Electrochemical treatment of phenolic waters in presence of chloride with boron-doped diamond (BDD) anodes: experimental study and mathematical model.

This work deals with an experimental and numerical study on the electrochemical treatment of waters containing phenolic compounds with boron-doped diamond (BDD) anodes. Anodic oxidation of m-cresol, as a model of phenolic compound, was investigated by galvanostatic electrolyses. The electrolyses were carried out under different experimental conditions by using an impinging-jet flow cell inserted in a hydraulic circuit in a closed loop.

Electrokinetic removal of 2,6-dichlorophenol and diuron from kaolinite and humic acid-clay system.

This paper presents the results of a study on the electrokinetic treatment of kaolinite and humic acid kaolinite complexes spiked with 2,6-dichlorophenol or 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron). In particular, the attention was paid to the interaction between solid surface and dissolved organics: the effects of contaminant sorption as well as the physicochemical reactions on the efficiency of electrokinetic remediation were investigated. Using a 3V/cm voltage gradient, approximately 90% of diuron was removed from kaolinite after one water pore volume was collected in the cathode reservoir, but much lower efficiency was obtained in the electrokinetic removal of this compound from humic acid-coated kaolinite.

Electrochemical oxidation of phenolic and other organic compounds at boron doped diamond electrodes for wastewater treatment: effect of mass transfer.

The paper presents the results of an experimental study on oxidation at boron doped diamond electrodes (BDD) of some phenolic compounds: phenol (PH), para-hydroxibenzoic acid (PHB), cathecole (CT), hydroquinone (HQ) are considered, singularly contained in aqueous solutions or in the presence of glucose (G), which was selected to represent the class of biodegradable compounds. Oxidation of benzoquinone (BQ) and maleic acid (MA), generally detected as intermediates products from phenol degradation, is also investigated. Great attention is paid to verify the feasibility of a selective process in which the oxidation is specifically addressed to the phenolic fraction up to non toxic intermediate products which are more biodegradable than the original phenols.

Application of electrochemical reactors for industrial waste-water treatment.

The effectiveness of electrochemical reactors for industrial wastewater treatment has been improved since three-dimensional electrodes have been introduced; in fact, limitations of mass transfer can arise, due to the low concentrations of pollutants which may be involved in the process. Three-dimensional electrodes offer a very high electrode area per unit electrode volume and they can act as turbulence promoters or give rise to high linear electrolyte velocity, resulting in high values of mass transport coefficient. However, careful selection of operative parameters is needed in order to obtain high performance.

Degradation of para-hydroxybenzoic acid by means of mixed microbial cultures.

Olive mill wastewater contains some phenolic compounds that cause antibacterial activity of a kind that prevents biological treatment without previous dilution. Among these phenolic compounds, p-hydroxybenzoic acid (PHB) is considered to be one of the most representative. This work examines the biodegradation of PHB by aerobic microbial mixed cultures previously acclimatized to glucose, which was used as an easily biodegradable model compound.

Electrochemical oxidation of p-hydroxybenzoic and protocathecuic acids at a dimensional stable anode (DSA) in the presence of NaCl.

This work is part of a wider research programme on innovative technologies for industrial wastewater treatment. Results from electrolyses at DSA commercial anodes of synthetic solutions with composition analogous to that of agro-industrial wastes are presented. The results obtained indicate that the rate of degradation of phenolic compounds is high, provided that chloride ions are present in solution.