Removal of Organic Pollutants

Buchhammer [129] described the design of new materials for removing organic pollutants such as p-nitrophenol or dyes from wastewater. The sorption of solved organic molecules on previously formed PSCs or PECs (PC/PA) was studied. The scheme of complex formation and possible structures is presented in Fig. 14. The sorption capability of such macromolecular assemblies increases with increasing molar mass and hydrophobicity of the macromolecules used. 

The solubilization of hydrophobic molecules such as pyrene (a fluorescence probe), or Nile Red (a solvatochromic probe) in nanoparticles was investigated by Nizri et al. [130]. They studied the morphology of the resulting nanoparticles and their ability to solubilize hydrophobic materials. As shown by AFM and SEM imaging, the particles are spherical, having a diameter of about 20 nm. From pyrene solubilization it appeared that the hydrophobicity of the nanoparticles depends on the ratio between SDS molecules and the charge unit of the polymer and therefore they confirmed the results described by other authors [128]. 

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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. 

Wang, L.K. and Wang, M.H.S., Removal of organic pollutants by adsorptive bubble separation processes, 1974 Earth Environment arid Resources Conference Digest of Technical Papers, Vol. 1, IEEE Cat. No. 74 CH0876-3EQC, pp. 56-57, September 1974. 

Microbiological conversion in molecular nitrogen by means of nitrification and denitrification, often in combination with the removal of organic pollutants... 

A screening study was conducted with samples from a Llobregat river WWTP in order to establish a better treatment for the removal of organic pollutants. Given that improvement of water quality is known to be achieved with the implementation of GAC filtration, the behaviour of surfactants (polyethoxylated nonylphenols, bromo-polyethoxylated nonylphenols) has been studied on seven different commercial GACs. These pollutants were efficiently removed using a bituminous coal-based GAC [38]. 

Solvent extraction has many features that make this separation technique applicable for the removal of organic pollutants from wastewater. The organic solutes can be recovered, and there is thus a potential for economic credit to the operation. In comparison with biological treatment, it is not subject to toxicity instabilities. The disadvantage is that, even with solvents having low solubilities in water, solvent losses can be substantial owing to... 

In recent years some studies were performed using submerged membrane modules coupled to photocatalytic systems for the removal of organic pollutants such as fulvic acid [84], bisphenol-A [85], para-chlorobenzoate [86]. 

Nevertheless, liquid-phase adsorption fundamentally onto activated carbon [2,85], silica [2,86,87], zeolites [2,88,89], and resins [90] provides a feasible technique, and is one of the most extensively used technologies for removal of organic pollutants from industrial wastewater [2,8,84-90],... 

Photochemical processes for solving pollution problems. Removal of organic pollutants and inorganic molecules (e.g. N03 and N02) from water. 

In this field, several authors have reported the complete removal of organic pollutants, such as formaldehyde (Do and Chen 1993), aniline (Brillas et al. 1996), phenol (Alvarez-Gallegos and Pletcher 1999), pesticides (Guivarch et al. 2003), herbicides (Boye et al. 2002), and industrial effluent containing naphthalene- and anthraquinone-sulfonic acids (Panizza and Cerisola 2001) by in situ electrogenerated hydrogen peroxide catalyzed by iron ions. 

Panizza, M. and Cerisola, G. (2001) Removal of organic pollutants from industrial wastewater by electrogenerated Fenton s reagent. Water Res. 35, 3987-3992. 

Photocatalytic reactions catalyzed by Ti02 powder have been investigated extensively because they provide effective routes for removal of organic pollutants... 

Anodic oxidation was shown to be a useful method for the removal of organic pollutants from aqueous solutions [15]. Partial decomposition of hazardous organic compounds to biodegradable compounds or complete decomposition to H2O and CO2 can be achieved by the electrochemical treatment of waste [14]. Two different categories of electrochemical treatment of waste-water or waste can be distinguished ... 

The effectiveness of activated carbon for the removal of organic pollutants from water by carbon adsorption is enhanced by its large surface area, an important factor in the adsorption process. The surface area of activated carbon typically can range from 500 to 1400 nP/g. Table 2 presents the surface areas of several commercially available activated carbons (6). Some have large surface areas as high as 2500 aP/g. 

A variety of cogeneration processes has been recently described in the literature. A brief list is shown in Table 10.2, where representative examples involving porous materials and different types of fuel cells are included. In most cases, electrocogeneration allows for a simultaneous removal of organic pollutants and flue gas emissions. Examples of this possibility will be treated in Chapter 12. 

Removal of organic pollutants from wastewaters using ELMs... 

Titania Titania has three common polymorphs, anatase, rutile, and brookite, and is widely used as a white pigment The technological applications are as a photocatalyst [293], the removal of organic pollutants from water, and in photovoltaic devices [294] which convert light to electricity. Bulk titania is a n-type semiconductor, the conductivity of which can be enhanced by either reduction or doping. 

Activated carbon Hydrophobic surface, favors organics over air or water Removal of organic pollutants from aqueous and gaseous effluents Cheapest hydrophobic adsorbent, workhorse of the pollution-control business Difficult to regenerate if fouling occurs, sometimes can catch fire during regeneration... 

Surfactant-modified cellulose fibres appeared to be effective sorbents for the removal of organic compounds dissolved in aqueous media. Given the ready availability of this type of substrate and its low cost, the present approach could be promising in applications related to the removal of organic pollutants and toxic substances in wastewaters. However, the adsorbed surfactant molecules were found to desorb from the cellulose surface during the recycUng of the substrate [29], limiting its possible use for multiple adsorption cycles in a... 

M. Akhtar, S.M. Hasany, M.I. Bhanger, and S. Iqbal, "Sorption potential of Moringa oleifera pods for the removal of organic pollutants from aqueous solutions". Journal of Hazardous Materials, Vol. 141, pp. 546-556,2007a. 

S. Alila and S. Boufi, "Removal of organic pollutants from water by modified cellulose fibres", Ind. Crops Prod., Vol. 30, issu 1, pp. 93-104,2009. 

Heterogeneous photocatalysis is a promising new alternative method for the removal of organic pollutants in water (Carey, 1976). The degradation of organic pollutants in water, using irradiated dispersions of titanium dioxide, is a growing area of both fundamental and applied research. 

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