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This study aimed to investigate the effect of aminating waste newsprint paper with different aminating agents (ammonia/ammonia water, ethylenediamine, and diethylenetriamine) for the sorption efficiency of Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) dyes. To increase the amination efficiency, the paper material was pre-activated with epichlorohydrin. The scope of this study included the characterization of the sorbents tested (FTIR, elemental analysis, BET surface area, porosity, and pHPZC), determination of the influence of pH on dye sorption efficiency, sorption kinetics, and the maximum sorption capacity of the dyes. The study results showed that amination with ethylenediamine and diethylenetriamine introduced 87% and 194% more amine groups into the sorbent's structure compared to the treatment with ammonia. The sorption efficiency of RB5 and RY84 on the sorbents tested was the highest in the pH range of 2–3. The sorption equilibrium time ranged from 90 to 150 min and was longer in the case of the unmodified sorbents. The experimental data from the study were best described by the pseudo-second-order model and the Langmuir 1 and 2 models. Amination had a very strong effect on the sorption capacity of newsprint. For example, the sorption capacity of newsprint paper towards RB5 (Qmax = 7.12 mg/g) increased after amination with ammonia, ethylenediamine, and diethylenetriamine to the value of Qmax = 182.78 mg/g, Qmax = 202.7 mg/g, and Qmax = 231.5 mg/g, respectively. [ABSTRACT FROM AUTHOR]

The article presents studies on the effect of the modification method of beech sawdust on the sorption capacity of the anionic dye Reactive Black 5 (RB5) as well as the cationic dye Basic Violet 10 (BV10). In the studies, the pH value, the dose of sawdust activated with epichlorohydrin and the dose of ammonia were determined for the efficiency of the removal of anionic and cationic dyes. In the next phase of the study, the pH and the dose of epichlorohydrin activator on the previously activated sorbent were determined. The modification proposed in the work, which consists in the amination of sawdust in direct reaction with ammonia, increased the efficiency of the sorption of anionic dyes. This reaction increased the positive charge on the surface of the sorbent by introducing –NH2 groups, which led to an increase in the electrostatic attraction between the sorbent and the anionic dye, but to a decrease in the interaction between the sorbent and the cationic dye. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effect of sorption of Basic Red 46 (BR46) dye by lignocellulosic biomass on the susceptibility of the sorbed waste to anaerobic decomposition by anaerobic digestion. The research material used in the experiment consisted of two types of biomass: stalks with leaves and inflorescences after mowing Canadian goldenrod (Solidago canadensis L.) (GB), and rapeseed hulls (RHs) after oil pressing. During the anaerobic decomposition of RHs, 732.30 NmL/gVS and 646.63 NmL/gVS of methane were obtained from the non-sorbed substrate and the plant material after dye sorption, respectively. Similarly, in the variants using Canadian goldenrod, the production was 220.70 NmL/gVS and 183.20 NmL/gVS. The GB sorbent sorbed 34% more BR46 dye than the RH sorbent, which is likely to have resulted in the accumulation of VFA and contributed to the partial inhibition of methane production. In light of the obtained results and the literature data, it is concluded that there is a possibility of effective use of dye sorption waste for methane production. [ABSTRACT FROM AUTHOR]

This article presents studies on the sorption of the anionic dyes Reactive Black 5 (RB5) and Reactive Yellow 84 (RY84) from solutions of single dyes and from dye mixtures onto three chitosan sorbents–chitin, chitosan DD75% and chitosan DD95%. In this work, the influence of pH on sorption efficiency, the sorption equilibrium time for the tested anionic dyes and the sorption capacity in relation to the individual dyes and their mixtures were determined. It has been found that the sorption process for both dyes was most effective at pH 3 for chitin and chitosan DD75 and at pH 4 for chitosan DD95%. The obtained results were described by the double Langmuir equation (Langmuir 2). The obtained constants made it possible to determine the affinity of the tested dyes for the three sorbents and the sorption capacity of the sorbents. For RB5, the highest sorption capacity for chitosan DD95% was achieved with sorption from a single solution–of 742 mg/g DM and with sorption from mixed dyes–of 528 mg/g DM. For RY84, the highest efficiency was also achieved for chitosan DD95% and was 760 mg/g DM for a single dye solution and 437 mg/g DM for a mixture of dyes. [ABSTRACT FROM AUTHOR]

The aim of this work was to determine the sorption capacity of the cationic dyes Basic Red 46 (BR46) and Basic Violet 10 (BV10) on the prepared sorbents: beech bark (BBe) and birch bark (BBi). Two fractions of bark were used in the research: fine (2–3 mm) and coarse (4–5 mm). The carried out tests made it possible to determine the influence of the pH value on the sorption efficiency, the sorption equilibrium time and the maximum sorption capacity of the two tested sorbents. The Langmuir model and the Freundlich model were used to describe the obtained experimental data. Beech and birch barks are effective sorbents for cationic dyes; however, the efficiency of dye sorption on both bark sorbents depends on the type of cationic dye. According to the obtained data, beech and birch bark sorbents showed higher sorption efficiency for Basic Red 46 than for Basic Violet 10. The pH correction was a necessary condition for sorption, and the sorption pH value for the cationic dyes Basic Red 46 and Basic Violet 10 was be determined individually for each dye. The most favourable pH value for the sorption of the BR46 dye on the beach and birch bark sorbents was pH = 6, while for the dye BV10, it was pH = 3. The sorption equilibrium time for Basic Red 46 was 300 min and for Basic Violet 10–240 min. The fine fraction of beech bark had the highest sorption capacity for both BR46 (128.45 mg/g dry matter) and BV10 (18.07 mg/g dry matter). [ABSTRACT FROM AUTHOR]

This study examined the possibility of using various types of waste paper—used newsprint (NP), used lightweight coated paper (LWC), used office paper (OP), and used corrugated cardboard (CC)—for the removal of anionic dyes, Acid Red 18 (AR18) and Acid Yellow 23 (AY23), and cationic dyes, Basic Violet 10 (BV10) and Basic Red 46 (BR46), from aqueous solutions. The scope of this research included the characterization of sorbents (FTIR, SEM, BET surface area, porosity, pHPZC, effectiveness of water coloration), determination of pH effect on the effectiveness of dye sorption, sorption kinetics (pseudo-first-order model, second-order model, intraparticular diffusion model), and the maximum sorption capacity (Langmuir models and Freundlich model) of the tested sorbents. The use of waste paper materials as sorbents was found to not pose any severe risk of aquatic environment contamination. AR18, AY23, and BV10 sorption intensities were the highest at pH 2, and that of RB46 at pH 6. The waste paper sorbents proved particularly effective in removing cationic dyes, like in the case of, e.g., NP, which had a sorption capacity that reached 38.87 mg/g and 90.82 mg/g towards BV10 and BR46, respectively, and were comparable with that of selected activated carbons (literature data). [ABSTRACT FROM AUTHOR]

The application of the immobilisation method -- which consists of immobilising modified sawdust in a carrier, a chitosan gel - enabled the development of a new sorbent. By combining waste products from chitin and sawdust, the properties of both adsorbents were utilised. This paper evaluated the adsorption efficiency of four dyes - Reactive Yellow 84, Reactive Black 8, Basic Violet 10 and Basic Green 4-on four adsorbents - chitin flakes, chitosan flakes, chitosan beads and sawdust immobilised in chitosan beads. The latter adsorbent showed good adsorption properties for both anionic and cationic dyes. The experimental results showed a relationship between the amount of adsorbed and desorbed dye and the type of adsorbent. Chitin flakes showed the lowest adsorption capacity, regardless of the type of dye. The immobilisation of modified sawdust in chitosan had a particularly positive effect on the binding efficiency of cationic dyes. [ABSTRACT FROM AUTHOR]

W pracy podjęto badania nad określeniem efektywności wykorzystania biosurfaktantów - saponiny, taniny oraz ramnolipidów JBR 515 i JBR 425 do wymywania kadmu, cynku i miedzi z osadu czynnego immobilizowanego w alginianie sodu 1,5% z alkoholem poliwinylowym 0,5%. Przeprowadzone badania pozwoliły określić wpływ odczynu na regenerację biosorbentu za pomocą testowanych biosurfaktantów, wyznaczyć krytyczne stężenie micelarne (CMC) w roztworach zawierających biosorbent i biosurfaktant oraz w próbach właściwych z metalami ciężkimi. Saponina charakteryzowała się najwyższą efektywnością wymywania metali przy pH 1-5, a ramnolipidy przy pH 5-6. Ponadto badania wykazały istotny wpływ stosunku masy biosorbentu do objętości eluatu (m/V) na skuteczność wymywania metali. Spośród analizowanych biosurfaktantów saponina wykazywała około 100% efektywność usuwania z biosorbentu cynku i miedzi. Skuteczność innych biosurfaktantów była niższa i zależała od rodzaju metalu

The study aim was to test the applicability of exoskeletons and molts from mealworm (Tenebrio molitor) cultures as sorbents for anionic dyes: Reactive Black 5 (RB5) and Reactive Yellow (RY84). Factors investigated included: characteristics of sorbents (FTIR, pHPZC), the influence of pH on sorption efficiency, sorption kinetics (pseudo-first, pseudo-second-order, intraparticle diffusion models), and determination of the maximum sorption capacity (Langmuir 1, Langmuir 2, Freundlich, and Dubinin–Radushkevich models). The sorption efficiency of anionic dyes on the tested sorbents was the highest at pH 2. The time needed to reach the sorption equilibrium for both dyes was 120–150 min. The sorption kinetics of the dyes were best described by the pseudo-second-order model. Maximum sorption capacity data showed the best fit to Langmuir 2 isotherm, suggesting that at least two types of sorption centers played an important role in dye sorption. Presumably, for both of the tested sorbents, the active sites in question were protonated amine (-NH3+), acetamide (NH2COCH3+), and hydroxyl groups (-OH2+) of chitin and protein. The maximum RB5 and RY84 sorption capacity of the tested sorbents was 78.70 mg/g and 60.49 mg/g, respectively, for mealworm exoskeletons, as well as 55.72 mg/g and 44.25 mg/g, respectively, for mealworm molts. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We analysed the feasibility of using unmodified chitin exoskeletons and moults of mealworms (Tenebrio molitor) as adsorbents to remove cationic dyes - Basic Violet 10 (BV10) and Basic Red 46 (BR46) - from aqueous solutions. We evaluated the characteristics of the adsorption materials using Fourier-transform infrared spectroscopy and determining the pH of the point of zero charge (pHPZC); the pH effect on dye adsorption effectiveness; dye adsorption kinetics (pseudo-first order, pseudo-second order, and intramolecular diffusion models); and the maximum adsorption capacity of the adsorbents (Langmuir 1 and 2 and Freundlich isotherms). BV10 adsorption on the tested adsorbents was the highest at pH 3, while adsorption of BR46 was highest at pH 6. The adsorption equilibrium time depended mainly on the dye type and its initial concentration; it was 150-210 min for BV10 and 120-150 min for BR46. The maximum adsorption capacity of mealworm exoskeletons reached 5.56 mg/g for BV10 and 31.53 mg/g for BR46, whereas mealworm moults exhibited a higher maximum adsorption capacity, reaching 6.44 mg/g for BV10 and 5.56 mg/g for BR46. Keywords: chitin moults, exoskeletons, mealworm, adsorption, cationic dyes. [ABSTRACT FROM AUTHOR]

Adsorption tests in the air-lift reactor were carried out for six dyes - four anionic (RR11, RB5, RB8, and RR18) and two cationic (BV10 and BG 4) - as well as three adsorbents - chitosan flakes, chitosan in the form of beads, and modified sawdust immobilised in chitosan (adsorbent 3). The dye concentration in the inflow to the reactor in all the conducted test series was 10 mg/dm3; the amount of adsorbent was also constant at 10 g dry matter (d.m./dm3, and the flow rate was 0.1 V/h. For all tested dyes, the obtained maximum adsorption capacity was high and ranged from 3802 to 2203 mg/g d.m. for chitosan flakes, from 3312 to 2076 mg/g d.m. for chitosan beads, and from 2734 to 2148 mg/g d.m. for modified sawdust immobilised in chitosan. The immobilisation of sawdust on chitosan resulted in effective adsorption of both anionic and cationic dyes. [ABSTRACT FROM AUTHOR]

This study aimed to determine the effectiveness of Reactive Black 5 (RB5) and Basic Red 46 (BR46) sorption on hen feathers (HF), being a post-slaughter waste from the poultry industry. The scope of the study included, i.a. FTIR spectra analysis of hen feathers, pH effect on dye sorption effectiveness, dye sorption kinetics (pseudo-first order model, pseudo-second order model, intramolecular diffusion model), and maximal sorption capacity of the sorbent (Langmuir 1 and 2 models, and Freundlich model). The effectiveness of RB5 sorption onto HF was the highest at pH 2 and that of BR46 - at pH 5. The time needed to reach RB5 and BR46 sorption equilibrium onto HF ranged from 180 to 210 min. The kinetics of dye sorption onto HF was best described by the pseudo-first order model, which indicates the typically physical nature of the sorption process. The constants determined from the intramolecular diffusion model demonstrated that RB5 and BR46 sorption onto HF proceeded in two main phases, differing in sorption intensity. The maximal sorption capacity of HF reached 5.19 mg/g for RB5 and 4.06 mg/g for BR46. The identical values of KC, K1, and K2 constants determined from the Langmuir 1 and Langmuir 2 models suggest that only one type of the sorption center played the key role in the sorption process. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

The influence of chitosan content in hydrogel beads on the sorption effectiveness of Reactive Black 5 (RB5) dye from aqueous solutions is presented in the following work. The dry mass of chitosan in the tested hydrogel chitosan sorbents was from 2 to 10%. The influence of pH (4- 11) on the sorption effectiveness of RB5 on chitosan hydrogels as well as the sorption capacity of the tested chitosan sorbents in relation to RB5 were studied. The optimal pH of RB5 sorption was determined along with the pH at the potential at zero point charge (pHPZC) of the tested sorbents. The maximum sorption capacity of the tested sorbents, depending on the amount of chitosan dry mass in the hydrogel beads, was determined. The obtained data was fit to Langmuir 1, Langmuir 2, and Freundlich models. [ABSTRACT FROM AUTHOR]