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Process Solution Control

Historically, solution maintenance in plating operations has been considered most important in high-value-added situations (e.g., circuit boards or semiconductors). [Pg.215]

When source reduction options are implemented, however, process solution control becomes critical. As was seen in the discussion of Material Substitutions, most new processes will operate only within windows which are much narrower than those which they replace. And fully integrated systems, such as those discussed under Process Modification, require tracking of contaminants heretofore lost to the sewer. Therefore, the plating plant operator who wishes to pursue source reduction must consider familiarity with and control of all processes as crucial. [Pg.215]


Volatilization. The susceptibility of a herbicide to loss through volatilization has received much attention, due in part to the realization that herbicides in the vapor phase may be transported large distances from the point of application. Volatilization losses can be as high as 80—90% of the total applied herbicide within several days of application. The processes that control the amount of herbicide volatilized are the evaporation of the herbicide from the solution or soHd phase into the air, and dispersal and dilution of the resulting vapor into the atmosphere (250). These processes are influenced by many factors including herbicide application rate, wind velocity, temperature, soil moisture content, and the compound s sorption to soil organic and mineral surfaces. Properties of the herbicide that influence volatility include vapor pressure, water solubility, and chemical stmcture (251). [Pg.48]

Desorption is the reverse of the sorption process. If the pesticide is removed from solution that is in equdibrium with the sorbed pesticide, pesticide desorbs from the sod surface to reestabUsh the initial equdibrium. Desorption replenishes pesticide in the sod solution as it dissipates by degradation or transport processes. Sorption/desorption therefore is the process that controls the overall fate of a pesticide in the environment. It accomplishes this by controlling the amount of pesticide in solution at any one time that is avadable for plant uptake, degradation or decomposition, volatilization, and leaching. A number of reviews are avadable that describe in detad the sorption process (31—33) desorption, however, has been much less studied. [Pg.219]

Eor pesticides to leach to groundwater, it may be necessary for preferential flow through macropores to dominate the sorption processes that control pesticide leaching to groundwater. Several studies have demonstrated that large continuous macropores exist in soil and provide pathways for rapid movement of water solutes. Increased permeabiUty, percolation, and solute transport can result from increased porosity, especially in no-tiUage systems where pore stmcture is stiU intact at the soil surface (70). Plant roots are important in creation and stabilization of soil macropores (71). [Pg.223]

As previously mentioned in Chapter 5, one of the most severe disturbances for the power recovery train (PRT) is a generator breaker opening. This event often causes the PRT to trip on overspeed or other process or machine conditions. A control solution has been developed to keep the PRT and the process under control during breaker opening. [Pg.404]

Note that H is simply Henry s constant corrected for units. When the solute gas is readily soluble in the liquid solvent, Henry s law constant (H or H ) is small and Kj approximately equals k, and the absorption process is controlled by the gas film resistance. For systems where the solute is relatively insoluble in the liquid, H is large and K( approximately equals k, and the absorption rate is controlled by the liquid phase resistance. In most systems, the solute has a high solubility in the solvent selected, resulting in the system being gas film resistance controlled. [Pg.260]

This occurs in strongly acid or strongly alkaline solutions, but there are specific exceptions. Thus in concentrated nitric acid the metal is passive and the kinetics of the process are controlled by ionic transport through the... [Pg.659]

A generalized scheme, which summarizes certain of the most frequently observed kinetic characteristics for the reactions of a solid alone or with a gas, a liquid (solute) or another solid, is given in Table 2. The following processes may control the rate of product formation. [Pg.12]

Has consideration been given to the recovery of materials through the application of integrated source control on a process-by-process basis, for example, direct or indirect recovery of materials by sidestream treatment, process solution enhancement through sidestream removal of contaminants, conversion of waste to byproduct of value ... [Pg.12]

Another pathway by which targeted pollutants enter the wastewater stream is through the disposal of spent batch process solutions into the sewer system. Spent solutions consist of aqueous wastes and may contain accumulated solids as well. Spent solutions are typically bled at a controlled rate into the wastewater stream. Other sources of pollutants in wastewater streams include cleanup of spills and washdown of fugitive aerosols from spray operations. [Pg.17]

Every chromatographic process is controlled by the equilibrium distribution of the solute between the mobile and stationary phases. The retention volume V describing the volume of mobile phase that is required to elute the analyte from the column, is given by Equation 17.4 ... [Pg.390]

In dilute solutions of surfactants adsorption processes are controlled by transport of the surfactant from the bulk solution towards the surface as a result of the concentration gradient formed in the diffusion layer the inherent rate of adsorption usually is rapid. For non-equilibrium adsorption the apparent (non-equilibrium) isotherm can be constructed for different time periods that are shifted with respect to the true adsorption isotherm in the direction of higher concentration (Cosovic, 1990) (see Fig. 4.10). [Pg.109]

Alternatively, if the reactions at the surface are slow in comparison with diffusion or other reaction steps, the dissolution processes are controlled by the processes at the surface. In this case the concentrations of solutes adjacent to the surface will be the same as in the bulk solution. The dissolution kinetics follows a zero-order rate law if the steady state conditions at the surface prevail ... [Pg.161]


See other pages where Process Solution Control is mentioned: [Pg.431]    [Pg.215]    [Pg.431]    [Pg.215]    [Pg.2669]    [Pg.207]    [Pg.468]    [Pg.123]    [Pg.392]    [Pg.358]    [Pg.885]    [Pg.447]    [Pg.236]    [Pg.293]    [Pg.477]    [Pg.313]    [Pg.810]    [Pg.76]    [Pg.148]    [Pg.126]    [Pg.162]    [Pg.143]    [Pg.381]    [Pg.37]    [Pg.382]    [Pg.544]    [Pg.374]    [Pg.12]    [Pg.19]    [Pg.421]    [Pg.33]    [Pg.163]    [Pg.192]    [Pg.125]    [Pg.162]    [Pg.222]    [Pg.448]    [Pg.7]   


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Solute process

Solution processability

Solution processes

Solution processing

Solutizer process

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