Drenagem de espumas gás-líquidos e influência da presença de partículas e anti-espumantes / Air-liquid foams drainage and influence of the presence of particles and antifoams

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

This Dissertation presents results of two comercial antifoams on the stability of gas-liquid foams formed in the presence of an anionic surfactant, a non-ionic surfactant and colloidal particles. Air-liquid foams are colloidal systems formed by air bubbles separated by liquid films. The drainage or flow of the liquid contained within these films pass through several steps. The antifoam performance was analyzed from the measurements of drained volume variation in function of time, in the presence and absence of antifoams. The Bartsch methodology was employed, recording the foam ageing during a certain time interval using a CCD camera. The drained volumes were retrieved from the recorded files using Windows Media Player? software. Model foam were chosen by using the same methodology, the drainage volumes were measured for foams formed from aqueous solutions containing: a anionic surfactant, sodium dodecil sulfate, SDS, a non-ionic surfactant, Triton X-100, a non-ionic polymer, poly(ethyleneglycol), PEG, (Mw = 200, 400, 600, 1000 e 3400), sodium chloride, as electrolyte and colloidal particles such as carbon black, silica, barium sulphate, calcium carbonate. The drainage rates for these foam follow the crescent order: (SDS 5.3 mmol/L + NaCl) = (SDS 5.3 mmol/L + CaCO3) <(SDS 30 mmol/L + NaCl) <(SDS 10 mmol/L + BaSO4) = (SDS 5.3 mmol/L + BaSO4) <(SDS 5.3 mmol/L + sílica) <(SDS + Triton X-100 + PEG 600) = (SDS + Triton X-100 + PEG 1000) = (SDS + Triton X-100 + PEG 3400)

ASSUNTO(S)

anti-espumantes tensoativos surfactants antifoams air-liquid foams espumas gás-líquido

ACESSO AO ARTIGO

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