Publications

Abstract Activated carbon modified by phosphoric acid noted CAa was successfully used as a new low-cost adsorbent for removing Cu2+, Ni2+ and Cr6+ metal ions from artificially contaminated aqueous solutions. Experiments were performed in batches for adsorption kinetics and isotherms. Scanning electron microscope (SEM) observations as well as a nitrogen adsorption-desorption BET surface area measurement showed the formation of mesoporous CAa with an average pore size of 3.1 nm and a surface area of ABET = 678.74 m(2) g(-1). The adsorption data for Cu2+, Ni2+ and Cr6+ fitted well with Langmuir adsorption model with maximum adsorbed amount of 238.10 mg g(-1) for Cu(II), 80.64 mg g(-1) for Ni(II) and 125 mg g(-1) of Cr(VI) with the maximal amount measured by N-2 adsorption of 231.5337 cm(3) g(-1) STP. The experimental variables studied were pH, temperature, amount of biomass and initial ion concentration. Maximum biosorption was observed for pH = 2. The adsorption capacity seems to be optimized by increasing the temperature, the amount of biosorbent and the initial concentration. Isotherm adsorptions are in agreement with Langmuir models. The calculated changes in adsorption free energy (Delta G degrees), enthalpy (Delta H degrees) and entropy (Delta S degrees) confirm that the present adsorption process is a favorable, endothermic and spontaneous phenomenon.

Abstract American trypanosomiasis or Chagas disease is caused by the protozoan parasite Trypanosoma cruzi, and is considered a neglected disease, being an important problem for public health. Benznidazole (BZN) is the drug used to treat the disease. However, it has limited efficacy and adverse side effects. Therefore, the development of new therapeutic alternatives is necessary. In this work, the trypanocidal activity and cytotoxicity of a series of catechol-containing 3-arylcoumarins, their combination with BZN, and the inclusion in β-cyclodextrins (β-CDs), were evaluated. The results obtained showed that the entire series has moderate trypanocidal activity on the trypomastigote form of the parasite, being the 3-(4′-bromophenyl)-6,7-dihydroxycoumarin (8) the most active compound (IC50 = 34 μM) and the most cytotoxic in Vero cells (IC50 = 162 μM) as well. By forming the inclusion complex 8-β-CDs, the trypanocidal activity and cytotoxicity decreased. In addition, the formation of inclusion complexes increased the solubility. The possible mechanism of action of 8 was evaluated and proved to be through the generation of oxidative stress. The combination with BZN presented a synergistic effect on the trypanocidal activity, reducing the necessary dose of BZN. The presence of a catechol in the studied scaffold seems to modulate the trypanocidal activity, and the combination of drugs proved to be a promising alternative strategy for treating the disease. © 2021 The Authors

Abstract Superoxide anion is a reactive oxygen species (ROS) of biological interest. More specifically, it plays a role in intra- and intercellular signaling, besides being associated with conditions such as inflammation and cancer. Given this, efforts have been made by the research community to devise new sensing strategies for this ROS species. Among them, the chemiluminescent reaction of marine Coelenterazine has been employed as a sensitive and dynamic probing approach. Nevertheless, chemiluminescent reactions are typically associated with lower emissions in aqueous solutions. Herein, here we report the synthesis of a new Coelenterazine derivative with the potential for superoxide anion sensing. Namely, this novel compound is capable of chemiluminescence in a dose-dependent manner when triggered by this ROS species. More importantly, the light-emission intensities provided by this derivative were relevantly enhanced (intensities 2.13 x 10(1) to 1.11 x 10(4) times higher) in aqueous solutions at different pH conditions when compared to native Coelenterazine. The half-life of the chemiluminescent signal is also greatly increased for the derivative. Thus, a new chemiluminescence molecule with significant potential for superoxide anion sensing was discovered and reported for the first time.

Abstract Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated (OPAHs) and nitrated (NPAHs) derivatives are main chromophores of the carbonaceous aerosol brown carbon (BrC), which is linked with radiative forcing. Here, we investigated the atmospheric absorption spectra of 64 PAHs, OPAHs, and NPAHs directly over the Chinese megacity of Xi'an, by employing a time-dependent density functional theory (TD-DFT) computational approach and correcting the results for the experimentally determined atmospheric concentration of the studied molecules. The obtained data showed that these molecules contribute more to radiative forcing by absorbing light in the UVA and (sub)visible region of the spectrum. Investigating daily absorption spectra revealed major seasonal variation in the intensity of light absorption, but little changes in the shape of the absorption spectra. The observed light absorption can be explained mainly by contributions from PAHs and to a lesser extent by carbonyl-OPAHs, with relatively low contributions of the other OPAHs and NPAHs. Among them, benzo[b+j+k] fluoranthenes, benzo[e]pyrene, benzo[a]pyrene, benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, 6H-benzo[cd] pyren-6-one, 7H-benz[de]anthracen-7-one, and benz[a]anthracene-7,12-dione are highlighted as potentially problematic contributors for radiative forcing over Xi'an.

Abstract A catalytic ozonation advanced oxidation process (AOP) with a copper(II)-doped carbon dot as catalyst, Cu-CD (using L-cysteine and polyethylene glycol (PEG) as precursors and passivation agents), was developed for textile wastewater treatment (T = 25 degrees C and pH = 7). Four dyes were analyzed-Methyl Orange (MO), Orange II sodium salt (O-II), Reactive Black 5 (RB-5) and Remazol Brilliant Blue R (RBB-R), as well as a real effluent from the dying and printing industry. The Cu-CD, with marked catalytic ozonation properties, was successfully synthesized by one-pot hydrothermal procedure with a size of 4.0 nm, a charge of -3.7 mV and a fluorescent quantum yield of 31%. The discoloration of the aqueous dye solutions followed an apparent first-order kinetics with the following rate constants (k(ap) in min(-1)): MO, 0.210; O-II, 0.133; RB-5, 0.177; RBB-R, 0.086. In the presence of Cu-CD, the following apparent first-order rate constants were obtained (k(ap)(C) in min(-1)) with the corresponding increase in the rate constant without catalyst (%Inc): MO, 1.184 (464%); O-II, 1.002 (653%); RB-5, 0.709 (301%); RBB-R, 0.230 (167%). The presence of sodium chloride (at a concentration of 50 g/L) resulted in a marked increase of the discoloration rate of the dye solution due to generation of other radicals, such as chlorine and chlorine oxide, resulting from the reaction of ozone and chloride. Taking into consideration that the real textile effluent under research has a high carbonate concentration (>356 mg/L), which inhibits ozone decomposition, the discoloration first-order rate constants without and with Cu-CD (k(ap) = 0.0097 min(-1) and k(ap)(C) = 0.012 min(-1) (%Inc = 24%), respectively) were relatively small. Apparently, the Cu-CD, the surface of which is covered by a soft and highly hydrated caramelized PEG coating, accelerates the ozone decomposition and dye adsorption, increasing its degradation.

Abstract Charge (ion and electron)-transfer reactions at a liquid/ liquid interface are critical processes in many important biological and chemical systems. An ion-transfer (IT) process is usually very fast, making it difficult to accurately measure its kinetic parameters. Nano-liquid/liquid interfaces supported at nanopipettes are advantageous approaches to study the kinetics of such ultrafast IT processes due to their high mass transport rate. However, correct measurements of IT kinetic parameters at nanointerfaces supported at nanopipettes are inhibited by a lack of knowledge of the nanometer-sized interface geometry, influence of the electric double layer, wall charge polarity, etc. Herein, we propose a new electrochemical characterization equation for nanopipettes and make a suggestion on the shape of a nano-water/1,2-dichloroethane (nano-W/DCE) interface based on the characterization and calculation results. A theoretical model based on the Poisson-Nernst-Planck equation was applied to systematically study how the electric double layer influences the IT process of cations (TMA(+), TEA(+), TPrA(+), ACh(+)) and anions (ClO4-, SCN-, PF6 (-), BF4-) at the nano-W/DCE interface. The relationships between the wall charge conditions and distribution of concentration and potential inside the nanopipette revealed that the measured standard rate constant (k(0)) was enhanced when the polarity of the ionic species was opposite to the pipette wall charge and reduced when the same. This work lays the right foundation to obtain the kinetics at the nano-liquid/liquid interfaces.

Abstract Matricaria chamomilla L. is a famous medicinal plant distributed worldwide. It is widely used in traditional medicine to treat all kinds of diseases, including infections, neuropsychiatric, respiratory, gastrointestinal, and liver disorders. It is also used as a sedative, antispasmodic, antiseptic, and antiemetic. In this review, reports on M. chamomilla taxonomy, botanical and ecology description, ethnomedicinal uses, phytochemistry, biological and pharmacological properties, possible application in different industries, and encapsulation were critically gathered and summarized. Scientific search engines such as Web of Science, PubMed, Wiley Online, SpringerLink, ScienceDirect, Scopus, and Google Scholar were used to gather data on M. chamomilla. The phytochemistry composition of essential oils and extracts of M. chamomilla has been widely analyzed, showing that the plant contains over 120 constituents. Essential oils are generally composed of terpenoids, such as alpha-bisabolol and its oxides A and B, bisabolone oxide A, chamazulene, and beta-farnesene, among other compounds. On the other hand, M. chamomilla extracts were dominated by phenolic compounds, including phenolic acids, flavonoids, and coumarins. In addition, M. chamomilla demonstrated several biological properties such as antioxidant, antibacterial, antifungal, anti-parasitic, insecticidal, anti-diabetic, anti-cancer, and anti-inflammatory effects. These activities allow the application of M. chamomilla in the medicinal and veterinary field, food preservation, phytosanitary control, and as a surfactant and anti-corrosive agent. Finally, the encapsulation of M. chamomilla essential oils or extracts allows the enhancement of its biological activities and improvement of its applications. According to the findings, the pharmacological activities of M. chamomilla confirm its traditional uses. Indeed, M. chamomilla essential oils and extracts showed interesting antioxidant, antibacterial, antifungal, anticancer, antidiabetic, antiparasitic, anti-inflammatory, anti-depressant, anti-pyretic, anti-allergic, and analgesic activities. Moreover, the most important application of M. chamomilla was in the medicinal field on animals and humans.

Abstract Lipid nanoparticles (LN) composed of biodegradable lipids and produced by green methods are candidates for the encapsulation of pesticides, potentially contributing to decreasing their release in the environment. From a safety-by-design concept, this work proposes LN for the encapsulation of insecticide active ingredients (AI). However, given the complexity of nanoparticles, ecotoxicological studies are often controversial, and a detailed investigation of their effects on the environment is required. Accordingly, this work aimed to produce and characterize LN containing the insecticide lambda-cyhalothrin (LC) and evaluate their safety to crops (Solanum lycopersicum and Zea mays), soil invertebrates (Folsomia candida and Eisenia fetida), and soil microbial parameters. The average particle size for LN-loaded with LC (LN-LC) was 165.4 +/- 2.34 nm, with narrow size distribution and negative charge (-38.7 +/- 0.954 mV). LN were able to encapsulate LC with an entrapment efficacy of 98.44 +/- 0.04%, maintaining the stability for at least 4 months. The LN-LC showed no risk to the growth of crops and reproduction of the invertebrates. The effect on microbial parameters showed that the activity of certain soil microbial parameters can be inhibited or stimulated by the presence of LN at highest concentrations, probably by changing the pH of soil or by the intrinsic properties of LN.

Abstract Carbon dots (CDs) are carbon-based nanomaterials with remarkable properties that can be produced from a wide variety of synthesis routes. Given that standard bottom-up procedures are typically associated with low synthesis yields, different authors have been trying to devise alternative high-yield fabrication strategies. However, there is a doubt if sustainability-wise, the latter should be really preferred to the former. Herein, we employed a Life Cycle Assessment (LCA) approach to compare and understand the environmental impacts of high-yield and standard bottom-up strategies, by applying different life cycle impact assessment (LCIA) methods. These routes were: (1) production of hydrochar, via the hydrothermal treatment of carbon precursors, and its alkaline peroxide treatment into high-yield CDs; (2) microwave treatment of carbon precursors doped with ethylenediamine; (3) and (6) thermal treatment of carbon precursor and urea; (4) hydrothermal treatment of carbon precursor and urea; (5) microwave treatment of carbon precursor and urea. For this LCA, four LCIA methods were used: ReCiPe, Greenhouse Gas Protocol, AWARE, and USEtox. Results identified CD-5 as the most sustainable synthesis in ReCiPe, Greenhouse Gas Protocol, and USEtox. On the other hand, in AWARE, the most sustainable synthesis was CD-1. It was possible to conclude that, in general, high-yield synthesis (CD-1) was not more sustainable than standard bottom-up synthesis, such as CD-5 and CD-6 (also with relatively high-yield). More importantly, high-yield synthesis (CD-1) did not generate much lower environmental impacts than standard approaches with low yields, which indicates that higher yields come with relevant environmental costs.