High efficiency iron removal from quartz sand using phosphoric acid

2012 ◽  
Vol 114-117 ◽  
pp. 30-34 ◽  
Author(s):  
Zhizhen Zhang ◽  
Jingsheng Li ◽  
Xiaoxia Li ◽  
Houquan Huang ◽  
Lifen Zhou ◽  
...  
2021 ◽  
Vol 17 ◽  
pp. 2729-2764
Author(s):  
Alemayehu Gashaw Woldegiorgis ◽  
Xufeng Lin

In recent years, the synthesis of axially chiral compounds has received considerable attention due to their extensive application as biologically active compounds in medicinal chemistry and as chiral ligands in asymmetric catalysis. Chiral phosphoric acids are recognized as efficient organocatalysts for a variety of enantioselective transformations. In this review, we summarize the recent development of chiral phosphoric acid-catalyzed synthesis of a wide range of axially chiral biaryls, heterobiaryls, vinylarenes, N-arylamines, spiranes, and allenes with high efficiency and excellent stereoselectivity.


2020 ◽  
Vol 27 (25) ◽  
pp. 31278-31288
Author(s):  
Mohamed H. Taha ◽  
Ahmed M. Masoud ◽  
Yasser M. Khawassek ◽  
Ahmed E. M. Hussein ◽  
Hisham F. Aly ◽  
...  
Keyword(s):  

2021 ◽  
Vol 5 (4) ◽  
pp. 71
Author(s):  
Alexander V. Klinov ◽  
Alexander V. Malygin ◽  
Alina R. Khairullina ◽  
Alisa R. Davletbaeva ◽  
Oleg O. Sazonov ◽  
...  

Amino ethers of ortho-phosphoric acid prepared using triethanolamine; ortho-phosphoric acid; polyoxyethylene glycol, diethylene glycol, triethylene glycol and glycerol (AEPA-DEG/TEG/Gl) were investigated as extractants for the separation of aqueous ethanol solutions by extractive distillation. Using the method of open evaporation, the influence of the molecular structure of AEPA-DEG/TEG/Gl on the conditions of vapor–liquid equilibrium in ethanol–water solutions was studied. It has been shown that the addition of AEPA-DEG/TEG/Gl removes the azeotropic point. At the same time, the observed effect turned out to be significantly higher in comparison with the use of pure glycerol or glycols for these purposes. The UNIFAC model was used to calculate the activity coefficients in a three-component ethanol–water–AEPA-DEG/TEG/Gl mixture. Within the framework of this model, a division of AEPA-DEG/TEG/Gl molecules into group components is proposed. Previously unknown parameters of the groups PO–CH, PO–CH2, PO–OCH2, PO–NHCH2, PO–OH, and PO–H2O were determined from our own and published experimental data. The concentration dependences of the density and dynamic viscosity of AEPA-Gl aqueous solutions have been experimentally measured. Experimental studies of the extractive distillation of ethanol–water using AEPA-Gl as an extractant have been carried out in a column with bubble cap plates and a packing, and its high efficiency has been established.


2018 ◽  
Vol 47 (4) ◽  
pp. 823-829
Author(s):  
Hongqiang Wang ◽  
Lieyu Zhang ◽  
Hong Liu

The phosphoric acid modified walnut and peanut shell were prepared and applied for the removal of the blue-green alga (Microcystis aeruginosa Kütz.). Orthogonal experiment was used to optimize the modified condition. For the efficient removal, 0.05 g of the modified walnut and peanut shell was added into 50 ml of algal culture and kept standing for 4 hrs. This condition was found best and under which the removal rate of algae can be reached > 90%. At the same time, a comparison between unmodified walnut and peanut shell and modified walnut and peanut shell on the removal of M. aeruginosa cells showed that, unmodified walnut and peanut shell have a removal rate of 31.51 and 29.90%, respectively. On the other hand, the modified walnut and peanut shell showed a removal rate of 96.55 and 93.75%, respectively. Walnut and peanut shells modified with phosphoric acid enhanced the removal efficiency of M. aeruginosa cells. So, the modified walnut and peanut shell were considered as a potential algaecide with high efficiency of obnoxious algae removal from the environment safely.


Author(s):  
Kou-Ming Lin ◽  
Ching-Tu Chang ◽  
Ming-Shin Wu ◽  
Wen-Chen Lee ◽  
Jen-Chieh Chung ◽  
...  

Metal scrap is a major waste generated from the decommissioning of nuclear facilities. Through a decontamination process, most of the metal scraps can be cleaned to meet the clearance levels, which can then be reused or released according to the regulatory procedure. Usually, chemical processes will be used in the cleaning step. Phosphoric acid and fluoroboric acid are the typical chemicals used for decontamination. Although the decontaminant could be reused multiple times after regeneration, its decontamination efficiency would decrease after 3 to 5 cycles. In addition, the radioactive nuclides such as Cs-137 are not easily removed during the regeneration process; it tends to accumulate slowly in the decontaminant. According to the ALARA principle, decontaminant must be replaced if its radioactive activity exceeds the regulatory levels. As a result, a significant amount of spent strong acid solution would be generated. The conventional way of treatment is to neutralize the acid solution with an alkaline solution. However, such method will produce a large amount of sludge that requires further stabilization, which offsets the advantages of metal decontamination by use of the decontaminant. A high-efficiency solidification method has been developed and used to treat the spent phosphoric acid and fluoroboric acid solution in Institute of Nuclear Energy Research (INER). The self-polymerization nature of highly concentrated phosphoric acid is adopted to immobilize the radioactive nuclides. The volume of solidified form is almost equal to that of the treated acid solution. The waste form demonstrates its quality by compression test and leaching test. This cementation process is an excellent method to minimize the secondary waste, which is generated from chemical decontamination for treating metal waste.


1998 ◽  
Vol 31 (2) ◽  
pp. 409-417
Author(s):  
Chuhua Wang ◽  
Maria T. Gallardo ◽  
Robert F. Benson ◽  
Melissa Derby ◽  
Dean F. Martin
Keyword(s):  

2021 ◽  
Vol 22 (14) ◽  
pp. 7690
Author(s):  
Ilya Nifant’ev ◽  
Dmitry Gavrilov ◽  
Alexander Tavtorkin ◽  
Maria Chinova ◽  
Victoria Besprozvannykh ◽  
...  

In bone surgery and orthopedics, bioresorbable materials can be helpful in bone repair and countering post-op infections. Explicit antibacterial activity, osteoinductive and osteoconductive effects are essential to achieving this objective. Nonwoven electrospun (ES) fibers are receiving the close attention of physicians as promising materials for wound dressing and tissue engineering; potentially, in high contrast with dense materials, ES mats hamper regeneration of the bone extracellular matrix to a lesser extent. The use of the compositions of inherently biodegradable polyesters (poly(ε-caprolactone) PCL, poly(lactoglycolide), etc.), calcium phosphates and antibiotics is highly prospective, but the task of forming ES fibers from such compositions is complicated by the incompatibility of the main organic and inorganic ingredients, polyesters and calcium phosphates. In the present research we report the synthesis of hydroxyapatite (HAp) nanoparticles with uniform morphology, and demonstrate high efficiency of the block copolymer of PCL and poly(ethylene phosphoric acid) (PEPA) as an efficient compatibilizer for PCL/HAp mixtures that are able to form ES fibers with improved mechanical characteristics. The materials obtained in the presence of vancomycin exhibited incremental drug release against Staphylococcus aureus (St. aureus).


2017 ◽  
Vol 2 (2) ◽  
pp. 83
Author(s):  
Kapustin F.L. ◽  
Furman E.L. ◽  
Ponomarenko A.A. ◽  
Kapustin A.F.

<p>Composition and regeneration properties of the molding sand mixtures worked out of casting production ‒ quartz sand and dust fraction. The results of the laboratory investigations as to their use in both building and refractory materials composition are presented. The industrial tests have shown the high efficiency of silica rich regenerated products in dinas products manufacture.</p>


2019 ◽  
Vol 135 ◽  
pp. 01030
Author(s):  
Larisa Belova ◽  
Alexandr Zhulin ◽  
Olga Sidorenko

In the Tyumen region, groundwater is widely used for household and drinking water supply, the chemical composition of which is influenced by the increased marshland and peat resistance of soils and, in some cases, the presence of oil and gas-bearing horizons. Underground water typically has a high content of dissolved organic impurities (permanganate oxidability 11.7 - 23.0 mg/dm3), elevated concentrations of free carbon dioxide (20.0 200.0 mg/dm3), hydrogen sulfide (0.20 - 1.95 mg/dm3) and methane (5.3 - 60.0 mg/dm3), dissolved forms of iron (1.14 - 14.00 mg/dm3), manganese (0.02 - 3.80 mg/dm3). Analysis of iron removal plants operation was performed. Analysis of the region's iron removal plants showed that the process of iron removal of water depends on the degree of saturation of water with air oxygen with parallel removal of dissolved gases. Pre-degassing of water with high efficiency degassers is a necessary link of the process chain even when reagent purification techniques are used. Analysis and systematization of existing degassers to remove dissolved carbon dioxide have shown that despite the high-efficiency of some degasser models, they are complex in design and require considerable capital construction and operation costs. There is a need to develop a design not complicated in design, having high degassing efficiency at low economic costs.


1991 ◽  
Vol 24 (7) ◽  
pp. 261-268 ◽  
Author(s):  
Y. P. Sedlukho

The problems of applying new method of coalescence of emulsified oil products on the surface of hydrophobic filtering materials during purification of oil-containing waste water are discussed. The results of some theoretical and experimental research are listed. During the research granulated polymers (polyethylene, polypropylene) and hydrophobic quartz sand were used as filtering materials. The research reveals the fundamental processes which are occurring. The main principles of technological computation as well as those of designing installations and separate elements of installations are worked out. The paper shows that it is possible to achieve rather a high efficiency of separating water/oil emulsions if filtering materials and technological parameters are selected properly. The paper is based on the results of recent research carried out under the guidance of the author at the Novopolotsk Polytechnic Institute.


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