Remoção de Fe em água empregando fluxo contínuo e adsorção em cerâmica porosa assistida por aplicação indireta de ultrassom

Abstract

The objective of this work was to develop a prototype for removal of Fe in water using continuous flow and adsorption in porous ceramics and assisted by indirect application of ultrasound. A bench prototype was developed using porous ceramics, continuous flow under pressure and indirect application of ultrasound. A design of experiments (DOE) was developed to optimize the working conditions of the prototype. Equilibrium isotherm models were evaluated for Temkin and Dubinin-Radushkevich (D-R) models. The results of the optimization of the methodology indicated that the best condition was: flow rate of 30 mL.min-1, mass of adsorbent equal to 140 g, temperature of 40 ºC and initial concentration of the solution of 6 mg.L-1 of Fe. equilibrium kinetics for the DR model indicated the apparent adsorption energy value equal to 0.29 kJ.mol-1, thus demonstrating physical adsorption as the main mechanism. Temkin's modeling also described the adsorptive process satisfactorily, indicating the formation of multiple adsorption layers. Comparing the efficiency of the system, the ultrasound test (US) proved to be 19% (m.v-1) more effective than in a test without ultrasound. The calorimetric evaluation of the energy released in the P-IV prototype was 73 W.dm-3 in 60 seconds of US application. The optimized system showed an efficiency of Fe removal of 96% (m.v-1) in a solution of 6 mg.L-1 of ferrous sulfate. The system was evaluated using groundwater and obtained 39% (m.v-1) and 8% (m.v-1) of total Fe removal with and without US application, respectively. It was concluded that the methodology developed, on a laboratory scale, intensified the process of adsorption of inorganic Fe in ceramics.