Papers by Keyword: 4-Chlorophenol

Abstract: The photocatalytic degradation of 4-Chlorophenol (4CP) using carbon C coated TiO₂ (C-TiO₂) and pristine TiO₂ under solar irradiation was carried out in a suspension mode under custom made glass cell reactor with continuous aeration supply. It was found that 0.3 and 0.6 g were the optimum loading for C-TiO₂ and pristine TiO₂ respectively in the degradation of 20 mg L^-1 4CP under solar irradiation. The optimum C-TiO₂ was found six times faster than pristine TiO₂ based on pseudo first order rate constant of 4CP photodegradation. No adsorption was observed in the photocatalysts. The intermediates observed during this photocatalytic degradation process were maleic acid, hydroquinone (HQ), benzoquinone (BQ), 4-chlorochetol (4CC) and resorcinol.

Abstract: The adsorption studies of 4-chlorophenol from aqueous solution on activated carbon derived from wheat straw (WAC) have been performed. Several experimental parameters like initial pH, p-CP concentration and solution temperature were evaluated. Solution pH within 2-8 is favor of adsorption and it is disadvantage of adsorption at higher temperature. Langmuir and Freundlich isotherm models were used to fit the experimental data and Langmuir was better. The maximum capacity was 64.8 mg g–1 at 293 K. The process is spontaneous and exothermic and physical action is major mechanism.

Abstract: Taking the organic modified montmorillonite as a carrier and dispersant, the supported nanoscale zero-valent iron materials with different iron contents were synthesized through the ferrous sulfate (FeSO4) and the sodium borohydride (NaBH4) in it. The structure and morphology of the materials were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). Finally, the performances of the supported nanoscale zero-valent iron were studied by high-performance liquid chromatography to determine the adsorption and degradation of 4-chlorophenol. The results indicate that the supported nanoscale zero-valent iron was well dispersed,different iron dosages imposed a visible effect on the morphology and particle diameter of iron;the degradation of 4-chlorophenol resulted from adsorption and degradation processes. Materials with different iron contents exhibited significantly different performance levels in terms of 4-chlorophenol adsorption and degradation.

Abstract: Electrooxidation of 4-chlorophenol in acidic solution was studied by cyclic voltammetry and in situ FTIR spectroscopy. Compared with platinum (Pt) and glassy carbon (GC) electrodes, carbon electrode exhibited a high electrocatalytic activity during the electrooxidation reaction of 4-chlorophenol. The possible mechanism of 4-chlorophenol on carbon electrode was studies by in situ FTIR. At first, 4-chlorophenol was electrooxidized to 4-chlorophenolic radical, and then to phenoxylic radical. Then, the radical was electrooxidized to hydroquinone, benzoquinone or unsaturated carboxylic acids with potential increasing. In addition, with the reaction of phenoxyl radicals, the insoluble aromatic ether oligomer generated on the carbon electrode surface and prevented the further oxidation reaction of 4-CP in some degree.

Abstract: Catalyst with manganese oxide highly dispersed on granular activated carbon (MnOx/GAC) was fabricated by impregnating GAC in MnCl₂ solution and characterized by several techniques. The performance of manganese catalyst was investigated in catalytic ozonation of 4-chlorophenol in water. Manganese catalyst exhibits better efficiency than the original granular activated carbon, due to the synergic effect between activated carbon and manganese oxide. MnOx/GAC, produced by a simple methodin situ, is promising in catalytic ozonation of refractory organic pollutants in waste water.

Abstract: Two kinds of hypercrosslinked resin ZH-01 and ZH-03 were prepared in this study. Experimental investigations were conducted to study the adsorption characteristics of 4-chlorophenol on the hypercrosslinked resins by method of static adsorption. The equilibrium adsorption data was fitted to Freundlich adsorption isotherm model to evaluate the related parameters. The results showed that the changes of enthalpy, free energy, entropy indicate an exothermic, spontaneous and disorder decreasing process happened in the adsorption. It was also shown that, respecting to the adsorption capacity, the adsorbents prepared here are better than the Amberlite XAD-4 for removing the 4-chlorophenol in aqueous solutions.

Abstract: In a diaphragm electrolyze system with a Ti/RuO₂/IrO₂ anode and the Pd/MWNTs gas diffusion cathode, the degradation of 4-chlorophenol was fully studied by the electrochemical reduction and the simultaneous oxidation of the cathode and anode. The results indicated that the optimization electrolyte concentration is 0.08 mol/L. The Cl- removal reached 94.8% after 80 min electrolysis with H2 feeding. After 120 min electrolysis, the removal of 4-chlorophenol in the anodic and cathode compartments were 98.5% and 90.6%, respectively. Additionally, the TOC removal reached 65% and 70% in the anodic and cathodic compartment respectively after 140 min. By the UV scanner analysis of the electrolyte, the 4-chlorophenol and benzoquinone were oxidized by the oxides formed on the cathode, while the benzoquinone was found accumulated in the anodic compartment.

Abstract: In this paper, using tetrabutyl titanate as source, H₂O₂(30%) as solvent, synthesis of titanium dioxide sol was achieved by sol-gel method. A transparent sol aging in air 30min, titanium dioxide films were prepared by using spin coating method. The photodegradation capability of 4-chlorophenol has been enhanced by using immobilized TiO₂ particles, where the titanium sol synthesized by a sol-gel method was used as the binder for the immobilization. Optimal conditions of TiO₂ film, 4-chlorophenol concentration, solution pH, and UV irradiation intensity have been found to enhance the photodegradation efficiency.