390/ma14092118.

Authors

Pierantonio De Luca¹, Carlo Siciliano², Anastasia Macario³, Jànos B Nagy¹

Affiliations

¹ Department of Mechanical, Energy and Management Engineering, University of Calabria, I-87036 Arcavacata di Rende, Italy.
² Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, I-87036 Arcavacata di Rende, Italy.
³ Department of Environmental Engineering, University of Calabria, I-87036 Arcavacata di Rende, Italy.

Abstract

Four different types of multi-walled carbon nanotubes (MWCNTs) were used and compared for the treatment of benzoic acid contaminated water. The types of nanotubes used were: (1) non-purified (CNTs^UP), as made; (2) purified (CNTs^P), not containing the catalyst; (3) oxidized (CNTs^OX), characterized by the presence of groups such as, -COOH; (4) calcined (CNTs⁹⁰⁰), with elimination of interactions between nanotubes. In addition, activated carbon was also used to allow for later comparison. The adsorption tests were conducted on an aqueous solution of benzoic acid at concentration of 20 mg/L, as a model of carboxylated aromatic compounds. After the adsorption tests, the residual benzoic acid concentrations were measured by UV-visible spectrometry, while the carbon nanotubes were characterized by TG and DTA thermal analyses and electron microscopy (SEM). The results show that the type of nanotubes thermally treated at 900 °C has the best performances in terms of adsorption rate and amounts of collected acid, even if compared with the performance of activated carbons.

Keywords: active carbons; adsorption; benzoic acid; carbon nanotubes; functionalization.