Persistent aromatic pollutants removal using a combined process of electrochemical treatment and reverse osmosis/nanofiltration

Abstract

The application of a combined electrochemical/ membrane filtration process for treatment of wastewaters containing persistent pollutants was investigated. Phenol and an azo dye (Acid Orange 7, AO7) were used as model pollutants. A boron doped diamond electrode, the state-of-the-art in electrode material, was used as anode in the electrochemical treatment, following previous excellent results obtained with this kind of electrodes in the removal of soluble organic compounds from aqueous solutions. Reverse osmosis and nanofiltration membranes were used in the concentration step of a two-stage combined process.The experimental conditions were selected in order to test the applicability of a model developed here, which predicts the chemical oxygen demand (COD) removal in the electrochemical treatment. The model was applied to estimate the COD evolution in the electrochemical reactor along a certain number of cycles of combined electrochemical/membrane filtration treatment using experimental data of observed rejections of the pollutants.In terms of the overall efficiency of the treatment, the results show that very high COD removal values can be obtained in both the cases of phenol and AO7, above 95%, when comparing the COD of the membrane permeates which constitute the treated effluent, with the feeding solutions.

A Review on Electrochemical Degradation and Biopolymer Adsorption Treatments for Toxic Compounds in Pharmaceutical Effluents

“…In addition, the application of electrolytes with higher conductivity (i. e. 1.5 μS/cm) reduces energy consumption [98]. The two studies by Santos et al [98] and Hamad et al [36], investigated the cost of the processes by determining energy consumption using the following equations 10 and 11: (10) (11) Where U is potential/ voltage (V), I is applied current (A), t is time (h or min. ), V is treated volume (m 3 ), C o , and C t are initial and final concentrations.…”

“…It has been reported [10] that OVIs are a potential risk for the quality and stability of drug products, as well as the human body if intake exceeds the permitted daily exposure (PDE). It is no longer a hidden fact that the wide occurrence of organic contaminants in wastewater poses a severe threat to public health regulatory bodies and ecosystems [11,12]. In view of the above fact, the consensus is that research efforts must be doubled to quickly address the problems, by providing technologies to remediate the contaminated water bodies.…”

Membrane Separation Coupled with Electrochemical Advanced Oxidation Processes for Organic Wastewater Treatment: A Short Review

“…These results showed that the EO process considerably reduced the organic load in the effluent, while a large part of TDS removal was attributed to the final RO treatment. Diogo et al [ 24 ] established a combined electrochemical/membrane filtration process for the treatment of wastewater containing phenol and an azo dye (Acid Orange 7, AO7). A boron-doped diamond (BDD) electrode was used as the anode in the electrochemical treatment, followed by RO and NF membranes, which were used in the concentration step.…”

Study on the Preparation and Characterizations of an Improved Porous Ti/TiO2/CdS‐CNT/C3N4 Photoelectrode and Photoelectric Catalytic Degradation of Methylene Blue

“…Organic impurities such as dyes, alcohols and acids are discharged into potable water sources and consequently causing water pollution . Color of dyestuffs in the wastewater generally becomes the main problem of wastewater treatment due to its serious environmental influences . There are some methods of sewage treatment, such as physical method, biological method, chemical method and so on.…”