Adsorption and Separation of Divalent Metals by Porous Glass using Citric Acid as Complexing Agent

2011 ◽  
Vol 37 (2) ◽  
pp. 150-155 ◽  
Author(s):  
Issei Fujiyoshi
Keyword(s):  
Citric Acid ◽  
Porous Glass ◽  
Complexing Agent ◽  
Divalent Metals

Research on Effects of Slurry Additives in Cu CMP for ULSI Manufacturing

2006 ◽  
Vol 304-305 ◽  
pp. 350-354 ◽  
Author(s):  
X.J. Li ◽  
Dong Ming Guo ◽  
R.K. Ren ◽  
Zhu Ji Jin
Keyword(s):  
Hydrogen Peroxide ◽  
Surface Roughness ◽  
Electrochemical Impedance Spectroscopy ◽  
Citric Acid ◽  
Chemical Mechanical Polishing ◽  
Electrochemical Impedance ◽  
Etching Rate ◽  
Complexing Agent ◽  
Cu Cmp ◽  
Static Etching

In this paper, in order to analyze the oxidation, dissolution and corrosive inhibition effects of additives in the slurry for copper Chemical-mechanical polishing(CMP), the slurry(pH5) with the peroxide as an oxidant, the citric acid as a complexing agent and the benzotriazole(BTA) as an inhibitor is studied. The static etching rate and polishing rate of the Cu-H2O2-Citric acid-BTA slurry are measured. The electrochemical behavior involved in the dissolution and corrosive inhibition of copper in the solutions containing additives is investigated by the electrochemical impedance spectroscopy (EIS) studies. The surface roughness is measured using ZYGO 3-D surface profiler. It is observed that when the slurry is with only 5wt% peroxide existing, copper is stable and slight etching rate on the copper is produced, and the etching rate is only 8.7nm/min. When 0.6wt% citric acid presents after adding 5wt% hydrogen peroxide, the etching rate will increase by 5.3 times, with a blue complexing product emerging. When the inhibitor BTA is added, the corrosion will be effectively restrained. From the EIS results, the impedance of copper in 5wt% peroxide solution which is in passivation can be greatly decreased by adding the citric acid as a complexing reagent. And the impedance of copper in the solution containing peroxide and citric acid can be increased by the addition of BTA. The surface roughness of the wafer polished with the slurry of 5wt% peroxide+0.6wt% citric acid+0.12wt% BTA slurry is Ra 4.7 Å.

Effect of complexing agents on desulphurization and deashing of coal by H2O2/H2SO4 leaching

2018 ◽  
Vol 29 (7) ◽  
pp. 1142-1154
Author(s):  
Hafiza Sana ◽  
Rizwan Haider ◽  
Muhammad Usman Rahim ◽  
Shahid Munir
Keyword(s):  
Hydrogen Peroxide ◽  
Citric Acid ◽  
Phosphoric Acid ◽  
Removal Efficiency ◽  
Coal Sample ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Chemical Leaching ◽  
Optimized Conditions

The present study was aimed at investigating the effect of the addition of complexing agents on the removal efficiency of sulphur and ash contents during chemical leaching by acidified hydrogen peroxide. Representative coal sample from Lakhra was subjected to chemical leaching under various conditions of the parameters including time (60 and 120 min), temperature (25 and 50°C), complexing agents (citric acid and phosphoric acid) and the concentration of complexing agents (100 and 1000 ppm). The addition of complexing agents, i.e. citric acid and phosphoric acid imparted significant effects on improving the removal efficiency of sulphur and ash contents. Under optimized conditions, it was found out that the addition of citric acid improved the removal efficiency for sulphur from 63.88 to 83.47% and from 33.12 to 66.25% for ash. In case of phosphoric acid, the removal in sulphur and ash contents was increased from 63.77 to 80.77% and from 33.12 to 59.18%, respectively. Apparently, citric acid happened to be the most effective complexing agent, as compared to phosphoric acid. These results warrant subsequent detailed studies for further optimization of the process, including the use of some other complexing agents, as well.

scholarly journals The Role of Nitrate on the Sol-Gel Spread Self-Combustion Process and Its Effect on the NH3-SCR Activity of Magnetic Iron-Based Catalyst

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 314
Author(s):  
Xing Ning ◽  
Zhi-bo Xiong ◽  
Bin Yang ◽  
Wei Lu ◽  
Shui-mu Wu
Keyword(s):  
Nitric Acid ◽  
Citric Acid ◽  
Sol Gel ◽  
Nox Reduction ◽  
Combustion Process ◽  
Catalytic Performance ◽  
Metal Nitrate ◽  
Acid Sites ◽  
Complexing Agent ◽  
Nh3 Scr

Sol-gel spread self-combustion is the burning of the complexing agent in dried gel and the oxidant. Meanwhile, high temperature takes place during the combustion process, which is harmful to the pore structure of the catalyst. The nitrate from metal nitrate precursors as an oxidant could participate in the spread of the self-combustion process. Therefore, the influence of nitrate from metal nitrate on the spread self-combustion of an iron–cerium–tungsten citric acid gel and its catalytic performance of NOx reduction were investigated by removing nitrate via the dissolution of washing co-precipitation with citric acid and re-introducing nitric acid into the former solution. It was found that the removal of nitrate contributes to enhancing the NH3–SCR activity of the magnetic mixed oxide catalyst. The NOx reduction efficiency was close to 100% for Fe85Ce10W5–CP–CA at 250 °C while the highest was only 80% for the others. The results of thermal analysis demonstrate that the spread self-combustion process of citric acid dried gel is enhanced by re-introducing nitric acid into the citric acid dissolved solution when compared with the removal of nitrate. In addition, the removal of nitrate helps in the formation of γ-Fe2O3 crystallite in the catalyst, refining the particle size of the catalyst and increasing its pore volume. The removal of nitrate also contributes to the formation of Lewis acid sites and Brønsted acid sites on the surface of the catalyst compared with the re-introduction of nitric acid. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) demonstrates that both Eley–Rideal (E–R) and Langmuir–Hinshelwood (L–H) mechanisms exist over Fe85Ce10W5–CP–CA at 250 °C with E–R as its main mechanism.

scholarly journals PEMBUATAN DAN KARAKTERISASI NANOKOMPOSIT MFe2O4 DAN MFe2O4-SiO2 (M = Cu, Ni)

2015 ◽  
Vol 4 (1) ◽  
pp. 55
Author(s):  
Rahmayeni ◽  
Syukri Arief ◽  
Yeni Stiadi ◽  
Herlin Oktavani
Keyword(s):  
Iron Oxide ◽  
Citric Acid ◽  
Iron Chloride ◽  
Polymerization Process ◽  
Complexing Agent ◽  
Sem Images ◽  
Nickel Iron ◽  
Oxide Crystal ◽  
Ft Ir ◽  
Polymerization Method

 Nanocomposites of MFe2O4 and MFe2O4-SiO2 (M= Cu, Ni) were prepared by complexation and complexs polymerization methods using citric acid as complexing agent, tetraethylorthosilicate (TEOS), metal (Cu, Ni) nitrate and iron chloride as precursors. FT-IR spectroscopy was used to analysis the complexation and polymerization process. The decomposition of material was investigated by TG-DTA. Microstructure characterization was carried out by XRD and SEM. Peaks in XRD pattern indicate that the nanocomposites products consist of copper iron oxide (CuFe2O4) and (NiFe2O4) crystals, copper iron oxide crystal distributed in silica (CuFe2O4-SiO2) and nickel iron oxide crystal distributed in silica (NiFe2O4-SiO2). SEM images of CuFe2O4 and NiFe2O4 show that the composites have porous and spherical texture. The surface texture of CuFe2O4-SiO2 composite is triangel like and has porous but NiFe2O4-SiO2 is not regulated texture and has porous.  Keywords: MFe2O4, MFe2O4/SiO2, citric acid and complexs polymerization method   

Removal of Chromium from Aqueous Solution by Polymer Enhanced Ultrafiltration Using Copolymer of Maleic Acid and Acrylic Acid

2013 ◽  
Vol 668 ◽  
pp. 241-245 ◽  
Author(s):  
Lian Jun Mao ◽  
Yong Qian Wang ◽  
Yun Ren Qiu
Keyword(s):  
Aqueous Solution ◽  
Citric Acid ◽  
Acrylic Acid ◽  
Maleic Acid ◽  
Complete Removal ◽  
Polyvinyl Butyral ◽  
Complexing Agent ◽  
Membrane Effects ◽  
Polymer Metal ◽  
Added Salt

Polymer enhanced ultrafiltration was used to remove Cr(III) from aqueous solution by using complexing agent, copolymer of maleic acid and acrylic acid (PMA-100), and polyvinyl butyral (PVB) ultrafiltration membrane. Effects of mass ratio of polymer/metal (P/M), pH, added salt and citric acid on the rejection of Cr(III) were investigated. Results show that the rejection of Cr(III) can be 97.2% for 10.0 mg/L aqueous solution at P/M 6.0 and pH 5.0, and the a complete removal occurs when pH is not smaller than 6.0, but the membrane will be fouled due to the formation of hydroxide precipitation at pH 6.0. The addition of the citric acid leads to a significant decrease of rejection while the added salt (up to 0.1M) has little effect on the rejection of Cr(III).

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