Adsorption agents

Sacrificial adsorption agents such as lignosulfonates (148—151) can be used to reduce the adsorption of more expensive polymers and surfactants. Other chemicals tested include poly(vinyl alcohol) (152), sulfonated poly(vinyl alcohol) (153), sulfonatedpoly(vinylpyrrohdinone) (153), low molecular weight polyacrylates (154), and sodium carbonate (155). 

Lignosulfonate has been reported to increase foam stabihty and function as a sacrificial adsorption agent (175). Addition of sodium carbonate or sodium bicarbonate to the surfactant solution reduces surfactant adsorption by increasing the aqueous-phase pH (176). 

Adsorption to activated carbon or another type of adsorption agent... 

In an adsorption process, molecules are collected on the surface of a substance or agent and held there by electrostatic force. That is in contrast to absorption, where the collection takes place within the agent, like a solvent. Hence, the uncornmon suffix ad. When the adsorption agent is a molecular sieve, it might seem that the collection of the liquid in the pores is more like ab- than ad-. But the collection is on the surface of the pores, so don t get too confused. 

Under certain process conditions, high yields of carbon filaments can be obtained on the catalyst during the catalytic decomposition of methane. Currently, there is a great interest in these carbon filaments, as the unique properties exhibited by these materials can be exploited in a number of applications such as catalyst support, energy storage devices, selective adsorption agents and... 

Chemicals Primary surfactant (e.g., petroleum sulfonate) Co-surfactant/co-solvent (e.g., C3 to C5 alcohol) Polymer (e.g., xanthan) Alkaline agents (e.g., sodium carbonate) Bactericides (e.g., formaldehyde) Sacrificial adsorption agents... 

In this section I examine some of the important properties of cells pertaining to applications in process engineering. Henceforth, the emphasis is on production of some desired compound considerations analogous to those outlined here apply to use of cells as adsorptive agents and decomposition catalysts in waste treatment. 

In a relatively few years zeolites were promoted from simple adsorption agents to catalysts of wide spread use in all fields of chemistry. Apart from their acidic properties generated by exchanging their Na+ or K+ starting forms by ammonium ions and subsequent decomposition of the latter, their unique properties as supports for various precious metals and their solution behaviour attracted much of the attention devoted to catalysis. 

Martin, G.J. Ion Exchange and Adsorption Agents in Medicine Little, Brown, Co. Boston, MA, 1955. 

Prior to their use as adsorption agents or after industrial utilization for the adsorption of water, zeolites have to be dehydrated. This is carried out at 450 to 650°C e.g. in a rotary tube furnace or a similar unit. Industrially zeolites charged with water or other compounds are regenerated directly by passing hot dry inert gas through the absorber. 

Figure 11 shows the change of the specific surface area of the gel with time after gelation. Specific surface area is measured by the Bru-nauer-Emmet-Teller (BET) method by using N2 gas as the adsorptive agent. The surface area decreases with time this observation corresponds to Figure 10, in which a rough particle surface turned smooth. 

Adsorption is the process of concentration of gases, vapours or liquids on the surface of pores of solid materials, as a result of adsorption forces. Two types of the adsorption forces may be considered — physical and chemical. When the substance adsorbed is bound to the surface of the adsorption agent by intermolecular forces (particularly dispersion forces), the adsorption is of a physical nature. Chemisorption occurs when these forces have the character of chemical interactions. The adsorption process depends on the temperature, pressure and chemical composition of the adsorbed gas and adsorbing material. The adsorption is always connected with a release of adsorption heat (and thus an appropriate level of cooling should be provided for large adsorption units). 

Hygroscopic powder, very similar in appearance to the above-described adsorption agent. The particles show a honeycomb-like secondary structure the preparations show very imiform powder patterns (according to Glemser [17], they consist of e-phase). Any water adsorbed during use is incorporated in the form of OH groups and thus causes rehydration [18]. 

Because of the unique gelling properties of alginates, they have been used as food thickeners, dental molds, and adsorption agents for removal of radioactive toxins (e.g., and In pharmaceutical and biomedical science, algi-... 

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