Removal of some cationic dyes from aqueous solutions using magnetic-modified multi-walled carbon nanotubes

• Published in: Journal of hazardous materials Vol. 196; pp. 109 - 114
• Main Authors: Madrakian, Tayyebeh, Afkhami, Abbas, Ahmadi, Mazaher, Bagheri, Hasan
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 30.11.2011; Elsevier
• Subjects: acetonitrile; Adsorbents; Adsorption; Applied sciences; aqueous solutions; Atmospheric pollution; carbon nanotubes; Cationic dyes; Cations; Chemical engineering; Coloring Agents - isolation & purification; Desorption; Exact sciences and technology; gentian violet; Hydrogen-Ion Concentration; Industrial Waste - analysis; Industrial Waste - prevention & control; Magnetic-modified multi-walled carbon nanotubes; Magnets; Mathematical models; methylene blue; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Multi wall carbon nanotubes; nanoparticles; Nanotubes, Carbon - chemistry; Optimization; Pollution; Removal; scanning electron microscopy; Solutions; solvents; Surface Properties; Time Factors; transmission electron microscopy; Water Pollutants, Chemical - isolation & purification; Water Purification - methods; X-Ray Diffraction; Removal; Adsorption; Magnetic-modified multi-walled carbon nanotubes; Cationic dyes; Scanning electron microscopy; Dyes; Nanoparticle; Adsorption capacity; Desorption; Ultrafine particle; Modeling; nanotubes; Internal diffusion; Transmission electron microscopy; Aerosols; pH; Air pollution; Magnetic-modified multi-walled carbon; Aqueous solution
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2011.08.078

► MMMWCNTs effectively removes color from dye-containing wastewater. ► MMMWCNTs has high adsorption capacity and fast adsorption rate. ► MMMWCNTs showed high efficiency. ► The modified nanoparticles are highly monodisperse and magnetically separable. An adsorbent, magnetic-modified multi-walled carbon nanotubes, was used for removal of cationic dyes crystal violet (CV), thionine (Th), janus green B (JG), and methylene blue (MB) from water samples. Prepared nanoparticles were characterized by SEM, TEM, BET and XRD measurements. The prepared magnetic adsorbent can be well dispersed in the water and easily separated magnetically from the medium after loaded with adsorbate. The influences of parameters including initial pH, dosage of adsorbent and contact time have been investigated in order to find the optimum adsorption conditions. The optimum pH for removing of all the investigated cationic dyes from water solutions was found to be 7.0. The experimental data were analyzed by the Langmuir adsorption model. The maximum predicted adsorption capacities for CV, JG, Th and MB dyes were obtained as 227.7, 250.0, 36.4 and 48.1 mg g −1, respectively. Desorption process of the adsorbed cationic dyes was also investigated using acetonitrile as the solvent. It was notable that both the adsorption and desorption of dyes were quite fast probably due to the absence of internal diffusion resistance.