scholarly journals Effect of Ultrasonic Assisted on The Degree of Deacetylation of Chitosan Extracted from Portunus Pelagicus

2021 ◽  
Vol 10 (1) ◽  
pp. 17-23
Author(s):  
Buanasari Buanasari ◽  
Warlan Sugiyo ◽  
Heri Rustaman
Keyword(s):  
Ultrasonic Method ◽  
Synthesis Method ◽  
Water Soluble ◽  
Portunus Pelagicus ◽  
Manufacturing Method ◽  
Degree Of Deacetylation ◽  
A Value ◽  
Deacetylation Degree ◽  
Ultrasonic Assisted ◽  
Chitin And Chitosan

The technology for extracting chitin from shell and other materials needs to be continuously improved, including its conversion to chitosan. Chitosan is a biocompatible polymer, biodegradable, non-toxic, water-soluble at pH below 6.5, and it has protonated amino groups. The benefits of chitosan in industry, food and medicine make it necessary to fully study an efficient chitosan synthesis method and the results can be applied on an industrial scale. This study examined the effect of ultrasonic-assisted in increasing the degree of deacetylation of chitosan produced from Portunus pelagicus shell waste. The production process of chitosan goes through the stages of deproteination, demineralization and deacetylation. All these steps are ultrasound assisted processes with a frequency of 40 kHz through a digital ultrasonic cleaner. Ultrasonic-assisted chitin and chitosan were examined using FTIR spectrometry. The results showed that the ultrasonic method was able to increase the deacetylation degree of chitin with a value of 68.45±0.11% compared to 62.52±0.08% without ultrasonic. Application of ultrasonic assisted deacetylation gave a deacetylation degree of 85.35 ± 0.20%, higher than without ultrasonic 80.24 ± 0.19%.  Physically, ultrasonic-assisted chitosan is smoother and brighter in color. The ultrasonic-assisted chitosan manufacturing method could increase the deacetylation degree and produce high grade chitosan.

scholarly journals Synthesis of novel adsorbent based on tetrasulfide-functionalized fibrous silica KCC-1 for removal of Hg(II) cations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Azam Marjani ◽  
Reza Khan Mohammadi
Keyword(s):  
Effective Interaction ◽  
Sol Gel ◽  
Aqueous Media ◽  
Synthesis Method ◽  
Mercury Ions ◽  
Toxic Heavy Metals ◽  
Uptake Capacity ◽  
Hydrothermal Preparation ◽  
Ultrasonic Assisted ◽  
First Time

AbstractHg(II) has been identified to be one of the extremely toxic heavy metals because of its hazardous effects and this fact that it is even more hazardous to animals than other pollutants such as Ag, Au, Cd, Ni, Pb, Co, Cu, and Zn. Accordingly, for the first time, tetrasulfide-functionalized fibrous silica KCC-1 (TS-KCC-1) spheres were synthesized by a facile, conventional ultrasonic-assisted, sol–gel-hydrothermal preparation approach to adsorb Hg(II) from aqueous solution. Tetrasulfide groups (–S–S–S–S–) were chosen as binding sites due to the strong and effective interaction of mercury ions (Hg(II)) with sulfur atoms. Hg(II) uptake onto TS-KCC-1 in a batch system has been carried out. Isotherm and kinetic results showed a very agreed agreement with Langmuir and pseudo-first-order models, respectively, with a Langmuir maximum uptake capacity of 132.55 mg g–1 (volume of the solution = 20.0 mL; adsorbent dose = 5.0 mg; pH = 5.0; temperature: 198 K; contact time = 40 min; shaking speed = 180 rpm). TS-KCC-1was shown to be a promising functional nanoporous material for the uptake of Hg(II) cations from aqueous media. To the best of our knowledge, there has been no report on the uptake of toxic Hg(II) cations by tetrasulfide-functionalized KCC-1 prepared by a conventional ultrasonic-assisted sol–gel-hydrothermal synthesis method.

scholarly journals Silica Monolith for the Removal of Pollutants from Gas and Aqueous Phases

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1316
Author(s):  
Vanessa Miglio ◽  
Chiara Zaccone ◽  
Chiara Vittoni ◽  
Ilaria Braschi ◽  
Enrico Buscaroli ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Water Solution ◽  
Synthesis Method ◽  
Textural Properties ◽  
Adsorption Properties ◽  
Water Soluble ◽  
Silica Monoliths ◽  
Physico Chemical ◽  
Gaseous Toluene ◽  
Mcm 41

This study focused on the application of mesoporous silica monoliths for the removal of organic pollutants. The physico-chemical textural and surface properties of the monoliths were investigated. The homogeneity of the textural properties along the entire length of the monoliths was assessed, as well as the reproducibility of the synthesis method. The adsorption properties of the monoliths for gaseous toluene, as a model of Volatile Organic Compounds (VOCs), were evaluated and compared to those of a reference meso-structured silica powder (MCM-41) of commercial origin. Silica monoliths adsorbed comparable amounts of toluene with respect to MCM-41, with better performances at low pressure. Finally, considering their potential application in water phase, the adsorption properties of monoliths toward Rhodamine B, selected as a model molecule of water soluble pollutants, were studied together with their stability in water. After 24 h of contact, the silica monoliths were able to adsorb up to the 70% of 1.5 × 10−2 mM Rhodamine B in water solution.

scholarly journals A Novel Photosynthesis of Carboxymethyl Starch-Stabilized Silver Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
M. A. El-Sheikh
Keyword(s):  
Silver Nanoparticles ◽  
Room Temperature ◽  
Colloidal Solution ◽  
Synthesis Method ◽  
Silver Ions ◽  
Water Soluble ◽  
Synthesis Process ◽  
Carboxymethyl Starch ◽  
Round Shape ◽  
First Time

The water soluble photoinitiator (PI) 4-(trimethyl ammonium methyl) benzophenone chloride is used for the first time in the synthesis of silver nanoparticles (AgNPs). A new green synthesis method involves using PI/UV system, carboxymethyl starch (CMS), silver nitrate, and water. A mechanism of the reduction of silver ions to AgNPs by PI/UV system as well as by the newly born aldehydic groups was proposed. The synthesis process was assessed by UV-vis spectra and TEM of AgNPs colloidal solution. The highest absorbance was obtained using CMS, PI and AgNO3concentrations of 10 g/L, 1 g/L, and 1 g/L, respectively; 40°C; 60 min; pH 7; and a material : liquor ratio 1 : 20. AgNPs so-obtained were stable in aqueous solution over a period of three weeks at room temperature (~25°C) and have round shape morphology. The sizes of synthesized AgNPs were in the range of 1–21 nm and the highest counts % of these particles were for particles of 6–10 and 1–3 nm, respectively.

Comprehensive Characterization of Agricultural By-Products for Bio-Aggregate Based Concrete

2022 ◽  
Author(s):  
Herinjaka Haga Ratsimbazafy ◽  
Aurélie Laborel-Préneron ◽  
Camille Magniont ◽  
Philippe Evon
Keyword(s):  
Water Absorption ◽  
Building Materials ◽  
Complete Characterization ◽  
Water Soluble ◽  
Dry Density ◽  
Characterization Methods ◽  
Manufacturing Method ◽  
West Part ◽  
Hemp Shiv ◽  
By Products

The valorization of available agricultural by-products is important for the development of bio-aggregate based concretes as eco-friendly solutions for building materials. However, their diversity requires to assess their potential of use in vegetal concretes. This study aims to propose simple and relevant multi-physical characterization methods for plant aggregates. Basic and complementary characterizations were carried out on hemp shiv as a reference plant aggregate, and nine by-products available in the South-West part of France, i.e., oleaginous flax shiv, sunflower pith and bark, coriander straw, wheat straw, wheat chaff, corn shuck, miscanthus stem and vine shoot. The basic characterizations performed were those recommended by the TC-RILEM 236 BBM, i.e., particle size distribution, bulk density, water absorption and thermal conductivity. Complementary characterizations have also been proposed, taking into account the possible environment of the binder and the vegetal concrete manufacturing method. The additional tests developed or adapted from previous research assess the following properties: the content of water-soluble compounds at pH 7 and 12, the dry density of plant aggregates compacted in wet state, the real water absorption after compaction and the compression behavior of these compacted aggregates. This complete characterization highlights the distinct behavior of the different agroresources and allows to correlate these characteristics to the use properties of hardened composites.

scholarly journals Chitin and Chitosan from Green Shell (Perna Viridis): Utilization Fisheries Wastes from Traditional Market in Jakarta

2018 ◽  
Vol 248 ◽  
pp. 04002 ◽  
Author(s):  
Flora Elvistia Firdaus ◽  
Indah Purnamasari ◽  
Pandu Gunatama
Keyword(s):  
Solid Waste ◽  
Water Content ◽  
Good Condition ◽  
Perna Viridis ◽  
Sour Taste ◽  
Degree Of Deacetylation ◽  
Organoleptic Test ◽  
Traditional Market ◽  
Chitin And Chitosan

Many advantages of burden wastes which adversely impact to the environment in the form of solid waste. Green shellfish wastes are used for resources of chitosan. The aim of this works is to identify the effectiveness of chitosan application into 2 kinds of moist foods; wet noodles and meatballs. The concentration of chitosan are 0%, 0.5%, 1%, 1.5%, and 2%. The samples are immersed for 0,15, 30, 45, and 60 minutes. The study has found the water content of chitin is 8.31% and chitosan is 6.83%. The degree of deacetylation of chitin is 37.81% and chitosan is 82%. The best concentration of chitosan for wet noodle is 1.5% -2% with the immersion of 45 -60 minutes, and for meatballs is 1.5%-2% with the immersion of 15 minutes. The organoleptic test, on day-3 noodle and meatball, is still in good condition. If no chitosan added the noodles sample is day-1 is in fair condition, while meatball should be consumed directly because in day-1 is becoming chewy with a sour taste, and on day-2 are overgrown with mushrooms.

scholarly journals Adsorption of Reactive Black M-2R on Different Deacetylation Degree Chitosan

2011 ◽  
Vol 6 (3) ◽  
pp. 155892501100600 ◽  
Author(s):  
Fang Li ◽  
Chunmei Ding
Keyword(s):  
Sorption Process ◽  
Order Kinetic ◽  
Sorption Data ◽  
Kinetic Experiment ◽  
Isotherm Equation ◽  
Degree Of Deacetylation ◽  
Deacetylation Degree ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Effects Of Temperature

Different degree of deacetylation (DD) chitosan was prepared and used for the removal of a Reactive black M-2R (RBM) from aqueous solution. The effects of temperature (298 K~323 K), chitosan dosage, degree of deacetylation on RBM removal were investigated. The adsorption equilibrium was reached within one hour. In order to determine the adsorption capacity, the sorption data were analyzed by using linear form of Langmuir, Freundlich and Tempkin isotherm equation. Langmuir equation shows higher conformity than the other two equations. From the kinetic experiment data, it was found that the sorption process follows the pseudo-second-order kinetic model. Activation energy value for sorption process was found to be 58.28 kJ mol-1. Chitosan with 66% deacetylation degree (DD) exhibited good adsorption performance for RBM. In order to determine the interactions between RBM and chitosan, FTIR analysis was also conducted.

scholarly journals Polymer-Assisted Modification of Metal-Organic Framework MIL-96 (Al): Influence on Particle Size, Crystal Morphology and Perfluorooctanoic Acid (PFOA) Removal

2020 ◽  
Author(s):  
Luqman Hakim Mohd Azmi ◽  
Daryl R. Williams ◽  
Bradley P. Ladewig
Keyword(s):  
Particle Size ◽  
Crystal Morphology ◽  
Low Cost ◽  
Metal Organic Framework ◽  
Synthesis Method ◽  
Perfluorooctanoic Acid ◽  
Water Soluble ◽  
Water Soluble Polymer ◽  
Metal Organic ◽  
Organic Framework

<div><b>Abstract</b></div><div>A new synthesis method was developed to prepare an aluminum-based metal organic framework (MIL-96) with a larger particle size and different crystal habits. A low cost and water-soluble polymer, hydrolyzed polyacrylamide (HPAM), was added in varying quantities into the synthesis reaction to achieve >200% particle size enlargement with controlled crystal morphology. The modified adsorbent, MIL-96-RHPAM2, was systematically characterized by SEM, XRD, FTIR, BET and TGA-MS. Using activated carbon (AC) as a reference adsorbent, the effectiveness of MIL-96-RHPAM2 for perfluorooctanoic acid (PFOA) removal from water was examined. The study confirms stable morphology of hydrated MIL-96-RHPAM2 particles as well as a superior PFOA adsorption capacity (340 mg/g) despite its lower surface area, relative to standard MIL-96. MIL-96-RHPAM2 suffers from slow adsorption kinetics as the modification significantly blocks pore access. The strong adsorption of PFOA by MIL-96-RHPAM2 was associated with the formation of electrostatic bonds between the anionic carboxylate of PFOA and the amine functionality present in the HPAM backbone. Thus, the strongly held PFOA molecules in the pores of MIL-96-RHPAM2 were not easily desorbed even after eluted with a high ionic strength solvent (500 mM NaCl). Nevertheless, this simple HPAM addition strategy can still chart promising pathways to impart judicious control over adsorbent particle size and crystal shapes while the introduction of amine functionality onto the surface chemistry is simultaneously useful for enhanced PFOA removal from contaminated aqueous systems.<br></div>

scholarly journals Polymer-Assisted Modification of Metal-Organic Framework MIL-96 (Al): Influence on Particle Size, Crystal Morphology and Perfluorooctanoic Acid (PFOA) Removal

2020 ◽  
Author(s):  
Luqman Hakim Mohd Azmi ◽  
Daryl R. Williams ◽  
Bradley P. Ladewig
Keyword(s):  
Particle Size ◽  
Crystal Morphology ◽  
Low Cost ◽  
Metal Organic Framework ◽  
Synthesis Method ◽  
Perfluorooctanoic Acid ◽  
Water Soluble ◽  
Water Soluble Polymer ◽  
Metal Organic ◽  
Organic Framework

<div><b>Abstract</b></div><div>A new synthesis method was developed to prepare an aluminum-based metal organic framework (MIL-96) with a larger particle size and different crystal habits. A low cost and water-soluble polymer, hydrolyzed polyacrylamide (HPAM), was added in varying quantities into the synthesis reaction to achieve >200% particle size enlargement with controlled crystal morphology. The modified adsorbent, MIL-96-RHPAM2, was systematically characterized by SEM, XRD, FTIR, BET and TGA-MS. Using activated carbon (AC) as a reference adsorbent, the effectiveness of MIL-96-RHPAM2 for perfluorooctanoic acid (PFOA) removal from water was examined. The study confirms stable morphology of hydrated MIL-96-RHPAM2 particles as well as a superior PFOA adsorption capacity (340 mg/g) despite its lower surface area, relative to standard MIL-96. MIL-96-RHPAM2 suffers from slow adsorption kinetics as the modification significantly blocks pore access. The strong adsorption of PFOA by MIL-96-RHPAM2 was associated with the formation of electrostatic bonds between the anionic carboxylate of PFOA and the amine functionality present in the HPAM backbone. Thus, the strongly held PFOA molecules in the pores of MIL-96-RHPAM2 were not easily desorbed even after eluted with a high ionic strength solvent (500 mM NaCl). Nevertheless, this simple HPAM addition strategy can still chart promising pathways to impart judicious control over adsorbent particle size and crystal shapes while the introduction of amine functionality onto the surface chemistry is simultaneously useful for enhanced PFOA removal from contaminated aqueous systems.<br></div>

Study on Photocatalytic Properties of Anatase Phase TiO2 Synthesized by Ultrasonic-Assisted Hydrolysis

2012 ◽  
Vol 573-574 ◽  
pp. 110-114 ◽  
Author(s):  
Jin Xia ◽  
Ri Ya Jin ◽  
Kai Xuan Guo ◽  
Si Jing Yang
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Uv Light ◽  
Anatase Phase ◽  
Ultrasonic Method ◽  
X Ray Diffraction ◽  
Hydrolysis Method ◽  
Titanium Tetra Isopropoxide ◽  
Ultrasonic Assisted ◽  
Ft Ir

Titanium dioxide powders were synthesized by ultrasonic-assisted hydrolysis reaction of titanium tetra-isopropoxide at the low-temperature. The samples were characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD). The photocatalytic activity of samples were investigated by the degradation of methyl orange under UV light radiation (6W, λ= 352nm) at room temperature. The results indicated that the products were mainly composed of high homogeneity anatase phases, and the methyl orange degradation rate can reach more than 90% under ultraviolet irradiation 180min. The photocatalytic activity of the samples prepared by ultrasonic method is higher than that of the samples prepared by conventional hydrolysis method.

value-rich exposures in medical education; synthesizing the concept

2021 ◽  
Author(s):  
Leila Afshar ◽  
Shahram Yazdani ◽  
Seyed Abbas Foroutan ◽  
hakimeh sabeghi
Keyword(s):  
Medical Education ◽  
Lived Experience ◽  
Life Experiences ◽  
Synthesis Method ◽  
Real Life ◽  
Educational Process ◽  
Phenomenological Method ◽  
Professional Identities ◽  
Hermeneutic Phenomenological ◽  
A Value

Abstract Background: Proper transfer of professional values is an essential part of medical education. Real-life experiences in the educational process are one of the most effective methods for achieving values and assisting the student in developing his/her value framework. This study aimed to develop and characterize the concept of value-rich exposures in medical education to bring this concept closer to the practice.Methods: We used Walker and Avant concept synthesis method. In order to perform the synthesis, a combination of hermeneutic phenomenological method and literature review was used.Results: We defined the concept of value-rich exposure in medical education under five themes while implementing the steps of Walker and Avant's concept synthesis: probing self-inner values, value-rich program, value mentor, value-rich interactions, and value-rich environment. The elements and relationships of the themes were depicted in the form of a conceptual matrix.Conclusions:A value-rich exposure is a type of lived experience that occurs during a student’s professional life, a necessity that, with proper planning, can play an important role in shaping medical students' professional identities.

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