**3.5. Characterization studies of dye absorption with prepared nanoparticle loaded membrane forms**

SEM images for the adsorption of DB15 azo dye with the membrane forms obtained in the study are given in **Figure 7**. SEM images were taken at a size of 10 μm at 8000× magnification. It is seen that the DB15 azo dye has drained the membrane forms like a cover.

As shown in **Figure 8**, membrane forms formed with LS material exhibit significant peaks, especially at permeability of 1000 cm−1. At the same time, certain peaks were observed at about 500 and around 3350 cm−1. In fact, FT-IR bands specific to the cellulose structure of LS seen here. C─H bands and ─OH groups are found at around 3350 and 2800–2900 cm−1 [46, 47]. In the adsorption of DB15 azo dye with LS membrane forms, FT-IR bands were observed especially for Fe<sup>3</sup> O4 nanoparticle-loaded membrane forms. ZnO NPs loaded membrane had higher permeability to dye adsorption than other membrane types.

The XRD spectrum of the LS membrane form showed peaks at 2θ = 15, 20, and 38 areas. The peak intensity is above 30,000 in the area 2θ = 20. However, in the XRD spectrum of DB15 azo dye adsorption with this membrane form, the 2θ = 20 area shifted to 2θ = 22 and the peak intensity approached 60.000 in this area. In addition, additional peak was observed at 2θ = 35, 38, 43, and 50 areas. Nanoparticle-loaded membrane forms exhibited significant changes in XRD spectra when DB15 azo dye adsorbed with these membrane forms. These membrane forms exhibited very low XRD peaks compared to the pure LS membrane form, but they exhibited very high XRD peaks especially in the 2θ = 15 and 20 areas after dye adsorption. A distinctive feature of ZnO and Fe<sup>3</sup> O4 NPs in the adsorption of this azo dye was not observed in the XRD spectrum. The values were very close to each other (**Figure 8**) [47–49].

### **3.6. Langmuir and Freundlich adsorption isotherm studies**

The following Langmuir isotherm equation is used to plot Langmuir adsorption isotherm graphs for the adsorption of DB15 azo dye with the membrane forms in this study. The correlation between \_\_\_ *Ce qe* and *Ce* calculated from experimental results is given in **Figure 9**.

$$\frac{Ce}{q\_{\epsilon}} = \frac{1}{k} \frac{C\_{\epsilon}}{V\_{m}} + \frac{C\_{\epsilon}}{V\_{m}} \tag{2}$$

Using the following Freundlich adsorption isotherm equation, Freundlich adsorption isotherm graph for the adsorption of DB15 azo dyes of the working membrane forms was drawn. This graph showing the relation between log q<sup>e</sup> and log C<sup>e</sup> was given in **Figure 9**.

$$
\log q\_{\epsilon} = \log \mathcal{K}\_{\mathbb{F}} + \frac{1}{N} \log \mathcal{C}\_{\epsilon} \tag{3}
$$

with 274.6 mg/g and the lowest qm value was obtained with pure LS membrane form with 45.0 mg/g. The highest b value was achieved with the pure LS membrane form with 1.186 L/mg

NPs membrane form with a minimum b value of 0.06 L/mg. High

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219

and the LS-ZnO/Fe<sup>3</sup>

O4

**Figure 7.** SEM images of adsorption of DB15 azo dye with membrane forms.

The Langmuir adsorption isotherm is generally used to describe the maximum adsorption capacity of an adsorbent. qm and b values were calculated from the above equation. b is a constant related to adsorption net enthalpy (L/mg), and qm is the amount of adsorbed material (mg/g) in the unit weight of the adsorbent to form a single layer at the surface. In the Langmuir isotherm study, the highest qm value was obtained LS-ZnO/Fe<sup>3</sup> O4 membrane form The Investigation of Removing Direct Blue 15 Dye from Wastewater Using Magnetic *Luffa sponge* NPs http://dx.doi.org/10.5772/intechopen.73216 219

**Figure 7.** SEM images of adsorption of DB15 azo dye with membrane forms.

**3.5. Characterization studies of dye absorption with prepared nanoparticle loaded** 

It is seen that the DB15 azo dye has drained the membrane forms like a cover.

higher permeability to dye adsorption than other membrane types.

O4

**3.6. Langmuir and Freundlich adsorption isotherm studies**

in the XRD spectrum. The values were very close to each other (**Figure 8**) [47–49].

*Ce qe*

Langmuir isotherm study, the highest qm value was obtained LS-ZnO/Fe<sup>3</sup>

SEM images for the adsorption of DB15 azo dye with the membrane forms obtained in the study are given in **Figure 7**. SEM images were taken at a size of 10 μm at 8000× magnification.

As shown in **Figure 8**, membrane forms formed with LS material exhibit significant peaks, especially at permeability of 1000 cm−1. At the same time, certain peaks were observed at about 500 and around 3350 cm−1. In fact, FT-IR bands specific to the cellulose structure of LS seen here. C─H bands and ─OH groups are found at around 3350 and 2800–2900 cm−1 [46, 47]. In the adsorption of DB15 azo dye with LS membrane forms, FT-IR bands were observed

The XRD spectrum of the LS membrane form showed peaks at 2θ = 15, 20, and 38 areas. The peak intensity is above 30,000 in the area 2θ = 20. However, in the XRD spectrum of DB15 azo dye adsorption with this membrane form, the 2θ = 20 area shifted to 2θ = 22 and the peak intensity approached 60.000 in this area. In addition, additional peak was observed at 2θ = 35, 38, 43, and 50 areas. Nanoparticle-loaded membrane forms exhibited significant changes in XRD spectra when DB15 azo dye adsorbed with these membrane forms. These membrane forms exhibited very low XRD peaks compared to the pure LS membrane form, but they exhibited very high XRD peaks especially in the 2θ = 15 and 20 areas after dye adsorption. A

The following Langmuir isotherm equation is used to plot Langmuir adsorption isotherm graphs for the adsorption of DB15 azo dye with the membrane forms in this study. The cor-

> = \_\_\_\_ <sup>1</sup> *k V<sup>m</sup>* + *C*\_\_\_\_\_\_\_\_ *<sup>e</sup> Vm*

Using the following Freundlich adsorption isotherm equation, Freundlich adsorption isotherm graph for the adsorption of DB15 azo dyes of the working membrane forms was drawn.

The Langmuir adsorption isotherm is generally used to describe the maximum adsorption capacity of an adsorbent. qm and b values were calculated from the above equation. b is a constant related to adsorption net enthalpy (L/mg), and qm is the amount of adsorbed material (mg/g) in the unit weight of the adsorbent to form a single layer at the surface. In the

calculated from experimental results is given in **Figure 9**.

and log C<sup>e</sup>

nanoparticle-loaded membrane forms. ZnO NPs loaded membrane had

NPs in the adsorption of this azo dye was not observed

was given in **Figure 9**.

*<sup>n</sup> logCe* (3)

O4

membrane form

(2)

**membrane forms**

218 Iron Ores and Iron Oxide Materials

especially for Fe<sup>3</sup>

O4

distinctive feature of ZnO and Fe<sup>3</sup>

*Ce qe* and *Ce*

\_\_\_

This graph showing the relation between log q<sup>e</sup>

*logq<sup>e</sup>* <sup>=</sup> log*K<sup>F</sup>* <sup>+</sup> \_\_1

relation between \_\_\_

with 274.6 mg/g and the lowest qm value was obtained with pure LS membrane form with 45.0 mg/g. The highest b value was achieved with the pure LS membrane form with 1.186 L/mg and the LS-ZnO/Fe<sup>3</sup> O4 NPs membrane form with a minimum b value of 0.06 L/mg. High

**Figure 8.** FT-IR and XRD spectrums of adsorption of DB15 azo dye with membrane forms.

correlation coefficient R2 (0.9605) was provided with Langmuir model, the linear form application for LS-Fe<sup>3</sup> O4 . This indicates that the sorption system of Langmuir isotherm provides a good model for this membrane form (**Table 4**).

kinetics was investigated. For this purpose, the time-dependence of ln(*q<sup>e</sup>*

**DB15**

qm (mg/g) 45.0 48.6 128.1 274.6 b(L/mg) 1.186 0.216 0.103 0.06 R2 0.9503 0.9371 0.9605 0.7641

(mg/g) (L/mg)1/n 6.85 1.84 1.53 1.36×10−4

n 1.29 2.65 1.899 0.44 R2 0.9885 0.9378 0.9637 0.9716

**LS LS-ZnO LS-Fe3**

The Investigation of Removing Direct Blue 15 Dye from Wastewater Using Magnetic *Luffa sponge* NPs

The second-order reaction equation is used to calculate the k2

, k<sup>2</sup> , R2

values were calculated for 10, 25, and 50 mg/L concentrations of dye (**Table 5**).

constant is calculated using the first order reaction equation given below:

ln(*q<sup>e</sup>* − *qt*) = ln *q<sup>e</sup>* − *k*<sup>1</sup> *t* (4)

Then, its suitability of second-order reaction kinetics was investigated to calculate the adsorption constants of DB15 azo dye. (t/qt) depicting the time dependence graphs were plotted and

values for 10, 25, and 50 mg/L concentrations of DB15 azo dyes were calculated (**Table 5**).

When **Table 5** is examined, there is high difference between values of qeexperimental and qecalculated in the reaction kinetics of the first- and second-order in dye adsorption with pure LS membrane

equate. There is lower difference than the other concentration between values of qeexperimental and qecalculated in reaction kinetics of the second order in adsorption of azo dye at a concentration of 10 mg/L with the LS-ZnO NPs membrane form. However, when we take into account the R2 values, there is a compatibility with the first-order reaction kinetics. We see that the adsorption

O4

Plots of LnKL against 1/T obtained in adsorption experiments with membrane forms of DB15

parameters for membrane forms used in the adsorption of DB15 azo dyes are given in **Table 6**.

R2

KF

R2

values (qeexperimental, qecalculated, k1

form. Furthermore, when the R2

azo dye are given in **Figure 10**.

Values for ΔG<sup>o</sup>

of azo dye at 25 mg/L concentration with Fe<sup>3</sup>

**Table 4.** Langmuir and Freundlich isotherm parameters.

**3.8. Calculation of thermodynamic parameters**

ate for the second-order reaction kinetics in terms of R2

The k<sup>1</sup>

**Langmuir constants**

**Freundlich constants**

− *q<sup>t</sup>*

**O4 LS-ZnO/Fe3**

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**O4**

221

constant and all calculated

) for adsorption of azo dye DB15 are shown in **Table 5**.

values are examined, it is clear that the second order is inad-

values.

Gibbs free energy, ΔH° enthalpy change and ΔS° entropy thermodynamic

NPs-loaded membrane forms is more appropri-

) was plotted and

Freundlich isotherm model is an empirical relationship that defines the adsorption of solubles from a liquid to a solid surface and assumes that there are different areas with several adsorption energies. Freundlich constants are related to the sorption capacity of the adsorbent (mg/g) and adsorption energy. In the Freundlich model, KF and n are constants that show the adsorption capacity and intensity, respectively. High KF and n values indicate high adsorption capacity and magnitude of n value is an indication of the suitability of adsorption. The LS-ZnO NPs membrane form with 2.65 values of n had a good adsorption capacity relative to the Freundlich isotherm. The pure LS membrane form is quite advantageous according to R2 (0.9885) (**Table 4**).

### **3.7. Reaction kinetics of first and second order**

The adsorption kinetics of DB15 azo dye with LS, LS-ZnO NPs, LS-Fe<sup>3</sup> O4 NPs, LS-ZnO/Fe<sup>3</sup> O4 NPs membrane forms and were investigated against 10, 25, 50, 100, and 200 mg/L concentrations of dye solutions. To determine the adsorption constants, first order conformity to reaction

**Figure 9.** Langmuir and Freundlich adsorption isotherm for DB15 azo dye adsorption with membrane forms.


**Table 4.** Langmuir and Freundlich isotherm parameters.

correlation coefficient R2

220 Iron Ores and Iron Oxide Materials

(0.9885) (**Table 4**).

O4

good model for this membrane form (**Table 4**).

**3.7. Reaction kinetics of first and second order**

(mg/g) and adsorption energy. In the Freundlich model, KF

The adsorption kinetics of DB15 azo dye with LS, LS-ZnO NPs, LS-Fe<sup>3</sup>

**Figure 8.** FT-IR and XRD spectrums of adsorption of DB15 azo dye with membrane forms.

adsorption capacity and intensity, respectively. High KF

cation for LS-Fe<sup>3</sup>

R2

(0.9605) was provided with Langmuir model, the linear form appli-

and n are constants that show the

and n values indicate high adsorp-

O4

NPs, LS-ZnO/Fe<sup>3</sup>

O4

. This indicates that the sorption system of Langmuir isotherm provides a

Freundlich isotherm model is an empirical relationship that defines the adsorption of solubles from a liquid to a solid surface and assumes that there are different areas with several adsorption energies. Freundlich constants are related to the sorption capacity of the adsorbent

tion capacity and magnitude of n value is an indication of the suitability of adsorption. The LS-ZnO NPs membrane form with 2.65 values of n had a good adsorption capacity relative to the Freundlich isotherm. The pure LS membrane form is quite advantageous according to

NPs membrane forms and were investigated against 10, 25, 50, 100, and 200 mg/L concentrations of dye solutions. To determine the adsorption constants, first order conformity to reaction

**Figure 9.** Langmuir and Freundlich adsorption isotherm for DB15 azo dye adsorption with membrane forms.

kinetics was investigated. For this purpose, the time-dependence of ln(*q<sup>e</sup>* − *q<sup>t</sup>* ) was plotted and R2 values were calculated for 10, 25, and 50 mg/L concentrations of dye (**Table 5**).

The k<sup>1</sup> constant is calculated using the first order reaction equation given below:

$$\ln \langle q\_{\varepsilon} - q\_{\iota} \rangle = \ln q\_{\iota} - k\_{\iota} t \tag{4}$$

Then, its suitability of second-order reaction kinetics was investigated to calculate the adsorption constants of DB15 azo dye. (t/qt) depicting the time dependence graphs were plotted and R2 values for 10, 25, and 50 mg/L concentrations of DB15 azo dyes were calculated (**Table 5**).

The second-order reaction equation is used to calculate the k2 constant and all calculated values (qeexperimental, qecalculated, k1 , k<sup>2</sup> , R2 ) for adsorption of azo dye DB15 are shown in **Table 5**.

When **Table 5** is examined, there is high difference between values of qeexperimental and qecalculated in the reaction kinetics of the first- and second-order in dye adsorption with pure LS membrane form. Furthermore, when the R2 values are examined, it is clear that the second order is inadequate. There is lower difference than the other concentration between values of qeexperimental and qecalculated in reaction kinetics of the second order in adsorption of azo dye at a concentration of 10 mg/L with the LS-ZnO NPs membrane form. However, when we take into account the R2 values, there is a compatibility with the first-order reaction kinetics. We see that the adsorption of azo dye at 25 mg/L concentration with Fe<sup>3</sup> O4 NPs-loaded membrane forms is more appropriate for the second-order reaction kinetics in terms of R2 values.

#### **3.8. Calculation of thermodynamic parameters**

Plots of LnKL against 1/T obtained in adsorption experiments with membrane forms of DB15 azo dye are given in **Figure 10**.

Values for ΔG<sup>o</sup> Gibbs free energy, ΔH° enthalpy change and ΔS° entropy thermodynamic parameters for membrane forms used in the adsorption of DB15 azo dyes are given in **Table 6**.


**Table 5.** First- and second-order adsorption rate constants in DB15 azo dye removal.

ΔG° values decreased as the temperature increases in adsorption of DB15 azo dye with all membrane forms. This shows an increasing tendency in the feasibility and spontaneity of DB15 azo dye adsorption. The fact that ΔG° has negative values means that the adsorption of DB15 azo dye is spontaneously. The negative values of ΔH° confirm the exothermic structure of the adsorption process. Therefore, the adsorption of DB15 azo dye with membranes formed by the use of LS and nanoparticle is a natural chemical. Positive values of ΔS° indicate increasing disorder and randomness at the solid solution interface of the adsorbent and DB15 azo dye [49]. This was

LS 20°C −24235.32 −417.7 −84.14

LS-ZnO NPs 20°C −19855.73 −346.62 −68.95

NPs 20°C −58727.95 −941.5 203.65

NPs 20°C −86188.31 −1386.46 298.89

In this study on remediation, the possibilities offered by the environment are evaluated. ZnO

purified from *Euphorbia amygdaloides* plant. In this phase of the study, a new plant source was presented to literature for the green synthesis of nanoparticles. It has also been shown that produced nanoparticles may play an active role in dye adsorption. The synthesis of this plant

LS is a natural plant that can grow in many countries, can be used for many purposes, and has recently undergone a lot of research. In this study, nanoparticles were immobilized successfully on this material. In this way, it is aimed to prevent the nanoparticles accumulation in the environment and the creation of a separate pollution. Adsorption of DB15, a carcinogenic azo dye, was studied with nanoparticle-loaded membrane forms. Optimization, characterization, kinetic, thermodynamic studies demonstrated effectiveness of the membrane forms used in dye adsorption. For this reason, we can easily say that this work will be a source for commer-

O4

NPs were produced by green synthesis with catalyzed peroxidase enzyme partially

NPs (**Table 6**).

**∆G° (kJ/mol K) ∆H° (kJ/mol) ∆S° (kJ/mol)**

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223

The Investigation of Removing Direct Blue 15 Dye from Wastewater Using Magnetic *Luffa sponge* NPs

observed in membrane forms immobilized with Fe<sup>3</sup>

LS 25°C −24656.02 LS 30°C −25076.72

LS-ZnO NPs 25°C −20200.48 LS-ZnO NPs 30°C −20545.23

NPs 25°C −59746.20

NPs 30°C −60764.45

NPs 25°C −87682.76

NPs 30°C −89177.21

with other nanoparticles will be further studied.

cialized membrane systems in the future.

**4. Conclusion**

O4

and Fe<sup>3</sup>

**DB15**

LS-Fe<sup>3</sup> O4

LS-Fe<sup>3</sup> O4

LS-Fe<sup>3</sup> O4

LS-ZnO/Fe<sup>3</sup>

LS-ZnO/Fe<sup>3</sup>

LS-ZnO/Fe<sup>3</sup>

O4

O4

O4

**Table 6.** Calculated thermodynamic constants.

**Figure 10.** Thermodynamic kinetics graph for adsorption of DB15 azo dye with formed membrane forms.


**Table 6.** Calculated thermodynamic constants.

LS and nanoparticle is a natural chemical. Positive values of ΔS° indicate increasing disorder and randomness at the solid solution interface of the adsorbent and DB15 azo dye [49]. This was observed in membrane forms immobilized with Fe<sup>3</sup> O4 NPs (**Table 6**).
