Wastewater from textile industries is loaded with synthetic dyes. These effluents are often not adequately treated, affecting the soil and groundwater quality and leading to environmental contamination. The Agreste mesoregion of the state of Pernambuco is home to one of the largest textile centers in Brazil. This work therefore aims to study the behavior of Remazol Black B (RB5) dye in subsurface mediums in this region. The kinetics and isotherm sorption experiments allowed an evaluation of RB5 retention capacity in two layers of alluvial soil of the dry riverbed of the Capibaribe Basin. The maximum sorption rate was 81.81 mg kg-1 and 21.7 mg kg-1 for the loamy sand and sand layers, respectively. The Pseudo-second order kinetic model described more appropriately the sorption kinetics for both soils. The isotherms behavior was nonlinear, and Freundlich model was the most suitable to describe this process for both soils, presenting KF values of 8.6407 L kg-1 for loamy sand and 0.1868 L kg-1 for sand. The isotherm parameters confirm a more significant interaction of RB5 with the loamy sand layer than with the sand layer, indicating lower leaching in the first layer, which is less mobile for RB5 contamination. Furthermore, the different sorption rates for both soils indicate the importance of studying the soil as a heterogeneous profile.
Resumo: O objetivo deste trabalho foi avaliar a capacidade de remoção do corante Remazol Black B, a partir de uma solução aquosa sintética, utilizando biomassa mista de Aspergillus niger e Capim elefante (Pennisetum purpureum Schum), em diferentes condições de temperatura (30, 40 e 50 ± 2 ºC), em concentrações na faixa de 25 a 85 mg•L-1 e tempo de 0 a 160 min. O estudo cinético foi caracterizado pelo modelo de pseudossegunda ordem. O modelo de isoterma de Langmuir apresentou o melhor ajuste a técnica de linearização e apresentou capacidade de adsorção máxima de 9,645 mg•g-1. A espontaneidade da reação de adsorção foi obtida pela energia livre de Gibbs. O estudo termodinâmico indicou que a adsorção foi favorável e espontânea, e que o aumento da temperatura provoca redução da capacidade adsortiva.Palavras-chave: Adsorção, biomassa mista, remoção de corantes.
O comportamento hidrodinâmico de solos em cultivo de vazante foi analisado por meio das curvas de retenção θ(h), da condutividade hidráulica K(h), da sorvidade S e do raio característico de poros λm, determinados em dois Neossolos Flúvicos das vazantes dos açudes Cajueiro e Flocos, em Tuparetama, PE. O solo de Cajueiro apresenta uma pequena transição de textura e de densidade do solo, já o de Flocos apresenta uma evidente transição dessas propriedades em profundidade. As curvas de θ(h) foram obtidas pelo ajuste da equação de van Genuchten aos valores de campo (por meio de medidas de tensiômetros e de sonda de nêutrons) e de laboratório (por meio da “câmara de pressão de Richards”). Para determinação de K e S, foram realizados ensaios com o infiltrômetro a disco (0,08 m diâmetro da base), com quatro tensões de fornecimentos, nas profundidades de 0, 0,20, 0,40, 0,60 e 0,80 m. As curvas de θ(h) mostraram boa concordância na faixa de potencial de -30 a -10 kPa, indicando coerência dos dados experimentais. A heterogeneidade hidrodinâmica do solo de Flocos é explicada pela textura e densidade do solo e em Cajueiro é induzida pela distribuição dos tamanhos dos poros. O diâmetro do infiltrômetro, combinado às tensões aplicadas, permitiu caracterizar a matriz porosa da camada argilosa do solo de Flocos.
This work investigated the biomasses (seeds, seed husks, oilseed grains, crude and purified oils, cakes by pressing and by hexane extraction and methyl biodiesel the oil) of Moringa oleifera Lamarck, starting with its seedpods (ripe and dry fruits) in energetic application. The oil obtained from the grains by mechanical pressing had an average yield of 11.36% and of 36.48% by hexane extraction. The moringa biomasses presented calorific values between 15.87 and 37.53 MJ/kg, being suitable as renewable biofuels. The mixed crude oil (1:4) was refined in four steps: degumming, neutralization, washing and drying. The crude and refined oils were characterised by acidity index, peroxide index, water content, turbidity, specific mass, kinematic viscosity, power calorific higher, calorific power below and ash content. The crude oils by pressing and by solvent extraction were characterised through of the saponification index and iodine value. The purified biodiesel presented specific mass of 889 kg/m3 (20 oC), kinematic viscosity of 5.5 m2/s (40 oC), content of ester of 86.2% and 98.23% (in microscale, ratifying the viability of the method), acidity index of 0.43 mg KOH/g and water content of 615.8 mg/kg. The solid moringa biomasses (seeds, cakes (or pies) and the seed husks) show high potential for the production of briquettes or ecological firewood due to its content energy expressed as lower calorific value (between 15.87 and 23.31 MJ/kg) and simple and accessible technological production. The results show that moringa is an easily exploitable plant in sustainable energy, especially from its seedpods and seeds.
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