Abstract
Due to its low cost, environmentally friendly process, and lack of secondary contamination, the photodegradation of dyes is regarded as a promising technology for industrial wastewater treatment. This technology demonstrates the light-enhanced generation of charge carriers and reactive radicals that non-selectively degrade various organic dyes into water, CO2, and other organic compounds via direct photodegradation or a sensitization-mediated degradation process. The overall efficiency of the photocatalysis system is closely dependent upon operational parameters that govern the adsorption and photodegradation of dye molecules, including the initial dye concentration, pH of the solution, temperature of the reaction medium, and light intensity. Additionally, the charge-carrier properties of the photocatalyst strongly affect the generation of reactive species in the heterogeneous photodegradation and thereby dictate the photodegradation efficiency. Herein, this comprehensive review discusses the pseudo kinetics and mechanisms of the photodegradation reactions. The operational factors affecting the photodegradation of either cationic or anionic dye molecules, as well as the charge-carrier properties of the photocatalyst, are also fully explored. By further analyzing past works to clarify key active species for photodegradation reactions and optimal conditions, this review provides helpful guidelines that can be applied to foster the development of efficient photodegradation systems.
Highlights
The widespread presence of organic dyes in industrial wastewaters from the textile, apparel, and paper industries results in significant environmental contamination
The overall efficiency of a photocatalysis system is closely dependent on operational parameters that dictate the adsorption and photodegradation of dye molecules
The results showed a decreased adsorption capacity upon increasing the ionic strength because the adsorption of charged moieties competed with that of dye molecules or adsorbents in the solution
Summary
The widespread presence of organic dyes in industrial wastewaters from the textile, apparel, and paper industries results in significant environmental contamination. Catalysts 2019, 9, 430; doi:10.3390/catal9050430 www.mdpi.com/journal/catalysts photocatalytic reaction involves heterogeneous catalysis, where a light-absorbing catalyst is put in contact with the target reactants, in either a solution or gas phase This heterogeneous approach was successfully employed as an effective tool for the degradation of various hazardous materials, including atmospheric and aquatic organic pollutants, and shows many advantages over traditional wastewater treatment techniques. The whole photodegradation fromthe thepH adsorption of dye steric structure highly related to photocatalytic efficiency In addition to these by operational molecules on thewere surface of the photocatalyst to the decomposition of dye molecules reactive parameters, the band position and charge-carrier utilization the photocatalysts have an radicals, is affected by operational parameters such as the pH ofofsolution, initial dye concentration, impact on the generation ofirradiation reactive radicals and [13,14,15,16,17].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
