JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2021
·
IF 6.789
Xiao Xia,Liqiang Zhang,Zhanyao Li,Xueliang Yuan,Chunyuan Ma,Zhanlong Song,Guifang Chen
CaSO 4 reduction decomposition for CaO preparation provides a theoretical basis for the utilization of the industrial byproduct, gypsum. In this study, the effects of temperature (950 °C–1150 °C), CO 2 /CO partial-pressure ratio (1–15), CO concentration (1%–5%), and O 2 concentration (1%–7%) on the preparation of CaO from CaSO 4 by CO reduction decomposition under different reaction atmospheres were investigated. The physical properties of CaO prepared by the decomposition of CaSO 4 and CaCO 3 were analyzed and compared. Finally, the reaction mechanism of the reduction decomposition of CaSO 4 to CaO by CO was studied. The findings reveal that CaSO 4 can be completely decomposed into CaO when the reaction temperature exceeds 1000 °C, CO% ≥ 2%, and P(CO 2 )/P(CO) ≥ 8. Furthermore, the addition of an appropriate amount of O 2 can improve the yield of CaO in the products. In an O 2 –CO–N 2 atmosphere, where O 2 % = 7% and CO% = 16%, CaSO 4 can be completely decomposed into CaO without the addition of CO 2 . The physical properties of CaO prepared by the reduction and decomposition of CaSO 4 are better than those prepared by the calcination of CaCO 3 . An analysis of the reaction mechanism of the reduction decomposition of CaSO 4 by CO reveals that CaSO 4 generates CaO and CaS simultaneously. In addition, CaS can react with unreacted CaSO 4 to form CaO. Furthermore, it can react with CO 2 to produce CaO if an appropriate amount of CO 2 is added to the reaction atmosphere. The secondary interactions of CaS with CaSO 4 and CO 2 can significantly improve the yield of CaO in the product.
研究领域:
化学工程
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材料科学
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DOI
PubMed
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2016
·Vol. 28
·期 3
·367-372
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IF 1.823
Zhenling Shen,Xin Zhi,Puyu Zhang
Polysuccinimide was synthesized from maleic anhydride and urea. A polyaspartic acid derivative (PASP-Try-SEA) was synthesized from the polysuccinimide with 2 -aminoethanesulfonic acid and tryptophan. The products were characterized by UV, FTIR, 1 H NMR, TGA and PL, respectively. The results showed that the fluorescent chromophore-indolyl groups were successfully incorporated into PASP. The relationship between the fluorescence intensity and the concentration of fluorescent polyaspartic acid (FPASP) is linear with the excitation wavelength of 366 nm and 422 nm. FPASP also showed excellent scale inhibition properties with a scale inhibition rate of 78% achieved for CaCO 3 with a dosage of 9 mg/L and a significantly enhanced scale inhibition effect for CaSO 4 , achieving an inhibition rate of 98%, which were determined using the static scale inhibition method. When FPASP was added to the solution, CaCO 3 and CaSO 4 deposits showed flower patterns with floppy accumulation by scanning electron microscopy. Copyright © 2016 John Wiley & Sons, Ltd.
研究领域:
材料科学
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环境工程
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DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2023
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IF 2.6
Qiongqiong Luo,Shaoheng Wang,Dehua Cai,Ning Zhang,Dewen Zeng
A ZnSO4 electrolyte solution with impurity salts such as MnSO4 and MgSO4 is often used in zinc hydrometallurgical processes over a wide temperature range. CaSO4·2H2O(s) scaling and fluorine corrosion are two encountered problems in the process. Understanding the CaF2(s) solubility behavior in MSO4 (M = Zn, Mn, Mg) aqueous solutions at various temperatures helps remove Ca2+ and F– ions from the solution. However, CaF2(s) solubility data, especially at temperatures >298 K, have not been published yet. In this work, CaF2(s) solubilities in the CaF2–CaSO4–MSO4–H2O (M = Zn, Mn, Mg) quaternary systems and its subsystems of the CaF2–MSO4–H2O (M = Zn, Mn, Mg) at 348.15 K and the CaF2–CaSO4–MSO4–H2O (M = Zn, Mg) quaternary systems and the CaF2–MgSO4–H2O ternary system at 298.15 K are systematically measured. The results show that the CaF2(s) solubility in the MSO4 (M = Zn, Mn, Mg) aqueous solution of a certain concentration at 348.15 K is considerably higher than that at 298.15 K. At 298.15 and 348.15 K, the salting-in effect of MSO4 (M = Zn, Mn, Mg) on CaF2(s) solubility is enhanced with the order ZnSO4 < MnSO4 < MgSO4. At both temperatures, CaF2(s) solubilities in CaSO4·2H2O(s)- or CaSO4(s)-saturated MSO4 (M = Zn, Mn, Mg) aqueous solutions are generally lower than those in pure MSO4 (M = Zn, Mn, Mg) aqueous solutions. Particularly, the salting-in effect of MgSO4 on CaF2 is so strong that CaF2(s) dissolves completely and is converted to CaSO4·2H2O(s) and MgF2(s) in a concentrated MgSO4 aqueous solution. Hence, this study indicates that high temperatures and high salt concentrations increase the CaF2(s) solubility, making the removal of Ca2+ and F– ions from the system challenging. Further, the existence of impurity salts MnSO4 and MgSO4 makes it more difficult.
研究领域:
化学
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材料科学
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冶金学
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DOI
高影响因子
ACS Omega
·
2019
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IF 2.584
Xinru Mu,Ganyu Zhu,Xu Li,Shaopeng Li,Xiaokang Gong,Huiquan Li,Guoxin Sun
Wet-process phosphoric acid is a fundamental process in the fertilizer industry. The influence of impurities on crystallization kinetics of CaSO4 was investigated in the Ca(H2PO4)2–H2SO4–H3PO4–H2O system using a mixed suspension mixed product removal crystallizer. Effects of Si, Al, Fe, Mg, K, and Na on crystal morphology and structure were examined in the highly acidic system through scanning electron microscopy and high-resolution transmission electron microscopy. Results show that the increase of Mg, K, and Na content facilitates crystal growth. Si, Al, and Fe are beneficial to CaSO4 crystal growth at a certain concentration range. Impurities also affect the crystal morphology, and the addition of Si, Fe, and Na promotes the formation of needle-like crystals compared with other impurities. X-ray diffraction results show that the preferred crystal growth direction is (020), and the interplanar spacing of the crystals is affected by the element radius of the impurities.
研究领域:
化学工程
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材料科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2024
·
IF 8.4
Xiaoyu Shi,Wei Chen,Xingzhao Ji,Hu Yang
A novel nonionic starch-based antiscalant (St- g -GMA) was designed and obtained by graft copolymerization of starch and glycidyl methacrylate (GMA). St- g -GMA not only achieved an obvious reduction of CaSO 4 scaling in static test, but also effectively mitigated the flux decrease in dynamic reverse osmosis (RO) system. This improvement is ascribed to the grafted poly(GMA) chains on St- g -GMA. A suitable grafting ratio of this starch-based antiscalant achieve a high performance cost in control of CaSO 4 scaling. Combination of the apparent antiscaling performance, observation under scanning electron microscopy, energy dispersive x-ray spectroscopy unit, x-ray diffraction pattern, conductivity measurement, and dispersion experiment, the scale-inhibition mechanism of St- g -GMA was investigated and mainly attributed to chelation, dispersion and lattice distortion effects. The oxygen-containing groups on poly(GMA) chains such as epoxy groups can chelate with Ca 2+ , causing the induction time of crystallization prolonged; St- g -GMA with the distinct branched chain configuration can well disperse the formed microcrystal of CaSO 4 . Moreover, molecular dynamics simulations confirmed that the grafted poly(GMA) chains well bind to the crystal surfaces and the oxygen-containing groups could even enter the crystal lattice to inhibit the crystal growth and change the morphologies. St- g -GMA still mitigated the flux decrease notably in treatment of a synthetic seawater during a 24-h RO measurement. This study provided an efficient, environmentally-friendly and low-cost antiscalant with high application potentials.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
Inorganic Chemistry Frontiers
·
2025
·
IF 6.4
Xihui Shan,Yi Zhang,Xulong Lv,Yanjie Liang
Far ultraviolet-C (far-UVC; 200–230 nm) luminescent materials have garnered significant interest in recent years, driven by the growing demands for applications such as disinfection and solar-blind imaging due to their distinct wavelength features. However, the research and development of far-UVC persistent phosphors are lacking. Here, we report the realization of far-UVC persistent luminescence in CaSO4:Pr3+ and CaSO4:Pb2+ phosphors, which show emissions peaking at 220 nm and 230 nm with a long persistence time of >24 h after ceasing X-ray excitation. This is by far the shortest UVC afterglow emission to the best of our knowledge. The far-UVC afterglow from the charged phosphors can be readily detected by a solar-blind UV camera in both indoor-lighting and outdoor environments owing to the absence of background noise from ambient light. The continuous photostimulation of indoor white LED light and outdoor sunlight has different impact on the far-UVC afterglow performance of CaSO4:Pr3+ and CaSO4:Pb2+ phosphors, which is elucidated by the decay time-dependent thermoluminescence (TL) curves in different light conditions. This study expands the field of persistent luminescence to the far-UVC spectral region and will inspire the discovery of more excellent far-UVC persistent phosphors.
研究领域:
材料科学
·
光学
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DOI
高影响因子
DESALINATION
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2022
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IF 11.211
Songchen Xie,Ngie Hing Wong,Jaka Sunarso,Qiang Guo,Chunguang Hou,Zhiguang Pang,Yuelian Peng
Mineral scaling is one of the major challenges for membrane distillation in concentrating high-salinity brine. This work first investigated the characteristic of CaSO 4 scaling, then explored different cleaning reagents to evaluate their efficiencies and mechanisms. By analyzing the SEM and EDX mapping images, the CaSO 4 scaling process could be divided into surface and pore scaling stages. Three cleaning solutions, i.e., commercial detergent (20 %), EDTA-4Na (0.05 M), and MgCl 2 (0.8 M), were chosen for their high CaSO 4 solubility (0.7 g CaSO 4 per 100 g H 2 O). At the surface scaling stage, three cleaning solutions exhibited excellent removal of CaSO 4 scaling with approximately similar 96 % cleaning efficiencies. However, at the pore scaling stage, only the commercial detergent showed high efficiency (89 %). Such high cleaning efficiency was mainly attributed to the detergent's high total dissolved solids (salinity), low pH, and high diffusion rate (5.46 μm cm −1 min −1 ) across the membrane. Moreover, periodic cleaning at the surface scaling stage with the commercial detergent followed by drying throughout a 43.5 h continuous concentration test on an actual RO brine could restore the PTFE membrane performance completely, giving 90 % of the total water recovery . This work provides new insights into the cleaning mechanism for gypsum scaling in a hydrophobic porous membrane.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2015
·Vol. 132
·期 45
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IF 1.768
Xiaoyu Sun,Junping Zhang,Chengxian Yin,Juantao Zhang,Jiao Han
Scale deposition, which severely damages oil exploration, is a difficulty encountered in oil fields. Scale inhibitors are widely used for controlling scales. Poly(aspartic acid) (PASP) is attracting more and more attention with increasing environmental concern and discharge limitations. However, PASP's poor inhibition in a high-temperature environment markedly limits its wide use. Thus, poly(aspartic acid)–tryptophan grafted copolymer (PASPTR) was synthesized to improve the inhibition efficiency of PASP. The results show that the reactant of PASPTR has a great effect on its inhibition performance. PASPTR was found to inhibit the precipitation of CaSO 4 close to 90% at concentrations as low as 0.4 mg/L at 50°C. The inhibition efficiency of PASPTR against CaCO 3 was close to 100% with the concentration of 2 mg/L at 50°C. Scanning electron microscopy and X-ray diffraction analyses, which showed the morphological and crystal structural changes of CaCO 3 and CaSO 4 precipitation, verified the excellent inhibition performance of PASPTR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42739.
研究领域:
材料科学
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环境工程
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DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2020
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IF 2.627
Zhong Ma,Chuan Yuan,Shuai Zhang,Yonggang Lu,Junhui Xiong
Chemical looping combustion (CLC) is a clean and efficient flame-free combustion technology, which combust the fuels by lattice oxygen from a solid oxygen carrier with inherent CO 2 capture. The development of oxygen carriers with low cost and high redox performance is crucial to the whole efficiency of CLC process. As the solid by-product from the sulfuric acid production, pyrite cinder presented excellent redox performance as an oxygen carrier in CLC process. The main components in pyrite cinder are Fe 2 O 3 , CaSO 4 , Al 2 O 3 and SiO 2 in which Fe 2 O 3 is the active component to provide lattice oxygen. In order to systematic investigate the functions of supports (CaSO 4 , Al 2 O 3 and SiO 2 ) in pyrite cinder, three oxygen carriers (Fe 2 O 3 -CaSO 4 , Fe 2 O 3 -Al 2 O 3 and Fe 2 O 3 -SiO 2 ) were prepared and evaluated in this study. The results showed that Fe 2 O 3 -CaSO 4 displayed high redox activity and cycling stability in the multiple redox cycles. However, both Fe 2 O 3 -Al 2 O 3 and Fe 2 O 3 -SiO 2 experienced serious deactivation during redox reactions. It indicated that the inert Fe-Si solid solution (Fe 2 SiO 4 ) was formed in the spent Fe 2 O 3 -SiO 2 sample, which decreased the oxygen carrying capacity of this sample. The XPS results showed that the oxygen species on the surface of Fe 2 O 3 -CaSO 4 could be fully recovered after the 20 redox cycles. It can be concluded that CaSO 4 is the key to the high redox activity and cycling stability of pyrite cinder.
研究领域:
能源科学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
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2021
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IF 3.196
Qi Yao,Ruifeng Zhan,Hegang Ren,Bo Yang,Ying Yang
Stringent water resources scarcity and severe environmental restriction requires environmentally friendly and efficient scale inhibitors exploitation. Functionalization of polyamidoamine dendrimers for scale inhibitor was performed using 2-phosphate-1, 2, 4-butane tricarboxylic acid (PBTCA) and succinic anhydride (SA). In this study, PBTCA modified polyamidoamine dendrimers (PAMAM-1), SA modified first and second generation polyamidoamine dendrimers (CAMAM-1 and CAMAM-2) are prepared. Static scale inhibition method is employed to assess the scale inhibition efficiency of linear low molecular polyacrylic (LPAA), PBTCA, PAMAM-1, CAMAM-1 and CAMAM-2 against CaCO 3 and CaSO 4 . The results show that carboxyl terminated polyamidoamine dendrimers has excellent scale inhibition performance comparable to PBTCA and PAMAM-1. Compared to LPAA and PBTCA, dendritic structure can effectively improve the scale inhibition performance of the scale inhibitor. Furthermore, the scale inhibition performance enhances with increasing generation of carboxyl-terminated polyamidoamine dendrimer. The inhibition efficiency of CAMAM-2 against CaCO 3 and CaSO 4 is about 96.3% and 95.2% at a concentration of 10 mg/ L. Moreover, The CAMAM-2 performs above 85% scale inhibition at Ca 2+ concentration is 4000 mg/L and 90% scale inhibition at border pH 5–9. The FT-IR, XRD and SEM-EDX results show that the CaCO 3 changes from stable calcite to metastable aragonite and vaterite, and the needle like structure of CaSO 4 is destroyed to small crystals. CAMAM-2 only occupies the crystallization site and distorts the lattice of calcium scale in the crystal growth process rather than adsorb on the final crystal surface. This paper provides data support for the application of phosphate or carboxyl terminated polyamidoamine dendrimer in scale inhibition.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2011
·
IF 3.074
Ning Ding,Ying Zheng,Cong Luo,Qi-long Wu,Pei-fang Fu,Chu-guang Zheng
Chemical-looping combustion (CLC) has been recognized as an energy-efficient method for CO 2 capture. For calcium sulfate (CaSO 4 ) oxygen carrier, the rapid fall in the mechanical strength and reactivity limits its application in CLC. In this study, Taguchi robust design method with L 9 orthogonal array was implemented to optimize extrusion condition for the preparation of binder-supported CaSO 4 oxygen carriers. The orthogonal experiment results showed the addition of SB powder enhanced both mechanical strength and conversion of CaSO 4 , and the optimal extrusion condition was 30 g CaSO 4 , 12 g SB powder, 2.5 mL acetic acid, and 15 mL water. The favorable oxygen carriers were comprehensively studied in a fixed bed reactor. The results of reduction test showed the mass-based reaction rates of the binder-supported CaSO 4 were significantly increased, because the fresh samples had the higher surface area which was evidenced by pore structure analysis. Moreover, the favorable performance of binder-supported CaSO 4 was explained by formation of CaAl 2 O 4 which had excellent thermal stability and provided a stable nanosized framework between the crystal grains observed by field emission scanning electron microscope (FESEM).
研究领域:
能源科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2024
·
IF 4.4
Xingang Wang,Jian Fu,Fubing Zou,Hongyun Luo,Jiukai Cai,Yong Yu
According to the chemical composition and structure properties of lepidolite lithium slag (i.e., LS), reinforcing materials were prepared to improve the mechanical properties and flame retardancy of poly(vinyl alcohol) (PVA)/montmorillonite (MMT) aerogels. Specifically, calcium sulfate anhydrous whiskers (CSAW) were synthesized from LS rich in CaO and SO3 (i.e., LS-B), and nanofillers were obtained from LS rich in Al2O3 and SiO2 (i.e., LS-A). A densified columnar-honeycomb structure of composite aerogels was obtained by adding the above CSAW and nano LS-A. The results show that the mechanical properties were improved remarkably, and the peaks of heat release rate, smoke production rate, and total smoke production were decreased significantly with the combined addition of CSAW and nano LS-A. The strength was increased by about 160%, and the modules were increased by about 130%. The fire safety was also promoted significantly, i.e., the peak of heat release rate was 128.37 kW·m–2, and the smoke production rate was cut down about 3.0 times. The enhancing mechanism of the combined effect from CSAW and nano LS-A on mechanical properties and flame retardancy should be due to the columnar-honeycomb structure formed by CSAW and PVA/MMT and the filling effect of nano LS-A. The proportion of LS utilized in the composite aerogels was achieved by more than 40%. The composite aerogel can be potentially applied in flame retardant fields. This study is of great significance for the high value and comprehensive utilization of LS. It also provides an idea for improving the mechanical properties and flame retardancy of PVA/MMT aerogels in the future.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）