Waste generated by the textile industry is one of the primary pollutants in aquatic environments. It is estimated that about 10 to 15% of the dyes used do not chemically interact with the fabric fibers, with a loss of this pollutant in the wastewater. One of the alternatives for pollutant removal is the adsorption process, which is viable compared to other separation methods. There is a range of materials that are used in adsorption processes. Among them, polysaccharides have numerous advantages regarding their use: they are non-toxic, abundant in nature, biodegradable, hydrophilic, and have several other properties. The study aimed to investigate a novel scaffold based on biopolymers and gallium-doped hydroxyapatite for dyes removal in an aqueous solution. The scaffold was characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy, and energy dispersive X-ray spectroscopy (SEM-EDS), swelling and adsorption tests. From the XRD, the gallium presence did not change the crystal structure of hydroxyapatite. The FTIR and TG spectra of the scaffold indicate that there were interactions between the precursor materials in the production of the same by shifting the characteristic bands and increasing thermal stability. SEM showed essential characteristics for the application of scaffolds in the adsorptive process through the presence of pores on the upper side and the inner surface of the scaffold. Open and interconnected pores with average diameters in the range of 60 mm on the upper and lateral face surface and 40 mm on the inside of the scaffold were observed. A more significant number of pores were observed inside, thus influencing the adsorption. In addition, EDS was possible to qualitatively prove the presence of precursor elements for the formation of the scaffold. It is concluded that the scaffolding was successful and showed excellent potential for removing Remazol Blue RGB and Remazol Red with adsorption of 341.41 ± 6.82 and 584.89 ± 23.39 mg/g, respectively.
Research Article
A Novel Scaffold Based on Biopolymers and Gallium-Containing Hydroxyapatite as Green Technology
https://doi.org/10.21203/rs.3.rs-2375574/v1
This work is licensed under a CC BY 4.0 License
Version 1
posted
You are reading this latest preprint version
Adsorption
Environmental remediation
Contaminants
Composite
anionic dye
and Polysaccharide
In recent years, society has witnessed the industrial rise of many means of production because environmental agencies are concerned about the pollution of aquatic systems and their harmful effects on living beings and organisms (GONÇALVES et al., 2020; PAULETTO et al., 2020). Most existing industries currently include pigments and dyes in their production chain (GONÇALVES et al., 2020; PANG et al., 2020; PAULETTO et al., 2020). In these industries, dyeing is a process of paramount importance. Pang and collaborators (PANG et al., 2020) estimated that in the textile industry, about 10–15% of the dyes used in the modification of the color of the fibers do not chemically interact with them. There is the loss and disposal of many dyes in wastewater.
Dyes are classified according to their chemical structure or ability to attach to the textile fiber. In addition, they are also classified according to their charge, and they are non-ionic dyes or ionic dyes. In the latter, they can be called cationic (positive charge) or anionic (negative charge) (SEMIÃO; HAMINIUK; MACIEL, 2020a). Dyes are challenging to be removed from the aqueous medium since they have complex chemical structures and therefore are stable to light and resistant to heat and biodegradation, for the most part (AKSU; DÖNMEZ, 2003; FELISTA; WANYONYI; ONGERA, 2020; ZHOU et al., 2019).
Several treatments, whether physical, biological or chemical, are used to reduce the concentration of dyes in an aqueous medium (PAULETTO et al., 2020). Precipitation, membrane separation, biodegradation, and oxidation are methods used to treat industrial effluents. However, an alternative stands out from the previous ones, adsorption (GONÇALVES et al., 2020; ZHOU et al., 2019). The treatments that use adsorption are advantageous because they have a lower energy expenditure due to this process being uncomplicated and economical concerning the mentioned methods (GONÇALVES et al., 2020). Many adsorbent materials are applied in the removal processes, including clays and other inorganic materials, biopolymers, and activated carbon (FELISTA; WANYONYI; ONGERA, 2020; PEREIRA et al., 2017; SEMIÃO; HAMINIUK; MACIEL, 2020b). Activated carbon is considered the best adsorbent for industrial effluents due to properties such as fast adsorption kinetics and good regeneration.
Clays and biopolymers have also been widely used due to the presence of other interesting properties (AKSU; DÖNMEZ, 2003; PEREIRA et al., 2017; SATHISHKUMAR; ARULKUMAR; PALVANNAN, 2012; SEMIÃO; HAMINIUK; MACIEL, 2020b). Biopolymers have numerous advantages regarding their use. They are non-toxic, abundant in nature, biodegradable, hydrophilic, and have antimicrobial and adsorbent properties (PEREIRA et al., 2017; SEMIÃO; HAMINIUK; MACIEL, 2020b). One example is gellan gum (GG), which can be found in the acetylated form. Its natural state, and in the deacetylated form, is commonly marketed due to its relatively accessible processing (ANANDAN et al., 2019; OLIVEIRA et al., 2010; STEVENS et al., 2016). GG has numerous advantages and properties, such as good mechanical properties and easy crosslinking (CHUN et al., 2020). Its molecular chain has carboxyl and hydroxyl groups that can interact, for example, with metallic sites (WANG et al., 2022). Another example of a polysaccharide is chitosan, which has amino and hydroxyl groups in its molecular chain and can interact with anionic dyes. However, its adsorption depends on structure, composition, and physical parameters such as porosity and surface area. superficial (ESQUERDO et al., 2014; GONÇALVES et al., 2020; KUEASOOK et al., 2020).
A solution for the effective use of polysaccharides in adsorption is combining polysaccharides or modifying their chain by inserting new functional groups, such as carboxyls and amines, thus making them more polar and hydrophilic (ANANDAN et al., 2019; KARTHIKA; VISHALAKSHI, 2015). Some studies report the use and materials combined with organic and inorganic matter. One of the objects of this work is the use of hydroxyapatite (HAp), as the inorganic part, in synergy with the polysaccharide. Among inorganic materials, hydroxyapatite (HAp) (Ca10(PO4)6(OH)2) is a ceramic compound that has properties such as good chemical stability and easy obtainment (YOU et al., 2019). Modification of the structure of HAp is carried out to improve its properties and can occur through cationic substitution from strontium (Sr2+), Sodium, or Silver ions.
Another example is calcium replacement by the metallic ion gallium (Ga3+) (PAI; KINI; SELVARAJ, 2021; RATNAYAKE; MUCALO; DIAS, 2017). Research on the adsorption of pollutants reported in the literature indicated that modifying the structure of HAp with metal or metal oxide can cause improvements in its properties (PAI; KINI; SELVARAJ, 2021), mainly because HAp does not have a good capacity for adsorbing dyes due to low interaction. In recent years there has been an increase in research relating materials with three-dimensional and porous structures with the adsorption of dyes in an aqueous medium (AL-SHEMY; AL-SAYED; DACRORY, 2022). These research indicate that materials with low density, low weight, and spongy appearance are more attractive for dye adsorption (KUEASOOK et al., 2020), which is impossible to obtain a high capacity when treating these indicated materials in their isolated forms. The main objective of this study is to synthesize and characterize a scaffold based on gellan gum and chitosan containing galliun-hydroxyapatite as a green technology for anionic dyes removal in an aqueous solution.
Materials and reagents
Two biopolymers were used: chitosan (CS) and gellan gum (GG) (Sigma Aldrich). The inorganic material used was gallium-containing hydroxyapatite (GaHAp), whose synthesis was carried out by our research group, according to (PEREIRA ROCHA et al., 2021). Lactic Acid (Synth) was used for the CS gelling process. The dye Remazol Blue RGB (Dystar) (RB) and Remazol Red (Dystar) (RR) were used in the adsorption process. Distilled water was used in this work.
Synthesis Of Scaffold
The scaffold was prepared from chitosan (CS), gallium-containing hydroxyapatite (GaHAp), and Gellan Gum (GG) due to its high molecular mass. Table 1 presents the proportions that were used for the synthesis of the scaffold. First, chitosan was dissolved in 35.0 mL of lactic acid solution (0.32% v/v), maintained under mechanical agitation at room temperature (25°C), and then added to GaHAp. Then, 0.25 g of GG was added to help gel formation. Subsequently, approximately 2000 µL of the gel was added to each well of a 24-well plate (diameter and height of the well – 16.25 x 17.3 mm) and frozen for 24 h. The last step was lyophilization, where the gel was dried under a vacuum at -50°C for 24 hours. After this step, a 3D structure with interconnected pores is finally obtained (the material was named CS/GG/ GaHAp). Figure 1 shows the finished scaffold measuring about 1 cm in diameter.
| Precursors | CS | GaHAp | GG |
|---|---|---|---|
| Proportion | 2 | 1 | 1 |
| Mass (g) | 0.50 | 0.25 | 0.25 |
Characterization
The microstructural analysis of the precursors and the scaffold were performed using X-ray Diffraction in a Labx–XRD 600 equipment, from Shimadzu, with Cu-Kα radiation (λ = 1.5406 Å), 2θ in the range between 2° to 75°, with a scanning rate of 2°/min. The spectra were obtained in the region of 4,000-400 cm− 1 from the pellet method in 1% KBr (Potassium bromide) in an Agilent equipment model Cary 660 FTIR, with 64 scans. For the study of thermal properties, thermogravimetric analysis was carried out in TGA-50 Shimadzu equipment, under a nitrogen atmosphere, with a gas flow of 50 ml.min− 1. The samples will be heated from room temperature to 800°C at a heating rate of 10°C.min− 1, with a mass of around 10 mg. The morphological characterization of the surface and pore structure of the samples was performed by microscopy scanning electronics and energy dispersive X-ray spectroscopy (SEM-EDS), using an FEI field emission electron source (SEM-EC) equipment, model Quanta FEG-250. The samples were mounted on “stubs” using double-sided carbon tape and covered in gold. The SEM working conditions were 10KV, and the working distance was 10 mm with point 3.
Dye Removal
The dye adsorption process on the CS/GG/GaHAp scaffold was carried out using a mass of about 16 mg, 33 mg, and 65 mg, that is, using the scaffold cut in 1/4 (SCA), 1/2 (SCB), and integer (SCC) (Fig. 2), respectively. A volume of 50.0 mL of RB dye solution was used in three different concentrations, 100 mg/L, 200 mg/L, and 300 mg/L. The scaffolds were immersed in the solutions, and the adsorbent-adsorbate system was kept under agitation on a shaker table at 130 rpm for 24 h. After the end of stirring, 2.0 mL aliquots were collected and subsequently centrifuged at 3000 rpm for 3 minutes. The concentrations were determined by reading the aliquots in a UV-Vis spectrophotometer (Agilent, Cary 60) using the pre-established calibration curve. The adsorbed amounts of q (mg.g− 1) were calculated by Eq. 1.
\(q=\frac{\left({C}_{0}-{C}_{e}\right)\text{*}V}{m}\) Eq. 1
where q (mg.g− 1) represents the amount adsorbed per gram of adsorbent; Co and Ce (mg.L-1) represent the initial and final concentrations of the samples, respectively; V is the volume of the solution in liters (L), and m is the mass of the dry adsorbent in grams (g) (BORAH; GOSWAMI; PHUKAN, 2015; TKACHENKO et al., 2014; VIGNESH et al., 2012). The same methodology as the RB dye was applied for the Remazol Red (RR) dye.
The color space system of the “Commission Internationale of l’Eclairage” CIE 1976 was applied to evaluate the color of the whole scaffold (SCC) before and after adsorption. Measurements were made as a function of L*, a*, and b* coordinates obtained from a Shimadzu UV-2600i UV-VIS spectrometer. Color differences between the external and internal parts of the SCC sample after adsorption compared to the sample before adsorption was calculated by Eq. 2 (BRANDÃO LIMA et al., 2020; DE CASTRO SILVA et al., 2020; LIMA et al., 2020).
\({{\Delta }\text{E}}^{\text{*}}=\sqrt{{\left({({\Delta }\text{L}}^{\text{*}}\right)}^{2}+{(\varDelta a}^{\text{*}})²+{(\varDelta b}^{\text{*}})²)}\) Eq. 2
The diffractograms of the precursor materials and the scaffold are shown in Fig. 3. In the CS diffractogram (Fig. 3a), it is possible to observe two characteristic peaks at 2θ = 9.86° and 20.04°, which correspond to the crystallographic planes (020) and (110), respectively (SOUSA et al., 2022). Through inter- and intramolecular hydrogen interactions, chitosan has a microcrystalline profile, thus promoting a particular organization (SOUSA et al., 2022). Figure 3b refers to the diffractogram of the GG material, showing a broad peak characteristic of materials with an amorphous structure located around 2θ = 19.78°. This region is attributed to several polymers and biopolymers (SANTOS et al., 2020; VASHISTH et al., 2016).
GaHAp (Fig. 3c) showed characteristic peaks of pure hydroxyapatite located in the region of 2θ = 25.8°, 31.9° and 32.9°, attributed, respectively, to planes (002), (211), and (300), with the peak at 2θ = 31.9° at highest intensity (DOS SANTOS et al., 2019a; FURKO et al., 2018; SANTOS et al., 2020). According to Beserra et al., 2020, with the doping process, there are no structural changes in the crystalline structure of hydroxyapatite. In the CS/GG/GaHAp scaffold (Fig. 3d), a broad peak was observed at 20.26°, possibly because GG has the properties of a material with the low organization. It influences the system's structure based on intermolecular interactions between the carboxyl groups of the GG and the CS amino groups, thus causing this enlargement (DE OLIVEIRA et al., 2020a; DOS SANTOS et al., 2019b; GENASAN et al., 2021). It was also possible to observe two peaks at 25.8° and 31.76°, which come from the presence of GaHAp in the scaffold.
FTIR was used to analyze the prominent bands and molecular interactions between the scaffold precursor materials, and their spectra are shown in Fig. 4. In the CS infrared spectrum (Fig. 4a), it is possible to observe a band around 3400 cm− 1 attributed to the axial stretching of OH groups in its polymeric chain (LIMA et al., 2021a). The band at wave number 2878 cm− 1 is assigned to the CH2 groups (BARBOSA et al., 2019). Continuing on the characteristic bands present in CS, bands were observed at 1379, 1590, and 1656 cm− 1 attributed to –C–H bonds in the –NHCOCH3 moieties, –N–H stretching vibrations, and –C = O groups of amide sites, respectively (DE OLIVEIRA et al., 2020a). For GG (Fig. 3b), a broad band between 3500 − 3400 cm− 1 is observed, attributed to stretching vibrations of the –OH groups (KAMER et al., 2022; LEE et al., 2020). In the GG spectrum, symmetric and asymmetric –C = O stretching vibrations are verified at 1414 and 1614 cm− 1, attributed to the carboxylate anions sequentially (DE OLIVEIRA et al., 2020b).
In the GaHAp spectrum, it was possible to observe the presence of bands characteristic of hydroxyapatite (HAp), with the wave number at 3436 cm− 1 corresponding to the elongation of the OH groups. The bands around 1089 and 1043 cm− 1 come from the asymmetric deformation of the phosphate groups (PO4-3) of HAp. In the bands at 602 and 566 cm− 1, a characteristic of the deformation of the phosphate groups is also observed (DOS SANTOS et al., 2019a).
In the spectrum of the CS/GG/GaHAp scaffold (Fig. 4d), there are bands from its precursor materials, with shifts in wavenumber, meaning that there were molecular interactions between the materials. The bands around 2929 and 2888 cm− 1 may be correlated with the presence of polymeric materials, indicating the presence of CH and CH2 groups (LIMA et al., 2021b; SANTOS et al., 2020). Thus, as it is possible to observe the presence of polymeric materials, it can also be noted that the presence of bands at 603 and 565 cm− 1 may be related to the asymmetric deformation of the phosphate groups from GaHAp [37,44], indicating the presence of all precursors after scaffold formation.
The thermal properties of precursor materials and scaffolds were studied using thermogravimetry (TG). Figure 5 shows the thermogravimetric curves, while Table 2 shows the maximum degradation temperatures, their respective thermal events, and the percentage of mass loss.
The first thermal event of CS (Fig. 5Aa1 and Table 2) has a maximum degradation temperature of around 68°C; such an event refers to the loss of adsorbed water, which has weak connections with the polymeric chain (PEREIRA et al., 2013; YALMAN et al., 2020). A mass loss of about 14.30% occurred in the first thermal event. In the second thermal event, there was a mass loss of around 44.09%, corresponding to the degradation of the polymeric chitosan chain (PEREIRA et al., 2013). The Gelana gum presented its first characteristic thermal event of surface water loss (Fig. 5Ab1), starting at 25°C and ending at 117°C, where the maximum degradation temperature was approximately 57°C. There was a weight loss of 13.29%. The maximum degradation temperature of the second thermal event occurs around 255°C, which is related to the beginning of the degradation of the polysaccharide structure (KARTHIKA; VISHALAKSHI; NAIK, 2016; LI et al., 2020; RAJESH et al., 2016), with the elimination of the outermost groups of the polysaccharide structure.
In the TG to GG curve, a third and fourth thermal event was also observed, which may be related to the final degradation of the polymeric structure. In the GaHAp TG curve (Fig. 5d1), it was found that the first thermal event refers to the release of water physically adsorbed on the surface of the material (Table 2). After the first thermal event that occurred at a maximum temperature of 85°C, it was still possible to observe two more mass loss events. It may be related to water loss from the condensation of hydroxyl groups existing in the structure of hydroxyapatite, Ca10(PO4)6(OH)2, occurring with more emphasis from temperatures to 800°C (DOS SANTOS et al., 2019a).
The scaffold CS/GG/GaHap presented three thermal events similar to the events of its precursor materials. The first thermal event occurred from 27°C to 108°C and had a mass loss of 15.22%, which may be related to the loss of moisture in the material. The second thermal event had a maximum degradation temperature of 256°C, in addition to the existence of a shoulder at 294°C. The second thermal event had a mass loss of around 22.69%, indicating that there is degradation at 256°C for Gellan Gum and the shoulder at 294°C for Chitosan. In the TG curve for CS/GG/GaHap, a third and fourth thermal event was also observed, which may be related to the interaction between the precursor materials and the final degradation of the polymeric structure. The temperature changes in the events indicate an interaction between the materials, as verified by the FTIR technique.
|
Materials |
Event |
mass loss [%] |
Temperature range [°C] |
Maximum degradation temperature [°C] |
|---|---|---|---|---|
|
CS |
1st |
14.30% |
27–140°C |
50°C |
|
2and |
44.09% |
214–370°C |
296°C |
|
|
3rd |
41.61% |
370–752°C |
600°C |
|
|
GG |
1st |
13.29% |
25–117°C |
59°C |
|
2and |
48.71% |
208–357°C |
255°C |
|
|
3rd |
26.01% |
418–800°C |
493°C |
|
|
4th |
2.59% |
791–987°C |
850°C |
|
|
GaHAp |
1st |
6.00% |
27–318°C |
85°C |
|
2and |
2.58% |
451–678°C |
613°C |
|
|
3rd |
4.56% |
678–986°C |
778°C |
|
|
CS/GG/GaHAp |
1st |
17.62% |
27–162°C |
51°C |
|
2and |
42.98% |
162–385°C |
256°C |
|
|
3rd |
26.57% |
385–577°C |
315°C |
|
|
4th |
2.69% |
577–709°C |
635°C |
Figure 6 shows the SEM analysis of the CS/GG/GaHap scaffold. It was possible to observe that the scaffold presented pores in its morphology, which gives it essential characteristics for application in adsorption processes. The dispersion of pores on different faces of the scaffold was verified, as shown in Fig. 6a. The presence of open and interconnected pores with average diameters in the range of 60 µm was observed on the upper surface (Figs. 6b and 6b1). Lateral surface (Figs. 6c and 6c1) and 40 µm towards the inside of the scaffold (Figs. 6a and 6a1), and a more significant number of pores was observed in the interior.
In the EDS (Fig. 7) observed, the dispersion of the GaHAp precursor is present in greater quantity inside the scaffold than on the scaffold surface, with values of P (3.07) and Ca (5.86) in mass percentage, P (0.53) and Ca (1.33), respectively (Table 3).
|
Element |
Mass (%) |
||
|---|---|---|---|
|
upper area |
lateral area |
internal area |
|
|
C |
46.57 |
46.23 |
40.69 |
|
O |
50.68 |
50.63 |
45.27 |
|
P |
0.28 |
0.55 |
3.07 |
|
Ca |
0.59 |
0.82 |
9.57 |
|
N |
1.89 |
1.77 |
1.40 |
Dyes Removal
Figure 8 shows the adsorption result of the CS/GG/GaHAp scaffold in the different proportions of SCA, SCB, and SCC on the RB and RR dye. The adsorption capacity was different for each scaffold cut. For SCA, the adsorption was more expressive concerning SCB and SCC in the three concentrations of RB (Fig. 8a and Table 4) and RR (Fig. 8c and Table 5). It showed that the possible greater contact area provided by cutting the scaffold, the greater exposure to interconnected pores, and the more significant amount of GaHAp present inside the scaffold (as shown by the results of SEM and EDS - Fig. 7). As a result, it provides more significant amounts of active sites for interactions with the dye, increasing its ability to adsorb. In the tests with the concentration of RB at 300 mg/L, the maximum adsorption capacities obtained with qe values of 341.41 ± 6.82, 275.00 ± 5.50, and 177.66 ± 3.55 mg/g for SCA, SCB, and SCC, respectively (Table 5).
The adsorption with RR at a concentration of 300 mg/L observes a much higher maximum adsorption capacity for RB, with qe values of 584.89 ± 23.39, 275.00 ± 10.16, and 239.57 ± 7.10 mg/g, for SCA, SCB, and SCC, respectively (Table 5), showing that the material using ¼ of the scaffold generates an increase of about two times in the adsorption capacity of both dyes.
The CS/GG/GaHAp scaffold used in its entire format was compared with an adsorption assay referring to the GG, GaHAp, and CS precursor materials using the same amount of scaffold mass, approximately 65 mg (Table 6). It was observed that CS qe values of 207.57 ± 3.37 mg/g of RB dye were more significant than the whole SCC scaffold, with qe values of 177.66 ± 3.55. The dye diffusion in the scaffold is ineffective due to the low porosity of the outer part of the scaffold, as shown in the SEM and histogram results (Fig. 7).
As for the RR dye, the CS adsorption was closer to the SCC scaffold value with qe values of 201.09 ± 5.04 mg/g (CS) and 239.57 ± 7.10 (SCC). The SCA scaffold has its internal part more exposed than the other SCB and SCC scaffolds. Therefore, a significant increase in the amount of adsorption compared to the CS was observed, with a value of qe 584.89 ± 23.39 for the SCA. With a smaller amount of material and the synergy of the precursors and their porosity, the scaffold proved to be more advantageous in adsorption than the precursors.
Table 4. The adsorbed amount of RB at different concentrations for the respective scaffold cuts.
Table 5. Amount of RR adsorbed at different concentrations for the respective scaffold cuts.
Table 6. Amount of RB and RR dye adsorbed to GG, GaHAp, and CS precursors.
Table 7compares the scaffold developed in this work with other chitosan-based scaffolds reported in the literature. Unfortunately, the adsorption of the dyes evaluated in this study was found for other scaffolds based on chitosan at the moment of the search. However, the comparison with the scaffolds applied in the adsorption of other dyes shows close results for the maximum adsorption capacities.
|
Adsorbate |
qmax (mg.g-1) |
Reference |
|---|---|---|
|
anionic methyl orange (MO) |
388.00 |
(CARVALHO et al., 2021) |
|
FD&C Red 40 |
259.94 |
(Inphonlek et al. 2020) |
|
methylene blue (MB) |
122.00 |
(Liu et al. 2020) |
|
methyl orange (MO) |
434.89 |
(Borsagli et al. 2019) |
|
(RB and RR) |
341.00 and 584.89 |
this work |
Diffuse reflectance measurements were performed for the SCC scaffold before and after the adsorption of RB and RR (concentration of 300 mg/L), and the colorimetric parameters were obtained using the CIEL*a*b* color space. The CIEL*a*b* color space is a system that represents color in three coordinates. The first is the L* coordinate representing brightness and can assume values from 0 (black) to 100 (white), while the coordinates a* and b* represent the four colors unique to human perception, with a* being indicative of the red-green component of a color, where positive and negative values indicate red and green, respectively. In contrast, b* indicates a color's yellow-blue component. Color, where positive and negative values indicate yellow and blue, respectively (Zhuang et al. 2019). The quantitative distinction between two colors can be obtained by the values of ΔE*, which represents the three-dimensional color distance between two points in CIEL*a*b* space.
Table 8 presents the CIEL*a*b* parameters for the SCC sample before and after adsorption and the calculated ΔE* values compared to the scaffold before incorporating the dye. The ΔE* values obtained show the most significant color difference in the external area of the scaffold (ΔE* color difference about 45% greater for RB and about 23% greater for RR). It can be attributed to a more significant amount of dye incorporated in this region, indicating a greater ease of penetration for the molecules of the RR dye or a greater formation of agglomerates of RB molecules on the scaffold surface, making it difficult for the RB to enter.
When the scaffold is used in its complete form (SCC), the dye has some difficulty diffusing into the pores of the material structure, reducing the adsorption capacity compared to the use of the cut scaffold. These results corroborate those obtained by SEM and EDS, indicating a greater porosity and amount of GaHAp inside the scaffold, which improves adsorption when exposed to the internal region.
Table 8. CIEL*a*b* color parameters for the SCC scaffold before and after adsorption of RB and RR with a concentration of 300 mg/L.
The scaffold based on biopolymers and hydroxyapatite containing Gallium was a practical synthesis. The characterizations indicate that the scaffold obtained has interconnected pores and a more excellent distribution of the amount of hydroxyapatite containing Gallium in the inner part of the material. It explains the better adsorption capacity of the RB and RR dye when using a ¼ cut of the scaffold (SCA sample) since the surface area is increased. The interaction with sites present within the three-dimensional structure of the material is facilitated. These results demonstrate excellent potential for removing pollutants from the textile industry in wastewater using the proposed scaffold.
Funding: This research was funded by CAPES, CNPq, and FAPEPI for all the financial support.
Acknowledgments: The authors want to thank their institutions, UFPI, UFPB, and IFPI Institutes.
Conflicts of Interest: The authors declare no conflict of interest.
- Aksu Z, Dönmez G (2003) A comparative study on the biosorption characteristics of some yeasts for Remazol Blue reactive dye. Chemosphere 50:. https://doi.org/10.1016/S0045-6535(02)00623-9
- Al-Shemy MT, Al-Sayed A, Dacrory S (2022) Fabrication of sodium alginate/graphene oxide/nanocrystalline cellulose scaffold for methylene blue adsorption: Kinetics and thermodynamics study. Sep Purif Technol 290:. https://doi.org/10.1016/j.seppur.2022.120825
- Anandan D, Madhumathi G, Nambiraj NA, Jaiswal AK (2019) Gum based 3D composite scaffolds for bone tissue engineering applications. Carbohydr Polym 214:. https://doi.org/10.1016/j.carbpol.2019.03.020
- Barbosa HFG, Attjioui M, Leitão A, et al (2019) Characterization, solubility and biological activity of amphihilic biopolymeric Schiff bases synthesized using chitosans. Carbohydr Polym 220:. https://doi.org/10.1016/j.carbpol.2019.05.037
- Borah L, Goswami M, Phukan P (2015) Adsorption of methylene blue and eosin yellow using porous carbon prepared from tea waste: Adsorption equilibrium, kinetics and thermodynamics study. J Environ Chem Eng 3:1018–1028. https://doi.org/10.1016/j.jece.2015.02.013
- Borsagli FGLM, Ciminelli VST, Ladeira CL, et al (2019) Multi-functional eco-friendly 3D scaffolds based on N-acyl thiolated chitosan for potential adsorption of methyl orange and antibacterial activity against Pseudomonas aeruginosa. J Environ Chem Eng 7:. https://doi.org/10.1016/j.jece.2019.103286
- Brandão Lima LC, Castro-Silva F, Silva-Filho EC, et al (2020) Saponite-anthocyanin pigments: Slipping between the sheets. Microporous and Mesoporous Materials 300:110148. https://doi.org/10.1016/j.micromeso.2020.110148
- Carvalho IC, Medeiros Borsagli FGL, Mansur AAP, et al (2021) 3D sponges of chemically functionalized chitosan for potential environmental pollution remediation: biosorbents for anionic dye adsorption and ‘antibiotic-free’ antibacterial activity. Environmental Technology (United Kingdom) 42:. https://doi.org/10.1080/09593330.2019.1689302
- Chun HJ, Reis RL, Motta A, Khang G (eds) (2020) Bioinspired Biomaterials. Springer Singapore, Singapore
- de Castro Silva F, Brandão Lima LC, Silva-Filho EC, et al (2020) Through alizarin-hectorite pigments: Influence of organofunctionalization on fading. Colloids Surf A Physicochem Eng Asp 587:. https://doi.org/10.1016/j.colsurfa.2019.124323
- de Oliveira AC, Sabino RM, Souza PR, et al (2020a) Chitosan/gellan gum ratio content into blends modulates the scaffolding capacity of hydrogels on bone mesenchymal stem cells. Materials Science and Engineering C 106:. https://doi.org/10.1016/j.msec.2019.110258
- de Oliveira AC, Sabino RM, Souza PR, et al (2020b) Chitosan/gellan gum ratio content into blends modulates the scaffolding capacity of hydrogels on bone mesenchymal stem cells. Materials Science and Engineering C 106:. https://doi.org/10.1016/j.msec.2019.110258
- dos Santos MVB, Feitosa GT, Osajima JA, et al (2019a) Development of a biomaterial made by hydroxyapatite and chlorhexidine for application to the oral cavity. Ceramica 65:. https://doi.org/10.1590/0366-69132019653732441
- dos Santos MVB, Rocha LBN, Vieira EG, et al (2019b) Development of composite scaffolds based on cerium doped-hydroxyapatite and natural gums-biological and mechanical properties. Materials 12:. https://doi.org/10.3390/ma12152389
- Esquerdo VM, Cadaval TRS, Dotto GL, Pinto LAA (2014) Chitosan scaffold as an alternative adsorbent for the removal of hazardous food dyes from aqueous solutions. J Colloid Interface Sci 424:. https://doi.org/10.1016/j.jcis.2014.02.028
- Felista MM, Wanyonyi WC, Ongera G (2020) Adsorption of anionic dye (Reactive black 5) using macadamia seed Husks: Kinetics and equilibrium studies. Sci Afr 7:. https://doi.org/10.1016/j.sciaf.2020.e00283
- Furko M, Havasi V, Kónya Z, et al (2018) Development and characterization of multi-element doped hydroxyapatite bioceramic coatings on metallic implants for orthopedic applications. Boletin de la Sociedad Espanola de Ceramica y Vidrio 57
- Genasan K, Mehrali M, Veerappan T, et al (2021) Calcium-silicate-incorporated gellan-chitosan induced osteogenic differentiation in mesenchymal stromal cells. Polymers (Basel) 13:. https://doi.org/10.3390/polym13193211
- Gonçalves JO, da Silva KA, Rios EC, et al (2020) Chitosan hydrogel scaffold modified with carbon nanotubes and its application for food dyes removal in single and binary aqueous systems. Int J Biol Macromol 142:. https://doi.org/10.1016/j.ijbiomac.2019.09.074
- Inphonlek S, Niamsiri N, Sunintaboon P, Sirisinha C (2020) Chitosan/xanthan gum porous scaffolds incorporated with in-situ-formed poly(lactic acid) particles: Their fabrication and ability to adsorb anionic compounds. Colloids Surf A Physicochem Eng Asp 603:. https://doi.org/10.1016/j.colsurfa.2020.125263
- Kamer DDA, Gumus T, Palabiyik I, et al (2022) The fermentation-based production of gellan from rice bran and the evaluation of various qualitative properties of gum. Int J Biol Macromol 207:. https://doi.org/10.1016/j.ijbiomac.2022.03.168
- Karthika JS, Vishalakshi B (2015) Novel stimuli responsive gellan gum-graft-poly(DMAEMA) hydrogel as adsorbent for anionic dye. Int J Biol Macromol 81:. https://doi.org/10.1016/j.ijbiomac.2015.08.064
- Karthika JS, Vishalakshi B, Naik J (2016) Gellan gum-graft-polyaniline-An electrical conducting biopolymer. Int J Biol Macromol 82:. https://doi.org/10.1016/j.ijbiomac.2015.10.061
- Kueasook R, Rattanachueskul N, Chanlek N, et al (2020) Green and facile synthesis of hierarchically porous carbon monoliths via surface self-assembly on sugarcane bagasse scaffold: Influence of mesoporosity on efficiency of dye adsorption. Microporous and Mesoporous Materials 296:. https://doi.org/10.1016/j.micromeso.2020.110005
- Lee S, Choi JH, Park A, et al (2020) Advanced gellan gum-based glycol chitosan hydrogel for cartilage tissue engineering biomaterial. Int J Biol Macromol 158:. https://doi.org/10.1016/j.ijbiomac.2020.04.135
- Li A, Xu H, Yu P, et al (2020) Injectable hydrogels based on gellan gum promotes in situ mineralization and potential osteogenesis. Eur Polym J 141:110091. https://doi.org/10.1016/J.EURPOLYMJ.2020.110091
- Lima F, Melo WG, de Fátima Braga M, et al (2021a) Chitosan-based hydrogel for treatment of temporomandibular joint arthritis. Polimeros 31:. https://doi.org/10.1590/0104-1428.20210026
- Lima F, Melo WG, de Fátima Braga M, et al (2021b) Chitosan-based hydrogel for treatment of temporomandibular joint arthritis. Polimeros 31:. https://doi.org/10.1590/0104-1428.20210026
- Lima LCB, Silva FC, Silva-Filho EC, et al (2020) Saponite-anthocyanin derivatives: The role of organoclays in pigment photostability. Appl Clay Sci 191:. https://doi.org/10.1016/j.clay.2020.105604
- Liu S, Ge H, Cheng S, Zou Y (2020) Green synthesis of magnetic 3D bio-adsorbent by corn straw core and chitosan for methylene blue removal. Environmental Technology (United Kingdom) 41:. https://doi.org/10.1080/09593330.2018.1556345
- Oliveira JT, Martins L, Picciochi R, et al (2010) Gellan gum: A new biomaterial for cartilage tissue engineering applications. J Biomed Mater Res A 93:. https://doi.org/10.1002/jbm.a.32574
- Pai S, Kini MS, Selvaraj R (2021) A review on adsorptive removal of dyes from wastewater by hydroxyapatite nanocomposites. Environmental Science and Pollution Research 28:11835–11849. https://doi.org/10.1007/s11356-019-07319-9
- Pang X, Bouzid M, dos Santos JMN, et al (2020) Theoretical study of indigotine blue dye adsorption on CoFe2O4/chitosan magnetic composite via analytical model. Colloids Surf A Physicochem Eng Asp 589:. https://doi.org/10.1016/j.colsurfa.2020.124467
- Pauletto PS, Gonçalves JO, Pinto LAA, et al (2020) Single and competitive dye adsorption onto chitosan–based hybrid hydrogels using artificial neural network modeling. J Colloid Interface Sci 560:. https://doi.org/10.1016/j.jcis.2019.10.106
- Pereira FAR, Sousa KS, Cavalcanti GRS, et al (2017) Green biosorbents based on chitosan-montmorillonite beads for anionic dye removal. J Environ Chem Eng 5:. https://doi.org/10.1016/j.jece.2017.06.032
- Pereira FS, Da Silva Agostini DL, Job AE, González ERP (2013) Thermal studies of chitin-chitosan derivatives. J Therm Anal Calorim 114:. https://doi.org/10.1007/s10973-012-2835-z
- Pereira Rocha RL, Silva TL, Araujo FP, et al (2021) Gallium-Containing Hydroxyapatite as a Promising Material for Photocatalytic Performance. Minerals 11:1347. https://doi.org/10.3390/min11121347
- Rajesh R, Ravichandran YD, Jeevan Kumar Reddy M, et al (2016) Development of functionalized multi-walled carbon nanotube-based polysaccharide-hydroxyapatite scaffolds for bone tissue engineering. RSC Adv 6:. https://doi.org/10.1039/c6ra16709h
- Ratnayake JTB, Mucalo M, Dias GJ (2017) Substituted hydroxyapatites for bone regeneration: A review of current trends. J Biomed Mater Res B Appl Biomater 105:1285–1299. https://doi.org/10.1002/jbm.b.33651
- Santos MVB, Oliveira AL, Osajima JA, Silva-Filho EC (2020) Development of composites scaffolds with calcium and cerium-hydroxyapatite and gellan gum. Ceram Int 46:3811–3817. https://doi.org/10.1016/j.ceramint.2019.10.104
- Sathishkumar P, Arulkumar M, Palvannan T (2012) Utilization of agro-industrial waste Jatropha curcas pods as an activated carbon for the adsorption of reactive dye Remazol Brilliant Blue R (RBBR). J Clean Prod 22:. https://doi.org/10.1016/j.jclepro.2011.09.017
- Semião MA, Haminiuk CWI, Maciel GM (2020a) Residual diatomaceous earth as a potential and cost effective biosorbent of the azo textile dye Reactive Blue 160. J Environ Chem Eng 8:. https://doi.org/10.1016/j.jece.2019.103617
- Semião MA, Haminiuk CWI, Maciel GM (2020b) Residual diatomaceous earth as a potential and cost effective biosorbent of the azo textile dye Reactive Blue 160. J Environ Chem Eng 8:. https://doi.org/10.1016/j.jece.2019.103617
- Sousa JM, Vieira ACC, Costa MP, et al (2022) Chitosan grafted with maleic anhydride and ethylenediamine: Preparation, characterization, computational study, antibacterial and cytotoxic properties. Mater Chem Phys 287:. https://doi.org/10.1016/j.matchemphys.2022.126301
- Stevens LR, Gilmore KJ, Wallace GG, in het Panhuis M (2016) Tissue engineering with gellan gum. Biomater Sci 4
- Tkachenko O, Panteleimonov A, Padalko I, et al (2014) Silica functionalized with 1-propyl-3-methylimidazolium chloride as an efficient adsorbent for the removal of Eosin Yellow and Reactive Blue 4. Chemical Engineering Journal 254:324–332. https://doi.org/10.1016/j.cej.2014.05.117
- Vashisth P, Nikhil K, Roy P, et al (2016) A novel gellan-PVA nanofibrous scaffold for skin tissue regeneration: Fabrication and characterization. Carbohydr Polym 136:. https://doi.org/10.1016/j.carbpol.2015.09.113
- Vignesh K, Suganthi A, Rajarajan M, Sakthivadivel R (2012) Visible light assisted photodecolorization of eosin-Y in aqueous solution using hesperidin modified TiO2 nanoparticles. Appl Surf Sci 258:4592–4600. https://doi.org/10.1016/j.apsusc.2012.01.035
- Wang L, Lyu W, Huang L, et al (2022) Utilization of gellan gum as a novel eco-friendly depressant in the flotation separation of fluorite from barite. Miner Eng 184:107640. https://doi.org/10.1016/j.mineng.2022.107640
- Yalman V, Çelik E, Arslan Ö, et al (2020) A study on bone tissue engineering: Injectable chitosan-g-stearic acid putty. Technology and Health Care 28:. https://doi.org/10.3233/THC-191775
- You Y, KeqiQu, Huang Z, et al (2019) Sodium alginate templated hydroxyapatite/calcium silicate composite adsorbents for efficient dye removal from polluted water. Int J Biol Macromol 141:. https://doi.org/10.1016/j.ijbiomac.2019.09.082
- Zhou Y, Lu J, Zhou Y, Liu Y (2019) Recent advances for dyes removal using novel adsorbents: A review. Environmental Pollution 252
- Zhuang G, Jaber M, Rodrigues F, et al (2019) A new durable pigment with hydrophobic surface based on natural nanotubes and indigo: Interactions and stability. J Colloid Interface Sci 552:. https://doi.org/10.1016/j.jcis.2019.04.072
No competing interests reported.