Acid Attack on Cement Paste Containing Limestone Powder

2013 ◽  
Vol 724-725 ◽  
pp. 1589-1592
Author(s):  
Shu Hua Liu ◽  
Zhi Gang Wang ◽  
Ya Ning Kong ◽  
Li Hua Li ◽  
Mei Juan Rao
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Acid Solution ◽  
Cement Paste ◽  
Ph Value ◽  
Acid Resistance ◽  
Limestone Powder ◽  
X Ray Diffraction ◽  
Acid Attack ◽  
Acid Ph

A comparative study has been performed on the acid resistance of cement paste exposed to acetic acid (pH=4) and sulfuric acid (pH=2). The pastes are prepared by replacing 30% and 50% cement with limestone powder. Their properties and microstructures are investigated by using strength test, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The paper reveals that erosion extent of pastes depends mainly not only on the pH value of acid solution and the w/b ratio of pastes, but also on the limestone powder mixed that contributes partly to the hydration. Though gypsum and ettringite formations are dominant to the deterioration of pastes exposed to sulfuric acid solution, the degree of decrease for the compressive strength of specimens exposed to sulfuric acid is retarded compared with the specimens exposed to acetic acid. This is attributed to the product of gypsum, which delays the further erosion to the internal paste.

scholarly journals Study on Strength and Microstructure of Cement Pastes Containing Limestone Powder under Flowing Acid Solution Condition

ISRN Ceramics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Shuhua Liu ◽  
Lihua Li ◽  
Zhigang Wang ◽  
Jiafeng Wang ◽  
Meijuan Rao
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Calcium Carbonate ◽  
Acid Solution ◽  
Calcium Hydroxide ◽  
Ph Value ◽  
Acetic Acid Solution ◽  
Limestone Powder ◽  
Acid Attack ◽  
Cement Pastes

Different cement pastes containing limestone powder were prepared and soaked, respectively, in flowing acetic acid solution with pH value of 4 and sulfuric acid solution with pH value of 2. The strength and microstructure of the pastes after different flowing acid attack periods were investigated by using strength test, X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques in this study, which reveals the effect of limestone powder on flowing acid resistance mechanism of cement paste. Testing results show that the strength of pastes suffered flowing acid attack decreases with the increase of water-binder ratio and the content of limestone powder. In flowing acetic acid solution, calcium hydroxide and calcium carbonate react with acetic acid, which therefore made deterioration of pastes proceed from the exterior to the interior. In flowing sulfuric acid solution, although calcium hydroxide and calcium carbonate could react with sulfuric acid and form gypsum, the flowing liquid would dissolve it out and thus the crystallization of gypsum was difficult which would somewhat inhibit the swell of pastes.

Baeyer-Villiger Oxidation of 10-Methyl-9-Anthraldehyde: Formation and Photochemical Dimerization of 9-Formyloxy-10-methylanthracene

1988 ◽  
Vol 41 (12) ◽  
pp. 1977 ◽  
Author(s):  
HD Becker ◽  
BW Skelton ◽  
AB Turner ◽  
AH White
Keyword(s):  
Molecular Structure ◽  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Sulfuric Acid ◽  
Diffraction Study ◽  
Crystalline State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tail Structure ◽  
Villiger Oxidation

Oxidation of 10-methyl-9-anthraldehyde with hydrogen peroxide in acetic acid in the presence of sulfuric acid gives 9-formyloxy-10-methylanthracene which dimerizes in solution upon exposure to light. The head-to-tail structure of the 4π+4π photodimer was established by a single-crystal X-ray diffraction study. In the crystalline state, the molecular structure is centrosymmetric, and the length of the photochemically formed bonds 1.646(4)Ǻ. Crystals are monoclinic, P21/c, a 7.980(5), b 16.143(7), c 9.571(3)Ǻ, β 114.38(3)°, Z=2 dimers; R was 0.041 for 1362 'observed' diffractometer reflections.

Comparative analysis of biogenic and chemical sulfuric acid attack on hardened cement paste using laser ablation-ICP-MS

2016 ◽  
Vol 87 ◽  
pp. 14-21 ◽  
Author(s):  
Bettina Huber ◽  
Harald Hilbig ◽  
Mariana M. Mago ◽  
Jörg E. Drewes ◽  
Elisabeth Müller
Keyword(s):  
Sulfuric Acid ◽  
Comparative Analysis ◽  
Laser Ablation ◽  
Cement Paste ◽  
Hardened Cement ◽  
Acid Attack ◽  
Hardened Cement Paste ◽  
Icp Ms

scholarly journals Study on the Concentration of Acrylic Acid and Acetic Acid by Reverse Osmosis

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 142
Author(s):  
Qian Liu ◽  
Lixin Xie ◽  
Hanxiao Du ◽  
Shichang Xu ◽  
Yawei Du
Keyword(s):  
Acetic Acid ◽  
Acrylic Acid ◽  
Acid Solution ◽  
Reverse Osmosis ◽  
Membrane Surface ◽  
Acid Resistance ◽  
Operating Conditions ◽  
Operating Pressure ◽  
Permeate Flux ◽  
Amide Bonds

In the production of acrylic acid, the concentration of acrylic acid solution from the adsorption tower was low, which would lead to significant energy consumption in the distillation process to purify acrylic acid, along with the production of a large amount of wastewater. Reverse osmosis (RO) was proposed to concentrate the acrylic acid aqueous solution taken from a specific tray in the absorption tower. The effects of operating conditions on the permeate flux and acid retention were studied with two commercial RO membranes (SWC5 and SWC6). When the operating pressure was 4 MPa and the temperature was 25 °C, the permeate fluxes of two membranes were about 20 L·m−2·h−1. The acrylic acid and acetic acid retentions were about 80% and 78%, respectively. After being immersed in the acid solutions for several months, the characteristics of the two membranes were tested to evaluate their acid resistance. After six months of exposure to the acid solution containing 2.5% acrylic acid and 2.5% acetic acid, the retentions of acrylic acid and acetic acid were decreased by 5.7% and 4.1% for SWC5 and 4.9% and 2.2% for SWC6, respectively. The changes of membrane surface morphology and chemical composition showed the hydrolysis of some amide bonds.

scholarly journals Effect of Silica Fume on Metakaolin Geopolymers’ Sulfuric Acid Resistance

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5396
Author(s):  
Oliver Vogt ◽  
Neven Ukrainczyk ◽  
Eddie Koenders
Keyword(s):  
Sulfuric Acid ◽  
Silica Fume ◽  
Acid Resistance ◽  
Sample Surface ◽  
Acid Attack ◽  
Solution Ph ◽  
X Ray ◽  
Dependent Change ◽  
Before And After ◽  
Time Dependent Change

To demonstrate the importance of the Si/Al ratio in terms of geopolymer mix designs for acid resistance, a metakaolin-based geopolymer was modified by replacing the aforementioned precursor with different percentages of silica fume. Durability tests were performed by exposing geopolymers with varying amounts of silica fume (up to 9%) to sulfuric acid solution (pH 1) over a period of 84 days. Geopolymer samples were analyzed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) before and after 7, 14, 28, 56 and 84 days of exposure. To show the time-dependent change of the elemental composition in the corroded layer after sulfuric acid attack, SEM-EDX elemental mappings were conducted and divided into 100 µm segments to generate element-specific depth profiles. The results show that above a critical silica fume content, the erosion of the sample surface by complete dissolution can be prevented and higher amounts of silica fume lead to a significant densification of large (protective) areas of the corroded layer, which delays the progress of corrosion.

scholarly journals Solid state interactions in the systems CaO(CaCO3)-Fe2O3 and CuFe2O4-CaO

2005 ◽  
Vol 41 (1) ◽  
pp. 67-77 ◽  
Author(s):  
B.S. Boyanov
Keyword(s):  
Sulfuric Acid ◽  
Solid State ◽  
Acid Solution ◽  
Diffraction Analysis ◽  
Sulfuric Acid Solution ◽  
Formation Process ◽  
X Ray Diffraction ◽  
Exchange Reactions ◽  
X Ray ◽  
Ferrite Formation

The solid state interactions in the systems CaO(CaCO3)-Fe2O3 and CuFe2O4-CaO have been studied using X-ray diffraction analysis. The influence of the temperature on the ferrite formation process has been investigated in the range of 900-1200 oC and duration up to 360 min. It has been shown that a mixture of ferrites forms at 1000 oC and interaction of 240 min. The exchange reactions in the systems CuFe2O4-CaO and Cu0.5Zn0.5Fe2O4-CaO have been studied, too. It has been established that Ca2+ ions exchange Cu2+ and Zn2 partially and the solubility of copper and zinc in a 7 % sulfuric acid solution increases 10-15 times.

scholarly journals Effects of Bentonite Activation Methods on Chitosan Loading Capacity

2018 ◽  
Vol 13 (1) ◽  
pp. 14 ◽  
Author(s):  
Tao Yu ◽  
Chengtun Qu ◽  
Daidi Fan ◽  
Renjun Xu
Keyword(s):  
Sulfuric Acid ◽  
Reaction Time ◽  
Metal Removal ◽  
Ph Value ◽  
Heavy Metal Removal ◽  
Bentonite Clay ◽  
Loading Capacity ◽  
X Ray Diffraction ◽  
Sulfuric Acid Treatment ◽  
Chitosan Concentration

The adsorption capacity of bentonite clay for heavy metal removal from wastewater can be significantly enhanced by a high loading of chitosan on the surface. In order to enhance the chitosan loading, we tested activating bentonite clay by three methods prior to chitosan loading: sulfuric acid, calcination, and microwave treatments. Meanwhile, several parameters during chitosan loading, namely the initial chitosan concentration, stirring speed, reaction time, temperature, and pH value were investigated. Our results indicate that chitosan is attached to bentonite clay through intercalation and surface adsorption according to X-ray Diffraction (XRD), Scanning Eelectron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) analyses. The maximum chitosan loading on 200-mesh raw bentonite clay (126.30 mg/L) was achieved under the following conditions: the initial chitosan concentration of 1000 mg/L, the stirring speed of 200 rpm, pH of 4.9, 60 min of reaction time, and temperature of 30 °C. The chitosan loading was further increased to 256.30, 233.70, and 208.83 mg/g, when using bentonite clay activated through 6 min of microwave irradiation (800 W), 10 % sulfuric acid treatment, and calcinations at 600 °C, respectively. When the chitosan loading was increased from 34.76 to 233.7 mg/g, the removal percentages of Cu(II), Cr(VI), and Pb(II) were improved, respectively from 78.90 to 95.5 %, from 82.22 to 98.74 %, from 60.09 to 86.18 %. Copyright © 2018 BCREC Group. All rights reservedReceived: 14th March 2017; Revised: 17th July 2017; Accepted: 18th July 2017; Available online: 22nd January 2018; Published regularly: 2 April 2018How to Cite: Yu, T., Qu, C., Fan, D., Xu, R. (2018). Effects of Bentonite Activation Methods on Chitosan Loading Capacity. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1): 14-23 (doi:10.9767/bcrec.13.1.1040.14-23) 

Eco-Friendly Synthesis and Applicability to Silver Ink of Silver Nanoparticles Prepared via Stepwise-Modified Tollens Method

2021 ◽  
Vol 21 (4) ◽  
pp. 2568-2575
Author(s):  
Nguyen Cong Tu ◽  
Ho Minh Sang ◽  
Luu Thi Lan Anh ◽  
Nguyen Huu Lam
Keyword(s):  
Silver Nanoparticles ◽  
Acetic Acid ◽  
Citric Acid ◽  
Acid Solution ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Silver Ink ◽  
Stepwise Method ◽  
Mean Size ◽  
The Mean

Silver nanoparticles were eco-friendly synthesized at room temperature via a Tollens process modified with the stepwise method using eco-friendly precursors (citric acid and acetic acid). The field emission scanning electron spectroscopy was used to study the morphology of silver nanoparticles. The mean size of silver nanoparticles and the components of products were theoretically determined using UV-Vis and X-ray Diffraction spectra. The mole ratio between the silver ion, citric acid and the buffer acid solution (acetic acid) strongly influences the mean size and the composition of the product. The appearance of acetic acid in the buffer acid solution helped increase the efficiency of silver nanoparticles preparation. With the mole ratio n[Ag+]:ncitric:nacetic = 1.0:2.5:2.5, the highest preparation efficiency was obtained, the silver nanoparticles had an average dimension of ˜11 nm and narrow size distribution. The silver nanoparticles were dispersed into different solvents to examine their applicability to silver ink. The silver ink using propylene glycol solvent showed good applicability to silver ink which could work at room temperature.

Characterization of Porous Anodic Aluminium Oxide Film on Aluminium Templates Formed in Anodizing Process

2010 ◽  
Vol 173 ◽  
pp. 55-60 ◽  
Author(s):  
A. Wahab Juyana ◽  
Mohd Nazree Derman
Keyword(s):  
Acetic Acid ◽  
Phosphoric Acid ◽  
Acid Solution ◽  
Acetic Acid Solution ◽  
Aluminium Oxide ◽  
X Ray Diffraction ◽  
Mixed Acid ◽  
Anodic Aluminium Oxide ◽  
Optimum Parameters ◽  
Xrd Techniques

A porous anodic aluminium oxide (AAO) films were successfully fabricated on aluminium templates by using anodizing technique. The anodizing process was done in the mixed acid solution of phosphoric acid and acetic acid. The growth, morphology and chemical composition of AAO film were investigated. During the anodizing process, the growth of the oxide pores was strictly influenced by the anodizing parameters. The anodizing was done by varying the voltage at 70 V to 130 V and temperature from 5 °C to 25 °C. The electrolyte concentration was remaining constant. In this study, all the samples were characterized using scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques. From this study, the optimum parameters to obtain porous AAO film with the mixture of phosphoric acid and acetic acid solution can be known.

scholarly journals Survival or Growth of Escherichia coli O157:H7 in a Model System of Fresh Meat Decontamination Runoff Waste Fluids and Its Resistance to Subsequent Lactic Acid Stress

2005 ◽  
Vol 71 (10) ◽  
pp. 6228-6234 ◽  
Author(s):  
John Samelis ◽  
John N. Sofos ◽  
Patricia A. Kendall ◽  
Gary C. Smith
Keyword(s):  
Escherichia Coli ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Acid Stress ◽  
Acid Resistance ◽  
Fresh Meat ◽  
Sterile Saline ◽  
E Coli ◽  
Acid Ph ◽  
Natural Flora

ABSTRACT A potential may exist for survival of and resistance development by Escherichia coli O157:H7 in environmental niches of meat plants applying carcass decontamination interventions. This study evaluated (i) survival or growth of acid-adapted and nonadapted E. coli O157:H7 strain ATCC 43895 in acetic acid (pH 3.6 ± 0.1) or in water (pH 7.2 ± 0.2) fresh beef decontamination runoff fluids (washings) stored at 4, 10, 15, or 25°C and (ii) resistance of cells recovered from the washings after 2 or 7 days of storage to a subsequent lactic acid (pH 3.5) stress. Corresponding cultures in sterile saline or in heat-sterilized water washings were used as controls. In acetic acid washings, acid-adapted cultures survived better than nonadapted cultures, with survival being greatest at 4°C and lowest at 25°C. The pathogen survived without growth in water washings at 4 and 10°C, while it grew by 0.8 to 2.7 log cycles at 15 and 25°C, and more in the absence of natural flora. E. coli O157:H7 cells habituated without growth in water washings at 4 or 10°C were the most sensitive to pH 3.5, while cells grown in water washings at 15 or 25°C were relatively the most resistant, irrespective of previous acid adaptation. Resistance to pH 3.5 of E. coli O157:H7 cells habituated in acetic acid washings for 7 days increased in the order 15°C > 10°C > 4°C, while at 25°C cells died off. These results indicate that growth inhibition by storage at low temperatures may be more important than competition by natural flora in inducing acid sensitization of E. coli O157:H7 in fresh meat environments. At ambient temperatures in meat plants, E. coli O157:H7 may grow to restore acid resistance, unless acid interventions are applied to inhibit growth and minimize survival of the pathogen. Acid-habituated E. coli O157:H7 at 10 to 15°C may maintain a higher acid resistance than when acid habituated at 4°C. These responses should be evaluated with fresh meat and may be useful for the optimization of decontamination programs and postdecontamination conditions of meat handling.

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