Navegando por Autor "Santos, Lucas de Azevedo"
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Item Experimental and theoretical studies of solvent polarity influence on the preparation of molecularly imprinted polymers for the removal of estradiol from water.(2019) Xavier, Leandro Pablo dos Santos; Dias, Ana Carolina; Baeta, Bruno Eduardo Lobo; Santos, Lucas de Azevedo; Ramalho, Teodorico de Castro; Aquino, Sergio Francisco de; Silva, Adilson Cândido daThe aim of this work was to study the synthesis of molecularly imprinted polymers (MIPs) for the selective adsorption of b-estradiol (E2). For this, six solvents with different polarities were tested and the results indicated that, for obtaining a good E2 adsorbent, the solvent should be moderately polar to favor the formation of a monomer–template complex during the synthesis. Synthesis with acetonitrile (ACN) or a mixture of chloroform (CFM) and dimethylsulfoxide (DMSO) 1 : 1 led to higher E2 adsorption capacities (from 26 to 37 mg g1). The use of MIP-CFM:DMSO resulted in better results than that of MIP-ACN relative to their NIPs (about 3 times more for CFM:DMSO, compared to 1.5 times for ACN) for the adsorption capacities. This can be explained by the fact that ACN is a porogen solvent, which on one hand increased the area of the adsorbent material but on the other reduced its selectivity towards E2 adsorption.Item Molecularly imprinted polymers for selective adsorption of quinoline : theoretical and experimental studies.(2018) Martínez Saavedra, Liz Nayibe; Penido, Ricardo Gonçalves; Santos, Lucas de Azevedo; Ramalho, Teodorico de Castro; Baeta, Bruno Eduardo Lobo; Pereira, Márcio César; Silva, Adilson Cândido daThe effects of solvent on the synthesis of molecularly imprinted polymers (MIPs) for the selective adsorption of quinoline were evaluated in this work. The MIPs were synthesized by the “bulk” method using the quinoline molecule (IQ) as a template in different solvents, such as toluene (MIPT) and chloroform (MIPC). The adsorbents were characterized by thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and N2 adsorption/desorption measurements. The influences of time, adsorbate concentration, and temperature on the adsorption of quinoline by MIPT and MIPC were evaluated. Maximum adsorption capacities (qe) of 35.23 and 24.10 mg g−1 were obtained for MIPT and MIPC, respectively. Thermodynamic studies indicate that occur physisorption and a spontaneous process (ΔadsG° < 0) entropically directed. Finally, the highest selectivity and reusability of MIPC for quinoline adsorption was ascribed to the better interaction between the chloroform and monomer, which favors the formation of porous adsorbents with higher numbers of adsorption sites.