Separation of oil-in-water emulsions by flow through fiber beds: A response surface approach

Separation of oil-in-water emulsions using fiber bed coalescer was studied by response surface methodology. The bed was formed of polyethylene terephthalate fibers. The aim was to investigate the possibility of using response surface regression for the analysis and prediction of both the effluent oil concentration and critical velocity in broad ranges of flow rates, bed permeabilities, and nature of dispersed oil phase. The developed response surface equations for a constant bed permeability are a responsive statistical method with the calculated multiple R higher than 90%. It was found that dispersed oil density, viscosity, neutralization number, and bed permeability influence significantly the oil removal efficiency of fiber bed coalescers. The region of highest critical velocity has been observed for a high viscosity and a high fiber bed permeability. The developed response surface models can be used to ensure high separation efficiency and improve coalescer performance when unexpected simultaneous changes in the bed permeability, hydrodynamic forces and dispersed oil properties take place. [Projekat Ministarstva nauke Republike Srbije, br. 172022

Separation of mineral oil droplets using polypropylene fibre bed coalescence

This paper investigates the separation possibilities of model emulsion oil-in-water using polypropylene fibre bed coalescence. Experiments were carried out over a wide range of physico-chemical characteristics of mineral oils, bed permeability and operating fluid velocities. The aim of this study was to analyse the influence of the dispersed oil phase nature and of the bed geometry on the separation efficiency. From the obtained results, it can be concluded that polypropylene fibres in the broadest studied range of bed permeabilities and fluid velocities, effectively separate oil that is highly polar. On the contrary, for the other two investigated oils at low values of bed permeability a region was detected in which the coalescer is incapable to operate. It has to be emphasized that the polypropylene fibres efficiently separate all three investigated oils at the highest studied bed permeability. [Projekat Ministarstva nauke Republike Srbije, br. 172022

Relationships between heavy metal content and magnetic susceptibility in road side loess profiles: A possible way to detect pollution

The vertical and horizontal contamination profile of the loess sediments located in the vicinity of the highway Novi Sad-Belgrade, with the intense frequency of vehicles, has been assessed. The heavy metal content (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) and hydrocarbon content were determined for the samples collected from two loess profiles in broad ranges of depth (0.15-4.50 m at 0.15 m intervals) and horizontally deeper in the sediment (0.01, 0.05 and 0.10 m). For all loess samples the contents of heavy metals were lower than the remediation intervention values. Hydrocarbon content in all analyzed sediment samples was below limit of quantification of 50 mg/kg. Magnetic susceptibility of the samples revealed the occurrence of one weak paleosol in one loess profile as well as the anthropogenic loess like deposits in the upper part of the second profile. The polynomial regression was successfully applied to estimate relationship between magnetic susceptibility of the loess and heavy metal content, total organic carbon and grain-size distribution. The developed second order equations are a responsive method with the calculated multiple R higher than 94%. The proposed statistical approach greatly simplifies the analysis of loess profile as a record of pollution, and it may serve to estimate the extremely high values of magnetic susceptibility influenced by small increase in heavy metal content, total organic carbon and grain size distribution

Liquid-liquid equilibrium constant for acetic acid in an olive oil-epoxidized olive oil-acetic acid-hydrogen peroxide-water system

The liquid-liquid equilibrium constant for acetic acid in a quinary system olive oil-epoxidized olive oil-acetic acid-hydrogen peroxide-water was experimentally determined for temperatures and component ratios relevant for in situ epoxidation of plant oils. The values has the constant range from 1.52 to 2.73. To predict the equilibrium constant for acetic acid, the experimental data were correlated with UNIQUAC (universal quasi chemical) and NRTL (non-random two liquid) activity coefficient models. For simplified calculation of the phase equilibrium the insolubility of olive oil and epoxidized olive oil in the water, as well as insolubility of water and hydrogen peroxide in the olive oil and epoxidized olive oil, was assumed. The root mean square deviation (RMSD) of the experimental and calculated values of the liquid-liquid equilibrium constant for acetic acid is 0.1910 for the UNIQUAC model and 0.1815 for the NRTL model. For rigorous flash calculation, when the partitioning of all components between the phases was assumed, the RMSD for the NRTL model is 0.1749. [Projekat Ministarstva nauke Republike Srbije, br. 45022