International Journal of Mining Science and Technology
·
2023
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IF 11.8
Fen Xu,Shiwei Wang,Rongjie Kong,Chengyong Wang
The utilization of an appropriate collector or surfactant is crucial for the beneficiation of low-rank coal. However, in previous studies, the selection of surfactants was primarily based on flotation procedures, which hinders the understanding of the interaction mechanism between surfactant groups and oxygen-containing functional groups at the surface of low-rank coal. In this study, we investigate the flotation of low-rank coal in the presence of a composite collector by using a combined theoretical and experimental approach. The maximum flotation mass recovery achieved was 82.89% using a 3:1 mixture of dodecane and castor oil acid. Fourier-transform infrared and X-ray photoelectron spectroscopic analyses showed that castor oil acid was effectively adsorbed onto the surface of low-rank coal, enhancing the hydrophobicity of the coal. In addition, the diffusion coefficient of water molecules in the water-composite collector-coal system was greater than that in the dodecane system. Moreover, due to the presence of castor oil acid in the flotation process, the adsorption distance of dodecane and low-rank coal became shorter. Molecular dynamics simulations revealed that the diffusion and interaction of surfactant molecules at the interface of low-rank coal particles and water was enhanced because the adsorption of the dodecane-castor oil acid mixture is primarily controlled by hydrogen bonds and electrostatic attraction. Based on these results, a better surfactant for flotation of low-rank coal is also proposed.
研究领域:
矿物加工工程
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表面化学
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产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2023
·
IF 6
Tao Shen,Qingya Liu,Zhenyu Liu
Balancing the rates of coal radical fragments’ generation and hydrogen donation is crucial to inhibit the radical fragments’ condensation for a high oil yield and low hydrogen consumption in direct coal liquefaction (DCL). Two-stage liquefaction (TSL) has been proposed to be effective for balancing these rates under mild conditions but little work can be found in the literature on the comparison of TSL with single-stage liquefaction (SSL). This work studies direct liquefaction of two low-rank coals (NMH and SW) of very different volatile content under various TSL and SSL schemes in systems with different hydrogen donation ability. The coal conversion and products yield in different liquefaction schemes are correlated with their organic structure characterized by 13 C NMR and predicted by a structure model. It is found that for the total 40 min liquefaction, the TSL scheme with 10 min at 420 ℃ followed by 30 min at 455 ℃ results in the highest liquid yield and lowest hydrogen consumption per liquid yield when the coal is very active but the hydrogen donation ability is insufficient. Otherwise, SSL at 455 ℃ is preferred. The coal conversion, liquid yield and hydrogen consumption per liquid yield of NMH under above TSL scheme at coal:THN= 1:2 are 85.5 wt%, 55.9% and 48.4 mmol-H/g-Liquid, respectively.
研究领域:
能源化学
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煤炭加工
✓ 已验证
DOI
高影响因子
ACS Omega
·
2022
·
IF 4.132
Maoyan An,Yinfei Liao,Zhe Yang,Yijun Cao,Xiaodong Hao,Xingwei Song,Hourui Ren,Aosheng Yang,Luojian Chen
It has been generally proved that mixed collectors can enhance the flotation of low-rank coal (LRC). However, the inhibition effect of mixed collectors on the detachment between particles and bubbles is still unclear. In this paper, the energy feature of air bubble detachment from the LRC surface in the presence of dodecane (D), oleic acid (OA), and the mixture of dodecane and oleic acid (OA–D) was studied. The effect of collectors on the LRC surface property was analyzed using contact angle measurement, X-ray photoelectron spectroscopy, and wetting heat measurement. The force and displacement during the detachment process were measured synchronously using microforce balance. The results showed that the collector treatment increased the C–C/C–H content and decreased the content of oxygen-containing groups on the LRC surface. The synergistic effect between OA and D enabled the mixed collector to exhibit higher contact angle and wetting heat. Bubble detachment from the LRC surface can be divided into two stages: bubble stretching and bubble sliding, which corresponded to activation energy and detachment work, respectively. The activation energy and detachment work decreased in the same order of OA–D > OA > D, indicating that the mixed collector OA–D increased the energy of bubble detachment from the LRC surface and enhanced the adhesion strength. The theoretical detachment work was calculated, and the calculated results were in agreement with the measured results. This research provides a new perspective on the mechanism of LRC flotation being improved by mixed collectors.
研究领域:
矿物加工工程
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界面化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENERGY & FUELS
·
2015
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IF 2.79
Haiyu Meng,Shuzhong Wang,Lin Chen,Zhiqiang Wu,Jun Zhao
Co-pyrolytic technology of plastic wastes and coal has been widely studied as a promising method to dispose of plastic wastes. Evaluation on pyrolytic behavior and product properties is important for optimizing this technology. In this work, pyrolytic behavior of poly(vinyl chloride) (PVC) blended with two typical coals from northern China (Pingzhuang lignite and Shenmu bituminous) was investigated by applying a nonisothermal thermogravimetric analyzer. Furthermore, scanning electron microscopy technique (SEM) was applied to explore the surface morphology of residual chars. Thermal analysis curves of PVC/coal blends showed nonadditivity performance meaning the existence of synergistic effects between PVC and coal during co-pyrolysis. Negative synergistic effects were observed in the temperature below about 370 °C, whereas positive synergistic effects happened at high temperature. In the final pyrolytic temperature, the formation of volatiles was promoted due to synergistic effects. In addition, isoconversional method was applied to calculate activation energy, and nonadditivity performance on the mean activation energies of PVC/coal blends was also found. The SEM results showed the fractal dimensions of the residual chars from pyrolysis of PVC/coal blends were larger than those from isolated samples, and increased with the increment of coal blending ratio. This variation trend showed that the inhomogeneous degree of the residual char from PVC increased by co-pyrolysis with coals, which can improve its reactivity of gasification or combustion.
研究领域:
能源科学
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2022
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IF 4.132
Haiyu Meng,Mengzhuo Wang,Zhiqiang Wu,Jun Zhao,Jiake Li,Shuzhong Wang
Co-pyrolysis of waste plastics and coal has been considered to be an environmentally friendly and scalable waste treatment technology. This study investigated the influence of polyvinyl chloride (PVC) on the physico-chemical structure and gasification performance of co-pyrolytic char with lignite (PZ) and bituminous (SM) coal. The structure characteristics were explored by applying an X-ray diffractometer and a specific surface area analyzer. The quantitative analysis on the influence of PVC on pore characteristics and carbon microcrystal structure was conducted by the fractal theory and deconvolution method. The gasification performance was explored using a thermogravimetric analyzer. When the PZ blending ratio was larger than 50%, the specific surface area of PVCPZ chars enlarged significantly due to the increment of mesopores. Nevertheless, the effect of SM on the pore structure was not pronounced, and the specific surface area of PVCSM chars was as small as PVC char. A higher PZ blending ratio benefited the formation of mesopores with an aperture smaller than 10 nm for PVCPZ chars, whereas SM had little influence on pore diameter distributions of PVCSM chars attributed to the remarkable coating effects. The values of fractal dimension of co-pyrolytic char were larger than PVC char, revealing that the adjunction of coal increased the pore surface coarseness and improved the complicacy of the pore structure. Quantitative analysis on XRD spectra indicated that the disorder extent of the carbon structure was improved because of coal addition, and the influence of lignite on the disorder degree of the carbon structure was more significant. The gasification reaction of co-pyrolytic char showed significant synergistic effects, resulting in the improvement of gasification performance.
研究领域:
能源与燃料
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Mining Metallurgy & Exploration
·
2024
·Vol. 41
·期 1
·363-378
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IF 1.5
Kong Rongjie,Wang Shiwei,Gui Dongjiao
Metal cations have significant effects on the flotation of coal and minerals. In this study, the effects of monovalent cations (Na + and K + ) on the flotation of low-rank coal (LRC) were investigated using flotation and particle–bubble attachment experiments and through X-ray photoelectron spectroscopy (XPS) and molecular dynamics simulations. Oleic acid (OA), methyl linoleate (ML), hexadecyltrimethylammonium chloride (CTAC), ricinoleic acid (RA), and kerosene were used as flotation collectors. The flotation experiments revealed that the flotation yields of LRC improved when OA, ML, RA, CTAC, and kerosene were used in pure deionized water. However, flotation was suppressed for these collectors in the presence of K + and Na + ions. In contrast, when using CTAC, the flotation yield increased in the presence of these ions. Specifically, the flotation yield increased from 41.24 to 87.03% when 2.0 kg/t CTAC was used in 10 mmol/L NaCl solution. Particle–bubble adhesion experiments and XPS revealed that the hydrophilic groups of CTAC were adsorbed on the LRC surfaces by electrostatic forces, whereas the oxygen-containing functional groups of OA, ML, and RA formed hydrogen bonds with the LRC surface in pure water. Finally, the simulating result revealed that the hydrophobic ends of the OA, ML, and RA collectors hinder the flotation of LRC by adsorbing monovalent cations, whereas the adsorption of monovalent cations on the hydrophobic end of the cationic surfactant (CTAC) promotes flotation via strong electrostatic interactions.
研究领域:
矿物加工工程
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物理化学
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材料科学与工程
✓ 已验证
DOI
高影响因子
JOURNAL OF PERIODONTOLOGY
·
2019
·Vol. 90
·期 7
·798-807
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IF 2.768
Jianxing Zhang,Hui Liang,Yixin Zheng,Dongcai Wang,Jiang Xia,Wenming Peng,Kangjie Cheng,Lianfei Wang,Yunfeng Liu,Wei Peng,Qingyong Li
Background To compare the therapeutic effect of photodynamic therapy (PDT) with Toluidine blue O hydrogel versus systemic antibiotic (SA) in treating periodontitis on rats. Methods Thirty-two Wistar rats were divided into four groups and treated differently: Negative control (NC) group, normal rats; positive control (PC) group, rats with periodontitis; SA group, rats with periodontitis treated with systemic antibiotic; PDT group, rats with periodontitis treated with PDT. After treatment, gingival sulcus bacterial load was measured by counting the colony forming units per milliliter (CFU mL −1 ). The tooth and periodontal tissues were histologically processed to analyze histological and immunohistochemical profile. Gingival samples were obtained to quantify interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels. Results Gingival sulcus bacteria load is significantly lower in PDT group compared with the SA group. The histological analysis showed that some extremely effective repair signs of periodontal tissue were presented in PDT group, such as no periodontal pocket, no bone resorption, few inflammatory cells, massive fibroblasts and collagen fibers. Several effective repair signs of periodontal tissue were also observed in SA group, such as shallow periodontal pocket, small amount of inflammatory cells, substantial fibroblasts and collagen fibers. There were lower cyclooxygenase-2, matrix metalloproteinase -8 (MMP-8) and RANK immunolabeling, higher osteoprotegerin immunolabeling in PDT group compared with SA group. The IL-1β and TNF-α levels in PDT group were lower than those in NC group, but higher than those in SA group. Conclusion PDT was effective to treat experimental periodontitis and was superior to systemic metronidazole as a treatment for periodontitis.
研究领域:
牙科学
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药理学
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治疗学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR GRAPHICS & MODELLING
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2022
·
IF 2.942
Qiu Bao,Jingzhi Xu,Wen Nie,Wenjin Niu,Qifan Tian,Mingyue Yuan
In this paper, the head group, tail group, and main chain of a single type of surfactant were constructed by a mesoscopic simulation, and the interaction between the simulated surfactant and coal dust both on its own and in a composite with polyacrylamide (PAM) was studied. The molecular adsorption behavior of cetyltrimethylammonium chloride (CTAC) surfactant mixed in different ratios with PAM was also experimentally characterized. The results showed that . From the above results, we can see that CTAC and PAM can form spherical, rod-shaped, and wormlike aggregates and a network structure as their volume fraction increases in an aqueous solution. The energy spectrum showed that when CTAC adsorbed on the surface of the coal, the content of carbon on the surface decreased from 63.8 to 50.4%, and the content of oxygen increased from 35.2 to 41.8%. The study on the adsorption mechanism of surfactants and polymers on the surface of low rank coal and the hydrophilicity of low rank coal is of great significance in developing efficient dust prevention technology for low rank coal to reduce coal dust pollution.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIOMEDICINE & PHARMACOTHERAPY
·
2023
·
IF 7.5
Ningning Jiang,Hui Jin,Kun Yang,Zhongyuan Zhang,Wenshu Xu,Xiaoxue Chen,Zhenhua Zhang,Hui Xu
The present study evaluated the in vitro effect of metformin (Met) and total flavonoids of Rhizoma Drynariae (TFRD) on osteoclasts, osteocytes, and osteoblasts at different stages. We also assessed the effect and mechanism of treatment with Met combined with TFRD on ovariectomy (OVX)-induced osteoporosis in rats. The results showed that Met combined with TFRD significantly promoted the migration of osteoprogenitor cells and stimulated the differentiation and maturation of osteoblast precursor cells. Furthermore, Met combined with TFRD treatment significantly inhibited the osteogenic inhibitor sclerostin (SOST)/dickkopf 1 (DKK1) protein expression and the osteoclast differentiation factor receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) ratio in osteocytes. In the in vivo study, Met combined with TFRD effectively reduced bone resorption markers levels, including type-I collagen carboxy-terminal peptide (CTX-1) and tartrate-resistant acid phosphatase (TRAP), and remarkably increased the bone formation marker propeptide of type I procollagen (PINP) level in the serum of rats with osteoporosis. Met combined with TFRD treatment improved bone mineral density (BMD), trabecular microstructure, and mechanical properties of osteoporotic rats. Mechanistically, Met combined with TFRD downregulated SOST and DKK1 levels, and upregulated Wnt10b, β-catenin, runt-related transcription factor 2 (Runx2) et al. Meanwhile, Met combined with TFRD treatment reduced the RANKL/OPG ratio, and reduced the receptor activator of nuclear factor-κB (RANK), nuclear factor of activated T cells c1 (NFATC1), and TRAP levels. In conclusion, Met combined with TFRD ameliorated bone mass in osteoporotic rats through regulating Wnt/β-catenin signaling pathway and OPG/RANKL/RANK axis.
研究领域:
药理学
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骨科
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内分泌学
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分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PHYTOMEDICINE
·
2021
·
IF 5.34
Kamarulzaman Karim,Nelli Giribabu,Naguib Salleh
Background M. pumilum has been claimed to protect the bone against the adverse effect of estrogen deficiency . Additionally, it also exhibits anti-diabetic activity. In view of these, this study aims to identify the mechanisms underlying the bone protective effect of M. pumilum in the presence of both estrogen deficiency and diabetes mellitus (DM). Methods Ovariectomized, diabetic female rats were given M. pumilum leave aqueous extract (MPLA) (50 and 100 mg/kg/day), estrogen, glibenclamide and estrogen plus glibenclamide for 28 consecutive days. At the end of the treatment , fasting blood glucose (FBG), serum insulin , Ca 2+ , PO 4 3− and bone alkaline phosphatase (BALP) levels were measured. Rats were sacrificed and femur bones were harvested for determination of expression level and distribution of RANK , RANKL , OPG and oxidative stress and inflammatory proteins by molecular biological techniques. Results 100 mg/kg/day MPLA treatment decreased the FBG and BALP levels but increased the serum insulin, Ca 2+ and PO 4 3− levels in estrogen deficient, diabetic rats. Expression and distribution of RANKL, NF-κB p65, IKKβ, IL-6, IL-1β and Keap-1 decreased however expression and distribution of RANK, OPG, BMP-2, Type-1 collagen, Runx2, TRAF6 , Nrf2, NQO-1, HO-1, SOD and CAT increased in the bone of estrogen deficient, diabetic rats which received 100 mg/kg/day MPLA with greater effects than estrogen-only, glibenclamide-only and estrogen plus glibenclamide treatments. Conclusion MPLA helps to overcome the adverse effect of estrogen deficiency and DM on the bone and thus this herb could potentially be used for the treatment and prevention of osteoporosis in postmenopausal women with diabetes.
研究领域:
药理学
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内分泌学
·
糖尿病研究
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骨生物学
·
炎症研究
·
氧化应激
✓ 已验证
DOI
PubMed
高影响因子
Molecular Medicine Reports
·
2017
·Vol. 17
·期 1
·158-164
·
IF 1.692
Yang‑Hua Tang,Zhen‑Shuang Yue,Guo‑Song Li,Lin‑Ru Zeng,Da‑Wei Xin,Zhong‑Qing Hu,Can‑Da Xu
The aim of the present study was to investigate the effect of glucocorticoids in osteoblasts and to examine the role of β‑ecdysterone in the pathogenesis of glucocorticoid‑induced osteoporosis. Osteoblasts were induced from bone marrow mesenchymal stem cells, which were isolated from C57BL/6 mice. Cell viability and apoptosis of osteoblasts were measured by Cell Counting Kit‑8 and flow cytometry analysis, respectively. The expression of related genes and proteins was measured by reverse transcription quantitative polymerase chain reaction and western blot analysis respectively. Dose‑dependent decreases in the cell proliferation and differentiation were observed in dexamethasone (Dex)‑treated osteoblasts, evidenced by downregulation in the activity of alkaline phosphatasedecreased expression levels of Runt‑related transcription factor 2 and osteocalcin, and upregulated expression of RANK ligand. Dex also induced apoptosis and inhibited autophagy of osteoblasts, evidenced by upregulated B‑cell lymphoma 2 (Bcl‑2)‑associated X protein/Bcl‑2 ratio and the activation of mammalian target of rapamycin (mTOR), and decreased expression levels of Beclin‑1, autophagy protein 5 and microtubule‑associated protein 1 light chain 3 II. The effects on cell proliferation, apoptosis and autophagy induced by Dex were reversed by β‑ecdysterone in a dose‑dependent manner. Therefore, β‑ecdysterone may be a promising candidate drug for the treatment of osteoporosis through inducing osteoblast autophagic activity by inactivating mTOR.
研究领域:
药理学
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骨科
·
细胞生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）