Organic pollutants, removal

Another treatment, currently used for industrial wastewater, is the adsorption on active carbon for organic pollutants removal. UV spectrophotometry can be proposed for the study of the effect of granular active carbon (GAC) on the adsorption of organic compound of a chemical effluent (Fig. 8). This example shows that the molecule, characterised by an absorption peak at 238 nm (not identified), is well adsorbed meanwhile, the one absorbing at 260-270 nm is not retained. The corresponding removal rates of TOC are, respectively, 27, 36 and 51% for the three GAC concentrations (5, 10 and 20 g.L-1). UV spectrophotometry can thus be used for process control and for the quality monitoring of the treated effluent. 

Since the relation between the UV spectrum shape and organic content (qualitative and quantitative) is evident in the previous industrial cases, a comparison concerning two ways of calculation of the efficiency of the organic pollution removal has been studied [3]. In Table 5, the results of TOC removal ratio and some UV yield estimations show that the TOC removal estimated from the UV semi-deterministic method is quite satisfactory. 

The Use of Modified Cellulose Fibres as a Sorbent for the Organic Pollutants Removal... 

FIGURE 1.275 MAS NMR (Vmas=5 kHz) spectra of (1, 3, 5) SiOj and (2,4, 6) hexyl-SiOj after CMP adsorption performed at 298, 258 K and 238 K. (Adapted from Micropor. Mesopor. Mater., 110, Baccile and Babonneau, Organo-modified mesoporous silicas for organic pollutant removal in water Solid-state NMR study of the organic/silica interactions, 534-542, 2008. Copyright 2008, with permission from Elsevier.)... 

Baccile, N. and Babonneau, F. 2008. Organo-modified mesoporous silicas for organic pollutant removal in water Solid-state NMR study of the organic/silica interactions. Micropor. Mesopor. Mater. 110 534-542. 

Catalysis Organic pollutant removal, noble metal salt reduction Membranes + Powders ... 

Organic pollutants removal in wastewater by heterogeneous photocatalytic ozonation. Chemosphere, 121, 1-17. 

Adsorption. Adsorption (qv) is an effective means of lowering the concentration of dissolved organics in effluent. Activated carbon is the most widely used and effective adsorbent for dyes (4) and, it has been extensively studied in the waste treatment of the different classes of dyes, ie, acid, direct, basic, reactive, disperse, etc (5—22). Commercial activated carbon can be prepared from lignite and bituminous coal, wood, pulp mill residue, coconut shell, and blood and have a surface area ranging from 500—1400 m /g (23). The feasibiUty of adsorption on carbon for the removal of dissolved organic pollutants has been demonstrated by adsorption isotherms (24) (see Carbon, activated carbon). Several pilot-plant and commercial-scale systems using activated carbon adsorption columns have been developed (25—27). 

Tubular reactors are used for reactions involving a gas and a liquid. In this arrangement, the gas phase is dispersed as bubbles at the bottom of a tubular vessel. The bubbles then rise through the continuous liquid phase that flows downwards as shown in Figure 4-14. An example of this process is the removal of organic pollutants from water by noncatalytic oxidation with pure oxygen. 

This chemistry has been investigated and implemented for wastewater minerahza-tion by oxidizing the organic pollutants. The process is very efficient, not selective and, as a consequence, almost all carbon matter can be removed. Topical areas also include soil and aquifer treatments, sometimes in combination with a secondary biotic process [145]. 

The primary target of studies on photocatalytic semiconductor suspensions has been water cleavage by visible light. Suspension-based photocatalytic processes are also useful for the removal of inorganic (metal ions) and organic pollutants, the reduction of CO2, the photodestruction of bacteria and viruses, and various organic reactions an example is the use of Pt-loaded CdS for the photocatalytic racemization of L-lysine [210]. 

The oxidative degradation of organic pollutants in water and air streams is considered as one of the so-called advanced oxidation processes. Photocatalytic decomposition of organics found widespread industrial interest for air purification (e.g., decomposition of aldehydes, removal of NO , ), deodorization, sterilization, and disinfection. Domestic applications based on Ti02 photocatalysts such as window self-cleaning, bathroom paints that work under illumination with room light, or filters for air conditioners operating under UV lamp illumination have already been commercialized. Literature-based information on the multidisciplinary field of photocatalytic anti-pollutant systems can be found in a number of publications, such as Bahnemann s [237, 238] (and references therein). 

Removability of Toxic Organic Pollutants from Wastewater in the Primary Aluminum Subcategory... 

---