资源与环境工程学院：
研究前沿（研究前沿为研究领域内最新文献）：
Abstracts：High-silicaphosphogypsum (PG) is a kind of industrial by-product with great utilizationpotential. However, it is difficult to reuse PG directly due to therelated gangue minerals (e.g., SiO2), and thus efficient purification isrequired to allow its further applications. Herein, a typical high-silicaphosphogypsum waste was purified by a new “reverse-direct flotation”method. The organic matters and fine slimes were removed by reverse flotation,and then, the silica impurity was removed by direct flotation. Via theclosed-circuit flotation process, the whiteness of the PG concentrate isimproved from 33.23 to 63.42, and the purity of gypsum in the PG concentrateincreases from 83.90% to 96.70%, with a gypsum recovery of 85%. Additionally,the content of SiO2 is significantly reduced from 11.11% to 0.07%.In-depth investigations suggest that the difference in the floatability ofgypsum and quartz is prominently intensified by flotation reagents at pH =2–2.5, and thus leads to good desilication performance. Further characteristicsof the PG concentrate prove that impurities have been well removed, and the PGconcentrate meets the requirement of related standards for gypsum buildingmaterials. The flotation method reported here paves the way for thepurification of high-silica phosphogypsum, which can be extended to thepurification and value-added reutilization of other industrial solid wastes.
Keywords：Desilication; Flotation; Phosphogypsum; Purification; Reutilization
详情页网址：Scopus-文献详情 -Flotation purification of waste high-silica phosphogypsum
Abstracts：A largenumber of solid wastes are produced in the process of demolishing oldbuildings, and waste red brick is one of such wastes. To discuss thereutilization of waste red brick powder (WRBP) in alkali-activatedmaterial, a novel ternary eco-friendly binder was prepared by using slag, flyash and WRBP as precursor. The impact of WRBP on the reaction kinetics,microstructure and life-cycle assessment of alkali-activated cement paste wereevaluated. The Johnson-Mehl-Avrami-Kolmogrov model was established based on theheat release results. With the incorporation of WRBP, the degree of reactionwas deepened, supporting the enhancement of matrix strength. X-ray diffractionand thermogravimetric analysis results show the consistent mineralogicalcomposition of reaction products and increase of gel quantity. Porecharacteristics determined by mercury intrusion porosimetry method exhibit thatlarge capillary pores were refined by enrichment of gels and filling effect ofWRBP. From the economic and environmental aspects, the reuse of WRBPsignificantly saved the energy consumption and reduced the carbon dioxide (CO2)emission. On the basis of the optimal compressive strength, the energyconsumption efficiency index and CO2 intensity index were 27.3 MJ/MPa and1.7 kg/MPa, which can provide 38.55% energy consumption and 44.90% carbon footprintsavings. Such work may shed valuable insights to the recycling of various typesof solid waste and low-carbonation of building field.
Keywords：Eco-friendlybinders; Life-cycle assessment; Microstructure; Reactionkinetics; Waste red brick powder
Abstracts：Conversionof sewage sludge to biochar for contaminants removal from water achieves thedual purpose of solid waste reuse and pollutionelimination, in line with the concept of circular economy and carbonneutrality. However, the current understanding of sludge-derived biochar (SDB)for wastewater treatment is still limited, with a lack of summary regarding theeffect of modification on the mechanism of SDB adsorption/catalytic removalaqueous contaminants. To advance knowledge in this aspect, this papersystematically reviews the recent studies on the use of (modified) SDB as adsorbentsand in persulfate-based advanced oxidation processes (PS-AOPs) as catalysts forthe contaminants removal from water over the past five years. Unmodified SDBnot only exhibits stronger cation exchange and surface precipitation for heavymetals due to its nitrogen/mineral-rich properties, but also can provideabundant catalytic active sites for PS. An emphatic summary of how certainadsorption removal mechanisms of SDB or its catalytic performance in PS-AOPscan be enhanced by targeted regulation/modification such as increasing thespecific surface area, functional groups, graphitization degree, N-doping ortransition metal loading is presented. The interference of inorganicions/natural organic matter is one of the unavoidable challenges that SDB isused for adsorption/catalytic removal of contaminants in real wastewater.Finally, this paper presents the future perspectives of SDB in the field ofwastewater treatment. This review can contribute forefront knowledge and newideas for advancing sludge treatment toward sustainable green circulareconomy.
Keywords：Advancedoxidation processes; Contaminant adsorption; Modificationmethod; Persulfate; Sludge-derived biochar
