Adsorption of Direct Blue 53 dye from aqueous solutions by multi-walled carbon nanotubes and activated carbon

• Published in: Journal of environmental management 2013-11, Vol.130, p.166-175
• Main Authors: Prola, Lizie D.T., Machado, Fernando M., Bergmann, Carlos P., de Souza, Felipe E., Gally, Caline R., Lima, Eder C., Adebayo, Matthew A., Dias, Silvio L.P., Calvete, Tatiana
• Format: Article
• Language: English
• Subjects: acetone; Activated carbon; Adsorbents; Adsorption; Animal, plant and microbial ecology; Applied ecology; aqueous solutions; Azo Compounds - chemistry; Biological and medical sciences; Carbon nanotubes; Charcoal - chemistry; Coloring Agents - chemistry; Conservation, protection and management of environment and wildlife; desorption; Direct Blue 53; effluents; Fundamental and applied biological sciences. Psychology; General aspects; Hydrogen-Ion Concentration; Kinetics; Nanotubes; Nanotubes, Carbon - chemistry; nitrogen; Nonlinear isotherm fitting; Raman spectroscopy; sodium hydroxide; temperature; Transmission electron microscopy; Water Purification - methods; Water treatment
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2013.09.003

Multi-walled carbon nanotubes (MWCNT) and powder activated carbon (PAC) were used as adsorbents for adsorption of Direct Blue 53 dye (DB-53) from aqueous solutions. The adsorbents were characterised using Raman spectroscopy, N2 adsorption/desorption isotherms, and scanning and transmission electron microscopy. The effects of initial pH, contact time and temperature on adsorption capacity of the adsorbents were investigated. At pH 2.0, optimum adsorption of the dye was achieved by both adsorbents. Equilibrium contact times of 3 and 4 h were achieved by MWCNT and PAC adsorbents, respectively. The general order kinetic model provided the best fit of the experimental data compared to pseudo-first order and pseudo-second order kinetic adsorption models. For DB-53 dye, the equilibrium data (298–323 K) were best fitted to the Sips isotherm model. The maximum sorption capacity for adsorption of the dye occurred at 323 K, with the values of 409.4 and 135.2 mg g−1 for MWCNT and PAC, respectively. Studies of adsorption/desorption were conducted and the results showed that DB-53 loaded MWCNT could be regenerated (97.85%) using a mixture 50% acetone + 50% of 3 mol L−1 NaOH. Simulated dye house effluents were used to evaluate the application of the adsorbents for effluent treatment (removal of 99.87% and 97.00% for MWCNT and PAC, respectively, were recorded). •Adsorption of DB-53 dye was studied using MWCNT and CAC as adsorbents.•MWCNT was characterised using Raman spectroscopy, SEM and TEM techniques.•Maximum adsorption capacities of MWCNT and CAC are 409.4 and 135.2 mg/g, respectively.•The adsorption processes are well described by general order kinetic model.•MWCNT and CAC have been proven effective for removal of DB-53 dye.