A photoelectrochemical system for hydrogen and chlorine production from industrial waste acids


Chehade G., Alrawahi N., Yuzer B., Dıncer I.

SCIENCE OF THE TOTAL ENVIRONMENT, vol.712, 2020 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 712
  • Publication Date: 2020
  • Doi Number: 10.1016/j.scitotenv.2019.136358
  • Journal Name: SCIENCE OF THE TOTAL ENVIRONMENT
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Analytical Abstracts, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chimica, Communication Abstracts, Compendex, EMBASE, Environment Index, Food Science & Technology Abstracts, Geobase, Greenfile, MEDLINE, Metadex, Pollution Abstracts, Public Affairs Index, Veterinary Science Database, Civil Engineering Abstracts
  • Keywords: Hydrogen production, Chlorine production, Industrial waste acid, Photoelectrocheinistry, Efficiency, H-2 PRODUCTION, WATER, ELECTROLYSIS, TIO2, PERFORMANCE, OXIDATION, TITANIUM, PHOTOCATALYST, WASTEWATERS, GENERATION
  • Istanbul University-Cerrahpasa Affiliated: Yes

Abstract

The galvanizing industry uses the concentrated hydrochloric acid in its metal surface treatment processes known as pickling. Every year tons of waste acid solutions polluted with metals ions arc discharged to the environment after neutralization process. In this study, a novel photoelectrochemical reactor is designed and developed for the production of hydrogen and chlorine gas from spent hydrochloric acid generated in the galvanizing industry. The novel reactor design allows all the hydrogen gas to flow from the reactor without any dead zone in the cathode compartment, while chlorine gas is carried out with aqueous 5 M HCl at the surface of the illuminated photoanode without any dissolution. Further, the unique design of the cathode corrosion-resistant high surface area (3 x the anode) results in good proton and H+ transfer rate while the TiO2 coated photoanode further enhances the charge transfer process and chlorine gas production. The characterization of the coated stainless steel is tested by the energy-dispersive X-ray (EDX) analysis and scanning electron microscope (SEM) images. The photoelectrochemical potentiostatic experiments with and without sunlight are performed on the reactor. The hydrogen and chlorine gas production rates are observed as 3 mL/min and 05 mL/min, respectively. Also, a comprehensive thermodynamic analysis of the photoelectrochemical reactor is conducted, and energy, exergy, and quantum efficiencies are found as 45.55%, 73.75%, and 6%, respectively. The exergoeconomic assessment study shows that the lowest exergy cost rate is achieved with sunlight illumination for a hydrogen exergy cost of 1.7 $/kg and chlorine exergy cost rate of 0.3 $/kg at an applied potential of 2 V. (C) 2020 Elsevier BM. All rights reserved.