Sueli Teresa Davantel de Barros

Sorption isotherm of agricultural residue of orange bagasse

Wet bagasse can be used as an adsorbent in effluent treatment process. However, before its use a previous drying is necessary. The water activity is an important parameter that affects the fermentation process, and thus its determination becomes most important in order to store this adsorbent. Thus, the objective of this work is to determine the sorption isotherms of orange bagasse at 25, 35 and 50 °C temperatures in order to correlate the moisture with a water activity. The equilibrium moisture content was determined by the static method using salts solution for a 10-80% relative humidity range. The following models were fitted to the experimental data: Henderson, Chung-Pfost, Modified Henderson, Halsey, Luikov and Motta Lima. All models results followed a sigmodal-type function. The equilibrium data for the orange bagasse were better represented by the Luikov and Halsey models.

Evaluation of the acerola juice concentrated by reverse osmosis

The aim of this study was to obtain the acerola juice using separation processes with membranes. The acerola pulp was initially defrosted and treated with 100 ppm of Citrozym Ultra L enzyme at 45oC for one hour, then ultrafiltrated at 3 bar at 45oC using 0.1 µm ceramic membrane, and concentrated by reverse osmosis using a spiral membrane of a compound film. The pressures on the reverse osmosis were 20, 30, and 40 bar at environmental temperature, thus, resulting a juice with 9.76, 14.56, and 17.36 oBrix, respectively. The physicochemical characteristics of the juice were preserved and, studies on evaluation of the public acceptability, showed that 75% of the consumers liked the juice.

Improvement on the concentrated grape juice physico-chemical characteristics by an enzymatic treatment and Membrane Separation Processes

In this work, the improvement on the concentrated grape juice physico-chemical characteristics by using an enzymatic treatment followed by Membrane Separation Process (MSP) has been investigated. By using Novozym 33095(r) and Ultrazym AFP L(r) enzymes varying three operating parameters, the best result on the grape pulp characteristics was attained for the Novozym 33095(r) performed at 35oC, 15 min. and 50 mgL-1. In micro/ultra filtration processes after enzymatic pretreatment, the best performance of the MSP with high permeate flux value and suitable grape juice characteristics was attained using 0.05 mm membrane pore size, 1 bar pressure and 40 oC treatment temperature. When reverse osmosis process is operated at 40 bar and 40oC, high soluble solid and low turbidity values are attained. An enzymatic treatment along with MSP has shown an alternative and efficient grape juice processing system, being possible to extend to other foods.

Beer Clarification with polysulfone membrane and study on fouling mechanism

The aims of the present work were to study the relationship between the fluxes, permeate quality, and fouling mechanism. A polysulfone membrane with 100 KDa and 0.12 m2 of surface area was used. Permeate fluxes were measured for different pressures (0.5, 1.0, 1.5, and 2.0 bar) at the same temperature of 8 oC. The fluxes measured for each pressure ranged from 22, 24, 27 and 30 kg h-1m-2 at 0.5, 1.0, 1.5 and 2.0 bar, respectively. Samples of the feed and permeate were analyzed for pH, color, turbidity, sugar, bitterness, and proteins. The fouling mechanisms observed were cake filtration, partial pore blocking, and complete pore blocking.

Recuperação da solução de soda cáustica usada no tratamento do couro bovino na produção de gelatina Recovery of the sodium hydroxide aqueous solution used in the treatment of bovine leather for the production of gelatin

The sodium hydroxide solution used in the treatment of bovine leather in the production of gelatin has the function of dissolving undesirable organic substances, such as proteins and fats. To avoid the discard of this solution as an effluent to the environment, the intention of this project was to develop a process of sodium hydroxide purification, avoiding the waste of the solution and making it appropriate to be re-utilised in the process. Ultrafiltration experiments were carried out in a micro/ultrafiltration unit, Koch Membrane System, model Protosep, modified IV, with transmembrane pressures of 2.5; 3.5 and 4.5 kgf/cm2 and temperatures of 25 and 50 °C. The membranes used were tubular ceramic (material: TiO2/a - Al2O3) with an average diameter of 0.01, 0.05 and 0.10 µm. The study was divided in two steps: in the first, the best pressure for each membrane was selected, and in the second, a pressure of 3.5 kgf/cm2 was adopted and two different forms of feeding were used to define the membrane. The best operational conditions were determined in terms of permeate flow and product quality. With the results, the following operational conditions were selected: pressure of 3.5 kgf/cm2, temperature of 25 °C and membrane with average pore diameter of 0.01 µm.The sodium hydroxide solution used in the treatment of bovine leather in the production of gelatin has the function of dissolving undesirable organic substances, such as proteins and fats. To avoid the discard of this solution as an effluent to the environment, the intention of this project was to develop a process of sodium hydroxide purification, avoiding the waste of the solution and making it appropriate to be re-utilised in the process. Ultrafiltration experiments were carried out in a micro/ultrafiltration unit, Koch Membrane System, model Protosep, modified IV, with transmembrane pressures of 2.5; 3.5 and 4.5 kgf/cm2 and temperatures of 25 and 50 °C. The membranes used were tubular ceramic (material: TiO2/a - Al2O3) with an average diameter of 0.01, 0.05 and 0.10 µm. The study was divided in two steps: in the first, the best pressure for each membrane was selected, and in the second, a pressure of 3.5 kgf/cm2 was adopted and two different forms of feeding were used to define the membrane. The best operational conditions were determined in terms of permeate flow and product quality. With the results, the following operational conditions were selected: pressure of 3.5 kgf/cm2, temperature of 25 °C and membrane with average pore diameter of 0.01 µm.