A Multi-Pumping Flow System with Pulsed Fluidization to Evaluate Soil Capacity for Phosphate Adsorption

• Autor(a) principal: Machado,Jeane M. C.
• Data de Publicação: 2017
• Outros Autores: Melchert,Wanessa R., Zagatto,Elias A. G., Kamogawa,Marcos Y.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532017000701149
• topic: solenoid micro-pumps; adsorption; kinetic; solid-liquid interaction

Soils with high levels of iron and aluminum, thus negatively the phosphorous availability, affecting crop yields. A prior determination of the soil capacity to adsorb phosphate is relevant to attaining good agricultural performance. To this end, a multi-pumping flow system with pulsed fluidization is proposed. The procedure takes into account the amount of remaining phosphorus (P-rem) in the solution after the adsorption step to indirectly estimate the soil retention capacity. A 1.0 mg L-1 P solution is passed through a fluidized bed column with 50 mg of soil (particles < 0.15 mm), where the analyte is adsorbed. P-rem was spectrophotometrically quantified by the molybdenum blue method. The coefficient of variation (n = 20), limits of detection and quantification (99.7% confidence level), and sampling rate were estimated as 1.54%, 17 and 51 µg L-1 P, and 87 h-1, respectively. Only 0.27 mg (NH4)6Mo7O24 and 0.10 mg SnCl2 were consumed per determination, generating 2.4 mL of waste. The results followed a linear relationship [y = 0.9702x + 1.483 (r = 0.9635; n = 20)] with the reference procedure. In comparison to the reference procedure, 100, 40 and 180-fold reductions in the required soil amount, waste generation and analytical time were attained.