Removal of ciprofloxacin and indigo carmine from water by carbon nanotubes fabricated from a low-cost precursor: Solution parameters and recyclability

Abstract

Water contamination is one of humanity's threatening problems. This study synthesized pristine carbon nanotubes (PCNTs) from commercial gasoline (CG) as a relatively low-cost precursor. 200 mL of CG yielded an average CNTs mass of 26.23 ± 0.97 g. The functionalized carbon nanotubes (FCNTs) were produced by acid-treatment of PCNTs, and the yield was 93.3%. The surface area of PCNTs and FCNTs was 29.69 and 66.16 m2 g−1. The FTIR and EDX indicated an introduction of oxygenated groups on the FCNTs. The FCNTs removed ciprofloxacin (CIP) and indigo carmine (IC) from water with an adsorption capacity of 95.5 and 93.0 mg g−1, respectively, while the PCNTs showed 78.9 and 63.7 mg g−1, respectively. The pH 4.0 and 6.0 suited the adsorption of CIP and IC on both sorbents. The adsorption processes for all sorbent-sorbate systems were spontaneous and exothermic. The FCNTs and PCNTs recyclability showed an average efficiency of 90.0%.

Keywords

• Carbon nanotubes
• Gasoline fuel
• High yield method
• Ciprofloxacin
• Indigo carmine