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Tytuł:
Determination of degree of deacetylation of chitosan - comparision of methods
Autorzy:
Czechowska-Biskup, Renata
Jarosińska, Diana
Rokita, Bożena
Ulański, Piotr
Rosiak, Janusz M.
Powiązania:
https://bibliotekanauki.pl/articles/1035372.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
chitosan
degree deacetylation
methods
Opis:
Degree of deacetylation (DD) is one of the main parameters characterizing chitosan. The most precise measurements of DD require sophisticated equipment (NMR spectrometer), not available at many laboratories worldwide working on chitosan. There is a need for low-cost, simple, yet sturdy and reliable methods and procedures for DD determination. The aim of this work was to test and compare – on the same set of chitosan samples - a few of the existing analytical techniques and provide recommendation for selecting DD determination methods. Tests were performed on four chitosans of nominal DD in the range 70 - 95%. Three different methods of titration, two different methods of spectroscopy UV / Vis and infrared spectroscopy using various calculation approaches were used. The results are summarized and compared with values obtained by 1H NMR, considered as the reference method. Moreover, evaluation of the ease of performance and availability of reagents in the given methods was performed. On that basis, recommendations for selection of DD determination methods were formulated.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2012, 17; 5-20
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of chitin structure on its enzymatic deacetylation
Autorzy:
Jaworska, M.
Roberts, G.A.F.
Powiązania:
https://bibliotekanauki.pl/articles/952676.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chitin
chitin deacetylase
enzymatic deacetylation
structure
crystallinity
conformation
chityna
krystaliczności
struktura
Opis:
The possibility of producing chitosan by enzymatic deacetylation of chitin has been the subject of numerous investigations over the last twenty years, but to date no satisfactory method has been developed. In this paper the influence of chitin chain conformation and chitin particle crystallinity on the enzymatic deacetylation of chitin is investigated to determine the relative importance of these two factors on the process. It is shown that the high crystallinity of chitin is the main obstacle to converting chitin to chitosan by enzymatic deacetylation.
Źródło:
Chemical and Process Engineering; 2016, 37, 2; 261-267
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of chitosan flake deacetylation degree on orthophosphate sorption efficiency from aqueous solutions
Autorzy:
Bugajska, Paula
Filipkowska, Urszula
Jóźwiak, Tomasz
Kuczajowska-Zadrożna, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/1034433.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
chitosan
deacetylation degree
orthophosphate
sorption
Opis:
The article presents the effectiveness of orthophosphate sorption from aqueous solutions depending on the deacetylation degree of chitosan flakes. The first stage of the research was to determine the pH value at which the sorption process was the most effective (from the pH range 2–11). In the second stage, research was carried out to determine the maximum sorption capacities of chitosan with deacetylation degrees of 75%, 85% and 90% in relation to PO43-. The highest effectiveness of orthophosphate removal on chitosan, regardless of its deacetylation degree, was obtained at pH 4. At pH 2 and 3, the chitosan flakes dissolved. This study showed that the sorption effectiveness of phosphorus compounds depends on the deacetylation degree of chitosan. Along with the increase in deacetylation degree, the sorption capacity of chitosan also increases in relation to orthophosphates. It is related to the higher number of amino groups in the structure of chitosan, which are responsible for the sorption of pollutants in the form of anions. The maximum sorption capacity of chitosan-DD = 75% in relation to biogen was 5.13 mg/g, chitosan-DD = 85% was 5.65 mg/g, and chitosan-DD = 90% was 5.91 mg/g. After 60 minutes, the desorption process had begun and was most likely caused by an increase in the pH of the solution. Due to chitosan's ability to neutralise the sample and the associated risk of desorption, the time of sorbent contact with sewage cannot be longer than 60 minutes.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2018, 23; 33-44
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of chitosan molecular weight and degree of deacetylation on membrane physicochemical and separation properties in ethanol dehydration by the vapour permeation process
Autorzy:
Gnus, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/1034007.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
chitosan
degree of deacetylation
molecular weight
separation properties
vapour permeation
Opis:
Membranes were prepared using three chitosans with different molecular weights and degrees of deacetylation. The influence of chitosan features on membrane physicochemical properties, i.e. degree of swelling, contact angle and tensile strength, as well as membrane separation properties in ethanol dehydration by the vapour permeation process are discussed. The conducted experiments showed that an increase in the chitosan molecular weight led to an increase in the membrane surface contact angle concomitant with a decrease in the material selectivity coefficient. On the other hand, an increase in the chitosan degree of deacetylation caused a reduction in ethanol and improved the water permeate flux. There was greater selectivity in the test process for membranes prepared from chitosan with the lowest molecular weight.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2020, 25; 79-93
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of chitosan deacetylation degree on reactive black 5 sorption efficiency from aqueous solutions
Autorzy:
Jóźwiak, Tomasz
Filipkowska, Urszula
Szymczyk, Paula
Kuczajowska-Zadrożna, Małgorzata
Mielcarek, Artur
Zyśk, Michał
Powiązania:
https://bibliotekanauki.pl/articles/1034679.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
Reactive Black 5
chitosan
deacetylation degree
sorption
Opis:
In the paper sorption capacity of chitosan having a deacetylation degree DD=75%, DD=85% and DD=90% relatively to the Reactive Black 5 were compared. Studies on the effectiveness of the dye sorption were carried out in a wide pH range – from 3 to 11. For each of the tested chitosan sorbents, sorption capacity has been determined. The results were described by isotherms Freundlich and Lagmuir isotherms, and a double Langmuir isotherm. Sorption of Reactive Black 5 most efficiently occurred at pH 4. At pH <4 chitosan sorbents underwent dissolution, regardless of the degree of deacetylation. The efficiency of dye sorption increased with the degree of deacetylation. The sorption capacity calculated after 12 h of the chitosan sorption with DD=75%, DD=85% and DD =90% was, relatively to the Reactive Black 5, respectively 433.03 mg/g and 464.52 mg/g and 532.14 mg/g. The impact of the deacetylation degree on pHZPC (zero point of charge) of the sorbent was also examined. Along with the increase in the deacetylation degree the value of chitosan pHZPC increased as well and at DD=75% DD=85% and DD=90%, pHZPC amounted respectively 7.6, 7.7 and 7.8.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2016, 21; 83-92
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of the deacetylation degree of chitosan in the form of flakes on the effectiveness of nitrates v sorption from aqueous solutions
Autorzy:
Jóźwiak, Tomasz
Filipkowska, Urszula
Bugajska, Paula
Kuczajowska-Zadrożna, Małgorzata
Mielcarek, Artur
Powiązania:
https://bibliotekanauki.pl/articles/1034527.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
chitosan
deacetylation degree
nitrate
sorption
Opis:
The influence of the degree of deacetylation of chitosan from the range of DD = 75–90% on the effectiveness of sorption of nitrates from aqueous solutions was investigated. The scope of the research included: determining the effect of pH on the effectiveness of N-NO3 binding on chitosan sorbents and determining the sorption capacity of chitosan sorbents with different degrees of deacetylation after 5, 15, 30 and 60 minutes. The effectiveness of sorption of nitrates on chitosan sorbents increased in the series DD=75% < DD=85% < DD=90%. Regardless of the degree of deacetylation, the sorption effectiveness of nitrates on chitosan was the highest at pH 4. The amount of nitrate-related sorbents was the highest after 30 min of sorption. A process time which was too long resulted in desorption of nitrates. The maximum sorption capacity for chitosan with the degree of deacetylation DD = 75, 85 and 90% was 0.59 mg N-NO3/g, 0.60 mg N-NO3/g and 0.87 mg N-NO3/g, respectively.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2018, 23; 88-96
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of FTNIR Spectroscopy for Evaluation of the Degree of Deacetylation of Chitosan Fibres
Zastosowanie spektroskopii w bliskiej podczerwieni do oznaczania stopnia deacetylacji włókien chitozanowych
Autorzy:
Biniaś, W
Biniaś, D
Powiązania:
https://bibliotekanauki.pl/articles/233601.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
FTNIR
deacetylation degree
dibutyrylchitin fibres
chitosan fibres
mikroporowate włókna
stopień deacetylacji
włókna dibutyrylochitynowe
włókna z chityny regenerowanej
Opis:
Microporous dibutyrylchitin (DBC) fibres spun from DBC solution in ethyl alcohol were subjected to alkaline treatment in potassium hydroxide aqueous solutions. Alkaline treatment with a diluted KOH solution at room temperature causes a gradual decrease in the number of butyric groups, which leads to obtaining fibres from the regenerated chitin. Further treatment of the fibres with a saturated KOH solution at an elevated temperature produces chitosan fibres with various degrees of deacetylation (DD), values which depend on the duration of the deacetylation process. The course of the deacetylation process was evaluated on the basis of the results of the near infrared (NIR) spectroscopy measurements. The method suggested allows for the precise measuring of the level of conversion without additional mechanical treatment (rubbing, powdering). A prepared sample is placed in the measuring chamber of the spectroscope. The FTNIR spectra of the fibres examined have characteristic bands whose analysis allows for clear determination of the level of deacetylation during chemical treatment.
Mikroporowate włókna z dibutyrylochityny formowane z roztworu sporządzonego w alkoholu etylowym, poddano alkalicznej obróbce przy zastosowaniu roztworów wodorotlenku potasu. Obróbkę alkaliczną włókien dibutyrylochitynowych prowadzono w temperaturze pokojowej w 5% roztworach wodorotlenku potasu. Obróbka ta spowodowała stopniowy spadek ilości grup butyrylowych i uzyskanie włókien z chityny regenerowanej. W dalszej kolejności otrzymane włókna z chityny regenerowanej poddano alkalicznej obróbce w nasyconych roztworach wodorotlenku potasu, która spowodowała stopniowy spadek ilości grup acetylowych prowadzący do uzyskania włókien chitozanowych o zróżnicowanym stopniu deacetylacji. Proces przemiany we włókna chitynowe oraz chitozanowe przebiega z różną szybkością w zależności od czasu, temperatury obróbki oraz stężenia wodorotlenku potasu. Oznaczanie stopnia deacetylacji, a tym samym przebieg procesu deacetylacji włókien oceniano za pomocą spektroskopii w bliskiej podczerwieni (NIR). Zastosowana metoda oceny stopnia deacetylacji włókien pozwala na dokładny pomiar stopnia przereagowania bez dodatkowej obróbki mechanicznej (ucierania proszkowania). Badaną próbkę umieszcza się w komorze spektrofotometru. Widma w zakresie bliskiej podczerwieni posiadają charakterystyczne pasma, których analiza w sposób jednoznaczny pozwala określić stopień deacetylacji włókien.
Źródło:
Fibres & Textiles in Eastern Europe; 2015, 2 (110); 10-18
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelowanie bioreaktora okresowego do enzymatycznej deacetylacji chitozanu
Batch reactor for enzymatic deacetylation of chitosan
Autorzy:
Jaworska, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/2070411.pdf
Data publikacji:
2009
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
deacetylaza chitynowa
chitozan
reaktor okresowy
chitin deacetylase
chitosan
batch reactor
Źródło:
Inżynieria i Aparatura Chemiczna; 2009, 3; 53-54
0368-0827
Pojawia się w:
Inżynieria i Aparatura Chemiczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Express analysis of chitosan and its derivatives by gel electrophoresis
Autorzy:
Konovalova, Mariya
Shagdarova, Balzhima Ts.
Zubov, Vitaliy
Svirshchevskaya, Elena
Powiązania:
https://bibliotekanauki.pl/articles/1034210.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
agarose gel electrophoresis
chitosan
chitosan derivatives
degree of deacetylation
molecular weight
Opis:
Chitosan is one of the most promising polymers for biomedical applications due to its unique properties, such as its biocompatibility, low toxicity, biodegradation, and the presence of reactive amino and hydroxyl groups. Analysis of physicochemical properties of chitosan and its derivatives is a time-consuming process and requires expensive equipment and large amounts of the sample. This paper proposes a method for express analysis of the molecular weight (MW), the degree of deacetylation (DD), the substitution degree (SD), and the charge of chitosan and its derivatives using agarose gel electrophoresis under acidic and neutral conditions with Coomassie staining. Positively charged chitosan samples required acidic Tris Acetate-EDTA (TAE) buffer to move in the gel. The electrophoretic mobility of chitosan depended on MW, DD, SD, and the chitosan charge. Based on the dependences obtained by the proposed method, the MW and DD of commercial chitosan samples were determined. Express analysis of chitosan and its derivatives in agarose gel can be used to monitor the reactions of chitosan modification and to analyse samples with unknown characteristics.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2019, 24; 84-95
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The investigations on process type influence on methyl violet adsorption on chitin and chitin deacetylation products
Autorzy:
Tórz, Artur
Łącka, Dorota
Turczyn, Roman
Gnus, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/1034871.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
adsorption
batch process
chitin
chitosan
continuous process
Opis:
The aim of this work was to a study various adsorption processes of methyl violet (model compound of aniline dye) on chitin and chitin deacetylation products. Two types of adsorption processes - batch and continuous - were tested. Results illustrated that raw chitin is an effective adsorbent for methyl violet and the adsorption activity of chitin deacetylation products strongly decrease with increasing degree of deacetylation (DDA). The continuous process is more effective then batch process.
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2015, 20; 273-280
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-10 z 16

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