Solubility size dependence

Fermentation broths are complex, aqueous mixtures of cells, comprising soluble extracellular, intracellular products and any unconverted substrate or unconvertible components. Recovery and extraction of product is important in bioprocess engineering. In particular separation is a useful technique it depends on product, its solubility, size of the process, and product value. Purification of high-value pharmaceutical products using chromatography such as hormones, antibody and enzymes is expensive and difficult to scale up.1 Tire necessary steps to follow a specific process depend on the nature of the product and the characteristics of the fermentation broth. There are a few steps for product recovery the following processes are discussed, which are considered as an alternative for product recovery from fermentation broth. 

The Size Dependence of the Solubility has also a thermodynamic base. As an example we follow arguments presented by Schindler (1967) and consider as an example the reaction... 

In 1803 Dalton read a paper to the Manchester Literary and Philosophical Society in which he mentioned his atomic theory for the first time. But his reference to it was cryptic. The paper dealt with the solubility of different gases in water. After conjecturing that the solubility might depend on the size of the particles of which the gases were composed, Dalton went on ... 

Emulsifying activity index (EAI) is a measure of the ability of protein to emulsify oil, which depends on solubility, size, charge, and surface activity of the protein molecules. The effect of proteolysis with pronase E on EAI of the modified protein was relatively insignificant (Figure 6) However, deamidation appeared to enhance EAI, especially at pH values more basic than the isoelectric point (pH 4.7). 

The supersaturation is expressed by S = C/C0, with Cthe amount dissolved and C0 the normal solubility (kg crystais/kg water). The mean growth velocity is that at one face of the crystal the length increase is G = 2v (m/sec). Data are for crystals in the size range 0.5-1.0 mm in the presence of other crystals. The asterisk denotes that the growth rate probably is size-dependent. 

Synthesis of oil soluble micellar calcium thiophosphate was performed in a one-step process involving the reaction of calcium oxide, tetraphosphorus decasulfide and water in the presence of an alkylaryl sulfonic acid. This product could be defined as a calcium thiophosphate hard-core surrounded by a calcium alkylarylsulphonate shell in accordance with a reverse micelle type association in oil. Three micellar products with the same chemical nature core were prepared, each with different core/shell ratio of 0.44, 0.92 and 1.54. Better performances are expected with products of higher core/shell ratios. The antiwear performance of micellar calcium carbonates is directly linked to the size of the mineral CaC03 colloidal particles. At a concentration of 2 % micellar cores, no antiwear effect is observed whatever the micellar size. At an intermediate concentration of 4 % of micellar cores, the wear scar diameter is clearly dependent on the micellar size, slipping from 1.70 mm to 1.10 mm, then to 0.79 mm when the core diameter moves from 4.37 nm to 6.07 nm, then to 6.78 nm. Size dependence is increased at a concentration of 5 % in colloidal cores. This clearly confirms the size dependence of the micellar cores on their antiwear performance (Delfort et al.,... 

It seems reasonable that molecules of a surfactant may diffuse from the spray droplet into the cuticle of leaves perhaps via imperfections and cracks and then align themselves in monolayers with their nonpolar ends oriented in the cutin and wax. The polar ends will thus also form a layer whose size depends on the length of the hydrophilic chain of the surfactant molecule. These layers or hydrophilic channels will presumably attract water, causing swelling of the cuticle, and thus channels or pores are formed along which herbicide molecules can diffuse according to their various chemical properties (solubility, residual chemical charge, polar properties, etc.). 

A polymer/monomer (polymer/repeat-unit or polymer/macrocycle) switch may become of practical importance where a polymer decorated with certain groups has specific size-dependent properties that the monomeric units do not have. The modulation of the conversion between polymeric and monomeric (or macrocyclic) states would also result in the modulation of these properties. Moreover, such size switches, represented by polymerization/depolymerization processes that operate under the control of external events, are examples of environmentally-friendly recyclable polymers (reduction of waste treatment). As well, if the polymer has low solubility and the polymer/monomer switch can work in spite of this, then it becomes possible to reversibly generate a precipitating (solid) polymeric material from a liquid solution of monomer. 

In Section 7.8 we showed that the size dependence of the solubility has also a thermodynamic base. In Figure 7.24a we demonstrated the influence of molar surface on solubility of CuO and Cu(OH)2 at pH = 7. This figure suggested that Cu(OH)2(s) becomes more stable than CuO(s) for very finely divided CuO crystals. In precipitating Cu(II), Cu(OH)2 may be precipitated incipiently d is very small) but CuO becomes more stable than Cu(OH)2(s) upon growth of the crystals, and an inversion of Cu(OH)2(s) into the more stable phase becomes possible (Schindler, 1967). 

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