Resumo O carvão ativado é um material que possui diversas aplicações ambientais, como a adsorção de íons de chumbo metálico (Pb2+). Pode ser obtido a partir de diferentes espécies de plantas. Nesta pesquisa, foi utilizada a semente de Persea americana (variedade abacate-HASS), proveniente de mercados locais da cidade de Cartagena, para ser usado na remoção de Pb2+ de águas residuais da indústria pesqueira. Para obtenção do carvão ativado, a semente foi carbonizada em forno de barro da marca Terrigeno, modelo DB 1200. Foi utilizado ácido ortofosfórico a 21% p/v como agente ativador. A água residual foi caracterizada seguindo as especificações da APHA. A turbidez foi determinada por nefelometria em um turbidímetro Turbiquant 300 IR. A concentração de Pb2+ foi determinada por espectroscopia de absorção atômica em um equipamento Thermo Scientific iCE 3300. A superfície química do material foi realizada por espectroscopia no infravermelho com transformada de Fourier (FTIR). Os carbonos foram caracterizados morfologicamente usando um microscópio eletrônico de varredura SEM (Jeol 5910LV), visualizado a 15kV. Obtém-se um rendimento de 20,38% em massa de carvão. Os poros são de tamanho irregular, variando de 16,2 a 55,98 μm. 65% de Pb2+, turbidez (57,6%), cor (57%), sólidos totais (50,2%), bem como DBO (53,12%) e DQO (36%) são removidos, encontrando diferenças estatisticamente significativas nos valores a 95 % Nível de significância. A semente de Persea americana (abacate HASS) pode servir como material vegetal para obter um material adsorvente (carvão ativado) e ser utilizado na remoção de metais pesados de águas residuais. ambientais Pb2+. Pb2 Pb . (Pb2+) plantas pesquisa variedade abacateHASS, abacateHASS abacate HASS , abacate-HASS) Cartagena pesqueira Terrigeno 1200 21 pv p v ativador APHA 30 IR 3300 FTIR. FTIR (FTIR) Jeol 5910LV, 5910LV LV 5910LV) 15kV kV Obtémse Obtém se 2038 20 38 20,38 irregular 162 16 2 16, 5598 55 98 55,9 μm 65 57,6%, 576 57,6% 57 6 (57,6%) 57%, 57% (57%) 50,2%, 502 50,2% 50 (50,2%) 53,12% 5312 53 12 (53,12% 36% 36 (36% removidos 9 significância (Pb2+ abacate-HASS 120 3 330 (FTIR 203 20,3 1 559 5 55, 57,6 (57,6% (57% 50,2 (50,2% 53,12 531 (53,12 (36 (Pb2 33 20, 57, (57,6 (57 50, (50,2 53,1 (53,1 (3 (Pb (57, (5 (50, 53, (53, ( (50 (53

Abstract Activated carbon is a material that has various environmental applications, such as the adsorption of metallic lead ions (Pb2+). It can be obtained from different plant species. In this research, the seed of Persea americana (Avocado- HASS variety) was obtained from local markets in the city of Cartagena to be used in the removal of Pb2+ from wastewater from the fishing industry. To obtain activated carbon, the seed was carbonized in a Terrigeno-brand clay oven, Model DB 1200. Orthophosphoric acid at 21% w/v was used as an activating agent. The residual water was characterized following the APHA specifications. The turbidity was determined by nephelometry in a Turbiquant 300 IR turbidimeter. The Pb2+ concentration was determined by atomic absorption spectroscopy in a Thermo Scientific iCE 3300 equipment. The chemical surface of the material was performed by Fourier transform infrared spectroscopy (FTIR). The carbons were morphologically characterized using a scanning electron microscope SEM (Jeol 5910LV), visualized at 15kV. A yield of 20.38% by mass of coal is achieved. The pores are of irregular size, ranging from 16.2 to 55.98 μm. 65% of Pb2+, turbidity (57.6%), color (57%), total solids (50.2%), as well as BOD (53.12%) and COD (36%) are removed, finding statistically significant differences in values at the 95% level of significance. The seed of Persea americana (HASS avocado) can serve as plant material to obtain an adsorbent material (activated carbon) and be used in the removal of Pb2+ from wastewater. applications Pb2+. Pb2 Pb . (Pb2+) species research Avocado (Avocado variety industry Terrigenobrand Terrigeno brand oven 1200 21 wv w v agent specifications 30 turbidimeter 330 equipment FTIR. FTIR (FTIR) Jeol 5910LV, 5910LV LV , 5910LV) 15kV kV 2038 20 38 20.38 achieved size 162 16 2 16. 5598 55 98 55.9 μm 65 57.6%, 576 57.6% 57 6 (57.6%) 57%, 57% (57%) 50.2%, 502 50.2% 50 (50.2%) 53.12% 5312 53 12 (53.12% 36% 36 (36% removed 95 significance avocado (Pb2+ 120 3 33 (FTIR 203 20.3 1 559 5 9 55. 57.6 (57.6% (57% 50.2 (50.2% 53.12 531 (53.12 (36 (Pb2 20. 57. (57.6 (57 50. (50.2 53.1 (53.1 (3 (Pb (57. (5 (50. 53. (53. ( (50 (53

Resumo Para determinar o papel que as substâncias húmicas (HS) desempenham como promotores do crescimento vegetal, foi avaliado o efeito do HS extraído do carvão mineral no crescimento de plantas de tomate (Solanum lycopersicum) e melão (Cucumis melo). Três concentrações de HS foram avaliadas em 200 gramas de solo. O fertilizante (uréia 0,3%) e ácido húmico nas concentrações de 0,05%, 0,1% e 0,2% foram adicionados diretamente e ao mesmo tempo na quantidade de solo, utilizando uma amostra controle sem adição de ácido húmico. As medições de aumento foram feitas em intervalos de três dias até 45 dias. Plantas tratadas com altas concentrações de HS demonstraram um aumento significativo nas raízes (p> 0,05). Em ambas as plantas, a concentração de 0,2% no HS apresentou o maior aumento de crescimento, com o melão apresentando a maior variação com o passar do tempo, com seu maior pico nos 36 dias (13,1 ± 0,05cm) do experimento, enquanto no no tomateiro o máximo crescimento ocorreu em 30 dias (9,2 ± 0,01 cm). O teste de Dunnett mostrou que não houve diferença estatisticamente significativa entre o controle e as concentrações de 0,05% e 0,1% (p> 0,05), enquanto entre o controle e a amostra de solo com concentração de 0,2% houve diferença estatisticamente significativa (p <0,05). Os resultados obtidos mostram uma notável influência do ácido húmico no crescimento das plantas estudadas, principalmente em altas concentrações.

Abstract This study evaluated the effect of HS extracted from mineral coal on the growth of tomato (Solanum lycopersicum) and melon (Cucumis melo) plants to determine the role that humic substances (HS) play as promoters of plant growth. Three concentrations of HS were evaluated in 200 grams of soil. The fertilizer (urea 0.3%) and humic acid in concentrations of 0.05%, 0.1%, and 0.2% were added directly and at the same time to the amount of soil, using a control sample without the addition of humic acid. Increase measurements were made at three-day intervals up to 45 days. Plants treated with high concentrations of HS demonstrated a significant increase in roots (p>0.05). In both plants, the concentration of 0.2% in HS showed the greatest increase in growth, with the melon plant showing the greatest variation as time passed, with its highest peak in 36 days (13.1 ± 0.05cm) of the experiment, while in the tomato plant the maximum growth occurred in 30 days (9.2 ± 0.01 cm). The Dunnett test showed that there was no statistically significant difference between the control and the concentrations of 0.05% and 0.1% (p>0.05), while among the control and the soil sample with a concentration of 0.2% there was a statistically significant difference (p<0.05). The results show a notable influence of humic acid on the growth of the studied plants, especially at high concentrations.

Resumo Os coagulantes podem ser extraídos de matéria vegetal e aplicados no tratamento de efluentes. Esses coagulantes são derivados de sementes, folhas, cascas, raízes e frutos. Este estudo enfoca o uso do extrato mucilaginoso de Stenocereus griseus (conhecido como Cardón Guajiro) para a remoção da demanda bioquímica de oxigênio (DBO5), demanda química de oxigênio (COD), sólidos totais, turbidez e cor em águas residuais domésticas de uma estação de bombeamento na cidade de Cartagena (Colômbia). A dose ideal de extrato de S. griseus foi determinada por um teste de jarro empregando um floculador digital E & Q F6-300. Todas as determinações físico-químicas foram realizadas seguindo as especificações dos métodos padrão para efluentes da APHA (Standard Methods for Water and Wastewater). Quando foram utilizados 1400 mgL-1 de coagulante natural no tratamento de esgoto, a turbidez obtida foi de 29,57 TNU, representando remoção de 67,24% considerando a turbidez inicial. Este parâmetro diminui até 68,61 PCU para uma remoção de 72,12% na mesma dosagem de coagulante em relação à cor. Deve-se notar que diferenças estatísticas significativas foram encontradas entre todas as doses testadas do coagulante. O extrato mucilaginoso de S. griseus, teve propriedades valiosas no tratamento primário de águas residuais domésticas.

Abstract Coagulants can be extracted from vegetal material and applied in the treatment of wastewater. These coagulants are derived from seeds, leaves, bark, roots and fruits. This study focuses on the use of the mucilaginous extract ofStenocereus griseus(known as Cardón Guajiro) for removal of biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total solids, turbidity and color in domestic wastewater from a pumping station in the city of Cartagena (Colombia). The optimal dose ofS. griseusextract was determined by a pitcher test employing an E&Q F6-300 digital flocculator. All physicochemical tests were carried out following the specifications of the standard methods for wastewater (APHA). When 1400 mgL-1 of natural coagulants were used in the sewage treatment, the turbidity obtained was 29.57 TNU, representing removal of 67.24%, considering the initial turbidity. This parameter decreases until 68.61 PCU, for a 72.12% removal at the same coagulant dosage regarding the color. It must be noted that significant statistical differences were found between all tested doses of the coagulant. The mucilaginous extract of S. griseus exhibited useful properties in the primary treatment of domestic wastewater.

Resumo Este estudo tem como foco o desenvolvimento de um modelo secundário para Yarrowia lipolytica em processos de tratamento de esgoto. Os dados brutos de crescimento de Y. lipolytica foram ajustados ao modelo de Buchanan a fim de obter parâmetros de crescimento como: contagem inicial de células (Y0), taxa de crescimento específico máximo (μmax), fase de latência (λ) e população máxima de células (Ymax). Os valores µ obtidos em diferentes níveis de pH (5,0 a 8,0) foram usados para construir o modelo secundário baseado em uma equação linear. Os resultados mostraram um efeito significativo do pH nos valores de µmax. O processo de validação dos modelos desenvolvidos apresenta valores de acurácia (Af) e fator de bias (Bf) próximos a um, enquanto os valores de root mean square error (RMSE) foram baixos, confirmando que tais modelos podem prever o crescimento de Y. lipolytica em águas residuais de laticínios. Isso pode ser interessante para otimizar tratamentos de esgoto que envolvem esse tipo de microrganismo. Além disso, as águas residuais do leite eram um bom substrato para apoiar o crescimento da Yarrowia lipolytica e poderiam ser utilizadas para produzir a produção de enzimas.

Abstract This study focuses on the development of a secondary model for Yarrowia lipolytica in a sewage treatment process. The raw data of Y. lipolytica growth were adjusted to the Buchanan model in order to obtain growth parameters such as initial count cells (Y0), maximum specific growth rate (μmax), latency phase (λ) and maximum cell population (Ymax). The µ values obtained at different pH levels (5.0 to 8.0) were used to build the secondary model based on a linear equation. The results showed a significant effect of pH on µmax values. The validation process of the developed models displays accuracy (Af) and bias factor (Bf) values close to one, while the values of root mean square error (RMSE) were low, confirming that such models can predict the growth of Y. lipolytica in dairy wastewater. This can be interesting to optimize sewage treatments that involve this kind of microorganism. Moreover, the dairy wastewater was a good substrate to support the Yarrowia lipolytica's growth and could be used to produce enzymes.

RESUMEN Las sustancias húmicas son un conjunto de macromoléculas provenientes de materia orgánica biodegradada. Estas sustancias, se pueden obtener de carbones de alto rango y son importantes en la eliminación de contaminantes en soluciones acuosas. En esta investigación, se evaluó la influencia del tamaño de partículas en la extracción de ácidos húmicos, a partir de muestras de carbón bituminoso. Se realizó una oxidación en solución acuosa de las muestras con peróxido de hidrógeno, a concentraciones de 50, 40 y 30%, respectivamente, tiempos de extracción de 3 y 6 horas y tamaño de partícula a número de malla 60 y 120. Se caracterizaron las muestras de carbón por espectrometría infrarroja (FTIR). Se realizó un análisis próximo, para determinar % de humedad, % de materia volátil (%MV), % de ceniza, % de carbono fijo (%CF) y relación %CF/MV. El análisis termogravimétrico (TGA), se realizó en equipo de termografía TGA Q-500. El mayor porcentaje de extracción (76,8±3,50), se obtuvo a una concentración de 50% de agente oxidante, tiempo de extracción de 6 horas y tamaño de partícula a malla No. 120. El tiempo de extracción influye en la cantidad de ácido húmico que se puede extraer, una concentración de 40% de agente oxidante; no se encontraron diferencias estadísticamente significativas (P> 0,05), para tiempos de 3h (32,8±1,0, malla 120) y 3h (30,6±2,4, malla 60). La materia carbonácea utilizada en esta investigación puede ser un candidato potencial para obtener ácidos húmicos útiles en la industria agrícola.

ABSTRACT Humic substances are a group of macromolecules from biodegradable organic matter. These substances can be obtained from high-rank coals and are important in the removal of contaminants in aqueous solutions. In this study, the influence of particle size on the extraction of humic acids from samples of bituminous coal is evaluated. Oxidation in aqueous solution of the samples with hydrogen peroxide was carried out at concentrations of 50, 40 and 30% respectively, extraction times of 3 and 6 hours and particle size at 60 and 120 mesh number. The carbon samples were characterized by infrared spectrometry (FTIR). A close analysis was performed to determine % moisture, % volatile matter (% MV), % ash, % fixed carbon (% CF) and % CF/MV ratio. Thermogravimetric analysis (TGA) was performed on TGA Q-500 thermography equipment. The highest percentage of extraction (76.8 ± 3.50) was obtained at a concentration of 50% of oxidizing agent, extraction time of 6 hours and particle size to mesh No 120. The extraction time influences the amount of humic acid that can be extracted, a concentration of 40% of oxidizing agent, no statistically significant differences were found (P> 0.05) for times of 3h (32.8±1.0, 120 mesh) and (30.6±2.4, 60 mesh). The carbonaceous material used in this research may be a potential candidate for obtaining useful humic acids in the agricultural industry.

RESUMEN Diversos investigadores sostienen que solo a través de una conciencia de las diferencias y de las similitudes entre la educación, el ambiente y las neurociencias será posible lograr una fundamentación común necesaria para una ciencia integrada de la educación, el cerebro, la mente y el aprendizaje. El objetivo de la investigación fue determinar si el ambiente de aprendizaje y la neurociencia influyen en la atención y en la motivación de los estudiantes, que traen, como consecuencia, cambios en el rendimiento académico. El experimento, se realizó con dos grupos de estudiantes universitarios, separados en aulas, con diferente ambiente de aprendizaje, que cursaban la asignatura química general, donde el 76% fueron de género masculino y el 24%, femenino, para el grupo 1 y el 60%, masculino y 40% del sexo femenino, para el grupo 2, con edades comprendidas entre los 17 y 21 años, para ambos grupos. Para evaluar la capacidad de atención, se empleó el test d2 elaborado por Brickenkamp - Zillmer y para el análisis de la influencia de los ambientes de aprendizaje, se diseñó un test tipo Likert. El primer grupo, se le realizó el ejercicio docente en un ambiente convencional, el segundo grupo trabajó en ambientes no convencionales, con docentes formados para la aplicación de los conceptos de neurociencia. Los resultados mostraron que existe una relación estadísticamente significativa entre los resultados, respecto al rendimiento académico, para los dos grupos, a un nivel de confianza del 95%, lo cual, es importante para tener en cuenta en futuros proyectos de educación, que permitan una verdadera transformación en la enseñanza de la química, en programas de ingenierías.

SUMMARY Many researchers stated that only through conscience about differences and similarities on education, environment and neurosciences it will be possible to achieve a solid base for get an integrated science including the education, brain, mind and learning. The objective of this study was to determine if the learning environment and neuroscience influence the attention and motivation of engineering students, resulting in changes on academic performance. The tests were conducted employing two university students groups taking the subject general chemistry of which 75% were male and 25% female, with ages between 17 and 21 years. It is important to clear that both students groups had different learning environment. The first group was taught in conventional learning environments, the second one was taught in a non-conventional environments, with teachers trained to apply the concepts of neuroscience. The Brickenkamp - Zillmer test d2 was employed to evaluate the student’s attention capacity while the Likert test was used in order to evaluate the influence of learning environments. The results showed that there is a statistically significant relationship between the results with respect to academic performance, for both groups which is important to take into account in future education projects that allow a real transformation teaching of chemistry in engineering programs.

En este estudio, se describe la adsorción de plomo (Pb2+) en soluciones acuosas, a partir de carbón modificado, mediante tratamiento con CS2 y NaOH, empleando una relación 16,6:1 NaOH/Carbón p/p y 4,08:1 CS2/carbón p/p. Se realizaron pruebas de pH, cinéticas e isotermas de adsorción, para evaluar la capacidad de adsorción del carbón xantado y carbón no xantado. Los grupos azufre en el carbón xantado fueron identificados por espectroscopia infrarroja de reflectancia difusa (FTIR) y comparados con los espectros del carbón no xantado. Los resultados muestran que la mejor remoción de plomo en la solución con una concentración de 100mg de Pb2+/L y dosis de 50mg de adsorbente/10mL, respectivamente, fue a un valor de pH 5,0, logrando un porcentaje de adsorción de 98%. Los estudios cinéticos indican que el proceso de adsorción puede alcanzar el equilibrio alrededor de 120min, siguiendo una cinética de pseudo-segundo orden, para ambos materiales. El estudio de las isotermas indica que el carbón se ajusta mejor a una isoterma de tipo Langmuir y cuando se somete a la xantación, se ajusta a una isoterma de tipo Freundlich.

This study describes the adsorption of lead (Pb2+) in aqueous solutions of modified coal by treatment with CS2 and NaOH, using a ratio of 16,6:1 NaOH/coal (w/w) and 4,08 CS2/coal (w/w). Different tests such as acidity, kinetic and adsorption isotherms were carried out in order to assess the adsorption capacity of xanted and non-xanted coal. The sulfur groups presented in the xanted coal were identified by infrared spectroscopy(FTIR) and they were compared with non-xanted coal spectrum. The results show that the best lead removal in the solution (with a concentration of 100mg Pb2+/L and 50mg of adsorbent) was obtained at pH 5.0 for both coal (xanted and non-xanted) with an adsorption percentage of 98%. The kinetic studies indicate that the adsorption process can reach the equilibrium in about 120 minutes, following a pseudo-second order kinetics for both materials. The isotherms study indicates that the coal fits best to a Langmuir-type isotherm, however when the coal is xanted, it fits best to a Freundlich-type isotherm.

In this paper, two models of humic acids, the Temple-Northeastern-Birmingham (TNB) and Kolla models, were studied. Also, the complexation reaction of the structures formed by the interaction of the TNB and Kolla models with Al3+, Ca2+, Mg2+, Zn2+, K+ and NH4+ cations, common in agricultural soils, was studied. These calculations were made for the complexes, at PM6 and DFT / LANL2DZ level of theory, both in vacuum and in aqueous medium. We found a strong affinity between Kolla and TNB models, and Al3+, Ca2+, Mg2+, Zn2+, K+ and NH4+ cations, influenced by the solvent that affected the interaction sites; the solvent increased the rate of reactivity and affinity for the cations in nucleophilic regions and decreased it in electrophilic regions of the structures. Calculations of molecular electronic potential, MEP and atomic charges, the local smoothness, Fukui functions and the HSAB principle adequately described the HA/cations interactions which were affected by the number of hydrogen bonds. The most reactive sites were the hydroxyl, phenolic, carbonyls oxygens and nitrogens at both vacuum and aqueous medium, especially carbonyl oxygens. These results are consistent with the properties of HA that make them attractive as components of agricultural soils.