Sorption capacity and mechanism of Cr3+ on tobermorite derived from fly ash acid residue and carbide slag

Zou, Jingjing; Guo, Chunbin; Zhou, Xiaojin; Sun, Yuan; Yang, Zhi

doi:10.1016/j.colsurfa.2017.11.073

Cited by 37 publications

(14 citation statements)

References 29 publications

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“…With the development of slash-and-char technology, the pyrolysis of biomass is more extensively used for the production of biochar and bioenergy. Biochar represents a promising alternative to activated carbon due to the low cost [7][8][9]. The purification of soil and water depends on several properties of biochar such as surface area (SA), the abundance and type of functional groups on the surface and pore volume (PV) [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Surface characterization of maize-straw-derived biochar and their sorption mechanism for Pb2+ and methylene blue

et al. 2020

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Biochar derived from straw is a potential low-cost adsorbent for metal ions and organic pollutants, but its practical application is still limited by the adsorption capacity. In this study, the correlation between the biochar's properties and pyrolysis temperature was explored. The adsorption mechanism was studied by monitoring the changes of biochar properties before and after adsorption using BET, SEM, XPS and FT-IR spectroscopy. The adsorption mechanism was revealed following the adsorption kinetics and the changes in biochar's properties before and after adsorption. The methylene blue (MB) and Pb 2+ adsorption removal efficiency reached 95% at the initial concentration of 125 and 500 mg/L, respectively. Physisorption, chemisorption, and pore filling mechanisms determined the adsorption process of MB and Pb 2+ on biochar. The Pb 2+ adsorption process was highly affected by chemical co-precipitation at higher pyrolysis temperatures. The appearance of tar particles increased the adsorption rate of Pb 2+. The biochar obtained at the pyrolysis temperature at 500, 800 and 900˚C proved to be applicable for Pb 2+ removal. Chemisorption and porosity dominated the MB adsorption, and biochars produced at pyrolysis temperatures of 200, 800 and 900˚C are potential materials for MB removal. This study provides optimal pyrolysis conditions for transforming maize straw into valuable, low-cost materials for the removal of different pollutants.

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Section: Introductionmentioning

confidence: 99%

Surface characterization of maize-straw-derived biochar and their sorption mechanism for Pb2+ and methylene blue

et al. 2020

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“…Tobermorite is one of the calcium silicate hydrate (CSH) compounds, and the main interest is related to its close relationship with the CSH phases formed during the hydration of Portland cement [10]. In addition, tobermorite may act as cation exchangers to absorb unhealthy elements and has potential applications in waste disposal [11][12][13]. Tobermorite is also a slow-release reservoir for some nutrients, such as [K + ] and [NH 4 + ] [14].…”

Section: Introductionmentioning

confidence: 99%

Study of K-Feldspar and Lime Hydrothermal Reaction: Phase and Mechanism with Reaction Temperature and Increasing Ca/Si Ratio

2019

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To elucidate the physicochemical properties of the artificial silicate composite material, K-feldspar and lime were reacted in mild hydrothermal conditions (different reaction temperatures and various K-feldspar/lime ratios). Formed phases were investigated using various techniques, such as X-ray powder diffraction, the Rietveld method, scanning electron microscopy (SEM), and inductively coupled plasma-optical emission spectrometry. The analysis revealed that tobermorite, grossular (hydrogarnet), alpha-dicalcium silicate hydrate (α-C2SH), amorphous calcium silicate hydrate, potassium carbonate, bütschliite, calcite, and calcium hydroxide formed with various conditions. Both the temperature and the Ca/Si molar ratio in the starting material greatly affected the formation of phases, especially the generation of tobermorite and α-C2SH. The substitution of H4O4 ↔ SiO4 proceeded with the increase of the Ca/Si molar ratio rather than the reaction temperature and the reaction time. More hydrogen was incorporated in hydrogarnet through the substitution of H4O4 ↔ SiO4 with the increase of the Ca/Si molar ratio in the starting material. Due to the properties of tobermorite as a cation exchanger and its potential applications in hazardous waste disposal, experimental parameters should be optimized to obtain better performance of the artificial silicate composite material from K-feldspar and lime hydrothermal reaction. The dissolution mechanism of K-feldspar was also discussed.

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“…The SiO 2 content in the residue is high, and its activity is high as well. It can be used as a raw material to prepare silicon-based products, such as zeolite, tobermorite, xonotlite, and geopolymers [5,[42][43][44]. Figure 14 shows the SEM images of CFA and the residue after calcination at 230 • C at different durations.…”

Section: Sem and Eds Resultsmentioning

confidence: 99%

“…Uncontrolled aggregation and discharge make CFA a main potential source of dangerous chemicals that could be released into the environment [3,4]. To enhance its utilization effectiveness, researchers made considerable efforts to study the potential of using CFA as a raw material for soil modification, production of glass/ceramics, zeolites or geopolymers, and metal extraction [5][6][7]. In particular, the CFA discharged in Shanxi and Inner Mongolia contains more alumina (40-50%) than the boundary bauxite in China and is a non-bauxite aluminum resource with high development and utilization potential [8].…”

Section: Introductionmentioning

confidence: 99%

Alumina Extraction from Coal Fly Ash via Low-Temperature Potassium Bisulfate Calcination

Guo

Zou

et al. 2019

Minerals

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Owing to the depletion of bauxite and increasing demand for alumina, calcination methods for extracting alumina from coal fly ash (CFA) were developed. However, these methods have disadvantages such as the need for high temperatures and the emission of toxic gases. Hence, in this study, Al2O3 was extracted from CFA via low-temperature potassium bisulfate calcination technology. Effects of the potassium bisulfate amount, calcination temperature, and calcination time on the alumina extraction efficiency were investigated using X-ray diffraction, thermal gravimetry, scanning electron microscopy, differential scanning calorimetry, and energy-dispersive spectroscopy. It was found that this technique could recover alumina efficiently, and potassium bisulfate significantly contributed to the degradation of mullite and corundum phases. Al2O3 in CFA was converted into soluble K3Al(SO4)3. With a KHSO4/Al2O3 molar ratio of 7:1, calcining temperature of 230 °C, and calcining time of 3 h, the alumina extraction efficiency reached a maximum of 92.8%. The Avrami–Erofeev equation showed the best fit with the kinetic data for the low-temperature calcination of CFA with KHSO4. The activation energy was 28.36 kJ/mol.

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Sorption capacity and mechanism of Cr3+ on tobermorite derived from fly ash acid residue and carbide slag

Cited by 37 publications

References 29 publications

Surface characterization of maize-straw-derived biochar and their sorption mechanism for Pb2+ and methylene blue

Surface characterization of maize-straw-derived biochar and their sorption mechanism for Pb2+ and methylene blue

Study of K-Feldspar and Lime Hydrothermal Reaction: Phase and Mechanism with Reaction Temperature and Increasing Ca/Si Ratio

Alumina Extraction from Coal Fly Ash via Low-Temperature Potassium Bisulfate Calcination

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