Fresh water becomes a limited resource in the industry. In order to help chemical industries use other water sources and close their water cycle for the production of steam, a well-founded insight on the challenges and possibilities of switching from one specific water quality to another is needed. A case study for Monsanto Europe N.V. was carried out, but the main findings hold for many more applications, as many industries struggle with water scarcity and feel the need to reuse wastewater. Besides demineralization by ion exchange (IEX), the total organic carbon (TOC) concentration, composition, and the formation of organic acids under boiler conditions were investigated for two different water qualities (Antwerp tap water and wastewater after reverse osmosis (RO) treatment). The comparison included the effect of TOC composition on its removal by IEX and the potential corrosiveness of TOC compounds. Despite tap water showing a more efficient and higher TOC removal compared to RO permeate (93% and 57%, respectively), tap water led to more organic acid formation under boiler conditions. Including the composition of the organic matter in TOC corrosiveness assessment may offer multiple advantages, not in the least economic benefits, when less treatment is required in order to meet the TOC limit value.
Chemical industries around the world show an increasing awareness of their ecological footprint, including their water use. A shift toward alternative water sources, such as wastewater streams or surface water, is slowly becoming a well-known concept to reduce the intake of ground and drinking water. However, a change of intake water often leads to unforeseen challenges (for example, faster breakthrough of organic matter and growth of biofilms) and requires a review of the currently used water treatment technology. A study of surface water used in various Antwerp companies was carried out, but the acquired knowledge can tackle multiple unexpected problems in different applications, as many industries undergo an alteration in their water management due to the increasing water scarcity. Demineralization of Biesbosch surface water by ion exchange and the associated removal of both total organic carbon and microbial cells were investigated with liquid chromatography in combination with organic carbon detection characterization and flow cytometric monitoring. The effect of monochloramine and sodium bisulfite on the ion exchange operation and the respective removal efficiencies were investigated. Considering a total organic carbon limit value of 250 ppb, the addition of both chemicals together had a positive effect on the demineralization operating time. On average, >93% of the organic matter was removed from the incoming feedwater. The organic matter removal mechanism by the anion exchange resins was mostly (acidic) adsorption at low pH in the scavenger and by ion exchange at neutral pH in the weak and strong anion exchange resins. The microbial cell concentration was reduced by almost 2 log units, from 8.16 × 10 5 cells/mL in the feedwater to 8.58 × 10 3 cells/mL in the demineralized water, and was the result of cell lysis due to a large pH drop over the consecutive resin columns. In addition, the end water quality was suited to be used as boiler feedwater, as little to no formation of corrosive organic acids occurred under boiler conditions.
We describe a rapid and simple procedure for the simultaneous quantitation of endogenous 13-cis-retinoic acid, all-trans-retinoic acid, and retinol by isocratic normal-phase HPLC with ultraviolet detection, in 0.5 mL of human plasma. A silica adsorption column was eluted with n-hexane:2-propanol:acetic acid (200:0.7:0.135 by vol) at 0.9 mL/min, and the effluent monitored at 350 nm. The arotinoid ethylsulfonic acid Ro 15-1570 was used as the internal standard. High sensitivity, allowing quantitation of physiological concentrations, was achieved, particularly for the retinoic acid isomers. The detection limits were 0.5 microgram/L in plasma for both 13-cis- and trans-retinoic acid, and 10 micrograms/L for retinol. The CVs for between-day determinations of the lowest quality-control concentration (n = 12) were 4.8% for 13-cis-retinoic acid, 3.4% for trans-retinoic acid, and 3.0% for retinol. The mean (+/- SD) concentrations of 13-cis-retinoic acid (1.79 +/- 0.56 microgram/L), trans-retinoic acid (1.35 +/- 0.42 microgram/L), and retinol (533 +/- 58 micrograms/L) measured in plasma from 22 healthy volunteers agreed well with those previously reported.
This work evaluates the effect of film-forming amines (FFA) on the acidic stress-corrosion cracking (SCC) resistance of NiCrMoV turbine steel. Contact angle measurements show an increased hydrophobicity of the surface when coating the steel with oleyl propylene diamine (OLDA). According to potentiodynamic measurements and post-mortem scanning electron microscopy (SEM) analysis, anodic dissolution and hydrogen embrittlement still occur when the steel is FFA coated. In situ constant extension rate testing (CERT) in acidic aqueous environment at elevated temperature of FFA-coated steel shows a ductility gain compared to non-coated steel, explained by a decrease in both corrosion rate and hydrogen uptake.
Summary. An electrophoretic method for the separation of acid poly-A description of the apparatus is given and some results of the separation electrolytes from proteins in cell extracts is described.of extracts from Bordetella pertussis are included.
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