Evaluation of the addition of soda-lime glass and yerba mate wastes in ceramic matrix

O presente trabalho avaliou os efeitos da adição de resíduos de vidro sodo-cálcico e de erva-mate sobre a absorção de água, porosidade e resistência mecânica de um material cerâmico. Os pós homogeneizados foram compactados por prensagem uniaxial e submetidos a queima de 900 e 1100 °C a 2 °C.min-1. Os resultados mostraram que a adição de vidro e erva-mate à argila produziu materiais cerâmicos com retração linear entre 0,3 e 6%, absorção de água entre 5,3 e 34%, porosidade aparente de até 41% e resistência mecânica entre 0,5 e 20 MPa. Os materiais queimados a 1100 °C foram os que obtiveram as melhores combinações de propriedades, podendo ser aplicados na produção de blocos, telhas ou revestimento cerâmico de acordo com as necessidades específicas da aplicação.The present work evaluated the effects of the addition of soda-lime glass and yerba mate wastes on the water absorption, porosity and mechanical resistance of a ceramic material. The homogenized powders were compacted by uniaxial pressing and subjected to firing at 900 and 1100 °C at 2 °C.min-1. The results showed that the addition of sodalime glass and yerba mate to the clay produced ceramic materials with linear shrinkage between 0.3 and 6%, water absorption between 5.3 and 34%, apparent porosity of up to 41% and mechanical strength between 0.5 and 20 MPa. The materials fired at 1100 °C resulted in the best combinations of properties and can be applied in the production of blocks, roof tiles or ceramic tiles according to the specific needs of the application

Porous ceramic supported TiO2 nanoparticles : enhanced photocatalytic activity for Rhodamine B degradation

Photocatalytic processes are an efficient and important technique to mineralize organic contaminants in aqueous effluents. However, it is paramount that there is a way to recover the catalyst after degradation. Based on this problem, this research seeks to evaluate the photocatalytic properties of TiO2 under porous ceramics support for the degradation of Rhodamine B (RhB). TiO2 was synthesized by sol-gel, dried at 100 ◦C and calcined at 400 ◦C. The morphological, optical and structural proprieties of the particles were characterized. The XRD patterns of samples calcined at 400 ◦C showed only the anatase phase, confirmed by Raman. Not heat-treated xerogel was amorphous. The agglomerates are composed of fine particles, in the nanometric scale of 15nm. The bandgap of the powder is 3.21 eV, and the surface area is 60.1m2 g−1. To evaluate its photocatalytic activity, the anatase TiO2 was supported in a porous ceramic substrate by a dip-coating process. The heterogeneous photocatalysis showed excellent results, with the degradation of up to 83% of RhB. It was possible obtained with successful an efficient technique for the treatment of wastewater with Anatase nanoparticles supported in the ceramic support obtained from of reuse of the residues.Los procesos fotocatalíticos son técnicas eficientes para la mineralización de contaminantes orgánicos en efluentes acuosos. Sin embargo, es fundamental que haya una forma de recuperar el catalizador después de la degradación. En base a este problema, esta investigación busca evaluar las propiedades fotocatalíticas del dióxido de titanio (TiO2) bajo el soporte de cerámica porosa para la degradación de la rodamina B (RhB). El TiO2 se sintetizó mediante sol-gel, se secó a 100 ◦C y se calcinó a 400 ◦C. Se caracterizaron las propiedades morfológicas, ópticas y estructurales de las partículas. Los patrones DRX de las muestras calcinadas a 400 ◦C mostraron solo la fase anatasa, confirmada por Raman. El xerogel no tratado térmicamente era amorfo. Los aglomerados están compuestos de partículas finas, en la escala de 15nm. El intervalo de banda es de 3,21 eV, y el área de superficie es de 60,1m2.g−1. Para evaluar la actividad fotocatalítica, se recubrió un sustrato cerámico poroso mediante el proceso de recubrimiento por inmersión. La fotocatálisis heterogénea mostró excelentes resultados, con la degradación de hasta el 83% de la RhB. Fue posible obtener con éxito una técnica eficiente para el tratamiento de aguas residuales con nanopartículas de anatasa soportadas en el soporte cerámico obtenido de la reutilización de los residuos

Evaluation of the influence of glycerol in ceramic matrix

O presente trabalho avalia os efeitos da adição de glicerol sobre a porosidade e resistência mecânica de um material cerâmico. As amostras foram compactadas por prensagem uniaxial e submetidas a temperaturas de queima de 950 °C e 1100 °C, com taxa de aquecimento de 7 °C min-1 . Foram realizados ensaios físicos e mecânicos para analisar porosidade aparente, absorção de água, retração linear e resistência mecânica a flexão. Os resultados mostram que a adição de 10% de glicerol à argila melhora principalmente suas propriedades mecânicas, podendo ser um aditivo promissor para gerar materiais cerâmicos estruturais com microestrutura mais resistente.The present work evaluates the effects of the glycerol addition on the porosity and mechanical resistance of a ceramic material. Samples were compacted by uniaxial pressing and were submitted to different sintering temperatures, 950 °C and 1100° C, with a heating rate of 7 °C min-1 . Physical and mechanical analysis were performed to evaluate porosity, water absorption and linear retraction. The results show that the addition of 10% of glycerol into the clay mainly improves its mechanical properties, being able to be a promising additive to generate structural materials with more resistant microstructure

Decolorizing associate of wastewater containing the dyeing of agates rhodamine B combination with different route photocatalytic advanced oxidation processes (POA's)

O tingimento é um dos processos de acabamento das pedras semi-preciosas até a sua comercialização. Este é muito usado na indústria da ágata utilizando elevada demanda de água o que gera uma grande quantidade de águas residuárias, contendo moléculas corantes complexas, como a Rodamina B, que apresenta características de poluente orgânico com ecotoxicidade e genotoxicidade elevadas. Neste trabalho objetivou-se buscar o desenvolvimento de POA’s capazes de degradar os efluentes sintéticos provenientes do tingimento de pedras semi-preciosas contendo o corante Rodamina B (C.I 45170). Para uma melhor eficiência de remoção da Rodamina B, utilizou-se dois métodos distintos de fixação do catalisador utilizado. Primeiramente se trabalho com sílica-gel branca (1-3 mm, Tyvek) e posteriormente com o Polietileno de baixa densidade (PEBD). Realizada a preparação dos materiais, investigou-se algumas combinações de métodos como UV/TiO2/SiO2/O3, UV/TiO2/PEBD/O3 bem como, o monitoramento de alguns parâmetros, como pH e a absorbância de amostras sintéticas. Os testes foram realizados em um reator em acrílico composto de lâmpada germicida (SCT – G13/T8/15W), onde se trabalhou com um volume útil de 1 L.Compondo ainda o reator, utilizou-se uma proveta de 1 litro e uma bomba peristáltica. A concentração de Rodamina B utilizada foi de 20 mg L-1. A partir dos resultados obtidos foi possível verificar que a combinação do UV/TiO2/PEBD/O3 mostrou-se ser mais eficiente. Essa combinação proporcionou um valor de constante cinética na ordem de 28,6 x 10-3 min-1. Se comparado aos demais processos investigados, pode-se observar que se teve um aumento do valor de k.The dyeing is one of the finishing processes of semi-precious stones until its commercialization. It is used in agate industry, making use of a lot of water that generates a big quantity of wastewater. This wastewater contains complex dye molecules, like Rhodamine B, that presents characteristics of an organic pollutant with a high rate of ecotoxicity and genotoxity. This work aimed at searching the development of AOPs capable of degrade synthetic effluents that come from the dyeing of semi-precious stones which contains Rhodamine B (C.I 45170). For a better removal efficiency of the Rhodamine B, two distinct methods of fixing the catalyst were used. Firstly it was used white silica gel (1 - 3 mm, Tyvek) and posteriorly it was used low-density polyethylene (LDPE). Once the materials preparation were made, combination methods were investigated, like UV/TiO2/SiO2/O3 and UV/TiO2/PEBD/O3. Furthermore, some parameters were monitored, as pH and the absorbance of synthetic samples. Tests were performed in a reactor made of acrylic germicidal lamp (SCT – G13/T8,15W), which worked with a working volume of 1L and a peristaltic pump. The concetration of Rhodamine B used was 20 mg L-1. It was verified that the UV/TiO2//PEBD/O3 combination was more efficient. That combination has resulted in a kinetic constant value in order of 28,6 x 10-3 min-1. It can be observed an increase of k value if compared with other investigated cases

Decolorizing associate of wastewater containing the dyeing of agates rhodamine B combination with different route photocatalytic advanced oxidation processes (POA's)

O tingimento é um dos processos de acabamento das pedras semi-preciosas até a sua comercialização. Este é muito usado na indústria da ágata utilizando elevada demanda de água o que gera uma grande quantidade de águas residuárias, contendo moléculas corantes complexas, como a Rodamina B, que apresenta características de poluente orgânico com ecotoxicidade e genotoxicidade elevadas. Neste trabalho objetivou-se buscar o desenvolvimento de POA’s capazes de degradar os efluentes sintéticos provenientes do tingimento de pedras semi-preciosas contendo o corante Rodamina B (C.I 45170). Para uma melhor eficiência de remoção da Rodamina B, utilizou-se dois métodos distintos de fixação do catalisador utilizado. Primeiramente se trabalho com sílica-gel branca (1-3 mm, Tyvek) e posteriormente com o Polietileno de baixa densidade (PEBD). Realizada a preparação dos materiais, investigou-se algumas combinações de métodos como UV/TiO2/SiO2/O3, UV/TiO2/PEBD/O3 bem como, o monitoramento de alguns parâmetros, como pH e a absorbância de amostras sintéticas. Os testes foram realizados em um reator em acrílico composto de lâmpada germicida (SCT – G13/T8/15W), onde se trabalhou com um volume útil de 1 L.Compondo ainda o reator, utilizou-se uma proveta de 1 litro e uma bomba peristáltica. A concentração de Rodamina B utilizada foi de 20 mg L-1. A partir dos resultados obtidos foi possível verificar que a combinação do UV/TiO2/PEBD/O3 mostrou-se ser mais eficiente. Essa combinação proporcionou um valor de constante cinética na ordem de 28,6 x 10-3 min-1. Se comparado aos demais processos investigados, pode-se observar que se teve um aumento do valor de k.The dyeing is one of the finishing processes of semi-precious stones until its commercialization. It is used in agate industry, making use of a lot of water that generates a big quantity of wastewater. This wastewater contains complex dye molecules, like Rhodamine B, that presents characteristics of an organic pollutant with a high rate of ecotoxicity and genotoxity. This work aimed at searching the development of AOPs capable of degrade synthetic effluents that come from the dyeing of semi-precious stones which contains Rhodamine B (C.I 45170). For a better removal efficiency of the Rhodamine B, two distinct methods of fixing the catalyst were used. Firstly it was used white silica gel (1 - 3 mm, Tyvek) and posteriorly it was used low-density polyethylene (LDPE). Once the materials preparation were made, combination methods were investigated, like UV/TiO2/SiO2/O3 and UV/TiO2/PEBD/O3. Furthermore, some parameters were monitored, as pH and the absorbance of synthetic samples. Tests were performed in a reactor made of acrylic germicidal lamp (SCT – G13/T8,15W), which worked with a working volume of 1L and a peristaltic pump. The concetration of Rhodamine B used was 20 mg L-1. It was verified that the UV/TiO2//PEBD/O3 combination was more efficient. That combination has resulted in a kinetic constant value in order of 28,6 x 10-3 min-1. It can be observed an increase of k value if compared with other investigated cases

Hybrid constructed wetlands integrated with microbial fuel cells and reactive bed filter for wastewater treatment and bioelectricity generation

The present study aimed to develop a pilot-scale integrated system composed of anaerobic biofilter (AF), a floating treatment wetland (FTW) unit, and a vertical flow constructed wetland coupled with a microbial fuel cell (CW-MFC) and a reactive bed filter (RBF) for simultaneously decentralized urban wastewater treatment and bioelectricity generation. The first treatment stage (AF) had 1450 L and two compartments: a settler and a second one filled with plastic conduits. The two CWs (1000 L each) were vegetated with mixed plant species, the first supported in a buoyant expanded polyethylene foam and the second (CW-MFC) filled with pebbles and gravel, whereas the RBF unit was filled with P adsorbent material (light expanded clay aggregate, or LECA) and sand. In the CW-MFC units, 4 pairs of electrode chambers were placed in different spacing. First, both cathode and anode electrodes were composed of graphite sticks and monitored as open circuit. Later, the cathode electrodes were replaced by granular activated carbon (GAC) and monitored as open and closed circuits. The combined system efficiently reduced COD (> 64.65%), BOD₅(81.95%), N-NH₃(93.17%), TP (86.93%), turbidity (94.3%), and total coliforms (removal of three log units). Concerning bioenergy, highest voltage values were obtained with GAC electrodes, reaching up to 557 mV (open circuit) and considerably lower voltage outputs with closed circuit (23.1 mV). Maximum power densities were obtained with 20 cm (0.325 mW/m²) and 30 cm (0.251 mW/m2). Besides the electrode superficial areas, the HRT and the water level may have influenced the voltage values, impacting DO and COD concentrations in the wastewater