Facile synthesis of pure vaterite using steamed ammonia liquid waste and ammonium carbonate without additives via simple mechanical mixing

2021 ◽  
Vol 386 ◽  
pp. 361-371
Author(s):  
Xuewen Song ◽  
Cunjian Weng ◽  
Yuwei Cao ◽  
Huimin Kong ◽  
Xianping Luo
2020 ◽  
Author(s):  
Hélène Caillet ◽  
Alain Bastide ◽  
Laetitia Adelard

Anaerobic digestion is a widely used process for waste treatment and energy production. This natural process takes place in a controlled environment, anaerobic digesters. Mixing is one of the main operating parameters. The understanding of the flows during the agitation of the medium is crucial for the optimization of the process yield. In fact, the mass and heat transfers are enhanced by the agitation. However, the complex biochemical reactions can be inhibited with overly vigorous agitation. A detailed and in-depth understanding of the phenomena occurring during agitation requires modeling studies. In this chapter, we propose a general approach, based on computational fluid mechanics (CFD), to analyze the mechanical mixing of an anaerobic reactor. We apply this work to the anaerobic digestion of the sugarcane vinasse, which is a liquid waste generated during the production of alcohol. The single-phase Reynolds-averaged Navier-Stokes (RANS) simulations of mechanical agitation of Newtonian fluids for different rotational speeds are presented. The equations system is closed with the standard k-epsilon turbulence model. The flow field is analyzed with the velocity profiles, the Q and Lambda2 fields, the pressure and the vorticity.


Author(s):  
S.D. Smith ◽  
R.J. Spontak ◽  
D.H. Melik ◽  
S.M. Buehler ◽  
K.M. Kerr ◽  
...  

When blended together, homopolymers A and B will normally macrophase-separate into relatively large (≫1 μm) A-rich and B-rich phases, between which exists poor interfacial adhesion, due to a low entropy of mixing. The size scale of phase separation in such a blend can be reduced, and the extent of interfacial A-B contact and entanglement enhanced, via addition of an emulsifying agent such as an AB diblock copolymer. Diblock copolymers consist of a long sequence of A monomers covalently bonded to a long sequence of B monomers. These materials are surface-active and decrease interfacial tension between immiscible phases much in the same way as do small-molecule surfactants. Previous studies have clearly demonstrated the utility of block copolymers in compatibilizing homopolymer blends and enhancing blend properties such as fracture toughness. It is now recognized that optimization of emulsified ternary blends relies upon design considerations such as sufficient block penetration into a macrophase (to avoid block slip) and prevention of a copolymer multilayer at the A-B interface (to avoid intralayer failure).


2019 ◽  
Vol 14 (8) ◽  
pp. 828-830 ◽  
Author(s):  
Weihua Meng ◽  
Weihong Wu ◽  
Weiwei Zhang ◽  
Luyao Cheng ◽  
Yunhong Jiao ◽  
...  

Synlett ◽  
1991 ◽  
Vol 1991 (09) ◽  
pp. 725-727 ◽  
Author(s):  
Takeshi Shimizu ◽  
Sayoko Hiranuma ◽  
Zhao-hui Qian ◽  
Hirosuke Yoshioka

1986 ◽  
Vol 84 ◽  
Author(s):  
Masahiro Okamoto ◽  
Koichi Chino ◽  
Tsutomu Baba ◽  
Tatsuo Izumida ◽  
Fumio Kawamura ◽  
...  

AbstractA new solidification technique using cement-glass, which is a mixture of sodium silicate, cement, additives, and initiator of the solidification reaction, was developed for sodium borate liquid waste generated from pressurized water reactor (PWR) plants. The cement-glass could solidify eight times as much sodium borate as cement could, because the solidifying reaction of the cement-glass is not hindered by borate ions.The reaction mechanism of sodium silicate and phosphoric silicate (initiator), the main components of cement-glass, was studied through X-ray diffraction and compressive strength measurements. It was found that three- dimensionally bonded silicon dioxide was produced by polymerization of the two silicates. The leaching ratio of cesium from the cement-glass package was one-tenth that of the cement one. This low value was attributed to a high cesium adsorption ability of the cement-glass and it could be theoretically predicted accordingly.


2015 ◽  
Vol 12 (1) ◽  
pp. 3910-3918 ◽  
Author(s):  
Dr Remon M Zaki ◽  
Prof Adel M. Kamal El-Dean ◽  
Dr Nermin A Marzouk ◽  
Prof Jehan A Micky ◽  
Mrs Rasha H Ahmed

 Incorporating selenium metal bonded to the pyridine nucleus was achieved by the reaction of selenium metal with 2-chloropyridine carbonitrile 1 in the presence of sodium borohydride as reducing agent. The resulting non isolated selanyl sodium salt was subjected to react with various α-halogenated carbonyl compounds to afford the selenyl pyridine derivatives 3a-f  which compounds 3a-d underwent Thorpe-Ziegler cyclization to give 1-amino-2-substitutedselenolo[2,3-b]pyridine compounds 4a-d, while the other compounds 3e,f failed to be cyclized. Basic hydrolysis of amino selenolo[2,3-b]pyridine carboxylate 4a followed by decarboxylation furnished the corresponding amino selenolopyridine compound 6 which was used as a versatile precursor for synthesis of other heterocyclic compound 7-16. All the newly synthesized compounds were established by elemental and spectral analysis (IR, 1H NMR) in addition to mass spectra for some of them hoping these compounds afforded high biological activity.


2019 ◽  
Author(s):  
Min Zhou ◽  
Jet Tsien ◽  
Tian Qin

<p>Herein we report a sulfur (IV) mediated cross-coupling for facile synthesis of heteroaromatic substrates. Addition of heteroaryl nucleophiles onto a simple, readily-accessible alkyl sulfinyl (IV) chloride allows formation of a trigonal bipyramidal sulfurane intermediate. Reductive elimination therefrom provides bis-heteroaryl products in a practical and efficient fashion. <br></p>


Author(s):  
Kathryn Kellett ◽  
Brendan M. Duggan ◽  
Michael Gilson

We have described simple, high-yield, protocols, which require only commonly accessible equipment, to synthesize a wide range of β-CD derivatives mono-substituted at the secondary face. These derivatives may be useful in their own right, and they are also scaffolds for further modification, and examples of the far broader array of derivatives that may be accessed by these procedures.


Sign in / Sign up

Export Citation Format

Share Document