Biochar: a Sustainable alternative in the development of electrochemical printed platforms

Biochar is a pyrolytic material with several environmental benefits such as reducing greenhouse gas emissions, sequestering atmospheric carbon and contrasting global warming. However, nowadays, it has moved to the forefront for its conductivity and electron transfer properties, finding applications in the fabrication of electrochemical platforms. In this field, researchers have focused on low-cost biomass capable of replacing more popular and expensive carbonaceous nanomaterials (i.e., graphene, nanotubes and quantum dots) in the realization of sensitive cost-effectiveness and eco-friendly electrochemical tools. This review discusses recent developments of biochar-modified screen-printed electrodes (SPEs). Special attention has been paid to biochar's manufacturing processes, electron-donating capabilities and sensing applications. Examples of representative works are introduced to explain the distinct roles of biochar in several electro-bioanalytical strategies

Immobilized Enzyme-based Novel Biosensing System for Recognition of Toxic Elements in the Aqueous Environment

Access to secure water sources has become one of the biggest challenges for human sustainability. Climate change and associated droughts make it difficult to guarantee the usual water source and move to groundwater use or to the re-use of treated wastewater remains unviable due the lack on the capacity of monitoring water quality. Moreover, reusing treated wastewater from repositories near anthropogenic sources represents a risk of high concentrations of emerging contaminants. The strategies involve a higher risk of encountering toxic elements with a heavy burden on human and environmental health. New accessible and reliable tools are required to detect any hazard from the waterbodies in real time to ensure safe management and also to decrease mismanagement or ilegal water discharges. One of the available options is to look into enzyme-based biosensors that can detect toxic elements in the water. The proposed biosensors require sensible elements to be accessible and durable for their proper function. The present revision shows in first place, the actual need of real time monitoring due the different sources and effects of emergent pollutants. Secondly, describes how enzymes can be immobilized for its application in biosensors and the rol enzymes play as bioreceptor element in biosensing. Thirdly, describes the transduction methods that can be observed, and finally the actual application of enzyme biosensors for the detection of different toxic elements. According to the presented literature enzyme-based biosensors have been successfully applied for the detection of a wide number of pollutants reaching detection limits comparable to traditional methods such as up to 0.018 nM of mercury. Furthermore, laccase seems to be the more applied enzyme in literature, but positive results are not limited to this enzyme and other candidates have been explored showing good detection rate. Graphical Abstract: [Figure not available: see fulltext.].This research was funded by Fundación FEMSA project entitled “Unidad de respuesta rápida al monitoreo de COVID19 por agua residual” (Grant Number NA).Peer reviewe

A review of nanocomposite-modified electrochemical sensors for water quality monitoring

Electrochemical sensors play a significant role in detecting chemical ions, molecules, and pathogens in water and other applications. These sensors are sensitive, portable, fast, inexpensive, and suitable for online and in-situ measurements compared to other methods. They can provide the detection for any compound that can undergo certain transformations within a potential window. It enables applications in multiple ion detection, mainly since these sensors are primarily non-specific. In this paper, we provide a survey of electrochemical sensors for the detection of water contaminants, i.e., pesticides, nitrate, nitrite, phosphorus, water hardeners, disinfectant, and other emergent contaminants (phenol, estrogen, gallic acid etc.). We focus on the influence of surface modification of the working electrodes by carbon nanomaterials, metallic nanostructures, imprinted polymers and evaluate the corresponding sensing performance. Especially for pesticides, which are challenging and need special care, we highlight biosensors, such as enzymatic sensors, immunobiosensor, aptasensors, and biomimetic sensors. We discuss the sensors’ overall performance, especially concerning real-sample performance and the capability for actual field application

Carbon-Based Nanomaterials for (Bio)Sensors Development

Carbon-based nanomaterials have been increasingly used in sensors and biosensors design due to their advantageous intrinsic properties, which include, but are not limited to, high electrical and thermal conductivity, chemical stability, optical properties, large specific surface, biocompatibility, and easy functionalization. The most commonly applied carbonaceous nanomaterials are carbon nanotubes (single- or multi-walled nanotubes) and graphene, but promising data have been also reported for (bio)sensors based on carbon quantum dots and nanocomposites, among others. The incorporation of carbon-based nanomaterials, independent of the detection scheme and developed platform type (optical, chemical, and biological, etc.), has a major beneficial effect on the (bio)sensor sensitivity, specificity, and overall performance. As a consequence, carbon-based nanomaterials have been promoting a revolution in the field of (bio)sensors with the development of increasingly sensitive devices. This Special Issue presents original research data and review articles that focus on (experimental or theoretical) advances, challenges, and outlooks concerning the preparation, characterization, and application of carbon-based nanomaterials for (bio)sensor development

Biochar de bagaço de cana-de-açúcar : produção, caracterização e aplicação na construção de sensores e biossensores eletroquímicos para determinação de cobre, creatinina e anticorpos contra o vírus Sars-CoV-2

Orientador: Prof. Dr. Márcio Fernando BergaminiCoorientadores: Dra. Ava Gevaerd e Prof. Dr. Luiz Humberto Marcolino Jr.Tese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Química. Defesa : Curitiba, 17/03/2023Inclui referências: p. 177-192Resumo: No presente estudo, biocarvões (biochar) foram preparados a partir da pirólise do bagaço de cana-de-açúcar, variando a temperatura final do processo entre 300 e 700 °C, e parte do material produzido foi quimicamente ativada com HNO3. Nas caracterizações dos materiais, observou-se aumento da degradação com o aumento da temperatura final empregada na pirólise, além da presença de maior quantidade de grupos funcionais nos materiais produzidos sob as menores temperaturas. Verificou-se, ainda, que a ativação química resultou na oxidação e na nitração da estrutura carbonácea, aumentando, portanto, a quantidade de grupos funcionais nos materiais. Diferentes abordagens de construção de eletrodo e determinação de espécies de interesse, empregando os materiais produzidos, foram, então, investigadas. Inicialmente, os materiais foram utilizados como modificadores de eletrodos de pasta de carbono, que, por sua vez, foram aplicados na pré-concentração espontânea de íons Cu²+, seguida da determinação voltamétrica. O material BCA400 forneceu a resposta de maior intensidade de corrente de pico, comportamento que pode estar relacionado com a presença de maiores quantidades de grupos superficiais, como grupos oxigenados, conforme previamente caracterizado, favorecendo a interação com o analito. Utilizando este material como modificador e a técnica de voltametria de pulso diferencial, desenvolveu-se um método para determinação de Cu²+ em água de torneira. Estimou-se a região linear entre 1,0 e 15,0 µmol L-¹, com limite de detecção (LOD) de 0,36 µmol L-¹ e limite de quantificação de 1,09 µmol L-¹; esses parâmetros foram considerados adequados para a finalidade proposta, visto que possibilitaram a detecção e quantificação do analito, de acordo com o limite máximo estabelecido pela legislação vigente. O eletrodo contendo Cu²+ imobilizado também foi utilizado para o desenvolvimento de um método para determinação indireta de creatinina, via formação do complexo com o íon metálico e supressão do sinal voltamétrico do cobre. Neste caso, obteve-se faixa linear de trabalho na região entre 0,3 e 0,7 mmol L-¹, com LOD = 0,091 mmol L-¹ e LOQ = 0,30 mmol L-¹, valores que também foram considerados adequados para a finalidade proposta, que era a determinação do analito em amostras de urina sintética. Por fim, dispersões preparadas com os diferentes materiais foram utilizadas para modificar um eletrodo impresso de carbono, empregado como plataforma para a imobilização da proteína RBD do vírus SARS-CoV-2, via reação de ligação cruzada com EDC/NHS, para posterior aplicação na detecção de anticorpos contra o vírus em amostras de soro fortificadas. Para esta abordagem e aplicação, o material BC700 possibilitou a obtenção das respostas mais adequadas. O dispositivo construído utilizando esse carbonáceo foi capaz de diferenciar qualitativamente respostas de amostras positivas e negativas a presença do anticorpo, com base em um valor de corte de 82,3 %, em um nível de confiança de 95 %. Além disso, a plataforma foi seletiva para a detecção do analito mesmo na presença de um interferente e pode ser armazenada por até 7 dias sem perdas de performance. Sendo assim, a partir de materiais ambientalmente amigáveis, diferentes abordagens de detecção e determinação de espécies de interesse foram investigadas e a versatilidade do biochar como modificador na construção de (bio)sensores eletroquímicos foi demonstrada.Abstract: In this study, biochars were prepared from sugarcane bagasse, with pyrolysis temperature varying from 300 to 700 °C, and part of the material was chemically activated with HNO3. Materials’ characterization showed that degradation increased as the pyrolysis final temperature increased; in addition, a higher number of functional groups was observed for the materials produced under the lowest temperatures. Also, chemical activation resulted in oxidation and nitration of carbonaceous structure, increasing, therefore, the number of functional groups on the materials. Next, different approaches for electrode construction and analytes determination were investigated. First, materials were used as carbon paste electrodes modifiers, applied to spontaneous Cu²+ ions pre-concentration, followed by voltammetric determination. BCA400 material provided the most intense response for peak current, a behavior that may be related to the presence of the highest numbers of surface groups, as oxygen groups, as previously characterized, favoring its interaction with the analyte. Using this material and differential pulse voltammetry technique, a method for Cu²+ determination in tap water was developed. Linear range was estimated from 1.0 to 15.0 µmol L-¹, with limit of detection (LOD) of 0.36 µmol L-¹, and limit of quantification (LOQ) of 1.09 µmol L-¹; those parameters were considered suitable for the intended purpose, since they enabled the analyte detection and quantification, according to the maximum limit established by the current legislation. The electrode with immobilized Cu²+ was also used for developing a method for indirect creatinine determination, through complex formation with the metallic ion and suppression of copper voltammetric signal. In this case, linear working range from 0.3 to 0.7 mmol L-¹, LOD = 0.091 mmol L-¹ and LOQ = 0.30 mmol L-¹ were obtained, and also considered suitable for the intended purpose, that was analyte determination in synthetic urine samples. At last, dispersions prepared with the different materials were used to modify a screen-printed carbon electrode, employed as a platform for SARS-CoV-2 virus RBD-protein immobilization, through crosslinking reaction with EDC/NHS, for further application in detection of antibodies against the virus in spiked serum samples. For this approach, BC700 enabled the most suitable responses. The device constructed using this material was able to qualitatively differentiate responses from samples positive and negative to antibodies presence, based on a 82,3 % cutoff value, at 95 % confidence level. Additionally, the platform was selective for analyte detection even in presence of an interferent and could be stored up to 7 days without losses of its performance. Therefore, from environmentally friendly materials, different approaches for detection and determination of analytes were investigated, and biochar versatility as a modifier in electrochemical (bio)sensors construction was demonstrated

Biodegradation Technology of Organic and Inorganic Pollutants

Bioremediation technologies for environments contaminated by organic and inorganic pollutants are a major focus of researchers and scientists worldwide. The chemical control of agricultural pests and advocacy for sustainable agriculture have led to the development of new paradigms in environmental remediation. This book covers recent advances in the bioremediation technology of organic and inorganic pollutants in the environment

Evaluation of functionalized silver and silica nanoparticles for the removal of deoxyribonucleic acid conveying antibiotics resistance genes from water

Antibiotic resistance genes ARGs are recognized as a serious public health emergency linked to extensive use of antibiotics by humans and animals as a prophylactic agent that treats and prevents infections. The occurrence of high concentrations being identified in wastewater treatment plants, rivers, etc is due to untreated effluents being discharged from households, hospitals, agriculture, and pharmaceutical industries. The application of adequate treatment techniques and material for the removal of bacteria DNA conveying ARGs from the effluents before their release to the environment cannot be overemphasized. Adsorption techniques seem to be effective due to their easy design, operation, and ability to regenerate adsorbents for use without producing toxic by-products. This concept was employed for the removal of bacteria DNA conveying ARGs from simulated aqueous solution, effluents from hospital, river and WWTPs using silver and silica metallic nanoparticles. This thesis investigated the effectiveness of metallic nanoparticles containing silver AgNPs and mesoporous silica nanoparticles MSNPs as well as magnetite Fe3O4 functionalized with 4 4hydroxyphenyl 2 262-terpyridine onto their surface, for the removal of bacteria DNA conveying antibiotic resistance genes from water samples from hospitals, river, and wastewater treatment plants WWTPs. Silver nanoparticles AgNPs of different molar concentrations 0.1M, 0.5M and 1.0 M and mesoporous silica nanoparticles MSNPs adsorbents were successfully synthesized in their original states and surface functionalization achieved by incorporating magnetite Fe3O4 and 4 4 hydroxyphenyl 2 2 6 2 terpyridine on the silver AgNPs Fe3O4 and silica MSNPs TPPY surfaces respectively. Their effectiveness as adsorbent for the removal of bacteria DNA conveying ARGs from aqueous solutions and real water/wastewater samples were investigated. The DNA uptake by the as-synthesized AgNPs and MSNPs were compared to the functionalized AgNPs Fe3O4 and MSNPsTPPY by determining the adsorbents with the highest removal efficiencies. All as synthesized and functionalized adsorbents were characterized by SEM, EDX, FTIR, XRD, UV spectroscopy and PZC before the removal process. The extraction of genomic DNA from antibiotic-resistant Enterococcus faecium and Vibrio parahaemolyticus was successfully achieved via the boiling method. Antibiotic susceptibility test was conducted using the disk diffusion method before the commencement of genomic DNA extraction. Molecular characterization via gel electrophoresis confirmed the presence of resistance genes at different base pairs. Adsorption batch experiment were investigated, and the best optimum parameters were evaluated through the influence of pH, contact time, initial DNA concentration, adsorbent dose, and competitive ions for each sorption process. The rate determining step were determined by fitting kinetic models such as Natarajan and Khalaf first order, pseudo first order, pseudo second order, Elovich model to experimental data. Also, the adsorption mechanisms determining adsorption equilibrium were investigated by fitting Freundlich, Langmuir and Sips model into the experimental data. The application of AgNPsFe3O4 nanocomposite and MSNPsTPPY for the removal of bacteria DNA demonstrated much enhancement for DNA uptake than the as-synthesized AgNPs and MSNPs materials. The incorporation of magnetite and 4 4hydroxyphenyl 2 2 6 2-terpyridine onto AgNPs and MSNPs significantly enhanced the binding affinity towards the removal the bacteria DNA via strong electrostatic attraction between the active sites on the adsorbent and the negative DNA molecules. Finally, high adsorption capacities were recorded with AgNPsFe3O4 nanocomposite and MSNPsTPPY compared to AgNPs and MSNPs with chaotropic salts. The kinetic adsorption models were mostly best fitted by the pseudo-second order and Elovich models while the adsorption equilibrium was best described by Langmuir and Sips isotherm models. MSNPs with different chaotropic salts, AgNPsFe3O4 nanocomposite and MSNPsTPPY also proved its effectiveness in DNA removal not only in the simulated aqueous solution but in three different real life water samples obtained from Cofimvaba hospital, Ndevana river and Uitenhage WWTPs. High adsorption efficiencies above 90 percent were achieved during the removal of DNA in all the three real water samples. Therefore, application of these adsorbents for the removal of bacteria DNA conveying ARGs may be a promising option that would tackle the consequences of consuming ARGs infected water globally.Thesis (MSc) -- Faculty of Science and Agriculture, 202

Evaluation of functionalized silver and silica nanoparticles for the removal of deoxyribonucleic acid conveying antibiotics resistance genes from water

Antibiotic resistance genes ARGs are recognized as a serious public health emergency linked to extensive use of antibiotics by humans and animals as a prophylactic agent that treats and prevents infections. The occurrence of high concentrations being identified in wastewater treatment plants, rivers, etc is due to untreated effluents being discharged from households, hospitals, agriculture, and pharmaceutical industries. The application of adequate treatment techniques and material for the removal of bacteria DNA conveying ARGs from the effluents before their release to the environment cannot be overemphasized. Adsorption techniques seem to be effective due to their easy design, operation, and ability to regenerate adsorbents for use without producing toxic by-products. This concept was employed for the removal of bacteria DNA conveying ARGs from simulated aqueous solution, effluents from hospital, river and WWTPs using silver and silica metallic nanoparticles. This thesis investigated the effectiveness of metallic nanoparticles containing silver AgNPs and mesoporous silica nanoparticles MSNPs as well as magnetite Fe3O4 functionalized with 4 4hydroxyphenyl 2 262-terpyridine onto their surface, for the removal of bacteria DNA conveying antibiotic resistance genes from water samples from hospitals, river, and wastewater treatment plants WWTPs. Silver nanoparticles AgNPs of different molar concentrations 0.1M, 0.5M and 1.0 M and mesoporous silica nanoparticles MSNPs adsorbents were successfully synthesized in their original states and surface functionalization achieved by incorporating magnetite Fe3O4 and 4 4 hydroxyphenyl 2 2 6 2 terpyridine on the silver AgNPs Fe3O4 and silica MSNPs TPPY surfaces respectively. Their effectiveness as adsorbent for the removal of bacteria DNA conveying ARGs from aqueous solutions and real water/wastewater samples were investigated. The DNA uptake by the as-synthesized AgNPs and MSNPs were compared to the functionalized AgNPs Fe3O4 and MSNPsTPPY by determining the adsorbents with the highest removal efficiencies. All as synthesized and functionalized adsorbents were characterized by SEM, EDX, FTIR, XRD, UV spectroscopy and PZC before the removal process. The extraction of genomic DNA from antibiotic-resistant Enterococcus faecium and Vibrio parahaemolyticus was successfully achieved via the boiling method. Antibiotic susceptibility test was conducted using the disk diffusion method before the commencement of genomic DNA extraction. Molecular characterization via gel electrophoresis confirmed the presence of resistance genes at different base pairs. Adsorption batch experiment were investigated, and the best optimum parameters were evaluated through the influence of pH, contact time, initial DNA concentration, adsorbent dose, and competitive ions for each sorption process. The rate determining step were determined by fitting kinetic models such as Natarajan and Khalaf first order, pseudo first order, pseudo second order, Elovich model to experimental data. Also, the adsorption mechanisms determining adsorption equilibrium were investigated by fitting Freundlich, Langmuir and Sips model into the experimental data. The application of AgNPsFe3O4 nanocomposite and MSNPsTPPY for the removal of bacteria DNA demonstrated much enhancement for DNA uptake than the as-synthesized AgNPs and MSNPs materials. The incorporation of magnetite and 4 4hydroxyphenyl 2 2 6 2-terpyridine onto AgNPs and MSNPs significantly enhanced the binding affinity towards the removal the bacteria DNA via strong electrostatic attraction between the active sites on the adsorbent and the negative DNA molecules. Finally, high adsorption capacities were recorded with AgNPsFe3O4 nanocomposite and MSNPsTPPY compared to AgNPs and MSNPs with chaotropic salts. The kinetic adsorption models were mostly best fitted by the pseudo-second order and Elovich models while the adsorption equilibrium was best described by Langmuir and Sips isotherm models. MSNPs with different chaotropic salts, AgNPsFe3O4 nanocomposite and MSNPsTPPY also proved its effectiveness in DNA removal not only in the simulated aqueous solution but in three different real life water samples obtained from Cofimvaba hospital, Ndevana river and Uitenhage WWTPs. High adsorption efficiencies above 90 percent were achieved during the removal of DNA in all the three real water samples. Therefore, application of these adsorbents for the removal of bacteria DNA conveying ARGs may be a promising option that would tackle the consequences of consuming ARGs infected water globally.Thesis (MSc) -- Faculty of Science and Agriculture, 202