scholarly journals Metal Rod Surfaces after Exposure to Used Cooking Oils

2021 ◽  
Vol 14 (1) ◽  
pp. 355
Author(s):  
Nina Bruun ◽  
Juho Lehmusto ◽  
Jarl Hemming ◽  
Fiseha Tesfaye ◽  
Leena Hupa

Used cooking oils (UCOs) have a high potential as renewable fuels for the maritime shipping industry. However, their corrosiveness during storage and usage are some of the concerns yet to be investigated for addressing compatibility issues. Thus, the corrosion of steels and copper exposed to the UCOs was studied through the immersion of metal rods for different periods. The changes on the rod surfaces were analyzed with a scanning electron microscope (SEM). After the immersion, the copper concentration dissolved in the bio-oils was measured using inductively coupled plasma-optical emission spectrometry (ICP-OES). The free fatty acids and glycerides were analyzed using gas chromatography with flame ionization detection (GC-FID). The acid number (AN), water concentration, as well as density and kinematic viscosity of the bio-oils were determined with standard methods. The UCOs with the highest water content were corrosive, while the oils with lower water concentrations but higher ANs induced lower corrosion. After mixing two different UCOs, the metal corrosion decreased with an increasing concentration of the oil with lower corrosive properties. The lower corrosion properties were most likely due to the monounsaturated fatty acids, e.g., oleic acid in oils. These acids formed a barrier layer on the rod surfaces, thereby inhibiting the permeation of oxygen and water to the surface. Even adding 0.025 wt% of tert-butylamine decreased the corrosivity of UCO against polished steel rod. The results suggested that mixing several oil batches and adding a suitable inhibitor reduces the potential corrosive properties of UCOs.

2013 ◽  
Vol 41 (2) ◽  
pp. 518 ◽  
Author(s):  
Vildan UYLASER ◽  
Gökçen YILDIZ

In this study, five different types of commercial table olive: Domat, Kalamata, Edremit (green), Edremit (black) and Gemlik, from Turkey, were investigated for the fatty acid composition and mineral content. Fatty acid analyses were performed by capillary gas chromatography. The fatty acid results showed that all table olives characterized by high level of were oleic acid (C18:1, 57.473-72.294%), linoleic acid (C18:2, 7.914-25.279%) and palmitic acid (C16:0, 9.735-16.441%). Moreover, in terms of the unsaturated oil content and a ratio of polyunsaturated fatty acids (PUFA) to saturated fatty acids (SFA) value, Kalamata olives were found to be more advantageous as compared to the other table olive types. The sodium (Na), magnesium (Mg), calcium (Ca), phosphorus (P), iron (Fe) and potassium (K) content of table olives were measured by inductively coupled plasma optical emission spectrometry (ICP-OES). Na was the most concentrated mineral detected (6637.722-20613.666 mg/kg), followed by K (2814.296-3386.520 mg/kg) and Ca (342.595-742.894 mg/kg). Results showed that there are differences among the fatty acid and mineral content of the commercial table olives depending on type.


2020 ◽  
Vol 16 ◽  
Author(s):  
Diogo L. R. Novo ◽  
Priscila T. Scaglioni ◽  
Rodrigo M. Pereira ◽  
Filipe S. Rondan ◽  
Gilberto S. Coelho Junior ◽  
...  

Background: Conventional analytical methods for phosphorus and sulfur determination in several matrices present normally analytical challenges regarding inaccuracy, detectability and waste generation. Objective: The main objective is proposing a green and feasible analytical method for phosphorus and sulfur determination in animal feed. Methods: Synergic effect between microwave and ultraviolet radiations during sample preparation was evaluated for the first time for the animal feed digestion associated with further phosphorus and sulfur determination by ion chromatography with conductivity detection. Dissolved carbon and residual acidity in final digests were used for the proposed method assessment. Phosphorus and sulfur values were compared with those obtained using conventional microwave-assisted wet digestion in closed vessels associated with inductively coupled plasma optical emission spectrometry and with those obtained using Association of Official Analytical Chemists International official method. Recovery tests and certified reference material analysis were performed. Animal feeds were analyzed using the proposed method. Results: Sample masses of 500 mg were efficiently digested using only 2 mol L -1 HNO3. The results obtained by the proposed method was not differing significantly (p > 0.05) from those obtained by the conventional and official methods. Suitable recoveries (from 94 to 99%), agreement with certified values (101 and 104%) and relative standard deviations (< 8%) were achieved. Phosphorus and sulfur content in commercial products varied in a wide range (P: 5,873 to 28,387 mg kg-1 and S: 2,165 to 4,501 mg kg-1 ). Conclusion: The proposed method is a green, safe, accurate, precise and sensitive alternative for animal feed quality control.


Author(s):  
Masoud Aghahoseini ◽  
Gholamhassan Azimi ◽  
M. K. Amini

Determination of traces of Cd, Co, Cu, Mn and Pb elements in zirconium and its alloys by inductively coupled plasma optical emission spectrometry (ICP OES) suffers from severe spectral interferences...


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