Effects of Acid on the Performance of Polishing Process

2016 ◽  
Vol 700 ◽  
pp. 50-59 ◽  
Author(s):  
Nurul Syafiqah Hasni ◽  
Noorina Hidayu Jamil ◽  
Abdullah Chik ◽  
Wi Wan Mohd Arif ◽  
Hong Eng Seong
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Chelating Agent ◽  
Polishing Process ◽  
Quality Problem ◽  
Difference Type ◽  
Magnetic Substrate ◽  
Lapping Machine

The serious quality problem in the magnetic substrate during polishing process by using conventional lapping machine had generate the idea to develop a doubled-sided lapping machine of polishing stone manufactured of an abrasive and resin. After certain parameter of polishing process, the polishing stone starts to clog because of debris agglomeration from the polishing substrate, thus lead to the scratches on the magnetic substrate which will affect its performance. Three difference type of acid were used as to dissolve the debris agglomeration in the polishing stone. The influence of oxalic, phosphoric and citric acid at three different times were examined. It was found that oxalic acid is the best chelating agent in dissolving the debris in the polishing stone.

Removal of Bound PAH Residues in Contaminated Soils by Fenton Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 619 ◽  
Author(s):  
Xuqiang Zhao ◽  
Li Qin ◽  
Michael Gatheru Waigi ◽  
Pengfei Cheng ◽  
Bing Yang ◽  
...  
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Contaminated Soils ◽  
Chelating Agent ◽  
Fenton Oxidation ◽  
Valuable Insight ◽  
First Order Kinetics ◽  
Bound Residues ◽  
Polycyclic Aromatic ◽  
Insight Into

The availability of bound residues of polycyclic aromatic hydrocarbons (PAHs), in reference to their parent compounds, can be enhanced by microbial activity and chemical reactions, which pose severe risks for the ecosystems encompassing contaminated soils. Considerable attention has been raised on how to remove these bound residues from PAH-contaminated soils. This paper provides a novel application of Fenton oxidation in the removal of bound residues of model PAHs, such as naphthalene (NAP), acenaphthene (ACP), fluorene (FLU) and anthracene (ANT), from naturally contaminated soils. The citric acid-enhanced Fenton treatment resulted in the degradation of bound PAH residues that followed pseudo-first-order kinetics, with rate constants within 4.22 × 10−2, 1.25 × 10−1 and 2.72 × 10−1 h−1 for NAP, FLU, and ANT, respectively. The reactivity of bound PAH residues showed a correlation with their ionization potential (IP) values. Moreover, the degradation rate of bound PAH residues was significantly correlated with H2O2-Fe2+ ratio (m/m) and H2O2 concentrations. The highest removal efficiencies of bound PAH residues was up to 89.5% with the treatment of chelating agent oxalic acid, which was demonstrated to be superior to other acids, such as citric acid and hydrochloric acid. This study provides valuable insight into the feasibility of citric acid-Fenton and oxalic acid-Fenton treatments in rehabilitating bound PAH residues in contaminated soils.

Electrochemical Action of FA/O II Chelating Agent and H2O2 on Copper Film in the Polishing Process

2018 ◽  
Vol 03 (01) ◽  
Author(s):  
Yi Hu ◽  
Zhi Su ◽  
Yangang He ◽  
Yuling Liu ◽  
Fangfang Jiang
Keyword(s):  
Copper Film ◽  
Chelating Agent ◽  
Polishing Process

The synergistic mechanisms of citric acid and oxalic acid on the rapid dissolution of kaolinite

2020 ◽  
Vol 196 ◽  
pp. 105756 ◽  
Author(s):  
Shao-Min Lin ◽  
Ya-Ling Yu ◽  
Zhi-Jie Zhang ◽  
Chen-Yang Zhang ◽  
Ming-Feng Zhong ◽  
...  
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Rapid Dissolution

scholarly journals Oxalic acid production by Aspergillus niger: an oxalate-non-producing mutant produces citric acid at pH 5 and in the presence of manganese

Microbiology ◽  
1999 ◽  
Vol 145 (9) ◽  
pp. 2569-2576 ◽  
Author(s):  
George J. G. Ruijter ◽  
Peter J. I. van de Vondervoort ◽  
Jaap Visser
Keyword(s):  
Citric Acid ◽  
Aspergillus Niger ◽  
Oxalic Acid ◽  
Acid Production

Preparation of Delafossite CuYO2 by Metal-citric Acid Complex Decomposition Method

2009 ◽  
Vol 1166 ◽  
Author(s):  
Keishi Nishio ◽  
Tomomi Okada ◽  
Naoto Kikuchi ◽  
Satoshi Mikusu ◽  
Tsutomu Iida ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Citric Acid ◽  
Single Phase ◽  
Raw Materials ◽  
Chelating Agent ◽  
Amorphous Powder ◽  
Heat Treating ◽  
Acid Complex ◽  
Synthesis Conditions ◽  
Starting Solution

AbstractDelafossite CuYO2 and Ca doped CuYO2 were prepared by thermal decomposition of a metal-citric acid complex. The starting solution consisted of Cu acetate, Y acetate and Ca acetate as the raw materials. Citric acid was used as the chelating agent, and acetic acid and distilled water were mixed as a solvent. The starting solutions were heated at 723 K for 5 h after drying at 353 K. The obtained powders were amorphous and single phase of orthorhombic Cu2Y2O5 was obtained by heat-treated the amorphous powder at a temperature range between 1073 and 1373 K for 3 h in air. Furthermore, Heat-treating the obtained orthorhombic Cu2Y2O5 at above 1373 K in air caused it to decompose into Y2O3, CuO and Cu2O. On the other hand, the sample powder prepared from a starting solution without citric acid, i.e., single phase of orthorhombic Cu2Y2O5 could not be obtained under the same synthesis conditions as that for a solution with citric acid. We were able to obtain delafossite CuYO2 and Ca doped CuYO2 from orthorhombic Cu2Y2O5 under a low O2 pressure atmosphere at above 1223 K. The obtained delafossite CuYO2 composed hexagonal and rhombohedral phases. The color of the CuYO2 powder was light brown and that of Ca-doped CuYO2 was light green. Diffraction peaks in the XRD pattern were slightly shifted by doping Ca for CuYO2, and these peaks shifted toward to a high diffraction angle with an increasing amount of doped Ca. From these results, we concluded that Ca doped delafossite CuYO2 could be obtained by thermal decomposition of a metal-citric acid complex.

Study the Properties of Abrasive Stone for Aluminum Grinding

2015 ◽  
Vol 754-755 ◽  
pp. 688-692
Author(s):  
Nurul Syafiqah Hasni ◽  
Noorina Hidayu Jamil ◽  
Abdullah Chik ◽  
Wi Wan Mohd Arif ◽  
Hong Eng Seong
Keyword(s):  
Hard Disk Drive ◽  
Disk Drive ◽  
Grinding Process ◽  
Ftir Analysis ◽  
Thermosetting Resin ◽  
Magnetic Substrate ◽  
Soft Spot ◽  
Lapping Machine ◽  
Abrasive Stone ◽  
Grinding Stone

A doubled-sided lapping machine of grinding stone manufactured of a SiC as an abrasive, specific resin and other thermosetting resin were developed for grinding process of the substrate of hard disk drive (HDD) made up of aluminum since the conventional lapping machine cause the serious quality problem of the magnetic substrate. However, at certain parameter during the grinding process, the abrasive stone was clogging due to the agglomeration of debris from the substrate which cause scratches on the magnetic substrates and affect its performance. The samples were classified into four parts (soft spot, border spot, hard spot, and unused spot). Characterizations of the samples were done using XRF, SEM and FTIR analysis. Based on all the above analysis, it can conclude that the porosity of the stone were not homogeneous and the percentage of Al was highest at the border spot which shows that, the area at the border spot cause the clogging to occur thus produces the hard spot that will damage the magnetic substrate during grinding process.

Preparation of LiFePO4/C Composite Powders

2011 ◽  
Vol 391-392 ◽  
pp. 377-380
Author(s):  
Guo Jun Li ◽  
Ming Yang ◽  
Hai Li Jing ◽  
Rui Ming Ren
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Specific Capacity ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Charge Capacity ◽  
X Ray ◽  
Initial Charge

LiFePO4/C composite powders were prepared by a simple reaction of as-synthesized FePO4•2H2O, LiOH•H2O, oxalic acid and citric acid. The influence of oxalic acid and citric acid in different ratios was investigated on morphology and electrochemical performance of LiFePO4/C composite powders. The characterization of the composites included X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis indicates that the material is well crystallized without impurities. The obtained LiFePO4/C composite powders with well dispersion at CA/OA ratio of 1:1.50 and the initial charge capacity reached 159.3 mAhg-1 at 0.1C rate, meanwhile, the particles prepared at 1:0.75 were close to spherical in shape and the specific capacity value was 149.8 mAhg-1 at 0.1C rate, with a slight decrease on greater C-rates reaching 141.3 mAhg-1 at 1C.

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