Artigos - Química Analítica - IQ

URI Permanente para esta coleçãohttps://hdl.handle.net/11449/25683

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Contribution of CuO on lamellar BiVO4/Bi2O3-based semiconductor for photoconversion of CO2
(2023-10-01) Corradini, Patricia Gon ; Brito, Juliana Ferreira de ; Blaskievicz, Sirlon F ; Salvati, Byanca S ; Menezes, Beatriz Costa e Silva ; Zanoni, Maria Valnice Boldrin ; Mascaro, Lucia Helena ; Universidade Federal de São Carlos (UFSCar) ; Science and Technology ; Universidade Estadual Paulista (UNESP)
Lamellar BiVO4 is a photocatalyst recognized as an effective visible-light-driven semiconductor that is active in CO2 reduction but faces challenges such as high recombination rate and low mobility of photogenerated charge carriers. Additionaly, CuXO are well-known materials for CO2 photosynthesis, and Bi2O3 improves the generation of organic compounds from CO2 reduction with more than one carbon. In this sense, this paper evaluates the influence of small amounts of copper oxide on lamellar BiVO4-Bi2O3 prepared by a microwave-assisted route on the CO2 photoreduction activity. Lamellar BiVO4-Bi2O3 powder catalysts modified by different percentages of CuO were synthesized using microwave heating at 140 °C and 1200 rpm for 15 min. Electrochemical and photochemical characterizations showed that small amounts of copper, such as 1.0%, enhanced the absorption of visible light, improved charge transfer, mitigated charge recombination, and increased the yield of products (acetone and methanol). Furthermore, the flat band potential of the catalyst modified with 1.0% of copper was located at a more negative potential than the unmodified sample, which favored the photocatalytic reduction of the CO2. As a result, the study achieved a 38-fold improvement in methanol generation (1373.5 µmol L−1 gcat−1) and a 62% increase in acetone formation (12.5 µmol L−1 gcat−1) under UV–Vis light incidence over 2 h of reaction at ambient pressure and temperature, compared to pure BiVO4 (36.3 µmol L−1 gcat−1 of methanol and 7.7 µmol L−1 gcat−1 of acetone).
Electrochemical sensor based on carbon nanotube decorated with manganese oxide nanoparticles for naphthalene determination
(2023-01-01) Alves, Ismael Carlos Braga ; dos Santos, José Ribamar Nascimento ; Marques, Edmar Pereira ; Sousa, Janyeid Karla Castro ; Beluomini, Maísa Azevedo ; Stradiotto, Nelson Ramos ; Marques, Aldaléa Lopes Brandes ; Federal University of Maranhão (UFMA) ; Universidade Estadual Paulista (UNESP)
In this work, an electrochemical sensor was developed for the determination of naphthalene (NaP) in well water samples, based on a glass carbon electrode (GCE) modified as a nanocomposite of manganese oxides (MnOx) and COOH-functionalized multi-walled carbon nanotubes (MWCNT). The synthesis of MnOx nanoparticles was performed by the sol–gel method. The nanocomposite was obtained by mixing MnOx and MWCNT with the aid of ultrasound, followed by stirring for 24 h. Surface modification facilitated the electron transfer process through the MnOx/MWCNT/GCE composite, which was used as an electrochemical sensor. The sensor and its material were characterized by cyclic voltammetry (CV), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Important parameters influencing electrochemical sensor performance (pH, composite ratios) were investigated and optimized. The MnOx/MWCNT/GCE sensor showed a wide linear range of 2.0–16.0 μM, a detection limit of 0.5 μM and a quantification limit of 1.8 μM, in addition to satisfactory repeatability (RSD of 7.8%) and stability (900 s) in the determination of NaP. The determination of NaP in a sample of water from a gas station well using the proposed sensor showed results with recovery between 98.1 and 103.3%. The results obtained suggest that the MnOx/MWCNT/GCE electrode has great potential for application in the detection of NaP in well water. Graphical abstract: [Figure not available: see fulltext.]
Designing Highly Photoactive Hybrid Aerogels for In-Flow Photocatalytic Contaminant Removal Using Silica-Coated Bacterial Nanocellulose Supports
(2023-05-17) Almeida da Silva, Thaís Caroline ; Marchiori, Leonardo ; Oliveira Mattos, Bianca ; Ullah, Sajjad ; Barud, Hernane da Silva ; Romano Domeneguetti, Rafael ; Rojas-Mantilla, Hernán Dario ; Boldrin Zanoni, Maria Valnice ; Rodrigues-Filho, Ubirajara Pereira ; Ferreira-Neto, Elias Paiva ; Ribeiro, Sidney José Lima ; Universidade Estadual Paulista (UNESP) ; Universidade de São Paulo (USP) ; University of Peshawar─UOP ; University of Araraquara─UNIARA ; Universidade Federal de Santa Catarina (UFSC)
This study explores the use of silica-coated bacterial nanocellulose (BC) scaffolds with bulk macroscopic yet nanometric internal pores/structures as functional supports for high surface area titania aerogel photocatalysts to design flexible, self-standing, porous, and recyclable BC@SiO2-TiO2 hybrid organic-inorganic aerogel membranes for effective in-flow photo-assisted removal of organic pollutants. The hybrid aerogels were prepared by sequential sol-gel deposition of the SiO2 layer over BC, followed by coating of the resulting BC@SiO2 membranes with a porous titania aerogel overlayer of high surface area using epoxide-driven gelation, hydrothermal crystallization, and subsequent supercritical drying. The silica interlayer between the nanocellulose biopolymer scaffold and the titania photocatalyst was found to greatly influence the structure and composition, particularly the TiO2 loading, of the prepared hybrid aerogel membranes, allowing the development of photochemically stable aerogel materials with increased surface area/pore volume and higher photocatalytic activity. The optimized BC@SiO2-TiO2 hybrid aerogel showed up to 12 times faster in-flow photocatalytic removal of methylene blue dye from aqueous solution in comparison with bare BC/TiO2 aerogels and outperformed most of the supported-titania materials reported earlier. Moreover, the developed hybrid aerogels were successfully employed to remove sertraline drug, a model emergent contaminant, from aqueous solution, thus further demonstrating their potential for water purification.
Simultaneous disinfection of urban wastewater and antibiotics degradation mediated by CuMgFe-B(OH)4 layered double hydroxide with different oxidizing agents
(2023-06-15) de Melo Costa-Serge, Nayara ; Li, Chan ; Fernandes Pupo Nogueira, Raquel ; Chiron, Serge ; Universidade Estadual Paulista (UNESP) ; IRD
The activation of peroxymonosulfate (PMS), peroxydisulfate (PDS) and hydrogen peroxide (H2O2) by CuMgFe-B(OH)4 layered double hydroxide (LDH) was investigated for the degradation of selected antibiotics (i.e., sulfamethoxazole, ciprofloxacin, cephalexin and amoxicillin) and for bacterial disinfection (Escherichia coli and Enterococcus faecalis) in secondary treated urban wastewater in dark condition. The catalyst synthesized behaved differently according to the oxidants used. H2O2 activated system was efficient for disinfection but not for antibiotics degradation due to the formation of complexes between LDH cations and H2O2. PDS activated system relied on a non-radical pathway mostly involving singlet oxygen and Cu(III) with antibiotics removal but with a disinfection capacity limited to E. coli. The comparison of the investigated systems for the removal of SMX in the secondary treated urban wastewater (STWW) showed 18% and 48% of SMX removal after 120 min of reaction with H2O2 and PDS, respectively. On the other hand, with PMS, SMX was below detection limit after 20 min of reaction, demonstrating the superior performance of LDH/PMS for the treatment of STWW. Furthermore, PMS activated with LDH provided > 90% removal of all antibiotics after 120 min and complete inactivation of the pathogens using 0.5 g L-1 of LDH and 4 mM of PMS.
Photobioelectrocatalysis of Intact Photosynthetic Bacteria Exposed to Dinitrophenol
(2023-01-01) de Moura Torquato, Lilian Danielle ; Matteucci, Rosa Maria ; Stufano, Paolo ; Vona, Danilo ; Farinola, Gianluca M. ; Trotta, Massimo ; Boldrin Zanoni, Maria Valnice ; Grattieri, Matteo ; Università degli Studi di Bari “Aldo Moro” ; Universidade Estadual Paulista (UNESP) ; Institute of Nanotechnology Consiglio Nazionale delle Ricerche ; IPCF-CNR Istituto per i Processi Chimico Fisici Consiglio Nazionale delle Ricerche
The outstanding metabolic versatility of purple non-sulphur bacteria makes these organisms an ideal candidate for developing photobioelectrochemical systems applicable in contaminated environments. Here, the effects of 2,4 dinitrophenol, a common contaminant, on purple bacteria photobioelectrocatalysis were investigated. The aromatic contaminant clearly affects current generation, with an enhanced photocurrent obtained at low dinitrophenol concentrations (0.5–1 μM), while higher values (up to 100 μM) resulted in a gradual decrease of photocurrent. The obtained electrochemical evidence, coupled to spectroscopic studies, allowed verifying the viability of the bacteria cells after exposure to dinitrophenol, and that no alteration of the photosynthetic apparatus was obtained. The results indicate that high dinitrophenol concentrations divert electrons from the extracellular electron pathway to an alternative electron sink. The present results open the door to the possible use of intact bacteria-based photoelectrodes to develop technologies for sustainable biosensors with simultaneous environmental remediation.
Sensing Materials: UV/Vis-Based Optical Sensors for Gaseous and Volatile Analytes
(2022-01-01) Barreto, Diandra Nunes ; Conrado, Josiele Aparecida Magalhães ; Lamarca, Rafaela Silva ; Batista, Alex Domingues ; Cardoso, Arnaldo Alves ; Lima Gomes, Paulo Clairmont F. de ; da Silveira Petruci, João Flávio ; Universidade Federal de Uberlândia (UFU) ; Universidade Estadual Paulista (UNESP)
Quantification of chemical compounds in the gas phase is essential in many different scenarios, such as the monitoring of gaseous analytes in environmental, clinical, and industrial samples, as well as the detection of volatile species from liquid or solid samples. The broad range of applications demands the development of versatile yet portable sensors devices featuring fast response, suitable sensitivity and selectivity, and accuracy. Optical sensors based on ultraviolet and visible radiation are an excellent alternative to fulfill such requirements. In this chapter, a variety of approaches for the determination of gaseous or volatiles species will be discussed.
Photoelectrocatalytic CO2 reduction
(2022-01-01) Brito, Juliana Ferreira de ; Bessegato, Guilherme Garcia ; Zanoni, Maria Valnice Boldrin ; Universidade Federal de São Carlos (UFSCar) ; Universidade Estadual Paulista (UNESP) ; Western Paraná State University (Unioeste)
Reuse or conversion of CO2 using economical and simple methods is one of the greatest challenges of this century. The present work aims to show how photoelectrocatalysis has gained attention in this field. A critical analysis is carried out identifying the best materials able to promote the conversion of CO2 to products with higher added value like hydrocarbon fuels by coupling light irradiation and bias potential. The high performance of different kinds of semiconductors and the best materials combinations are also revisited showing as photoelectrocatalysis enhances the process efficiency and can work hours without a decrease in the production of the different compounds obtained from the reduction of CO2. This chapter shows an overlook about the historic evolution and performance of semiconductors used for the photoelectrocatalytic (PEC) reduction of CO2 and their role on the type of synthesized products.
A Novel Synthesis of a Magnetic Porous Imprinted Polymer by Polyol Method Coupled with Electrochemical Biomimetic Sensor for the Detection of Folate in Food Samples
(2022-11-01) Khan, Sabir ; Wong, Ademar ; Rychlik, Michael ; Sotomayor, María del Pilar Taboada ; Federal Rural University of the Semi-Arid ; Universidade Estadual Paulista (UNESP) ; Technical University of Munich ; Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM)
The present study reports the development and application of a novel, sensitive, and selective voltammetric sensor for the quantitation of folate or vitamin B9 in foodstuffs. The sensor was made from magnetic molecularly imprinted polymers (MMIPs), which were synthesized by the core–shell method using magnetite nanoparticles obtained by the polyol method. The MMIP-based sensor was used for the selective and specific detection of folate in different food samples. The MMIP material was constructed using magnetic water-dispersible nanomaterial, which was prepared by immersing iron (III) acetylacetonate in tri-ethylene-glycol (TEG) solvent. The magnetic water-dispersible nanomaterial was then subjected to polymerization using allyl alcohol as a functional monomer, ethylene-glycol-dimethacrylate (EGDMA) as a cross-linking agent, and 2,2-Azobisisobutyronitrile (AIBN) as a radical initiator. The proposed magnetic materials were characterized by Brunauer–Emmett–Teller (BET), field emission gun scanning electron microscopy (FEG-SEM), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM) analysis. The quantification of folate was performed by square wave voltammetry under optimized conditions using 15 mg of MMIPs and 85 mg of carbon paste. The modified electrode presented a linear dynamic range (LDR) of 2.0–12 µmol L−1 and a limit of detection (LOD) of 1.0 × 10−7 mol L−1 in 0.1 mol L−1 acetate buffer solution (pH 4.0). The proposed sensor was successfully applied for folate detection in different food samples, where recovery percentages ranging from 93 to 103% were obtained. Finally, the results obtained from the analysis of selectivity showed that the modified biomimetic sensor is highly efficient for folate determination in real food samples. Adsorption tests were used to evaluate and compare the efficiency of the MMIPs and magnetic non-molecularly imprinted polymer (MNIPs)—used as control material, through the application of HPLC as a standard method.
Self-Supported Biopolymeric Films Based on Onion Bulb (Allium cepa L.): Gamma-Radiation Effects in Sterilizing Doses
(2023-02-01) da Costa Borges, Marco Antonio ; Sorigotti, Amanda Rinaldi ; Paschoalin, Rafaella Takehara ; Júnior, José Alberto Paris ; da Silva, Lucas Henrique Domingos ; Dias, Diógenes Santos ; Ribeiro, Clóvis Augusto ; de Araújo, Elmo Silvano ; Resende, Flávia Aparecida ; da Silva Barud, Hernane ; University of Araraquara (UNIARA) ; Universidade Federal de São Carlos (UFSCar) ; Biosmart Nanotechnology ; Universidade Estadual Paulista (UNESP) ; Universidade Federal de Pernambuco (UFPE)
Sterilization is a fundamental step to eliminate microorganisms prior to the application of products, especially in the food and medical industries. γ-irradiation is one of the most recommended and effective methods used for sterilization, but its effect on the properties and performance of bio-based polymers is negligible. This work is aimed at evaluating the influence of γ-radiation at doses of 5, 10, 15, 25, 30, and 40 kGy on the morphology, properties, and performance of bioplastic produced from onion bulb (Allium cepa L.), using two hydrothermal synthesis procedures. These procedures differ in whether the product is washed or not after bioplastic synthesis, and are referred to as the unwashed hydrothermally treated pulp (HTP) and washed hydrothermally treated pulp (W-HTP). The morphological analysis indicated that the film surfaces became progressively rougher and more irregular for doses above 25 kGy, which increases their hydrophobicity, especially for the W-HTP samples. In addition, the FTIR and XRD results indicated that irradiation changed the structural and chemical groups of the samples. There was an increase in the crystallinity index and a predominance of the interaction of radiation with the hydroxyl groups—more susceptible to the oxidative effect—besides the cleavage of chemical bonds depending on the γ-radiation dose. The presence of soluble carbohydrates influenced the mechanical behavior of the samples, in which HTP is more ductile than W-HTP, but γ-radiation did not cause a change in mechanical properties proportionally to the dose. For W-HTP, films there was no mutagenicity or cytotoxicity—even after γ-irradiation at higher doses. In conclusion, the properties of onion-based films varied significantly with the γ-radiation dose. The films were also affected differently by radiation, depending on their chemical composition and the change induced by washing, which influences their use in food packaging or biomedical devices.
Microwave-assisted hydrothermal synthesis of Sn3O4 and SnO for electrocatalytic reduction of CO2 to high-added-value compounds
(2023-02-01) Romeiro, Fernanda da Costa ; Martins, Alysson Stefan ; Perini, João Angelo Lima ; Silva, Beatriz Costa e ; Zanoni, Maria Valnice Boldrin ; Orlandi, Marcelo Ornaghi ; Universidade Estadual Paulista (UNESP)
Sn-based electrocatalysts have recently been applied for CO2 reduction to generate fuels. Here, tin oxide crossed architectures (SnO) and petal-like Sn3O4 semiconductors were synthesized using the microwave-assisted hydrothermal method. The synthesized materials were applied in electrochemical reduction of CO2 and promoted the formation of methanol, ethanol and acetone. The best condition (greatest amount of products) was obtained with − 0.5 V vs Ag/AgCl for both electrocatalysts. For the first time, acetone formation was observed using both SnO and Sn3O4 materials. The SnO electrocatalyst exhibited the best electrochemical activity for CO2 reduction, ascribed to higher charge transfer corroborated by the higher current densities and lower resistance in the Nyquist diagram. Differences in methanol concentration obtained by the samples were ascribed to the different morphology and charge transfer over the films. The results showed that Sn-based electrocatalysts can be applied to generate important products, such as methanol and ethanol, aside from promoting acetone formation. Graphical Abstract: [Figure not available: see fulltext.].
Closed-Vessel Conductively Heated Digestion System for the Elemental Analysis of Agricultural Materials by High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS)
(2023-01-01) Traversa, Leonardo Clemente ; Santiago, João Victor Biagi ; de Oliveira, Evilim Martinez ; Ferreira, Edilene Cristina ; Virgilio, Alex ; Gomes Neto, José Anchieta ; Universidade Estadual Paulista (UNESP) ; Universidade de São Paulo (USP)
Novel applications of the closed-vessel conductively heated digestion system (CHDS) are proposed to digest biomass, biochar, oyster shell flour, bone meal and swine manure for the determination of Ca, K, Mg, Na, Cu, Fe, Mn, and Zn by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). The performance of the digestion method using 14 and 7 mol L−1 HNO3 was checked by analyzing soil, rock, and plant certified reference materials (CRMs). For comparative purposes, all samples were analyzed after microwave-assisted digestion (MW-AD). Results obtained for most analytes by the closed-vessel conductively heated digestion system (CHDS) were in agreement with certified values and those attained by the comparative digestion method. The use of 7 mol L−1 HNO3 furnished lower blanks for most analytes and was effective to prepare challenging samples as biomass, biochar, shell and bone meal, swine manure, plants, soil, phosphate rock, and may be a good alternative for elemental determinations using most analytical techniques that rely on solution-based sample introduction systems. The detection limits (dry basis, mg kg−1) for Ca, Cu, Fe, K, Mg, Mn, Na, and Zn were 3, 0.4, 4, 4, 0.7, 0.4, 3, and 2, respectively. The mean relative standard deviations were close to 4.9% for closed-vessel conductively heated digestion (CHDS) and 5.9% for microwave-assisted digestion (MW-AD).
Disposable three-dimensional graphene oxide electrode with sandwich-like architecture for the determination of ascorbic acid in fruit juices
(2023-06-01) Buffon, Edervaldo ; Stradiotto, Nelson Ramos ; Universidade Estadual Paulista (UNESP)
This work reports the development of a three-dimensional graphene oxide structure on the screen-printed electrode surface for the detection of ascorbic acid. This electrode was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, RAMAN spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The present work also investigated the electrochemical behavior of ascorbic acid and its electrooxidation mechanism on the three-dimensional graphene oxide surface. The detection of ascorbic acid was conducted by linear scanning voltammetry in the concentration range from 1.0 × 10−5 to 1.0 × 10−2 mol L−1, and the limits of detection and quantification obtained for the proposed electrode were 3.4 × 10−6 and 1.1 × 10−5 mol L−1 (n = 3), respectively. The device also exhibited excellent selectivity, repeatability, reproducibility and stability. The methodology developed was applied for the determination of ascorbic acid in grape and orange juice samples with an accuracy rate ranging from 99% to 105%. These results show that the proposed electrode can be safely and reliably applied for the monitoring of ascorbic acid in fruit juices.
Disposable p-coumaric acid sensor containing reduced graphene oxide, nickel nanoparticles and biodegradable molecularly imprinted polymer for fruit peel analysis
(2023-05-01) Buffon, Edervaldo ; Stradiotto, Nelson Ramos ; Universidade Estadual Paulista (UNESP)
This work reports the development of a disposable molecularly imprinted electrochemical sensor based on the electropolymerization of 3-indoleacetic acid on an electrode containing reduced graphene oxide and nickel nanoparticles for the sensitive and selective detection of p-coumaric acid. The molecularly imprinted sensor was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The obtained results showed that reduced graphene oxide and nickel nanoparticles increased the sensitivity of the sensor for selective recognition of p-coumaric acid. Under optimal conditions, the developed sensor presented linear concentration ranges from 1.0 × 10−10 to 1.0 × 10−8 mol L−1. The detection and quantification limits calculated for this sensor were 8.1 × 10−11 and 2.7 × 10−10 mol L−1, respectively. The proposed device exhibited excellent selectivity, repeatability and stability over time, as well as good accuracy for the detection of p-coumaric acid. As a proof of concept, the sensor was applied for the determination of this molecule in banana and orange peels. The mean recovery values obtained during the analyses ranged from 96% to 102%, with relative standard deviations of ≤ 4.8%.
Polymer of intrinsic microporosity (PIM-1) enhances hydrogen peroxide production at Gii-Sens graphene foam electrodes
(2022-10-01) Azevedo Beluomini, Maisa ; Wang, Yu ; Wang, Lina ; Carta, Mariolino ; McKeown, Neil B. ; Wikeley, Simon M. ; James, Tony D. ; Lozano-Sanchez, Pablo ; Caffio, Marco ; Ramos Stradiotto, Nelson ; Valnice Boldrin Zanoni, Maria ; Marken, Frank ; University of Bath ; Universidade Estadual Paulista (UNESP) ; Zhengzhou University ; College of Science ; University of Edinburgh ; Henan Normal University ; Euro House
3D-graphene foam electrodes (Gii-Sens) immersed in a phosphate buffer solution of pH 7 are shown to generate hydrogen peroxide at a significantly faster rate in the presence of a nanoparticulate polymer of intrinsic microporosity (PIM-1). The effect is demonstrated to be associated at least in part with oxygen binding into PIM-1 under triphasic conditions. The release of the oxygen at the electrode|solution interface quadruples H2O2 production. Generator–collector experiments are performed with a graphene foam disk generator and a platinum disk electrode collector to allow in situ detection of hydrogen peroxide and oxygen.
An Automated, Self-Powered, and Integrated Analytical Platform for On-Line and In Situ Air Quality Monitoring
(2022-11-01) da Silva Sousa, Danielle ; Leal, Vanderli Garcia ; dos Reis, Gustavo Trindade ; da Silva, Sidnei Gonçalves ; Cardoso, Arnaldo Alves ; da Silveira Petruci, João Flávio ; Universidade Federal de Uberlândia (UFU) ; Universidade Estadual Paulista (UNESP)
Air quality monitoring networks are challenging to implement due to the bulkiness and high prices of the standard instruments and the low accuracy of most of the described low-cost approaches. This paper presents a low-cost, automated, self-powered analytical platform to determine the hourly levels of O3 and NO2 in urban atmospheres. Atmospheric air was sampled at a constant airflow of 100 mL min−1 directly into vials containing 800 µL of indigotris sulfonate and the Griess–Saltzman reagent solutions for ozone and nitrogen dioxide, respectively. The analysis holder, containing a light-emitting diode and a digital light sensor, enabled the acquisition of the analytical signal on-site and immediately after the sampling time. The data were transmitted to a laptop via Bluetooth, rendering remote hourly monitoring. The platform was automated using two Arduino Uno boards and fed with a portable battery recharged with a solar panel. The method provided a limit of detection of 5 and 1 ppbv for O3 and NO2, respectively, which is below the maximum limit established by worldwide regulatory agencies. The platform was employed to determine the levels of both pollutants in the atmosphere of two Brazilian cities, in which one of them was equipped with an official air quality monitoring station. Comparing the results of both techniques revealed suitable accuracy for the proposed analytical platform. Information technology (IT) allied to reliable chemical methods demonstrated high potential to create air quality monitoring networks providing valuable information on pollutants’ emissions and ensuring safety to the population.
Molecularly imprinted polymers in hybrid materials using inorganic nanoparticles
(2020-11-02) Ruiz-Córdova, Gerson ; López, Rosario ; Vega-Chacón, Jaime ; Khan, Sabir ; Picasso, Gino ; del Pilar Taboada Sotomayor, Maria ; National University of Engineering ; Universidade Estadual Paulista (UNESP) ; Toxicological Evaluation & Removal of Micropollutants and Radioactives (INCT-DATREM)
Molecularly imprinted polymers (MIPs) have been widely implemented in the elaboration of analytical tools for the detection and separation of molecules due to their capacity of interacting specifically with target molecules. Molecular imprinting expertise is a possible synthetic route for preparing materials with mimic recognition function towards target molecules on the nanosized surface with high binding capacity and mass transfer rate. However, the MIPs could present some drawbacks, particularly, in extended washings to remove the template, related to the tedious procedures of grinding, irregular particle in size and shape and low reproducibility that would cause limit their practical applications. Inorganic nanoparticles-MIPs hybrid materials in a core-shell structure (IN-MIPs) present some features that allow overcoming the limitations of conventional MIPs. The core is composed of inorganic nanoparticles such as silica nanoparticles (SiO2), superparamagnetic iron oxide nanoparticles (SPION) and semiconductor nanoparticles, mainly quantum dots (QD). After an appropriate modification of the surface of the nanoparticles, the MIP matrix is formed around the nanoparticles and a hybrid material in a core-shell structure is obtained. This chapter reviews the recent advances in the preparation and applications of IN-MIPs. Due to the specific binding sites, the resulting IN-MIP exhibits good selectivity, reproducibility, high binding capacity and fast kinetics for the rebinding of the analyte. Additionally, this chapter summarizes the challenges and opportunities related to the suitable applications of the systems in chemical analysis (sensors), extraction of target molecules (solid-phase extraction), among others.
Precipitation polymerization
(2022-01-01) Khan, Sabir ; Vega-Chacón, Jaime ; Ruiz-Córdova, Gerson A. ; Pizan-Aquino, Charles ; Jara-Cornejo, Eduardo EJ ; Torres, Sergio Espinoza ; Jacinto-Hernández, C. ; López, Rosario ; Sotomayor, Maria D.P.T. ; Picasso, Gino ; Villa, Javier E.L. ; National University of Engineering ; Universidade Estadual Paulista (UNESP) ; Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM)
Polymerization method has become the most extended procedure of chemical synthesis, characterization of nanoparticles with novel morphology and their wide applications in separation, drug delivery via intravenous and some biological system and nanotechnology. Polymerization by precipitation is based on the development of uniform and clean polymer particles, such as microspheres, nanoparticles, core–shell particles, and hollow nanostructures. Although precipitation technique has low production efficiency, the low concentrations of the monomers maintain the stability of the particles. In this chapter, a general introduction of precipitation polymerization and their synthesis mechanisms like controlled radical precipitation polymerization, thermal, photopolymerization, accumulation, nucleation as applications is presented. The development of complex nanostructures and their applications in separation and drug delivery is highlighted as well.
Characterization of polymeric nanoparticles
(2022-01-01) Khan, Sabir ; Wong, Ademar ; Zeb, Shakeel ; Mortari, Bianca ; Villa, Javier E.L. ; Sotomayor, Maria D.P.T. ; Universidade Estadual Paulista (UNESP) ; National University of Engineering ; Federal Rural University of the Semi-Arido ; Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM)
Polymeric nanoparticles (PNPs) are solid colloidal particals ranging in size from 10 to 1000nm(1µm), and these are broadly used due to their exceptional properties and high surface areas. Polymeric-based nanoparticles competently take drugs, DNA, and proteins to their target cells or organs. Owing to their nanosize, the stability of dosage is a big issue, and it also requires excellent manufacturing skills, sophisticated technology, and also expensive industrial application. The fabricated materials are characterized by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, zeta potential, nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. Polymer nanoparticles have received increased attention worldwide due to extensive range of use in multidisciplinary fields such as analytical chemistry, physics, electronics, biopharmaceutics, and biology. This chapter covers the general elucidation of PNPs, its synthesis, characterization and its applications in pesticides, environmental, textile, medicine and other industries.
Degradation of contaminants of emerging concern in a secondary effluent using synthesized MOF-derived photoanodes: A comparative study between photo-, electro- and photoelectrocatalysis
(2023-02-01) Candia-Onfray, Christian ; Irikura, Kallyni ; Calzadilla, Wendy ; Rojas, Susana ; Boldrin Zanoni, Maria Valnice ; Salazar, Ricardo ; USACh ; Universidade Estadual Paulista (UNESP) ; Universidad de Valparaíso
Three metal-organic framework (MOF)-based photoanodes were prepared by deposition on TiO2 nanotubes using Ti as substrate (Ti/TiO2NT): i) Ti/TiO2NT-Au@ZIF-8, ii) Ti/TiO2NT-Ru3(BTC)2, iii) Ti/TiO2NT-UiO-66(Zr)NH2. These photoanodes were characterized by FEG-SEM, EDX and DRX. The analyses showed a successful modification and a high homogeneity of the different MOFs on the Ti/TiO2NT surface. The photoanodes were studied in the degradation of Contaminants of Emerging Concern (CECs) in a spiked secondary effluent from a Municipal Wastewater Treatment Plant (MWWTP). Sodium diclofenac (DCF), sulfamethazine (SMT) and carbamazepine (CBZ) were used as CECs at low concentration (200 μg/L each CEC). The samples were preconcentrated using Solid Phase Extraction (SPE) and analyzed by a HPLC-DAD system. The MOF-based photoanodes exhibited a high photoelectrochemical (PEC) activity towards the oxidation of CECs, achieving up to 50%, 70% and 80% of removal using Ti/TiO2NT-Au@ZIF-8, Ti/TiO2NT-UiO-66(Zr)NH2, Ti/TiO2NT-Ru3(BTC), respectively. The influence of the generation of hydroxyl radical was then studied. The results indicate that PEC degradation using Ti/TiO2NT-Ru3(BTC)2 and Ti/TiO2NT-UiO-66(Zr)NH2 is more affected by the concentration of the radical.
Endocrine disrupting activity in sewage sludge: Screening method, microbial succession and cost-effective strategy for detoxification
(2023-03-15) Mazzeo, Dânia Elisa C. ; Dombrowski, Andrea ; Oliveira, Flávio Andrade ; Levy, Carlos Emílio ; Oehlmann, Jörg ; Marchi, Mary Rosa R. ; Universidade Federal de São Carlos (UFSCar) ; Goethe University Frankfurt am Main ; Universidade Estadual de Campinas (UNICAMP) ; Universidade Estadual Paulista (UNESP)
Sewage sludge (SS) presents a high agronomic potential due to high concentrations of organic matter and nutrients, encouraging its recycling as a soil conditioner. However, the presence of toxic substances can preclude this use. To enable the safe disposal of this waste in agriculture, SS requires additional detoxification to decrease the environmental risks of this practice. Although some alternatives have been proposed in this sense, little attention is provided to eliminating endocrine-disrupting chemicals (EDCs). To fill this gap, this study aimed to develop effective and low-cost technology to eliminate EDCs from SS. For this, a detoxification process combining microorganisms and biostimulating agents (soil, sugarcane bagasse, and coffee grounds) was performed for 2, 4, and 6 months with aerobic and anaerobic SSs. The (anti-)estrogenic, (anti-)androgenic, retinoic-like, and dioxin-like activities of SSs samples were verified using yeast-based reporter-gene assays to prove the effectiveness of the treatments. A fractionation procedure of samples, dividing the target sample extract into several fractions according to their polarity, was conducted to decrease the matrix complexity and facilitate the identification of EDCs. A decrease in the abundance and microbial diversity of the SS samples was noted along the biostimulation with the predominance of filamentous fungal species over yeasts and gram-positive bacteria and non-fermenting rods over enterobacteria. Among the 9 EDCs quantified by LC-ESI-MS/MS, triclosan and alkylphenols presented the highest concentrations in both SS. Before detoxification, the studied SSs induced significant agonistic activity, especially at the human estrogen receptor α (hERα) and the human aryl hydrocarbon receptor (AhR). The raw anaerobic sludge also activated the androgen (hAR), retinoic acid (RARα), and retinoid X (RXRα) receptors. However, no significant endocrine-disrupting activities were observed after the SS detoxification, showing that the technology applied here efficiently eliminates receptor-mediated toxicity.

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