scholarly journals Synthesis, Characterization and Mechanism Study of Green Aragonite Crystals from Waste Biomaterials as Calcium Supplement

2020 ◽  
Vol 12 (12) ◽  
pp. 5062
Author(s):  
Lulit Habte ◽  
Mohd Danish Khan ◽  
Natnael Shiferaw ◽  
Adeeba Farooq ◽  
Mee-hye Lee ◽  
...  
Keyword(s):  
Calcium Oxide ◽  
Morphological Analysis ◽  
Crystal Size ◽  
Low Cost ◽  
Environmentally Benign ◽  
Carbon Dioxide Injection ◽  
Mechanism Study ◽  
Commercial Scale ◽  
Aragonite Crystal ◽  
Crystal Growth Mechanism

In present work, environmentally benign green aragonite crystals were synthesized from waste chicken eggshells and bivalve seashells through a simple and low-cost wet carbonation method. This method involves a constant stirring of calcium oxide slurry and magnesium chloride suspension in aqueous solution with constraint carbon dioxide injection at 80 °C. The physicochemical properties of the synthesized aragonite were further compared with the aragonite synthesized from commercial calcium oxide. The morphological analysis, such as acicular shape and optimum aspect ratio (~21), were confirmed by scanning electron microscopy. The average crystal size (10–30 µm) and specific surface area (2–18 m2 g−1) were determined by particle size and Brunauer–Emmett–Teller analysis, respectively. Moreover, a schematic crystal growth mechanism was proposed to demonstrate the genesis and progression of aragonite crystal. Green aragonite can bridge the void for numerous applications and holds the potential for the commercial-scale synthesis with eggshells and bivalve seashells as low-cost precursors.

Improved photocatalytic conversion of high−concentration ammonia in water by low−cost Cu/TiO2 and its mechanism study

Chemosphere ◽  
2021 ◽  
Vol 274 ◽  
pp. 129689
Author(s):  
Jianpei Feng ◽  
Xiaolei Zhang ◽  
Guan Zhang ◽  
Ji Li ◽  
Wei Song ◽  
...  
Keyword(s):  
Low Cost ◽  
Mechanism Study ◽  
High Concentration

scholarly journals An Overview of Biodiesel Production via Calcium Oxide Based Catalysts: Current State and Perspective

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3950
Author(s):  
Hoora Mazaheri ◽  
Hwai Chyuan Ong ◽  
Zeynab Amini ◽  
Haji Hassan Masjuki ◽  
M. Mofijur ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Calcium Oxide ◽  
Heterogeneous Catalysts ◽  
Low Cost ◽  
Biodiesel Production ◽  
Catalyst Synthesis ◽  
Process Improvements ◽  
Current State ◽  
The Common ◽  
Activity Mechanism

Biodiesel is a clean, renewable, liquid fuel that can be used in existing diesel engines without modification as pure or blend. Transesterification (the primary process for biodiesel generation) via heterogeneous catalysis using low-cost waste feedstocks for catalyst synthesis improves the economics of biodiesel production. Heterogeneous catalysts are preferred for the industrial generation of biodiesel due to their robustness and low costs due to the easy separation and relatively higher reusability. Calcium oxides found in abundance in nature, e.g., in seashells and eggshells, are promising candidates for the synthesis of heterogeneous catalysts. However, process improvements are required to design productive calcium oxide-based catalysts at an industrial scale. The current work presents an overview of the biodiesel production advancements using calcium oxide-based catalysts (e.g., pure, supported, and mixed with metal oxides). The review discusses different factors involved in the synthesis of calcium oxide-based catalysts, and the effect of reaction parameters on the biodiesel yield of calcium oxide-based catalysis are studied. Further, the common reactor designs used for the heterogeneous catalysis using calcium oxide-based catalysts are explained. Moreover, the catalytic activity mechanism, challenges and prospects of the application of calcium oxide-based catalysts in biodiesel generation are discussed. The study of calcium oxide-based catalyst should continue to be evaluated for the potential of their application in the commercial sector as they remain the pivotal goal of these studies.

Iron Phosphates as Cathodes of Lithium-Ion Batteries

2006 ◽  
Vol 973 ◽  
Author(s):  
Shijun Wang ◽  
M. Stanley Whittingham
Keyword(s):  
Lithium Ion Batteries ◽  
Lithium Iron Phosphate ◽  
Low Cost ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
Environmentally Benign ◽  
Iron Phosphates ◽  
Electrochemical Capacity ◽  
High Theoretical Capacity ◽  
Olivine Structure

ABSTRACTThis study focusses on optimizing the parameters of the hydrothermal synthesis to produce iron phosphates for lithium ion batteries, with an emphasis on pure LiFePO4 with the olivine structure and compounds containing a higher iron:phosphate ratio. Lithium iron phosphate (LiFePO4) is a promising cathode candidate for lithium ion batteries due to its high theoretical capacity, environmentally benign and the low cost of starting materials. Well crystallized LiFePO4 can be successfully synthesized at temperatures above 150 °C. The addition of a reducing agent, such as hydrazine, is essential to minimize the oxidation of ferrous (Fe2+) to ferric (Fe3+) in the final compound. The morphology of LiFePO4 is highly dependent on the pH of the initial solution. This study also investigated the lipscombite iron phosphates of formula Fe1.33PO4OH. This compound has a log-like structure formed by Fe-O octahedral chains. The chains are partially occupied by the Fe3+ sites, and these iron atoms and some of the vacancies can be substituted by other cations. Most of the protons can be ion-exchanged for lithium, and the electrochemical capacity is much increased.

A Facile Preparation of Environmentally-Benign and Flame-Retardant Coating on Wood by Comprising Polysilicate and Boric Acid

2021 ◽  
Author(s):  
Kaihao Wang ◽  
Shuheng Wang ◽  
Dan Meng ◽  
Dong Chen ◽  
Chenzhong Mu ◽  
...  
Keyword(s):  
Boric Acid ◽  
Flame Retardant ◽  
Wood Sample ◽  
Low Cost ◽  
Treated Wood ◽  
Environmentally Benign ◽  
Wood Combustion ◽  
Flame Resistance ◽  
Limiting Oxygen Index ◽  
Index Value

Abstract For the sake of direct using on the built wooden buildings, a green flame resistance coating comprising sodium polysilicate (SPS) and boric acid was prepared. With weight gain of only 10 wt.%, the treated wood sample (SPS/B-wood) performed improved limiting oxygen index value of 40.3% and passed the V-0 rating in UL-94 test. Additionally, the total heat release, total smoke production and peak carbon monoxide production of SPS/B-wood sample were decreased by 24.5%, 36.0% and 59.4% respectively, compared with that of control wood sample. The residue of SPS/B-wood sample was increased to 54.0% from 18.4% of control wood sample at 800oC in the thermogravimetry analysis. The flame retardant mechanism was suggested that SPS and boric acid formed Si-O-B and Si-O-Si contained structures, isolating the heat and smoke transfer during wood combustion. Notably, NaOH, introduced by the SPS/B coating, catalyzed the lignin to form compact and high-quality char. To conclude, this low-cost and easily-operated coating has a promising future utilizing in the villages with dense wood buildings.

Weka Trainable Segmentation Plugin in ImageJ: A Semi-Automatic Tool Applied to Crystal Size Distributions of Microlites in Volcanic Rocks

2018 ◽  
Vol 24 (6) ◽  
pp. 667-675 ◽  
Author(s):  
Charline Lormand ◽  
Georg F. Zellmer ◽  
Károly Németh ◽  
Geoff Kilgour ◽  
Stuart Mead ◽  
...  
Keyword(s):  
Crystal Size ◽  
Low Cost ◽  
Volcanic Rocks ◽  
Scattered Electron ◽  
Promising Alternative ◽  
Wide Range ◽  
Segmented Images ◽  
Electron Microscopes ◽  
Automatic Tool ◽  
Magmatic History

AbstractCrystals within volcanic rocks record geochemical and textural signatures during magmatic evolution before eruption. Clues to this magmatic history can be examined using crystal size distribution (CSD) studies. The analysis of CSDs is a standard petrological tool, but laborious due to manual hand-drawing of crystal margins. The trainable Weka segmentation (TWS) plugin in ImageJ is a promising alternative. It uses machine learning and image segmentation to classify an image. We recorded back-scattered electron (BSE) images of three volcanic samples with different crystallinity (35, 50 and ≥85 vol. %), using scanning electron microscopes (SEM) of variable image resolutions, which we then tested using TWS. Crystal measurements obtained from the automatically segmented images are compared with those of the manual segmentation. Samples up to 50 vol. % crystallinity are successfully segmented using TWS. Segmentation at significantly higher crystallinities fails, as crystal boundaries cannot be distinguished. Accuracy performance tests for the TWS classifiers yield high F-scores (>0.930), hence, TWS is a successful and fast computing tool for outlining crystals from BSE images of glassy rocks. Finally, reliable CSD’s can be derived using a low-cost desktop SEM, paving the way for a wide range of research to take advantage of this new petrological method.

Construction of benzothiophene fused pyrrolidone in water via a catalyst-free process and a mechanism study

2020 ◽  
Vol 22 (20) ◽  
pp. 6798-6803 ◽  
Author(s):  
Jinhui Shen ◽  
Aimin Yu ◽  
Lei Zhang ◽  
Xiangtai Meng
Keyword(s):  
Environmentally Benign ◽  
Domino Reaction ◽  
Mechanism Study ◽  
Catalyst Free ◽  
Free Process

A novel three-component domino reaction towards benzothiophene fused pyrrolidone derivatives was developed in an environmentally benign manner.

scholarly journals Green and efficient three-component synthesis of 4H-pyran catalysed by CuFe 2 O 4 @starch as a magnetically recyclable bionanocatalyst

2020 ◽  
Vol 7 (7) ◽  
pp. 200385
Author(s):  
Maryam Kamalzare ◽  
Mohammad Bayat ◽  
Ali Maleki
Keyword(s):  
Low Cost ◽  
Environmentally Benign ◽  
Pharmaceutical Chemistry ◽  
X Ray Diffraction ◽  
Natural Polymers ◽  
X Ray ◽  
Benign Nature ◽  
Catalytic Behaviour ◽  
Work Up ◽  
Derivatives Of

The development of simple, practical and inexpensive catalysis systems using natural materials is one of the main goals of pharmaceutical chemistry as well as green chemistry. Owing to the ability of easy separation of nanocatalyst, those goals could be approached by applying heterogeneous bionanocatalyst in combination with magnetic nanoparticles. Starch is one of the most abundant natural polymers; therefore, preparing bionanocatalyst from starch is very valuable as starch is largely available and inexpensive. An ecologically benign and efficacious heterogeneous nanocatalyst was prepared based on a biopolymer, and its attributes and morphology were specified by using Fourier transform infrared spectra, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermal analysis and vibrating sample magnetometer measurements; followed by studying catalytic behaviour of bionanocomposite in a multicomponent reaction to synthesize of 4H-pyran derivatives. 4H-pyran is extremely valuable in pharmaceutical chemistry, and the development of methods for synthesis of different derivatives of 4H-pyran is momentous. Revealing environmentally benign nature, mild condition, easy work-up, low cost and non-toxicity are some of the advantages of this protocol. Besides, the bionanocomposite was recovered using an external magnetic bar and could be re-used at least six times with no further decrease in its catalytic activity.

A Facile Arc-Discharge Method to Deposit Metal Nanoparticles on Glass Substrate

2019 ◽  
Vol 11 (10) ◽  
pp. 1425-1429
Author(s):  
Md. Mydul Islam ◽  
Hasan Sarwar ◽  
Md. Abdul Matin ◽  
Mohammad Junaebur Rashid ◽  
Md. Fakhrul Islam ◽  
...  
Keyword(s):  
Crystal Size ◽  
Arc Discharge ◽  
Low Cost ◽  
Atmospheric Environment ◽  
Use Case ◽  
Cu Nanoparticles ◽  
Xrd Pattern ◽  
A Charge ◽  
Discharge Method ◽  
Deposition Techniques

This paper presents a simple low-cost approach to produce nanoparticles using arc-discharge method. Unlike existing deposition techniques, this is the first instance that nanoparticles are deposited on a charge neutral substrate by arc discharge method. In an atmospheric environment, copper (Cu) has been used as both anode and cathode in the process. The use of same material in both the electrode happens to be the first use case with arc discharge method. A simple airflow has been used to direct the evaporated nanomaterials towards the substrate. XRD, UV and FESEM were employed to confirm the presence of Cu nanoparticles and its properties. XRD pattern shows a crystal size of Cu nanoparticles as 7.4 nm.

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