Phenol recovery

Several studies are devoted to the extraction of phenolic compounds. These compounds are particularly interesting from a practical viewpoint, as phenol derivatives are toxic pollutants that have marked detrimental effects on living organisms in general therefore, the development of effective methods of phenols recovery is a long-standing problem of analytical chemistry. To determine phenolic compounds at the trace level, typically preconcentration and separation from accompanying substances is required, but the extraction of phenolic compounds with conventional solvents is often not quantitative. From a more theoretical viewpoint, phenolic compounds exhibit a wide structural variability, thus, a study of their... 

Removal of sulfanilic acid from wastewater Lactic acid purification and concentration Enrichment of bisphenol A Phenol recovery from aqueous solutions Zinc(ll) recovery from HCI solution Hydrogen separation from methane steam conversion products... 

Selected data published by Patsias and Papadopoulou-Mourkidou [114] illustrate sorption s dependence on sample volume (Figure 2.36). Their research pursues development of an automated online SPE-HPLC methodology for analysis of substituted anilines and phenols. Recovery (%) was measured for numerous compounds on various polymeric sorbents, but the only data presented here are those in which a styrene-divinylbenzene polymeric sorbent was used for analysis of aniline, phenol, 4-nitroaniline, and 4-nitrophenol. Aqueous sample volumes of 5, 10, 25, 50, 75, 100, 125, and 150 mL were acidified to pH 3 before SPE. 

The phenol recovery (6) section separates and recycles the phenol contained in various streams from different plant sections. 

The general proportions may be varied from one end of the tower to the other to accommodate changing liquid volumes and physical properties. These towers have been used in diameters ranging from a few inches for laboratory work up to 2.4 m (8 ft) in diameter by 12.2 m (40 ft) tall for purposes of deasphalting petroleum. Other commercial services include furfural extraction of lubricating oils, desulfurization of gasoline, phenol recovery from wastewaters, and many others. Columns up to 4.5 m in diameter and up to 50 m in height have been constructed. 

Finally, if the solvent recovery unit is operating at 67% efficiency, then it operates as though it has only four theoretical stages. This means that the fraction of phenol recovery from the toluene reduces to 0.1 (verify this for yourself using Fig. 3). 

F. Pithan, C. Staudt-Bickel, CrossUnked copolyimide membranes for phenol recovery from process water by pervaporation, ChemPhysChem, 4(9), 2003, 967... 

Savkovic-Stevanovic, J., S. Krstic (2006) Risk reduction support system of the phenol recovery plant. Petrol. Coal, 48, 6-13. 

The pretreatment unit operations generally consist of equalization, neutralization, and oil separation. In addition, phenol recovery (to reduce the phenol concentration) and spill protection for spent acids and spent caustics may be required in some cases. 

Al-Megren et al. (2013) apphed a semibatch membrane system and a continuous membrane reactor (flat-sheet membranes of polypropylene and polyethersuUbne) for the direct hydroxylation of benzene using H2O2 as an oxidant. With the help of water on the stripping side of the membrane unit, the produced phenol was recovered. They explored the effect of the hydrophUic and hydrophobic character of the membrane material on the phenol recovery at different flow rates of the feed and the stripping phases. The obtained results showed that the hydrophUic membrane has a better performance. What is more, the continuous removal of the phenol from the reaction side contributed to a reduction in byproduct (such as benzoquinone) formalion and a halt in biphenyl and tars formalion. The performance of a continuous system was better than the semibatch system, mainly because of the total amount of phenol recovered in the permeate. In particular, more than 25% of the produced phenol was recovered in the continuous membrane reactor whereas this value for the semibatch membrane system was less than 1%. 

A. M. Urtiaga, M. I. Ortiz, and J. A. Irabien, Mathematical modeling of phenol recovery with supported liquid membranes. Abstract of paper of the International Solvent Extraction Conference, Kyoto, Japan (July 16-21, 1990). 

AC provide one of the most efficient materials for the removal of phenols from aqueous media. Traditionally, powdered AC and GAC have been used with new attention being given to the use of ACFs, Rodriguez-Reinoso (1997). It has been known for some time that adsorptions of phenols exhibits irreversibility and D browski et al. (2004) review this topic. Applications of AC to water purification must produce a pollution-free water supply, with little interest in phenol recovery. Hence, irreversible adsorption ensures an efficient way of trapping the phenols. 

According to the diagram, tower 1 requires a still and 15 theoretical plates. Since the bottoms of this tower are essentially water, live steam could be used, but if the same phenol recovery (99.99 per cent) were obtained, a total of 20 theoretical plates would be required. The large increase in the number of plates is due to dilution by the large amount of vapor used. If the same bottoms composition had been maintained instead of the same recovery, 16 theoretical plates would be required and the recovery would be 98.9 per cent. 

Ta Acid EyactionatiOn. As another example of such calculations, considei the fractionation of a 35 mol per cent phenol, 15 mol per cent o-cresol, 30 mol per cent w-cresol, 15 mol per cent xylenols, and 5 mol per cept heavier. Kie overhead is to be 95 mol per cent phenol, and the phenol recovery is to be 90 per cent. The still pressure will be 250 mm. Hg abs., and 4 mm. Hg pressure drop will be allowed per theoretical plate. A reflux ratio 0/D equal to 10 will be employed. 

Wu H S and Li C C (2008), Kinetic study of phenol recovery using phase-transfer catalysis in horizontal membrane reactor , Chem Eng J, 144,502-508. 

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