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Thermal treatment methods are used extensively in the process of municipal solid waste incineration fly ash. However, the characterization of heavy metals during this process should be understood more clearly in order to control secondary pollution. In this paper, the content, speciation and leaching toxicity of mercury (Hg), plumbum (Pb), cadmium (Cd) and zinc (Zn) in fly ash treated under different temperatures and time were firstly analysed as pre-tests. Later, pilot-scale pyrolysis equipment was used to explore the concentration and speciation changes in the heavy metals of fly ash. Finally, the phase constitution and microstructure changes in fly ash were compared before and after pyrolysis using X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The results showed that (a) The appropriate processing temperature was between 400°C and 450°C, and the processing time should be 1 h. (b) The stability of heavy metals in fly ash increased after pyrolysis. (c) XRD and SEM results indicated that phase constitution changed a little, but the microstructure varied to a porous structure similar to that of a coral reef after pyrolysis. These results suggest that pyrolysis could be an effective method in controlling heavy metal pollution in fly ash.
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http://dx.doi.org/10.1080/09593330.2018.1480663 | DOI Listing |
Environ Res
September 2025
Materials Science, Engineering, and Commercialization (MSEC) Program, Texas State University, San Marcos, TX-78666, USA; Department of Engineering Technology, Texas State University, San Marcos, TX-78666, USA.
Fly ash (FA) landfills are overflowing with materials, and unexplored waste streams like waste spent garnet (WSG) and waste foundry sand (WFS) are often dumped in onsite storage spaces, limiting land availability for future use and exacerbating environmental concerns related to waste disposal. Therefore, this research proposes recycling FA to produce reclaimed FA (RFA) as a binder, replacing 40-60% of ground granulated blast furnace slag (GGBFS) and 30-50% of river sand (RS) with WSG and WFS to produce geopolymers. The performance of geopolymers was assessed under different curing regimes, including ambient-temperature curing (ATC), ambient-temperature water curing (AWC), high-temperature curing (HTC), and high-temperature water curing (HWC).
View Article and Find Full Text PDFJ Environ Manage
September 2025
Interdisciplinary Research Center for Construction and Building Materials, Department of Materials Science and Engineering, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia.
The disposal of municipal solid waste incineration fly ashes (MSWI-FA) is complicated by soluble chlorides, which increase the risk of heavy metals (HMs) leaching toxicity and hinder the further use of remediated MSWI-FA. In this study, the self-assembly potentiality of magnesium oxychloride cement (MOC) in geopolymerization was explored and utilized to enhance the solidification/stabilization (S/S) of the MSWI-FA. The MOC-self-assembled geopolymerization kinetics can be suitably described by the JMAK model.
View Article and Find Full Text PDFPLoS One
September 2025
School of Chemical Engineering, University of New South Wales, Sydney, New South Wales, Australia.
Coal blending in thermal power plants is a complex multi-objective challenge involving economic, operational and environmental considerations. This study presents a Q-learning-enhanced NSGA-II (QLNSGA-II) algorithm that integrates the adaptive policy optimization of Q-learning with the elitist selection of NSGA-II to dynamically adjust crossover and mutation rates based on real-time performance metrics. A physics-based objective function takes into account the thermodynamics of ash fusion and the kinetics of pollutant emission, ensuring compliance with combustion efficiency and NOx limits.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
September 2025
School of Energy Science and Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
This present investigation focuses on desulphurization of high sulphur North-East Indian coal under ultrasonic and microwave irradiation-aided chemical leaching. The powdered coal was treated under four different conditions, such as alkali leaching under low-energy ultrasound energy (US), acid leaching under ultra-high frequency microwave energy (MW), ultrasonic followed by microwave treatment (US-MW) and microwave followed by ultrasonic treatment (MW-US). The ultrasonic treatment was conducted using 0.
View Article and Find Full Text PDFFront Plant Sci
August 2025
International Center of Insect Physiology and Ecology, Nairobi, Kenya.
Vegetables are crucial for food security and income, but in developing countries their production is hindered by low soil fertility. Although the insect frass fertilizer is a potential solution, its use is constrained by limited product choices. Unlike conventional fertilizers, which are available in different forms, the insect frass fertilizer is mostly available in solid form.
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