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1

EFFECTIVENESS OF DYE ADSORPTION ONTO NON-CROSS-LINKED AND CROSS-LINKED CHITOSAN BEADS

100%

Filipkowska U.

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tom 17

43 - 52

EN

The study was established to analyze the effectiveness of Reactive Black (RB5) and Basic Green (BG4) dyes adsorption onto chitosan beads and onto chitosan beads cross-linked with glutaraldehyde depending on the initial dye concentration in the solution (1, 5, 100 and 200 mg/dm3). It demonstrated that both the initial concentration of dye in the solution as well as the type of adsorbent affected the effectiveness of the adsorption process. An increase in the initial dye concentration in the solution was increasing adsorption effectiveness, irrespective of the type of dye and adsorbent. The cross-linking of chitosan beads with glutaraldehyde turned out to be beneficial only in the case of the RB5 dye.

2

REUSABILITY OF CHITOSAN AND SAWDUST-MODIFIED CHITOSAN FOR ADSORPTION/DESORPTION OF ANIONIC AND CATIONIC DYES

63%

Filipkowska U. , Tomasz J.

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tom 28

14-25

EN

We explored the multiple uses of chitosan in the form of beads and beech sawdust immobilised in chitosan to remove anionic (Reactive Yellow 85 and Reactive Blue 5) and cationic (Basic Violet 10 and Basic Green 4) dyes. For both anionic dyes, with the next adsorption/desorption cycle, the amount of dye accumulated in the adsorbent increased, which resulted in a decrease in the desorption efficiency. The number of possible adsorption/desorption cycles was regulated by the occupation of all active sites. We observed the opposite trend for the cationic dyes: the charge accumulated in the adsorbent after both adsorption and desorption decreased with subsequent cycles. Despite the low accumulated charge compared with the total adsorption capacity of the adsorbents, it was impossible to further adsorb and desorb the dye. The results demonstrated that for both adsorbents tested, it was possible to carry out 6–7 adsorption/desorption cycles, but the desorption efficiency decreased with each cycle.

3

THE USE OF ACTIVE CARBON IMMOBILISED ON CHITOSAN BEADS FOR RB5 AND BV10 DYE REMOVAL FROM AQUEOUS SOLUTIONS

51%

Filipkowska U. , Jóźwiak T. , Szymczyk P. , Kuczajowska-Zadrożna M.

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tom 22

14-26

EN

This paper presents the adsorption of dyes – the anionic Reactive Black 5 (RB5) and cationic Basic Violet 10 (BV10) dyes – on activated carbon (AC) immobilised on chitosan (CHs). The results were compared with the removal efficiency of RB5 and BV10 on the individual sorbents: chitosan beads and activated carbon. In this study, the sorption capacities of the sorbents, sorption pH and the point of zero charge (pHZPC) were determined. For the description of the obtained results, the Freundlich, Langmuir and double Langmuir models were used. The results show that the developed sorbent (CHs-AC) is effective for both types of dye (RB5 or BV10) over a broad pH range 4–10, which makes it a universal sorbent. The maximum sorption capacity of CHs-AC with RB5 was 639.8 mg/g, while for BV10 it was 50.7 mg/g.

4

THE USE OF CHITIN AND CHITOSAN FOR THE REMOVAL OF REACTIVE BLACK 5 DYE

51%

Szymczyk P. , Filipkowska U. , Jóźwiak T. , Kuczajowska-Zadrożna M.

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tom 20

260-272

EN

In this study, we investigated the effectiveness of Reactive Black 5 dye adsorption onto chitin and chitosan flakes. Adsorption capacity of chitin and chitosan, optimal pH of the adsorption process and reaction equilibrium time were determined. Results achieved were described with Freundlich, Langmuir and double Langmuir models. The pH value ensuring the highest dye adsorption effectiveness onto chitosan was pH 4. In turn, the highest dye adsorption effectiveness onto chitin was determined at pH 2, however considering that the pH value of industrial wastewater containing reactive dyes ranges from pH 3 to pH 4, further analyses with chitin were continued at pH 3. The time needed to reach the equilibrium concentration of dye was 360 min for chitin and 72 hours for chitosan. The study demonstrated that chitosan is the most effective sorbent of RB5. Its maximum adsorption capacity of the reactive dye accounted for 696.99 mg/g d.m., compared to 131.56 mg/g d.m. determined for chitin. Higher effectiveness of RB5 removal by chitosan is result of more number of amine groups in the chemical structure of this polymer, compared to chitin.

5

THE INFLUENCE OF SALINITY ON REACTIVE BLACK 5 DYE SORPTION EFFICIENCY ON HYDROGEL CHITOSAN SORBENTS

51%

Jóźwiak T. , Filipkowska U. , Bolozan L. , Gache L.

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tom 24

49 - 60

EN

This study examined the effect of salt concentration (NaCl/Na2SO4) on the sorption efficiency of Reactive Black 5 (RB5) dye on chitosan hydrogel granules (CHs). The tested salt concentration was in the range of 0.0 to 0.5 mol/L. The scope of the research included the effect of salinity on RB5 sorption at different pH values (4–11), equilibrium time, and maximum sorption capacity (Langmuir 2 model). At low pH (pH 4, pHpHPZC), an opposite trend was observed (the sorption efficiency of RB5 on CHs increased with increasing salinity). The concentration of salt in the solution did not have a major impact on the equilibrium time of sorption, which depended mainly on the initial pH of the solution (and ranged from 36 to 60 h). The relatively long sorption time resulted from the hydrogel structure of the sorbent used, which slowed the dye absorption ability. The maximum sorption capacity of CHs in relation to RB5 at the optimum pH (pH 4) in the solution without the addition of salt determined after 60 h of sorption was 1.386 mmol RB5/g (1373.5 mg RB5/g). Under conditions of high salinity (0.5 mol Na2SO4/L), at pH 4, the capacity was 17.2% lower (1.148 mmol RB5/g to 1139.7 mg RB5/g), and at pH 11, it was 6.3% higher (1.474 mmol RB5/g to 1460.7 mg RB5/g).

6

ADSORPTION OF BASIC YELLOW 28 (BY 28) AND ACID YELLOW 23 (AY 23) DYES ONTO CHITIN

45%

Filipkowska U. , Kuczajowska-Zadrożna M. , Jóźwiak T. , Szymczyk P. , Kaczyński A.

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tom 20

34-42

EN

The present study investigated the sorption of Basic Yellow 28 (BY 28) and Acid Yellow 23 (AY 23) by chitin flakes. The study determined the influence of pH value on adsorption effectiveness and the adsorption capacity of chitin flakes. The results were described with Freundlich, Langmuir, Sips and double Langmuir isotherms. Similar values of adsorption capacities were achieved for both tested dyes using Langmuir, Sips and Langmuir2 models, i.e. 16.804, 17.740 and 18687 mg/g d.m. for BY28 as well as 24.195, 27.930 and 24.196 mg/g d.m. for AY23, respectively. The isotherms were compared with the use of average relative error (ARE) of approximation. In the case of both dyes, the best fit to experimental data was achieved with the use of tri-parametric Sips equilibrium isotherm, which was indicated by ARE values of 3.10% (BY 28) and 5.26% (AY 23).

7

REMOVAL OF DYES FROM AQUEOUS SOLUTIONS BY GLAUCONITE IMMOBILISED ON CHITOSAN HYDROGEL BEADS

45%

Jóźwiak T. , Filipkowska U. , Szymczyk P. , Kuczajowska-Zadrożna M. , Mielcarek A.

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tom 22

54-65

EN

The sorption capacity of glauconite, glauconite immobilised on chitosan hydrogel beads and unmodified chitosan hydrogel beads against Reactive Black 5 and Basic Violet 10 was compared in this article. The effect of pH on the sorption effectiveness of dyes on the tested sorbents was investigated and the sorption capacity of sorbents after 24 and 72 h was determined. Langmuir sorption, double Langmuir and Freundlich isotherms were used to describe the experimental data. The adsorption efficiency of the dyes on sorbents containing chitosan was highest at pH 4. In the case of glauconite, Reactive Black 5 removal efficiency was the highest at pH 3, and Basic Violet 10 removal efficiency was highest at pH 2. The sorption capacity of glauconite immobilised on chitosan hydrogel spheres obtained after 72 h was -656.73 mg/g and -32.77 mg/g for Reactive Black 5 and Basic Violet 10, respectively.