The Phase Morphology of Citrogypsum Waste Controlled by a Hydrothermal Process in Ethylene Glycol/Water Solutions

2019 ◽  
Vol 824 ◽  
pp. 128-133 ◽  
Author(s):  
Thanakit Sirimahasal ◽  
Yutthana Kalhong ◽  
Lida Simasatitkul ◽  
Siriporn Pranee ◽  
Semih Durmus ◽  
...  
Keyword(s):  
Water Molecule ◽  
Ethylene Glycol ◽  
Hydrothermal Process ◽  
High Strength ◽  
Exothermic Peak ◽  
Crystal Water ◽  
Water Solutions ◽  
Hexagonal Shape ◽  
Ft Ir ◽  
Main Component

The acid purification of calcium citrate from citric acid production using sulfuric acid as a reagent resulted in citrogypsum waste. The identification of citrogypsum by XRD technique indicates that the main component consists of CaSO4∙2H2O (DH). Furthermore, the comparison of the colours between citrogypsum and natural gypsum are also different. Hence, this research mainly focused on the phase transformation of DH to α-CaSO4 ∙0.5H2O (α-HH) due to high strength and heat resistant. The preparation of α-HH carry out in different volume ratios of ethylene glycol (EG): water solutions at 95oC for 7 hrs under atmospheric pressure. The FT-IR spectra of DH and α-HH results reveal that the absorption frequencies at 1700 and 1800 cm-1 of –OH group are 0.5 and 1.5 water molecule in CaSO4 respectively. TGA thermograms show the theoretical crystal water content of DH approximately 20.1 wt% and the converted α-HH about 4-5 wt%. DSC thermograms of the citrogypsums show two endothermic peaks regarding to two steps of water molecule loss at 151.2oC and 168.5oC respectively. In addition, the α-HH shows exothermic peak at 238.7oC. The morphology of citrogypsum and α-HH are observed by SEM, showing the plate-like shape of citrogypsum and hexagonal shape of α-HH. Moreover, the products could be applied to several other industries for increasing the value and reducing the environmental concerns.

The Effect of Solvent Polarity on Phase Transformation of Citrogypsum via Hydrothermal Process

2019 ◽  
Vol 803 ◽  
pp. 351-355 ◽  
Author(s):  
Thanakit Sirimahasal ◽  
Yutthana Kalhong ◽  
Lida Simasatitkul ◽  
Siriporn Pranee ◽  
Samitthichai Seeyangnok
Keyword(s):  
Physical Properties ◽  
Calcium Sulfate ◽  
Hydrothermal Process ◽  
Solvent Polarity ◽  
Sem Images ◽  
Crystal Water ◽  
Calcium Sulfate Dihydrate ◽  
Hexagonal Shape ◽  
Ft Ir ◽  
Hexane Solution

Calcium sulfate dihydrate (CaSO4•2H2O, CSD), gypsum is a by-product in the production of citric acid (citryogypsum). This by-product could neither be exploited nor distributed as a reactant because of its physical properties including those that are not equivalent to natural gypsum. Moreover, the mentioned citrogypsum has been continually increasing environmental problems. Therefore, this research aims at how to recycle gypsum that is synthesized by hydrothermal method at 95oC for 7 hrs under the atmospheric pressure via different solutions (MeOH, EtOH, PrOH, BuOH and Hexane). In order to produce alpha-calcium sulfate hemihydrate (α-CaSO4•0.5H2O, α-CSH) with improved physical properties that will be used for different industries. FT-IR reveals the chemical composition of crystal and the adsorption of methyl group on the surface. Besides, TGA thermogram shows the theoretical crystal water content of CSD and α-CSH 20.9 wt% and 6.2 wt% respectively. The DSC thermogram, shows that endothermic peaks at 151.2 oC and 168.5 oC. There were two steps of loss at 1.5 and 0.5 water molecule respectively. With SEM images of crystal shows the plate-like shape of citrogypsum, while α-CSH shows the hexagonal shape excluding hexane solution. Of all the results, the polarity of solution has an impact on the transition of CSD to α-CSH under this condition.

Nanocellulose-Based Filters as Novel Barrier Systems for Chemical Warfare Agents

2021 ◽  
Vol 317 ◽  
pp. 180-186
Author(s):  
Mohd Nor Faiz Norrrahim ◽  
Noor Aisyah Ahmad Shah ◽  
Siti Hasnawati Jamal ◽  
Wan MD Zin Wan Yunus ◽  
Victor Feizal Knight Victor Ernest ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Interaction ◽  
Chemical Warfare Agents ◽  
High Strength ◽  
Initial Step ◽  
Chemical Weapon ◽  
Chemical Inertness ◽  
Warfare Agents ◽  
Filtration Material ◽  
Ft Ir

Current world events have made several countries as a target for terrorism. Chemical weapon such as nuclear weapon is commonly referred as a weapon of mass destruction. Organophosphorus (OP) compounds have long been used as pesticides and developed into warfare nerve agents such as tabun, soman, sarin, and VX. They are highly toxic and considered to be the most dangerous chemical weapons. Development on the protection material against OP compounds has gained interest among researcher. Nanocellulose has shown a great potential for high-performance filtration material due to its interesting characteristics such as high adsorption capacity, large surface area, high strength, renewable, chemical inertness, and versatile surface chemistry. Therefore, the evaluation of the chemical interaction between nanocellulose and organophosphorus is important. The analyses of fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible (UV-Vis), and elemental analysis were carried out in this study. It was found that the nanocellulose is capable to adsorb OP compound by forming the hydrogen bonding. The adsorption rate was increased as the nanocellulose concentration increased. This is the initial step to discover the potential of nanocellulose to be used in military protection mask.

Solvent-mediated crystalline phases of NixSy anchored on rGO sheets as electrocatalysts for hydrogen evolution application

2019 ◽  
Vol 12 (01) ◽  
pp. 1850089
Author(s):  
Hou Lin Yu ◽  
Wenliang Shi ◽  
Shuaishuai Li ◽  
Junma Zhang ◽  
Xiaobo Zhang ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Hydrogen Evolution ◽  
Hydrothermal Process ◽  
Volume Ratio ◽  
Decisive Role ◽  
Catalytic Performance ◽  
Deionized Water ◽  
Alkaline Media ◽  
One Pot ◽  
Alkaline Environments

A facile, one-pot solvent-mediated hydrothermal process was adopted to prepare nickel sulfide nanoparticles decorated on reduced graphene oxide (NixSy/rGO) as electrocatalysts for hydrogen evolution reaction (HER). The designed solvent (ethylene glycol and deionized water) played a decisive role in controlling both crystalline phase and morphology of NixSy/rGO composites, leading to pure [Formula: see text]-NiS nanoparticles uniformly distributed on rGO sheets under suitable volume ratio of ethylene glycol and deionized water (2:1). The optimized [Formula: see text]-NiS/rGO showed prominent HER catalytic performance with a rather small Tafel slope of 93[Formula: see text]mV/decade and prominent current density of 10[Formula: see text]mA/cm2 at the overpotential of 177[Formula: see text]mV in alkaline environments when compared to pristine [Formula: see text]-NiS and NiS2/rGO catalysts. The excellent catalytic performance and long-term durability even after 8000 cycles confirmed the potential of [Formula: see text]-NiS/rGO composites as efficient electrocatalysts for HER in the alkaline media.

Preparation of Calcium Sulfate Anhydrate Whisker and a Primary Investigation of its Arsenic Removal Performance

2013 ◽  
Vol 690-693 ◽  
pp. 1013-1019
Author(s):  
Xiao Juan Chen ◽  
Liu Chun Yang ◽  
Jun Feng Zhang ◽  
Yan Huang
Keyword(s):  
Calcium Sulfate ◽  
Arsenic Removal ◽  
Removal Rate ◽  
Optical Microscope ◽  
Alkaline Condition ◽  
Crystal Water ◽  
Arsenic Uptake ◽  
Ft Ir ◽  
High Removal Rate ◽  
Calcium Sulfate Whisker

Calcium sulfate whisker (CSW) was prepared through the method of cooling recrystallization. In an attempt to develop its new application in environmental protection, we investigated the effect of calcination on the material properties and arsenic uptake performance of calcium sulfate whisker anhydrate (CSAW), which was obtained from CSW calcined at 600 °C for 2 h. Moreover, XRD, SEM, optical microscope, and FT-IR were used to characterize CSW samples. It was found that calcination played an important role in the whisker structure through changing the content of crystal water and the morphology. The CSAW material exhibited a high removal rate of As3+/As5+under strongly alkaline condition.

scholarly journals Polymerization of Ethylene Glycol Dimethacrylate (EGDM), Using An Algerian Clay as Eco-catalyst (Maghnite-H+ and Maghnite-Na+)

2020 ◽  
Vol 15 (1) ◽  
pp. 221-230 ◽  
Author(s):  
Sara Haoue ◽  
Hodhaifa Derdar ◽  
Mohammed Belbachir ◽  
Amine Harrane
Keyword(s):  
Ethylene Glycol ◽  
Exchange Process ◽  
Ethylene Glycol Dimethacrylate ◽  
Glycol Dimethacrylate ◽  
Green Catalyst ◽  
Ion Exchange Process ◽  
Ft Ir ◽  
Uv Visible ◽  
Thermal Stability Of ◽  
End Group

In this paper we have explored a novel and green method to synthesis and polymerize ethylene glycol dimethacrylate (EGDM). This technique consists on using Maghnite (Algerian clay) as a green catalyst to replace toxic catalysts. The Algerian clay has been modified using two ion exchange process to obtain Maghnite-H+ (proton exchanged process) and Maghnite-Na+ (sodium exchanged process). Synthesis experiments of EGDM and Poly (EGDM) are performed in bulk respecting the principles of green chemistry. The structure of the obtained monomer and the obtained polymer was confirmed by FT-IR, 1H-NMR and 13C-NMR, where the methacrylate end groups are clearly visible. The presence of unsaturated end group in the structure of monomer was confirmed by UV-Visible analysis. Thermogravimetric analysis (TGA) was used to study the thermal stability of these obtained products. Copyright © 2020 BCREC Group. All rights reserved 

Characteristics of Konjac Glucomannan (KGM) in A.bulbifer Compared with that in A.rivieri and A.albus

2011 ◽  
Vol 236-238 ◽  
pp. 2045-2052 ◽  
Author(s):  
Qiao Wang ◽  
Jian Wang ◽  
Geng Zhong
Keyword(s):  
Chemical Structure ◽  
Average Molecular Weight ◽  
Konjac Glucomannan ◽  
Water Soluble ◽  
Soluble Dietary Fiber ◽  
Physiochemical Properties ◽  
Ft Ir ◽  
Main Component ◽  
Ft Ir Spectroscopy ◽  
Southwest Part

Amorphophallus bulbifer (A. bulbifer) is a promising species in Amorphophallus sp., with great potentiality of developing, low risk for cultivation and considerable commercial benefits, mainly locates in tropical and subtropical regions or near the equator. Konjac glucomannan (KGM) is the main component of Amorphophallus tuber which is a water-soluble dietary fiber. In this work, some physiochemical properties of KGM in three Amorphophallus species flour [one was A.bulbifer, the other two were current main species namely Amorphophallus rivieri (A. rivieri) and Amorphophallus albus (A. albus)] were studied and compared with each other. The KGM content in A. rivieri, A. albus and A. bulbifer flour were 85.03%, 76.28% and 88.07% (w/w), respectively. The apparent viscosity, viscosity average molecular weight, whiteness, gel-forming properties and chemical structure of KGM in the three flours were investigated by using viscometer, colorimeter, texture analyzer and Fourier transform infrared (FT-IR) spectroscopy. The results indicated that the viscosity and Mw of A. bulbifer was the largest, gel strength was almost same (p>0.05) and the molecular structure were of no differences of three KGM. It may be proposed that transplanting A. bulbifer from its native land in the tropical and subtropical regions to temperate zone in the southwest part of China would be feasible, and it would cause the revolution of Amorphophallus sp. and more considerable benefits.

Study on Adsorption Characteristics of Klebsiella Biological Adsorbent to Leaded Wastewater

2014 ◽  
Vol 926-930 ◽  
pp. 4353-4356
Author(s):  
Jing Zhao ◽  
Xiao Jun Xu ◽  
Qiang Zhan ◽  
Xuan Li ◽  
Shu Li Liu ◽  
...  
Keyword(s):  
Physical Adsorption ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Adsorption Properties ◽  
Amide Group ◽  
Langmuir Isotherm Model ◽  
Ft Ir ◽  
Resistant Strains ◽  
Main Component

A lead-resistant strains was isolated from activated sludge of the sewage treatment plant in Chenggong County, Kunming, which was identified as Klebsiella by 16 SrDNA. The wet microbial cells were used as adsorbent, we studied adsorption properties for water Pb (II) ions in water of sorbent. The results showed that when the adsorbent treated the waste water with Pb (II) ions, the pH was 5, the time was 60min, the temperature was 30°C, the equilibrium adsorption amount was 73.45mg/g; Adsorbent’s adsorption of Pb (II) ions can better fit Langmuir isotherm model. The FT-IR result presented that the main component of adsorbent was polysaccharide, the physical adsorption and chemisorption occurred between the adsorbent and the Pb (II) ions in the solution, adsorption mainly involved with hydroxyl functional groups, the amide group and the carboxyl group, etc.

scholarly journals Enhanced dispersion stability of gold nanoparticles by the physisorption of cyclic poly(ethylene glycol)

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yubo Wang ◽  
Jose Enrico Q. Quinsaat ◽  
Tomoko Ono ◽  
Masatoshi Maeki ◽  
Manabu Tokeshi ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Ethylene Glycol ◽  
Dispersion Stability ◽  
Chemical Inhomogeneity ◽  
Poly Ethylene Glycol ◽  
Alternative Approach ◽  
Ft Ir ◽  
Poly Ethylene ◽  
Tumor Accumulation ◽  
Key Techniques

AbstractNano-sized metal particles are attracting much interest in industrial and biomedical applications due to the recent progress and development of nanotechnology, and the surface-modifications by appropriate polymers are key techniques to stably express their characteristics. Herein, we applied cyclic poly(ethylene glycol) (c-PEG), having no chemical inhomogeneity, to provide a polymer topology-dependent stabilization for the surface-modification of gold nanoparticles (AuNPs) through physisorption. By simply mixing c-PEG, but not linear counterparts, enables AuNPs to maintain dispersibility through freezing, lyophilization, or heating. Surprisingly, c-PEG endowed AuNPs with even better dispersion stability than thiolated PEG (HS–PEG–OMe). The stronger affinity of c-PEG was confirmed by DLS, ζ-potential, and FT-IR. Furthermore, the c-PEG system exhibited prolonged blood circulation and enhanced tumor accumulation in mice. Our data suggests that c-PEG induces physisorption on AuNPs, supplying sufficient stability toward bio-medical applications, and would be an alternative approach to the gold–sulfur chemisorption.

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