Phenol

About: Phenol is a research topic. Over the lifetime, 10722 publications have been published within this topic receiving 182898 citations. The topic is also known as: carbolic acid & Karbolsaeure.

Clay-organic complexes as adsorbents for phenol and chlorophenols.

Abstract: Several clay-organic complexes were synthesized by placing quaternary ammonium cations on smectite by cation exchange. They were then examined for their ability to adsorb phenol and several of its chlorinated congeners. The organic cations used were: hexadecylpyridinium (HDPY+), hexadecyltri- methyl ammonium (HDTMA+), trimethylphenyl ammonium (TMPA+), and tetramethylammonium (TMA+). The complexes containing long-chain alkyl (hexadecyl) groups were the most hydrophobic and adsorbed the phenols from water in proportion to their hydrophobicities, which increase with chlorine addition (phenol < chlorophenol < dichloropohenol < trichlorophenol). With n-hexane as the solvent, different adsorption was found which depended on the type and degree of solvent interactions with the compound and the clay-organic complex. Thus, the amount of adsorption of these phenols on clay-organic complexes was dependent on the relative energies of adsorbent-adsorbate and adsorbate-solvent inter- actions.

Peroxidase-catalyzed removal of phenols from coal-conversion waste waters

Abstract: A novel, enzymatic approach has been developed for the removal of phenols from coal-conversion aqueous effluents. Treatment with horseradish peroxidase and hydrogen peroxide precipitates 97 to 99 percent of the phenol in a wide range of pH and phenol concentrations; both model mixtures and real industrial waste-water samples have been treated successfully. Other pollutants, such as polychlorinated biphenyls, can be enzymatically coprecipitated with the phenols.

Manganese oxides at different oxidation states for heterogeneous activation of peroxymonosulfate for phenol degradation in aqueous solutions

Abstract: A series of manganese oxides (MnO, MnO2, Mn2O3 and Mn3O4) were synthesized and tested in heterogeneous activation of peroxymonosulfate (PMS) for phenol degradation in aqueous solutions. Their properties were characterized by several techniques such as X-ray diffraction (XRD), thermogravimetric-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), and N2 adsorption/desorption isotherms. Catalytic activities of Mn oxides were found to be closely related to the chemical states of Mn. Mn2O3 is highly effective in heterogeneous activation of PMS to produce sulfate radicals for phenol degradation compared with other catalysts (MnO, MnO2, and Mn3O4). The activity shows an order of Mn2O3 > MnO > Mn3O4 > MnO2. Mn2O3 could completely remove phenol in 60 min at the conditions of 25 mg/L phenol, 0.4 g/L catalyst, 2 g/L PMS, and 25 °C. After heat regeneration, the activity could be fully recovered. A pseudo first order model would fit to phenol degradation kinetics and activation energy was obtained as 11.4 kJ/mol.

Different crystallographic one-dimensional MnO2 nanomaterials and their superior performance in catalytic phenol degradation.

Abstract: Three one-dimensional MnO2 nanoparticles with different crystallographic phases, α-, β-, and γ-MnO2, were synthesized, characterized, and tested in heterogeneous activation of Oxone for phenol degradation in aqueous solution. The α-, β-, and γ-MnO2 nanostructured materials presented in morphologies of nanowires, nanorods, and nanofibers, respectively. They showed varying activities in activation of Oxone to generate sulfate radicals for phenol degradation depending on surface area and crystalline structure. α-MnO2 nanowires exhibited the highest activity and could degrade phenol in 60 min at phenol concentrations ranging in 25-100 mg/L. It was found that phenol degradation on α-MnO2 followed first order kinetics with an activation energy of 21.9 kJ/mol. The operational parameters, such as MnO2 and Oxone loading, phenol concentration and temperature, were found to influence phenol degradation efficiency. It was also found that α-MnO2 exhibited high stability in recycled tests without losing activity, demonstrating itself to be a superior heterogeneous catalyst to the toxic Co3O4 and Co(2+).

Quantification of the Oxidizing Capacity of Nanoparticulate Zero-Valent Iron

Abstract: Addition of nanoparticulate zero-valent iron (nZVI) to oxygen-containing water results in oxidation of organic compounds. To assess the potential application of nZVI for oxidative transformation of organic contaminants, the conversion of benzoic acid (BA) to p-hydroxybenzoic acid (p-HBA) was used as a probe reaction. When nZVI was added to BA-containing water, an initial pulse of p-HBA was detected during the first 30 min, followed by the slow generation of additional p-HBA over periods of at least 24 h. The yield of p-HBA increased with increasing BA concentration, presumably due to the increasing 'ability of BA to compete with alternate oxidant sinks, such as ferrous iron. At pH 3, maximum yields of p-HBA during the initial phase of the reaction of up to 25% were observed. The initial rate of nZVI-mediated oxidation of BA exhibited a marked reduction at pH values above 3. Despite the decrease in oxidant production rate, p-HBA was observed during the initial reaction phase at pH values up to 8. Competition experiments with probe compounds expected to exhibit different affinities for the nZVI surface (phenol, aniline, o-hydroxybenzoic acid, and synthetic humic acids) indicated relative rates of reaction that were similar to those observed in competition experiments in which hydroxyl radicals were generated in solution. Examination of the oxidizing capacity of a range of Fe0 particles reveals a capacity in all cases to induce oxidative transformation of benzoic acid, but the high surface areas that can be achieved with nanosized particles renders such particles particularly effective oxidants.