The total annual output of synthetic dyes exceeds 7 × 10 tons. About 1,000 tons of non-biodegradable synthetic dyes are released every year into the natural streams and water sources from textile wastes. The release of these colored wastewater exerts negative impact on aquatic ecology and human beings because of the poisonous and carcinogenic repercussions of dyes involved in coloration production. Therefore, with a growing interest in the environment, efficient technologies need to be developed to eliminate dyes from local and industrial wastewater. Supercritical water oxidation as a promising wastewater treatment technology has many advantages, such as a rapid reaction and pollution-free products. However, due to corrosion, salt precipitation and operational problems, supercritical water oxidation process did not gain expected industrial development. These technical difficulties can be overcome by application of non-corrosive subcritical water as a reaction medium. This work summarizes the negative impacts of dyes and role of subcritical and supercritical water and their efficiencies in dye oxidation processes.
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http://dx.doi.org/10.1016/j.jenvman.2021.112605 | DOI Listing |
Waste Manag
December 2024
School of Chemistry and Life Resources, Renmin University of China, No. 59 Zhongguancun Street, Beijing 100872, China.
The high chlorine content in municipal solid waste incineration (MSWI) fly ash is a key factor restricting its treatment and disposal. In this study, a new treatment method was proposed to enhance the deep dechlorination of fly ash by coupling supercritical CO (SC) treatment with water washing. Simultaneously the alkaline compounds in fly ash can fix CO and achieve CO credits.
View Article and Find Full Text PDFChem Sci
December 2024
Institutes of Physical Science and Information Technology, Key Laboratory of Structure and Functional Regulation of Hybrid Material (Ministry of Education), Anhui University Hefei 230601 China
Lithium metal batteries (LMBs) promise high-energy-density storage but face safety issues due to dendrite-induced lithium deposition, irreversible electrolyte consumption, and large volume changes, which hinder their practical applications. To address these issues, tuning lithium deposition by structuring a host for the lithium metal anode has been recognized as an efficient method. Herein, we report a supercritical water molecular scissor-controlled strategy to form a carbon framework derived from biomass wood.
View Article and Find Full Text PDFACS Omega
December 2024
Shaanxi Yanchang Petroleum (Group) Co., Ltd., Xi'an, Shaanxi Province 710000, P. R. China.
Supercritical-dense phase CO pipeline transportation has been proven to have excellent economic and safety benefits for long-distance CO transportation in large-scale. Hydrates are easily generated in the high-pressure and low-temperature sections, resulting in blockage, so it is necessary to build the prediction model for hydrate formation in the long-distance CO pipeline transportation. In the prediction model of hydrate formation of our work, the phase equilibrium was determined by the Chen-Guo model, and the lateral growth of hydrate was calculated by the comprehensive growth model, and the hydrate growth was estimated by analogy with the condensation process.
View Article and Find Full Text PDFChemosphere
December 2024
University of Washington, Mechanical Engineering Department, Seattle, WA, 98195, USA. Electronic address:
Granular activated carbon (GAC) is widely used to treat contaminated per- and polyfluoroalkyl substances (PFAS) waste streams, resulting in the accumulation of large quantities of spent GAC that need to be landfilled or regenerated. A novel modified supercritical CO (scCO) extraction for regeneration of spent GAC is developed. With the addition of organic solvents and acid modifiers, the procedure yielded >99% perfluorooctanoic acid (PFOA) desorption after a 60-min treatment in a continuous flow reactor.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Akdeniz University, Faculty of Science, Department of Chemistry, Antalya, Turkey.
In this study, activated halloysite nanotube (HNT) and phenyltriethoxysilane (PTES) were utilized for the first time to fabricate modified HNT materials and coat them onto melamine sponge (MS) substrate in the supercritical carbon dioxide (scCO) atmosphere. The successful coating of MS substrate was confirmed using SEM, EDS, XPS, and contact angle measurements. The drainage technique applied in the CO medium achieved the uniform coating of both the inner and outer surfaces of the MS.
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