Papers by Andre Luiz Tessaro
Molecules, 2020
β-Cyclodextrin (β-CD) is an oligosaccharide composed of seven units of D-(+)-glucopyranose joined... more β-Cyclodextrin (β-CD) is an oligosaccharide composed of seven units of D-(+)-glucopyranose joined by α-1,4 bonds, which is obtained from starch. Its singular trunk conical shape organization, with a well-defined cavity, provides an adequate environment for several types of molecules to be included. Complexation changes the properties of the guest molecules and can increase their stability and bioavailability, protecting against degradation, and reducing their volatility. Thanks to its versatility, biocompatibility, and biodegradability, β-CD is widespread in many research and industrial applications. In this review, we summarize the role of β-CD and its derivatives in the textile industry. First, we present some general physicochemical characteristics, followed by its application in the areas of dyeing, finishing, and wastewater treatment. The review covers the role of β-CD as an auxiliary agent in dyeing, and as a matrix for dye adsorption until chemical modifications are applied a...
ꞵ-Cyclodetrin (ꞵ-CD) is an oligosaccharide composed by seven units of 20 D-(+)-glucopyranose join... more ꞵ-Cyclodetrin (ꞵ-CD) is an oligosaccharide composed by seven units of 20 D-(+)-glucopyranose joined by α-1,4 bonds, which is obtained from starch. Its singular trunk 21 conical shape organization with a well-defined cavity provides an adequate environment for a 22 several types of molecules to be included. The complexation changes the properties of the guest 23 molecules increasing its stability, bioavailability, protecting against degradation, reducing its 24 volatility, etc. Thanks to its versatility, biocompatibility and biodegradability ꞵ-CD is widespread 25 in many researches and industrial applications. In this review, we summarize the role of ꞵ-CD and 26 its derivatives in the textile industry. First we present some general physicochemical characteristics 27 followed by its application in the areas of dyeing, finishing and wastewater treatment. The review 28 covers since the role of ꞵ-CD as auxiliary agent on dyeing, as matrix to dye adsorption until the 29 chemical modificat...
Química Nova, 2018
A simple and low cost experiment is proposed to chemistry students associating the Photodynamic A... more A simple and low cost experiment is proposed to chemistry students associating the Photodynamic Activity involving Chemical and Biochemical concepts. The inclusion of this experiment in undergraduate courses in Chemistry promotes interdisciplinarity and contextualization, combining current and relevant topics to the teaching of program content. The experiment used the Methylene Blue and Erythrosine B as dyes to demonstrate the photodynamic action of these photosensitizers in the inhibition of microbial growth. Both dyes presented satisfactory results against environmental microorganisms. The growth inhibition was caused exclusively by the photochemical processes undergone by the dye/light/oxygen, with LED light exposure.
One of the major problems today is the improper disposal of waste from the textile industry, espe... more One of the major problems today is the improper disposal of waste from the textile industry, especially dyes. They affect effluent characteristics and, consequently, the life there. For this reason, it is necessary to study methods of removal of this dye in order to reduce environmental impacts. In this work, hydrophilic cotton was used as adsorbent of dyes and it was studied in natura and with chemical treatment in HCl and NaOH. Adsorption was evaluated in methylene blue (MB) solutions, monitored by spectrophotometry, and with the aid of adsorption isotherms. The results indicated that treatment with NaOH is the most effective for AM adsorption, and that adsorption balance is achieved before 4 hours.
Environmental Technology
This work proposes a novel technology for environmental remediation based on mesoporous silica sp... more This work proposes a novel technology for environmental remediation based on mesoporous silica spheres, which were successfully synthesized by the solvothermal method using the cetyltrimethylammonium bromide as a structuring agent. The adsorbent was designed to remove cationic dyes at strong acidic conditions. The surface was modified by a careful thermal treatment aiming at the condensation of silanol to siloxane groups. The adsorbent was characterized by XRD, SEM, FTIR, N2 adsorption/desorption and the equilibrium technique to determine the pHpzc. The kinetic of the adsorption followed a pseudo-second-order model and the process was ruled by physical forces. The isotherms were fitted to Freundlich and Temkin models, indicating that the physisorption occurred with multilayer formation, with the interaction adsorbate-adsorbate being relevant to the whole process. The adsorption capacity was approximately 60 mg g-1 and the adsorbents performance in the fast-contact system showed removal of 65%wt. of a 93 mg L-1 methylene blue (MB) solution in a single application.
Journal of Molecular Liquids
Ciência e Engenharia de Materiais: conceitos, fundamentos e aplicação
Química Nova, 2015
Aluminum phthalocyanine chloride (AlPcCl) is a photoactive compound which has been used as a phot... more Aluminum phthalocyanine chloride (AlPcCl) is a photoactive compound which has been used as a photosensitizer (PS) in photodynamic therapy (PDT). Its spectroscopic properties have been studied in solvents of different polarities (ethanol, acetone, dimethylsulfoxide and chloroform). Its solubility has been found to decrease with increasing solvent polarity, together with full self-aggregation in aqueous solution. The binding of AlPcCl to the copolymer Pluronic TM micellar class P-123 and F-127 used as solubilizer/carriers was studied. Greater interaction between the more hydrophobic copolymer P-123 and AlPcCl was observed, besides a complex interaction profile involving different AlPcCl forms (self-aggregate/monomeric form) in the copolymers. Time-and temperature-dependent structural organization of AlPcCl in the copolymers was also observed. Thus, AlPcCl has a strong tendency to self-aggregate with increasing solvent polarity, an effect also observed in micellar media.
Journal of Photochemistry and Photobiology A: Chemistry, 2015
Química Nova
An experiment is proposed that can be included in undergraduate courses of chemistry. The subject... more An experiment is proposed that can be included in undergraduate courses of chemistry. The subject is the acidity of organic compounds, which are employed as pH indicators, particularly in acid-base titrations. The indicators used are methyl orange, bromophenol blue and bromocresol green in aqueous medium. The influence of colloidal systems on the equilibrium is evaluated by the pKa. The colloids employed are surfactants like sodium dodecyl sulfate, cetyl-trimethylammonium bromide and a polymeric non-ionic F127 (pluronics). The effect of stabilization promoted by the system on the acidic or basic structureof the indicator establishes the action mechanism of the colloid on the pKa values.
Photochemistry and Photobiology, 2015
Aluminum Chloride Phthalocyanine (AlPcCl) can be used as a photosensitizer (PS) for Photodynamic ... more Aluminum Chloride Phthalocyanine (AlPcCl) can be used as a photosensitizer (PS) for Photodynamic Inactivation of Microorganisms (PDI). The AlPcCl showed favorable characteristics for PDI due to high quantum yield of singlet oxygen (ΦΔ ) and photostability. Physicochemical properties and photodynamic inactivation of AlPcCl incorporated in polymeric micelles of tri-block copolymer (P-123 and F-127) against microorganisms Staphylococcus aureus, Escherichia coli and Candida albicans were investigated in this work. Previously, it was observed that the AlPcCl undergoes self-aggregation in F-127, while in P-123 the PS is in a monomeric form suitable for PDI. Due to the self-aggregation of AlPcCl in F-127, this formulation did not show any effect on these microorganisms. On the other hand, AlPcCl formulated in P-123 was effective against S. aureus and C. albicans and the death of microorganisms was dependent on the PS concentration and illumination time. Additionally, it was found that the values of PS concentration and illumination time to eradicate 90% of the initial population of microorganisms (IC90 and D90 , respectively) were small for the AlPcCl in P-123, showing the effectiveness of this formulation for PDI.
Química Nova, 2014
The physicochemical properties (solubilization, structural organization and stability) of meso-te... more The physicochemical properties (solubilization, structural organization and stability) of meso-tetrakis(p-methoxyphenyl)porphyrin (TMPP), a promising photosensitizer for photodynamic therapy, solubilized in polymeric micelles of tri-block copolymers Pluronic TM P-123 and F-127, were studied. The formulations obtained by the solid dispersion method led to monomerization of TMPP in these copolymers. Solubility studies showed that P-123 solubilizes double the photosensitizer than F-127. The selfaggregation phenomenon was affected by the [TMPP]/[poloxamer] ratio and medium temperature. The decrease in the temperature of these systems promoted the formation of different kinds of TMPP aggregates intrinsically connected with the structural changes occurring in the micelles.
Química Nova, 2014
ABSTRACT An experiment was proposed applying the Chemometric approach of Multivariate Analysis fo... more ABSTRACT An experiment was proposed applying the Chemometric approach of Multivariate Analysis for inclusion in undergraduate Chemistry courses to promote and expand the use of this analytical-statistical tool. The experiment entails the determination of the acid dissociation constant of dyes via UV-Vis electronic spectrophotometry. The dyes used show from simple equilibrium to very complex systems involving up to four protolytic species with high spectral overlap. The Chemometric methodology was more efficient than univariate methods. For use in classes, it is up to the teacher to decide which systems should be utilized given the time constraints and laboratory conditions.
Química Nova, 2006
Recebido em 31/1/05; aceito em 12/8/05; publicado na web em 14/3/06 THE pK a OF ACID-BASE INDICAT... more Recebido em 31/1/05; aceito em 12/8/05; publicado na web em 14/3/06 THE pK a OF ACID-BASE INDICATORS AND THE INFLUENCE OF COLLOIDAL SYSTEMS. An experiment is proposed that can be included in undergraduate courses of chemistry. The subject is the acidity of organic compounds, which are employed as pH indicators, particularly in acid-base titrations. The indicators used are methyl orange, bromophenol blue and bromocresol green in aqueous medium. The influence of colloidal systems on the equilibrium is evaluated by the pK a . The colloids employed are surfactants like sodium dodecyl sulfate, cetyl-trimethylammonium bromide and a polymeric non-ionic F127 (pluronics). The effect of stabilization promoted by the system on the acidic or basic structureof the indicator establishes the action mechanism of the colloid on the pK a values.
Química Nova, 2014
SELF-AGGREGATION OF 5,10,15,20-TETRAKIS(4-METHOXYPHENYL)PORPHYRIN (TMPP): SPECTROSCOPIC STUDIES A... more SELF-AGGREGATION OF 5,10,15,20-TETRAKIS(4-METHOXYPHENYL)PORPHYRIN (TMPP): SPECTROSCOPIC STUDIES AND MULTIVARIATE ANALYZES. In this work, the spectroscopic properties of 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin (TMPP) in solvents of different polarities and water/ethanol mixtures were studied by electronic absorption spectroscopy and resonance light scattering associated with statistical analysis. The molar absorption coefficient and emission maximum of TMPP were dependent on solvent polarity. In the water/ethanol mixture, TMPP remained monomeric up to 25% of water, when it reaches its critical aggregation percentage. Oblique head-to-tail aggregate was found at intermediate water content (35 -55%), while formation of a J-type aggregate was observed at higher water content (> 60%).
Química Nova, 2013
Recebido em 27/4/12; aceito em 7/8/12; publicado na web em 28/11/12 CHEMOMETRIC STUDIES OF PHEO F... more Recebido em 27/4/12; aceito em 7/8/12; publicado na web em 28/11/12 CHEMOMETRIC STUDIES OF PHEO FORMULATED IN PLURONICS ® : PHOTODYNAMIC ACTION AGAINST Artemia salina. The self-aggregation of pheophytin, a possible photosensitizer for Photodynamic Therapy, is solved by formulation in polymeric surfactant as P-123. The photosensitizer incorporation was found to be time dependent, exhibiting two steps: a partition at the micellar interface followed by an incorporation into the micelle core. The photodynamic efficiency of the formulation was tested by the bioassays against Artemia salina. In order to evaluate how the experimental parameters: pheophytin concentration, P-123 percentage and illumination time influenced the death of artemia, the factorial design 2 3 was chosen. The illumination time was found to be the main factor contributing to the mortality of artemia.
Química Nova, 2006
Recebido em 24/5/05; aceito em 5/10/05; publicado na web em 31/3/06 A SIMPLE APPARATUS TO FOLLOW ... more Recebido em 24/5/05; aceito em 5/10/05; publicado na web em 31/3/06 A SIMPLE APPARATUS TO FOLLOW RAPID REACTIONS: A LOW-COST STOPPED-FLOW. The modern stopped-flow reaction analyzer has shown high efficiency and flexibility, which provides outstanding sample economy with a dead-time of less than 1 ms. However the cost of the equipment imposes a serious restriction to many Brazilian scientists and teachers. In this work we describe the construction of a low-cost stopped-flow system coupled to a UV-Vis spectrophotometer. The performance of the system was checked by monitoring the kinetics of two reactions: the fading of phenolphthalein in aqueous alkaline solution and the chlorophyll a demetallation in acid medium. The apparatus showed reasonable efficiency with a dead-time of 0.3 to 0.5 s. The very good results obtained in these two illustrative processes show that the system is satisfactory for determining rate constants with mean reaction times ranging from seconds to minutes.
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Papers by Andre Luiz Tessaro