Search Results (4)

The waste oil emulsion liquid membrane produced by waste oil from oil refineries (WELM) is used to separate the phenol in purified water from the sour water stripper in oil refinery facilities, and the stability of WELM was studied. It is verified that waste refinery oil can be produced into emulsion liquid membrane with good stability and high removal rate for the first time. The WELM stability models were established by response surface methodology (RSM) and artificial neural network (ANN), respectively. The principle and mechanism of various parameters, as well as the interaction effects on the stability of WELM, are proposed. The effects of parameters, including the ratio of Span-80, liquid paraffin, the ratio of internal and oil, and the rotational speed of the homogenizer, were investigated. Under the optimal operating parameters, the WELM had a demulsification percentage of just 0.481%, and the prediction results of RSM and ANN were 0.536% and 0.545%, respectively. Both models demonstrate good predictability. The WELM stability model has a high application value in the treatment of phenol-containing wastewater in the oil refining industry, and provides a green method of resource recovery. Full article

The treatment of oily sludge (OS) can not only effectively solve environmental pollution but also contribute to the efficient use of energy. In this study, the separation effect of OS was analyzed through sodium lignosulfonate (SL)-assisted sodium persulfate (S/D) treatment. The effects of SL concentration, pH, temperature, solid–liquid ratio, revolving speed, and time on SL adsorption solubilization were analyzed. The effects of sodium persulfate dosage, demulsification temperature, and demulsification time on sodium persulfate oxidative demulsification were analyzed. The oil removal efficiency was as high as 91.28%. The results showed that the sediment was uniformly and finely distributed in the S/D-treated OS. The contact angle of the sediment surface was 40°, and the initial apparent viscosity of the OS was 56 Pa·s. First, the saturated hydrocarbons and aromatic hydrocarbons on the sediment surface were adsorbed by the monolayer adsorption on SL. Stubborn, cohesive oil agglomerates were dissociated. Sulfate radical anion (SO₄⁻·) with a high oxidation potential, was formed from sodium persulfate. The oxidation reaction occurred between SO₄⁻· and polycyclic aromatic hydrocarbons. A good three-phase separation effect was attained. The oil recovery reached 89.65%. This provides theoretical support for the efficient clean separation of oily sludge. Full article

The use of cement emulsified asphalt mortar (CA mortar) in the track structure of high-speed speed railways has been gaining considerations by many researchers due to its coupled merits of the strength of cement as well as the flexibility of asphalt material. The asphalt to cement ratio (A/C) and the compatibility among constituent materials are crucial to the properties of CA mortar. To improve the performance properties and application of CA mortar, it is imperative to have a broad understanding of the composition mechanisms and compatibility between constituent materials. This paper summarizes interesting research outcomes related to the composition and properties of CA mortar. The consumption of water by cement promotes the breakdown of emulsified asphalt, likewise, the adsorption of asphalt droplets on the surface of cement grains retards the hydration process of cement. An appropriate A/C is required for the cement hydration rate to match the speed of demulsification of asphalt emulsion. Depending on the type and properties for which the CA mortar is designed to possess, the A/C ranges from 0.2 to 0.6 for type 1 (CAM I), and 0.6 to 1.2 for type 2 (CAM II). This paper also discusses measures taken to improve performance properties, compatibility, the interaction between constituent materials of CA mortar, and the use of additives as a partial replacement of cement in CA mortar production. The current review also suggests areas of interest for future research studies. This paper is useful to those who aim to understand or study the composition mechanisms and performance properties of CA mortar. Full article

Aggregate is an indispensable raw material for emulsified asphalt construction. For the purpose of explaining the influence of aggregate characteristics on the demulsification speed of emulsified asphalt, the surface energy and specific surface area (SSA) characteristics of aggregates were calculated based on the capillary rise method and the BET (Brunauer-Emmett-Teller) adsorption test. Afterwards, the effect of the surface energy and specific surface area of the aggregate on the emulsified asphalt demulsification speed was systematically studied by using ultraviolet spectroscopy as well as the orthogonal test. Experimental results indicate that the specific surface energy parameter of the aggregate is certainly related to the particle size of the aggregate. That is, the surface free energy of the unit system is proportional to the surface area A and the density of the interface unit. The specific surface area parameter of aggregates increases with the decrease of particle size, when the particle size is reduced to 600 mesh, the specific surface area parameters of the three aggregates selected in this paper tend to be consistent. Orthogonal experimental analysis demonstrates that the surface energy and specific surface area have an impact on the emulsion breaking speed and they are proven to be positively correlated. Meanwhile, in the case of small particle sizes, there is no statistically significant correlation between the physical properties of aggregates and the demulsification speed of emulsified asphalt, and the physical property of aggregates is not the main factor that affects the demulsification speed of the emulsified asphalt. On the contrary, the material properties of the aggregate, such as acid-base property and chargeability, are the dominant factors. Full article