NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 42
·19726-19736
·
IF 3.3
Xingxin Xu,Hualiang Huang
In this work, Ca(H2PO4)2 was used as a green corrosion inhibitor for AZ91D magnesium alloy in 3.5 wt% NaCl solution. The corrosion inhibition behavior and mechanism were analyzed using electrochemical tests, high-definition video measuring microscopy, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). The electrochemical testing results showed that the optimal corrosion inhibition concentration of Ca(H2PO4)2 was 0.6 g L−1, and the highest corrosion inhibition efficiency was 89.29% after 48 h immersion in the corrosive medium. Optical microscopy and SEM images showed that an obvious protective film formed on the Mg alloy surface in solution inhibited with Ca(H2PO4)2. EDS and XRD results showed that the protective layer was composed of Mg(OH)2 + MgHPO4 + Ca3PO4, and MgHPO4 played a major role. The precipitation mechanism of Ca(H2PO4)2 as a corrosion inhibitor was proposed.
研究领域:
材料科学
·
电化学
·
腐蚀与防护
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 13
·50099
·
IF 2.52
Dan Zhang,Dehai Meng,Zhongying Ma,Zhihao Zhang,Haozhe Ning,Yuhua Wang
To optimize the poor thermal stability and flammable of polyvinyl alcohol (PVA), a novel environmental-friendly organic–inorganic hybrid flame retardant Ca(H 2 PO 4 ) 2 @HCCP was successfully designed and synthesized via surface treatment technology and used to advance the flame retardancy of PVA. The thermogravimetric analysis implied that Ca(H 2 PO 4 ) 2 @HCCP can enhance significantly the thermal stability and char forming ability of PVA. Combustion results demonstrate that Ca(H 2 PO 4 ) 2 @HCCP could effectively suppress the melt dripping of PVA in the process of combustion. The presence of Ca(H 2 PO 4 ) 2 @HCCP can sharply reduce peak heat release rate and the total heat release up to 75% and 22.9%, respectively, in the microscale combustion calorimeter measurement. The results manifested that Ca(H 2 PO 4 ) 2 @HCCP could endow PVA with superior flame retardancy. Moreover, char residues analysis explained the flame retardant mechanism in condensed and gas phase, which is mainly attributed to the strong catalytic char formation, free radical trapping, and gas barrier effect. Therefore, the green flame retardant has great application s prospect in fire safety.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2021
·
IF 6.186
Youjian Zhu,Yun Liu,Liang Wang,Wei Yang,Haiping Yang,Long Jiang,Zhenyi Du,Jingai Shao,Hanping Chen
Combustion of agricultural residues for heat and electricity production is an efficient way to reduce amount of such waste source and emissions due to inappropriate treatment of them. However, unlike other biomass materials, agricultural residues often have high content of ash and certain ash forming elements with low meting temperatures, resulting in sintering and slagging during combustion processes . It complicates combustion of agricultural residues and restricts further utilization of this renewable energy source . In this work, sintering of a typical agricultural biomass cornstalk and effect of two phosphate additives, Ca(H 2 PO 4 ) 2 ·H 2 O and NH 4 H 2 PO 4 , were investigated by a combination of various techniques. Results indicated that the addition of Ca(H 2 PO 4 ) 2 ·H 2 O increased the initial melting temperature of cornstalk ash by 64–209 °C. The ash sintering behavior was greatly improved as a result of formation of high melting temperature K–Ca phosphates, Ca 9 MgK(PO 4 ) 7 and Ca 2 KP 3 O 10 upon addition of the Ca(H 2 PO 4 ) 2 ·H 2 O. It is accompanied with reduced generation of low melting temperature K-rich silicates and the formation of large ash aggregates. Addition of NH 4 H 2 PO 4 increased the initial ash melting temperature by 28–116 °C, but it had slight influence on the cornstalk ash sintering characteristics. The analysis revealed that, although the addition of NH 4 H 2 PO 4 resulted in the formation of high melting temperature K 2 CaP 2 O 7 , certain amount of K phosphates and silicates eutectics were still formed, initiating and promoting sintering of ash from mixture of cornstalk and NH 4 H 2 PO 4 . Reactions between Ca(H 2 PO 4 ) 2 ·H 2 O and potassium salts under different conditions were also studied. It was found that reactions between Ca(H 2 PO 4 ) 2 ·H 2 O and potassium salts might already start as the temperature higher than 300 °C. K 2 CaP 2 O 7 , Ca 2 P 2 O 7 , Ca(PO 3 ) 2 and KCa(PO 3 ) 3 were identified as main products from these reactions and amounts of them considerably depends on the heat treatment temperatures and mixing ratios between Ca(H 2 PO 4 ) 2 ·H 2 O and potassium salts. Compared to KCl, K 2 CO 3 had a higher reactivity toward the Ca(H 2 PO 4 ) 2 ·H 2 O under same study conditions. The current work shows the addition of Ca(H 2 PO 4 ) 2 ·H 2 O is a promising approach to alleviate the ash sintering issues and assure efficient and smooth combustion of cornstalk.
研究领域:
能源与环境科学
·
生物质能研究
✓ 已验证
DOI
高影响因子
ACS Omega
·
2019
·
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
·
材料科学
✓ 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）