Enhanced organic removal for shale gas fracturing flowback water by electrocoagulation and simultaneous electro-peroxone process

Autor: Jin fu Chen, Fan xin Kong, Yuefeng F. Xie, Guang dong Sun, Xiao feng Lin, Chun mei Guo
Rok vydání: 2019
Předmět:
Environmental Engineering
Health
Toxicology and Mutagenesis
medicine.medical_treatment
0208 environmental biotechnology
02 engineering and technology
Natural Gas
010501 environmental sciences
Electrochemistry
01 natural sciences
Electrocoagulation
Water Purification
law.invention
chemistry.chemical_compound
Ozone
law
medicine
Environmental Chemistry
Coagulation (water treatment)
Organic Chemicals
Electrodes
0105 earth and related environmental sciences
Gas diffusion electrode
Hydraulic Fracking
Hydroxyl Radical
Extraction (chemistry)
Public Health
Environmental and Occupational Health
Electrochemical Techniques
General Medicine
General Chemistry
Sulfuric Acids
Pollution
Carbon
Cathode
020801 environmental engineering
Anode
Kinetics
chemistry
Chemical engineering
Hydroxyl radical
Oxidation-Reduction
Water Pollutants
Chemical
Zdroj: Chemosphere. 218:252-258
ISSN: 0045-6535
Popis: Colloids and organics in shale gas fracturing flowback water (SGFFW) during shale gas extraction are of primary concerns. Coagulation combined with oxidation might be a promising process for SGFFW treatment. In this study, a novel electrocoagulation-peroxone (ECP) process was developed for SGFFW treatment by simultaneous coagulation and oxidation process with a Al plate as the anode and a carbon-PTFE gas diffusion electrode as the cathode, realizing the simultaneous processes of coagulation, H2O2 generation and activation by O3 at the cathode. Compared with electrocoagulation (EC) and peroxi-electrocoagulation (PEC), COD removal efficiency mainly followed the declining order of ECP, PEC and EC under the optimal current density of 50 mA cm−2. The appearance of medium MW fraction (1919 Da) during ozonation and PEC but disappearance in ECP indicated that these intermediate products couldn't be degraded by ozonation and PEC but could be further oxidized and mineralized by the hydroxyl radical produced by the cathode in ECP, demonstrating the hydroxyl radical might be responsible for the significant enhancement of COD removal. The pseudo-first order kinetic model can well fit ozonation and EC process but not the PEC and ECP process due to the synthetic effect of coagulation and oxidation. However, the proposed mechanism based model can generally fit ECP satisfactorily. The average current efficiency for PEC was 35.4% and 12% higher than that of ozonation and EC, respectively. This study demonstrated the feasibility of establishing a high efficiency and space-saving electrochemical system with integrated anodic coagulation and cathodic electro-peroxone for SGFFW treatment.
Databáze: OpenAIRE
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