Removal of methyl orange by multiwall carbon nanotube accelerated by ultrasound devise: Optimized experimental design

• MWCNT used as reusable support for removal of methyl orange.
• A high efficiency removal technology is proposed for fast removal of methyl orange.
• Methyl orange removal significantly was accelerated under application of ultrasound.
• The novel sorbent was characterized by SEM and TEM analysis.
• This model is applicable for rapid removal of large quantity of this dye.

This study investigates the methyl orange (MO) removal from aqueous solution through the application of ultrasound onto multiwalled carbon nanotubes (MWCNTs). Characterization of MWCNT was carried out using scanning electron microscopy (SEM) and tunneling electron microscopy (TEM). The influences of various parameters on the removal percentage were studied and optimized by a central composite design (CCD) and response surface methodology (RSM). Results indicate that a small amount of proposed adsorbent (0.025 g) is responsible for successful removal of 15 mg L−1 of MO (RE > 99%) in a short time (3.4 min) and pH of 1–2. Adsorption kinetic data are fitted well with pseudo second order model. Equilibrium data followed Langmuir isotherm model with maximum adsorption capacity of 53.76 mg g−1.

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