Preparation of NiMo/KIT-6 hydrodesulfurization catalysts with tunable sulfidation and dispersion degrees of active phase by addition of citric acid as chelating agent

Abstract In this work, novel trimetallic catalysts based on transition metal sulphides (Ru, Mo and Ni) supported on SBA-15 were synthesized. Citric acid (CA) was used as chelating agent in order to enhance the dispersion of the active phase and minimize the metal-support interaction. Sulfided catalysts were evaluated in the reaction of hydrodesulfurization (HDS) of dibenzothiophene (DBT) at 320 °C and 54.5 atm of total H2 pressure. The effects of different Ru/(Ni + Mo) atomic ratios on the active phase were studied. The catalysts were characterized using Micro-Raman spectroscopy, DRIFTS, XRD, XPS, HR-TEM and SEM techniques. Results have shown that there was a better dispersion of the metallic phases, which improves the physicochemical properties of the catalysts, increasing the catalytic activity. The trimetallic RuxMoNi catalyst with the lowest atomic ratio, have shown superior catalytic activity compared to their higher atomic ratio counterparts. The interaction of the chelating agent improved the catalytic activity, which was superior to that observed for NiMo based catalysts, considered one of the most active hydrotreating catalysts.

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Removal of Bound PAH Residues in Contaminated Soils by Fenton Oxidation

Catalysts ◽

10.3390/catal9070619 ◽

2019 ◽

Vol 9 (7) ◽

pp. 619 ◽

Cited By ~ 4

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.

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

MRS Proceedings ◽

10.1557/proc-1166-n03-13 ◽

2009 ◽

Vol 1166 ◽

Cited By ~ 2

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.

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CoMo/ZrO2 Hydrodesulfurization Catalysts Prepared by Chelating Agent Assisted Spreading

Catalysis Letters ◽

10.1007/s10562-012-0857-6 ◽

2012 ◽

Vol 142 (8) ◽

pp. 969-974 ◽

Cited By ~ 4

Author(s):

Luděk Kaluža ◽

Daniela Gulková ◽

Zdeněk Vít ◽

Miroslav Zdražil

Keyword(s):

Chelating Agent ◽

Hydrodesulfurization Catalysts

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Perbedaan daya pembersih kavitas saponin ekstrak kulit manggis (Garcinia mangostana Linn) 0,78% dan asam sitrat 6% (The difference of 0,78% saponin from mangosteen pericarp extract and 6% citric acid for cleanliness of cavity)

Conservative Dentistry Journal ◽

10.20473/cdj.v7i1.2017.6-11 ◽

2019 ◽

Vol 7 (1) ◽

pp. 6

Author(s):

Ivon Dewi Setianingrum ◽

Ketut Suardita ◽

Ari Subiyanto ◽

Dian Agustin Wahjuningrum

Keyword(s):

Citric Acid ◽

Chelating Agent ◽

Smear Layer ◽

Control Group ◽

Garcinia Mangostana ◽

Human Teeth ◽

Inorganic Particles ◽

The Difference ◽

Dental Cavities ◽

Better Than

Background: Cleanliness of cavity is considered important for a restoration. Smear layer formed after cavity preparation should be removed in order not to disrupt the bond adhesion between restorative materials and dental cavities. Saponins contained in mangosteen pericarp (Garcinia mangostana L.) have surfactant properties that can eliminate the smear layer assessed. 6% citric acid is a chelating agent which can eliminate the inorganic particles of the smear layer. Until now, the research on the differences of 0,78% saponin from mangosteen pericarp extract and 6% citric acid for cleanliness of cavity has never been done. Purpose: To see the differences between 0,78% saponin from mangosteen pericarp extract and 6% citric acid as cavity cleanser. Method: Eighteen human teeth with complete crown, no caries, and no fractures were randomized in 3 groups (n≥6), in this experiment use (n=6). The cavity was prepared using wheels bur for hand use instrument. After instrumentation, each cavity on the first group used 0,78% saponin from mangosteen pericarp extract as cavity cleanser, the second group used 6% citric acid as cavity cleanser, and the control group used aquadest. Then, the teeth were split to be observed on Scanning Electron Microscope (SEM). Result: For Mann- Whitney test there were significant differences just between 078% saponin from mangosteen pericarp extract with 6% citric acid, and 6% citric acid with aquadest, but not for 0,78% saponin from mangosteen pericarp extract with aquadest. Median value of 6% citric acid showed 2,000 which is the smallest value compared to the value of the other groups. Conclusion: The cleanliness of cavity with 6% citric acid is better than that with 0,78% saponin from mangosteen pericarp extract.

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Microwave assisted sol-gel auto-combustion synthesis of NiCuFe2O4 nanoparticles using citric acid as an organic chelating agent: structural and optical studies

10.3390/ecsoc-19-c005 ◽

2015 ◽

Author(s):

Faranak Manteghi ◽

Mahnaz Kamel Attar Kar ◽

Mahdi Ghahari

Keyword(s):

Citric Acid ◽

Combustion Synthesis ◽

Sol Gel ◽

Chelating Agent ◽

Optical Studies ◽

Microwave Assisted ◽

Auto Combustion

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Effect of Treatment Conditions on Nisin Inactivation of Gram-negative Bacteria

Journal of Food Protection ◽

10.4315/0362-028x-55.10.763 ◽

1992 ◽

Vol 55 (10) ◽

pp. 763-766 ◽

Cited By ~ 101

Author(s):

KELLY A. STEVENS ◽

BRIAN W. SHELDON ◽

N. ARLENE KLAPES ◽

TODD R. KLAENHAMMER

Keyword(s):

Citric Acid ◽

Incubation Temperature ◽

Chelating Agent ◽

Gram Negative Bacteria ◽

Citric Acid Monohydrate ◽

Gram Negative ◽

Treatment Conditions ◽

Effect Of Treatment ◽

Gram Negative Organisms ◽

Sodium Phosphate Dibasic

A method using nisin and a chelating agent to inactivate Salmonella species and other gram-negative bacteria has been developed. The objective of this study was to determine the effect of treatment conditions on the application of this method. Ten gram-negative organisms were used in this study, including six Salmonella species commonly associated with foodborne illness. Organisms were selected on the basis of sensitivity to nisin and a chelating agent. The following parameters were examined: (a) chelating agent, (b) nisin concentration, (c) incubation temperature, and (d) protein interference. Chelating agents included EDTA, ethylenebis (oxyethylene-nitrilo) tetraacetic acid, citric acid monohydrate, and sodium phosphate dibasic. The most effective treatment consisted of 50 to 100 μg/ml nisin applied in combination with 20 mM EDTA or citric acid monohydrate at a temperature range of 30 to 42°C. All of the chelators examined exhibited some inhibitory activity. The addition of bovine serum albumin to the treatments containing nisin and EDTA did not result in a significant decrease in inhibitory action.

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Recent Advances in Hydrotreating/Hydrodesulfurization Catalysts: Part I: Nature of Active Phase and Support

Catalysis for Clean Energy and Environmental Sustainability ◽

10.1007/978-3-030-65021-6_1 ◽

2021 ◽

pp. 1-33

Author(s):

G. Valavarasu ◽

B. Ramachandrarao

Keyword(s):

Active Phase ◽

Hydrodesulfurization Catalysts ◽

Recent Advances

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Preparation and Characterization of Cordierite Powder via Tween-80 Modified Citrate Sol-Gel Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.148-149.929 ◽

2010 ◽

Vol 148-149 ◽

pp. 929-933

Author(s):

Yu Yue Wang ◽

Juan Juan Feng ◽

Yi Liu

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Citric Acid ◽

Metal Ion ◽

Sol Gel ◽

Chelating Agent ◽

Particle Morphology ◽

Tween 80 ◽

Solvent Evaporation Process ◽

Scanning Electron

In this paper, cordierite (2MgO•2Al2O3•5SiO2) precursors are synthesized using TEOS and aluminum and magnesium nitrates as starting materials, citric acid as chelating agent and Tween-80 as dispersant. The effect of citric acid and Tween-80 on the formation mechanism of α-cordierite phase is investigated by using X-ray diffraction (XRD), while the effect of citric acid and Tween-80 on the particle morphology of α-cordierite is examined by using scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM). The results show that citric acid used as chelating agent can reduce the formation temperature of α-cordierite to 1150°C by forming stable salt of citric acid with all the metal ion to avoid composition deviation from the sample components during solvent evaporation process and sub-micron cordierite particles without hard agglomeration can be obtained. Nano-sized α-cordierite can be obtained with the introduction of Tween-80 as dispersant by modifying the surfaces of the colloidal sol particles.

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