Sorption material

TESTING OF SORPTION MATERIALS FOR ARSENIC REMOVAL FROM WATERS... 

Effective sorption materials for arsenic are needed for decentralized water cleaning or for effluent treatment and downstream remediation (on site or in situ) of contamination sources. 

This sorption material was suggested by Peraniemi et al. [2] for analytical enrichments of phosphate and arsenate. The activated carbon was shaken with a solution of Zr0(N03)2 as described in [2] and a final concentration of 28 mg Zr per g activated carbon was yield. 

This porous material is a commercial sorption material of the company Dr. Ecker GmbH (GERMANY) which is a composition of calcite, brucite, fluorite and iron hydroxides (RFA 14 % Fe203). 

An amount of 0.5 g of sorption material was shaken with 50 mL of carbonate buffered water (pH = 7, 10 mg/L sulfate, 14 mg/L chloride) containing 500 pg/L of each As(III) and As(V). Samples were taken in increasing time intervals to investigate the kinetics of the sorption process. The arsenic species were measured by IC-ICP-MS [5]. 

Another technique is gaining interest because of the ease of regeneration and improved flow characteristics (small and constant pressure drops). Instead of physically trapping a pollutant in its pores, the technique involves direct attachment of the contaminant molecules to the sorption material, usually a polymer. All molecules are composed of a number of atoms with a confluence of electrons spinning around them in what is called an electrostatic field or electron cloud. The cloud, however, is not necessarily uniformly distributed. 

All these types of solute-solvent associations are summed up in a rule of thumb learned by all chemists like dissolves like. The chemical processing industry depends on the ability to separate a useful chemical from a solvent by an extraction process. If a chemist wants to extract nonpolar chemicals, he or she would use a nonpolar sorption material. The opposite is equally true. In a mixture of polar and nonpolar chemicals, the two classes of compounds could be separated from each other. The analytical techniques of gas and liquid chromatography are based on this principle. In applying this principle to an enviromnental issue, however, the fact that the pollutants have a range of polarities makes the system problematic. Thus, carbon is the material of choice because its affinity is based on molecular size, not on polarity. 

Daus, B., Wennrich, R. and Weiss, H. (2004) Sorption materials for arsenic removal from water a comparative study. Water Research, 38(12), 2948-54. 

Sorption effects in the macroscopic scale are usually used for non-continuous pumping. They contain a highly porous sorption material like activated carbon or zeolites with a huge inner surface. The sorption material is usually cooled down by liquid nitrogen. They are regenerated by heating the sorption material to temperatures of several hundred degrees Celsius after a disconnection of pump and vacuum-chamber. 

Abstract. Activated carbons were chosen as an efficient hydrogen sorption materials to design gas storage systems. Based on experimental data empirical dependences for choosing commercially available carbon hydrogen sorbents systems were proposed. To increase gas sorption capacity technology of carbon additional activation was applied. 

Application of sorption material based on activated carbon in solid sorption... 

The attachment of particular solute molecules to the surface of the particulate sorption packing material can be achieved by a number of different methods, which are outside the scope of this paper. There are a large number of different sorption materials and complex physical and chemical interactions which must be considered. The most common sorption materials are activated carbon, silica gel, activated alumina, molecular sieves, and ion exchange resins. This chapter deals with the industrial aspects of handling these materials and operating process-scale equipment, but does not look at the choice of sorption material for a particular process. 

Backwashing of some packed beds is practiced to remove impurities and to regenerate the sorption material. It may also be necessary to chemically sanitise the column to minimise the build up of microorganisms. 

Synthesis and study of sorption materials for uranium recovery... 

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