Adsorção de amina aromática em negro de fumo
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Data
2021-08-27
Autores
Rodrigues, Layza
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Universidade Federal do Espírito Santo
Resumo
Aromatic amines, such as ortho tolidine (o-tolidine), are used as raw material for dye synthesis and are also used as reagent for analyzing residual chlorine level within treated drinking water. Due to the high toxicity, these compounds require proper disposal and treatment of wastes to avoid the contamination of water resources. Adsorption is an efficient, low-cost, and simple design technique in the treatment of liquid waste, compared to other conventional methods used in the removal of contaminants. In this context, the study of adsorbent materials has been developed with an emphasis on low-cost and highly available materials. Carbon black is considered a versatile recycled material with great applicability, but despite the suitable characteristics, its use as adsorbent material is still scarce. Therefore, in this work, the removal of aromatic amine (otolidine) from aqueous solutions using carbon black (Vulcan XC 72R) as adsorbent material was studied. The Vulcan XC 72R was characterized by Raman spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), energy dispersive spectroscopy (EDS) and hydrogen ion potential corresponding to the zero point of charge (pHzpc). Batch adsorption experiments were performed for evaluating the effects of contact time, pH and concentration on adsorption. Moreover, the study of the adsorption equilibrium and kinetics were carried out. According to the Raman spectrum, Vulcan XC 72R showed two characteristic bands of amorphous and graphitic phase, D and G respectively. Furthermore, the intensity ratio of the two bands showed that the amorphous phase prevails. The SEM images showed a rough surface with small agglomerates uniformly distributed. TGA showed a rapid thermal decomposition, which is assigned the presence of carbon and oxygen. The elemental analysis performed by EDS confirms the TGA results. The pHPZC was found as 6.74. The Avrami kinetic model best fit the process. The Webber and Morris model indicated that the adsorption mechanism is controlled by the boundary layer effect in addition to intraparticle diffusion. The Temkim isotherm best fitted the equilibrium results and a maximum removal capacity around 64 mg g-1 at 25°C. Temperature and pH did not significantly influence the o-tolidine adsorption mechanism. According to the results, the carbon black Vulcan XC-72 R showed high potential to be used as an adsorbent material for decontamination of effluents containing the aromatic amine o-tolidine.
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Adsorção , Carbono Vulcan XC 72R , orto- tolidina , isotermas