The increase in anthropogenic activity over time has led to an exponential increase in greenhouse gas emissions, especially CO2. Proftable technologies for CO2 capture and separation are conspicuous, and porous biochars derived from biomass waste can be a useful solution. Herein, we produced activated nitrogen-doped biochars for CO2 capture from corn husk waste, urea and K2CO3, named N-Bio-X (X = 600, 700, and 800 °C). N-Bio-X exhibited microporosity and different nitrogen contents and thus played an important role in the adsorption of CO2. N-Bio-700 exhibited the highest CO2 adsorption capacity, fastest adsorption kinetics and excellent stability after multiple adsorption-desorption cycles. N-Bio-600 showed excellent CO2/N2 selectivity, induced by nitrogen sites, particularly pyridinic and graphitic nitrogen. The cost-effectiveness of the raw material, coupled with its high adsorption capacity, rapid kinetics, and stable properties, provided highly promising N-doped biochars for practical implementation in CO2 capture and separations in postcombustion processes. emissions CO conspicuous solution Herein nitrogendoped doped K2CO3 KCO K NBioX N Bio X 600 700 80 °C. C °C . °C) NBio700 NBio N-Bio-70 capacity adsorptiondesorption desorption cycles NBio600 N-Bio-60 CO2N2 CON N2 CO2/N selectivity sites costeffectiveness cost effectiveness material properties Ndoped processes K2CO 60 70 8 NBio70 N-Bio-7 NBio60 N-Bio-6 CO2N 6 7 NBio7 N-Bio- NBio6 N-Bio

CO2 emissions into the atmosphere have been rapidly rising due to human activities, resulting in the escalation of global warming. To mitigate climate change, it is imperative to develop materials for CO2 capture with high CO2 capacity and low production costs. Herein, we developed a facile method to obtain adsorbents based on reduced graphene oxide (rGO) sheets, NrGO(1 – X)700, where X represents the mass of diethylenetriamine (DETA) (X = 1, 2 and 4 g) used in the preparation. The materials NrGO(1 – 1)700, NrGO (1 – 2)700, and NrGO(1 – 4)700 were obtained from graphene oxide dispersions, followed by DETA impregnation and chemical activation with K2CO3. N2 isotherms demonstrated that the materials simultaneously presented micro and mesopores with similar values of specific surface area (280.16 to 310.32 m2 g–1), pore volume (0.26 to 0.28 cm3 g–1) and pore size (3.78 to 3.80 nm). CO2 sorption experiments revealed that the material NrGO(1 – 4)700, containing the highest amount of pyridinic, graphitic, and amino nitrogen functionalities, showed the best CO2 adsorption capacity. Diffuse reflectance Fourier transformed infrared spectroscopy experiments indicated stronger solid-gas interactions for NrGO(1 – 4)700 than for the other materials. CO activities warming change costs Herein rGO (rGO sheets NrGO1 1 NrGO( X700, X700 700, 700 X)700 (DETA g preparation 1700, 1700 1)700 ( 2700, 2700 2)700 4700 4)70 dispersions K2CO3 KCO K N 280.16 28016 280 16 (280.1 31032 310 32 310.3 m g–1, g1 g–1 , 0.26 026 0 26 (0.2 028 28 0.2 cm 3.78 378 3 78 (3.7 380 80 3.8 nm. nm . nm) 4700, pyridinic graphitic functionalities solidgas solid gas X70 70 X)70 170 1)70 270 2)70 470 4)7 K2CO 280.1 2801 (280. 3103 31 310. g– 02 (0. 0. 3.7 37 7 (3. 38 8 3. X7 X)7 17 1)7 27 2)7 47 4) 280. (280 (0 (3 X) 1) 2) (28 (2

An alternating magnetic field (AMF)-stimuli responsive nanodevice based on magnetic nanoparticles (MNP) functionalized with water-soluble carboxylate-substituted pillar[5]arene (CP[5]A), namely MNP-CP[5]A, as a multiplatform for cancer treatment has been designed. MNP-CP[5]A was loaded with doxorubicin (DOX), showing a loading capacity of 9.5 mg g-1. The nanodevice demonstrated good colloidal stability, superparamagnetic behavior, and was capable to generate detectable heat in solution induced by AMF application. DOX release, monitored by ultraviolet-visible (UV-Vis) spectroscopy, was investigated by varying the temperature (37 and 45 °C) without AMF and in the presence of AMF (frequency (f) = 307 kHz, field amplitude (H) = 200 Oe, 45 °C) at pH = 7.4. Thermo-induced DOX release without AMF was 1.9% (1.8 μg mL-1) and 2.3% (3.3 μg mL-1) at 37, and 45 °C within 50 min, respectively. In an AMF DOX release increased to 5.7% (8.2 μg mL-1) within 50 min. Therefore, MNP-CP[5]A-DOX works as a chemo-hyperthermia nanodevice.

The high free fatty acids content in some vegetable oils can have a negative impact in the sustainable production of biodiesel. The previous treatment of these feedstock oils can contribute to the reduction of the process total costs as well as the environment, turning the biodiesel a more competitive in relation to the fossil diesel. The aim of this work was to adequate low cost vegetable oils to the production of biodiesel by homogeneous catalysis. The feedstock was evaluated by its acidity, by its free fatty acids content, by its saponification index and its specific mass. The Biodiesel produced was characterized by high performance liquid chromatography. The results showed significant free fatty acids and humidity content, which are the main factors in the raising of the production costs. The results also showed that the esterification of the vegetable oils reduced its acidity in about 99%. The transesterification of the Brazilian nut oil previously esterified yields about 98% of biodiesel. Even though the biodiesel processing presents an alternative to the energetic self-sufficiency of Brazil, there are many challenges in the adequacy of these high acidity oils and fats for its production.

This work has focused on the synthesis of three nanosystems composed of superparamagnetic iron oxide nanoparticles (SPIONs) coated either with a carboxylate platinum(IV) complex (PD = cis,cis,trans-[Pt(NH3)2Cl2(HOOCCH2CH2COO)(OH)]) or with platinum(II) complex functionalized dextrans (DexPt1 = [Pt(Dex-NH2)Cl3] and DexPt2 = [Pt(Dex-NH2)(NH3)2(H2O)]). All nanosystems have shown superparamagnetic behavior. Powder X-ray diffraction (XRD) has confirmed that the SPIONs were iron oxide phase and transmission electron microscopy (TEM) has shown average size of 6 nm (M6). Characterization of the nanosystems by inductively coupled plasma atomic emission spectroscopy (ICP AES) has revealed the presence of platinum on their surface (M6@PD, 0.54 mmol g-1 of Fe and M6@CA@DexPt1-2, 0.32-1.20 mmol g-1 of Fe); infrared spectroscopy (IR) and thermogravimetric and differential thermal analyses (TG-DTA) have confirmed the presence of dextran. Furthermore, the colloidal properties of these nanosystems (M6@PD and M6@CA@DexPt1-2) have been evaluated in water and in PBS buffer. Although M6@PD has shown good colloidal dispersion in water in the pH range of 2.0-8.0, the system underwent rapid agglomeration in PBS buffer. The M6@CA@DexPt1-2 nanosystems have exhibited improved colloidal behavior both in water and in PBS, where hydrodynamic sizes were kept below 100 nm over a large pH range (2.0-12.0). Furthermore, the latter systems have displayed isoelectric points below pH 5.0 and low surface charges at pH 7.0 (ζ-potential = -10 mV) and therefore PBS did not affect their colloidal stability.

Quatro novos conjugados do tipo 6-aminocumarina-naftoquinona foram sintetizados e suas propriedades fotofísicas e eletroquímicas, investigadas. O composto 2-cloro-3-(2-oxo-2H-cromen-6-ilamino)-1,4-naftoquinona 1 não apresentou fluorescência apreciável, em comparação com a 6-aminocumarina, 6-AC. Visando entender as razões da extinção da fluorescência neste composto, duas estratégias foram imaginadas. Primeiramente, o composto 1 foi metilado no nitrogênio para remover a interação eletrostática intramolecular N-H...O=C que mantém as duas unidades fixas. Entretanto, as propriedades de emissão do produto 2 não se mostraram significantemente diferentes das do precursor 1. Como os cálculos usando a teoria do funcional da densidade dependente do tempo (TD-DFT) dos compostos 1 e 2 indicaram que a supressão da fluorescência relaciona-se ao caráter aceptor no anel naftoquinônico, a segunda estratégia envolveu a substituição do átomo de cloro na posição 2 do núcleo naftoquinônico por diferentes grupos doadores de elétrons (compostos 3-5). Novamente não houve mudanças apreciáveis nas propriedades de emissão. Para explicar estes resultados foram feitos cálculos TD-DFT dos estados fundamental (S0) e excitado (S1) de todas as moléculas em solução, os quais indicaram que o grupo fluorescente (6-AC) doa elétrons para o LUMO da naftoquinona, resultando em uma transferência de elétron fotoinduzida oxidativa (oxidative-PET).

Four novel 6-aminocoumarin-naphthoquinone conjugates were synthesized and their photophysical and electrochemical properties, investigated. 2-Chloro-3-(2-oxo-2H-chromen-6-ylamino)-1,4-naphthoquinone 1 did not present appreciable fluorescence in solution in comparison with 6-aminocoumarin, 6-AC. In order to understand the reasons for the fluorescence quenching in this compound, two strategies were attempted. Firstly, compound 1 was N-methylated to remove the intramolecular N-H...O=C electrostatic interaction that maintained the two units fixed, but the emission properties of the product 2 were not significantly different from those of 1. Time-dependent density functional theory (TD-DFT) calculations of compounds 1 and 2 indicate that the fluorescence quenching is related to the electron acceptor character of the naphthoquinone ring. The second strategy, therefore, involved the substitution of the chlorine atom in position 2 of the naphthoquinone nucleus for different electron donor groups (compounds 3-5), but again the emission properties did not change significantly. To explain these experimental findings, TD-DFT calculations of the ground (S0) and excited (S1) states of all molecules in solution were carried out. The results suggest that the energy states in these conjugates are such that the fluorescent group (6-AC) donates electrons to the naphthoquinone LUMO resulting in an oxidative photoinduced electron transfer (oxidative-PET).

As propriedades químicas e mineralógicas do flogopitito, uma rocha que contém flogopita, foram estudadas tendo em vista o emprego como fonte alternativa de potássio. A caracterização mineralógica da rocha foi realizada por difratometria de raios X, fluorescência de raios X, microscopia eletrônica de varredura e espectroscopia na região do infravermelho. De acordo com os resultados, flogopita contém 82,6 g K2O kg-1 (ca. 9%). A cinética de liberação do íon potássio a partir do mineral foi avaliada em meio ácido (nítrico, cítrico, oxálico e Mehlich-1) e em uma solução salina (tetrafenilborato de sódio, Na[B(C6H5)4]). Os resultados experimentais obtidos a partir dos estudos cinéticos foram ajustados para determinar uma relação matemática entre a concentração de íons potássio liberada em solução e o tempo de liberação.

The chemical and mineralogical properties of phlogopitite, a rock containing the mineral phlogopite, were studied aiming at employment as an alternative source of potassium. Mineralogical characterization of this rock was performed using X-ray diffractometry, X-ray fluorescence, scanning electron microscopy and infrared spectroscopy. According to the results, phlogopite contains approximately 82.6 g K2O kg-1 (ca. 9%). The kinetics involved in the release of the potassium ions from the mineral were examined using acidic solutions (nitric, citric, oxalic and Mehlich-1) and a salt solution (sodium tetraphenylboron, Na[B(C6H5)4]). The experimental results from the kinetic studies were used to determine the mathematical relationship between the concentration of potassium released and the reaction time.

Nanopartículas de sílica (NPs) modificadas covalentemente com uma aminonaftoquinona foram sintetizadas e caracterizadas. A aminopropilsilicagelnaftoquinona (APSGNQ) foi obtida por substituição nucleofílica do grupo metóxi da 2-metóxi-1,4-naftoquinona por NPs modificadas com o grupo aminopropil (APSG). Os espectros de ressonância magnética nuclear de 13C e 29Si no estado sólido confirmaram que a naftoquinona encontra-se ligada covalentemente à aminopropilsilicagel. Como o composto APSGNQ é solúvel em solventes orgânicos comuns, foi possível quantificar o ancoramento da naftoquinona na superfície das NPs modificadas por espectroscopia no ultravioleta-visível (0,56 mmol de naftoquinona ancorada por grama de APSGNQ), por comparação com o espectro do composto análogo 2-aminobutil-1,4-naftoquinona (ABNQ). Os dados das análises elementares indicaram que aproximadamente 8% da propilamina presente na superfície do composto APSGNQ não reagiu com a metóxinaftoquinona. Essas NPs de sílica multifuncionais têm potencial para aplicações médicas.

The synthesis and characterization of silica nanoparticles (NPs) covalently modified with an aminonaphthoquinone are reported. The aminopropylsilicagelnaphthoquinone (APSGNQ) was obtained by nucleophilic substitution of 2-methoxy-1,4-naphthoquinone with aminopropylsilicalgel (APSG) NPs. Solid state 13C and 29Si nuclear magnetic resonance spectra confirmed that the naphthoquinone is covalently bonded to APSG. Due to the solubility of APSGNQ in common organic solvents, solution ultraviolet-visible spectroscopy was used to determine the amount of naphthoquinone on the NPs surface (0.56 mmol of incorporated naphthoquinone per gram of APSGNQ) by comparison with the spectrum of 2-aminobutyl-1,4-naphthoquinone (ABNQ). Elemental analysis indicated that about 8% of the surface propylamine remained unreacted in APSGNQ. These multifunctional silica NPs have potential in medical applications.