River water stability

In seawater the thickness" of the double layer as given by k1 (Eq. 3.9) is a few Angstroms, equal approximately to a hydrated ion. In other words, the double layer is compressed and hydrophobic colloids, unless stabilized by specific adsorption or by polymers, should coagulate. Some of this coagulation is observed in the estuaries where river water becomes progressively enriched with electrolytes (Fig. 7.14a). That these colloids exist in seawater for reasonable time periods is caused... 

A very large petrochemical facility has many cooling systems and a variable water quality due to seasonal fluctuations. The river water makeup supply water is pumped approximately 100 km across a desert plain. The supply water pH can quickly increase to 8.6, the TDS rises to 1300 ppm, SS to 500 ppm (before clarification), chlorides to 650 ppm, and total hardness to 600 ppm. As a consequence, priority is given to stabilizing the makeup water quality as much as possible using acid dosing, but control is poor and acid incursions take place. 

Several water compositions are plotted on the stability diagrams in Figure 8.2. It can be seen that at shallow Earth surface pressures and temperatures, seawater plots in the stability field of dolomite whereas solutions of average river water composition and most shallow groundwaters plot in the field of calcite. With burial of carbonate sediments and elevated P and T, the dolomite field shrinks, but subsurface fluid compositions evolve toward a composition in equilibrium with dolomite. This conclusion is probably one of the most important arguments for the formation of dolomite during deep burial diagenesis (see also Hardie, 1987). Thermodynamic considerations favor this reaction path, as well as the fact that... 

Biodegradability - Metabolix PHA offer hydrolytic stability under normal service conditions but when exposed to microbial organisms naturally present they break down enzymatically in soil, composting, waste treatment processes, river water and marine environments. They also rapidly decompose to carbon dioxide and water and will degrade in anaerobic environments, unlike some other biodegradable polymers. 

Scatchard plots. Stability constants for the binding of Ou by a model ligand (histidine) and by natural organic ligands in river water were computed using Scatchard plot diagrams as described previously by Mantoura and Riley (1 ). The general equation for this analysis was ... 

Figure 6. Copper titrations of Neuse River water at 25°C. (%) Untreated water at in situ pH 6.78 glass-fiber filtered water at pH 6.78 (A) glass-fiber filtered water at pH 8.00 (0) UV-treated glass—fiber filtered water at 6.78 (4) twice filtered XJV-treated water at pH 6.78, first filtration by glass-fiber prior to UV-irradiation, second filtration by membrane (0.2fxm nuclepore) after irradiation. Model curves through data points were calculated according to stability constants determined in this work (Tables I and II). Dotted lines indicate limits on data used for calculation of conditional stability constants for organic binding.

It would appear likely that small amounts of Ale could be present as colloidal solid particles in many river waters. Conditions favorable for stabilizing polymeric Alb ionic species are readily... 

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