scholarly journals Titanium anodizing in a choline dihydrogencitrate salt–oxalic acid deep eutectic solvent: a step towards green chemistry in surface finishing of titanium and its alloys

RSC Advances ◽  
2021 ◽  
Vol 11 (34) ◽  
pp. 21104-21115
Author(s):  
Juliusz Winiarski ◽  
Anna Niciejewska ◽  
Monika Górnik ◽  
Jakub Jakubowski ◽  
Włodzimierz Tylus ◽  
...  

Fabrication of nanometric color TiO2 layers through polarization of titanium in a choline dihydrogencitrate–oxalic acid DES anodizing bath.

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 3344-3355
Author(s):  
Hongyan Yang ◽  
Jinyan Lang ◽  
Junliang Lu ◽  
Ping Lan ◽  
Heng Zhang

The direct conversion of microcrystalline cellulose (MCC) degrading into 5-hydroxymethyl furfural (5-HMF) was studied using four synthetic deep eutectic solvents (DESs) as solvents and choosing four metal chlorides as catalysts. The factors that affected the yields of the products, such as the type of DESs, the type and dosage of catalysts, the ratio of DESs to MCC, and reaction temperature were researched. It was found that the DES synthesized from oxalic acid and choline chloride (O-DES) and SnCl4 showed the better performance. The highest 5-HMF and glucose yields of 11.0% and 22.0% were obtained, respectively, for a reaction carried out at 160 °C for 90 min in O-DES (the ratio of it to MCC was 25:1) using 1.42 wt% SnCl4 as the catalyst. As a new type of dissolution and catalysis system, the DESs were not only cheaper but also easy to obtain. Most importantly, the realization of the concept of green chemistry was achieved in this study.


2021 ◽  
Vol 131 ◽  
pp. 368-375
Author(s):  
Filipa Lima ◽  
Luis C. Branco ◽  
Nuno Lapa ◽  
Isabel M. Marrucho

BioResources ◽  
2017 ◽  
Vol 12 (4) ◽  
pp. 7301-7310
Author(s):  
Veronika Majová ◽  
Silvia Horanová ◽  
Andrea Škulcová ◽  
Jozef Šima ◽  
Michal Jablonský

This study aimed to resolve the issue of the lack of detailed understanding of the effect of initial lignin content in hardwood kraft pulps on pulp delignification by deep eutectic solvents. The authors used Kappa number of the concerned pulp, intrinsic viscosity, and selectivity and efficiency of delignification as the parameters of the effect. The pulp (50 g oven dry pulp) was treated with four different DESs systems based on choline chloride with lactic acid (1:9), oxalic acid (1:1), malic acid (1:1), and system alanine:lactic acid (1:9); the results were compared to those reached by oxygen delignification. The results showed that the pulp with a higher initial lignin content had a greater fraction of easily removed lignin fragments.


2018 ◽  
Vol 101 (2) ◽  
pp. 593-600 ◽  
Author(s):  
Rizwan Ali Zounr ◽  
Mustafa Tuzen ◽  
Muhammad Yar Khuhawar

Abstract In present study, we proposed the application of a deep eutectic solvent (DES) made up of choline chloride (ChCl) and oxalic acid (Ox) for the dissolution of different edible mushroom samples for the determination of selenium (Se) and arsenic (As) ions. Therefore, an innovative, green, novel, and inexpensive method based on ChCl–Ox as the DES was developed for the determination of Se and As ions in mushroom species by graphite furnace-atomic absorption spectrometry. The important analytical parameters were also optimized. The LODs for Se and As ions were found to be 0.32 and 0.50 µg/L, respectively. The LOQs for Se and As ions were found to be 1.06 and 1.65 µg/L, respectively. The RSD was observed to be less than 5% for both analyte ions. The accuracy of the developed method was confirmed by analyzing mushroom powder Certified Reference Material CS-M-3 (Boletus edulis). The developed technique was effectively useful for the determination of Se and As ions in different species of mushroom samples from Turkey.


2020 ◽  
Vol 75 (3) ◽  
pp. 269-279
Author(s):  
Mohammad Hosein Sayahi ◽  
Maryam Gorjizadeh ◽  
Melan Meheiseni ◽  
Soheil Sayyahi

AbstractAn effective method based on choline chloride (ChCl)-oxalic acid (Ox) deep eutectic solvent was proposed for the synthesis of 4-azaphenanthrene-3,10-dione, 1,8-dioxo-octahydroxanthene and tetrahydrobenzo[b]pyran derivatives. The eutectic mixture worked as both the solvent and acidic catalyst for conversion. The impacts of different variables, including the composition and volume of ChCl-Ox, and temperature, on reaction yield were studied for optimization. The crucial advantages of this process are simplicity of the experimental procedure, high yields, short reaction times, high recyclability, and the use of safe and inexpensive components.


2000 ◽  
Vol 42 (1-2) ◽  
pp. 347-352
Author(s):  
E.H. Smith ◽  
S. Chatterjee

Waste shot-blast fines from surface finishing processes have been demonstrated to be effective for removing heavy metals from solution by adsorption.The technology offers the potential for inexpensive recovery and reuse of a material normally discarded as a solid waste. While metal removals compare favorably with those achieved by commercial sorbents, applications issues such as the impact of background metal-complexing agents require investigation. The presence of oxalic acid, a complexing organic compound, impacted cadmium and lead adsorption in accordance with predictions from metal speciation equilibria; i.e., a small but measurable reduction in lead removal was observed, but cadmium adsorption was relatively unaffected. The effects were repeated in dynamic column experiments, with lead removals reduced by 15 to 20% in the presence of the ligand. Efforts to model adsorption equilibria in the presence of oxalic acid did not fully capture the reduced lead removal, presumably because the model does not consider the complete formation of metal-oxalic acid complexes prior to contact with the sorbent.


Author(s):  
Xin Xiong Chang ◽  
Nabisab Mujawar Mubarak ◽  
Shaukat Ali Mazari ◽  
Abdul Sattar Jatoi ◽  
Awais Ahmad ◽  
...  

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