**3. Results and discussion**

#### **3.1 X-ray diffraction**

The X-ray diffraction patterns of Zn3-Al-Cl-LDH depicted in **Figure 1** of the sample are characteristic to those of a double lamellar hydroxide. The sample was crystallized in a rhombohedral symmetry (space group: R-3m) with (c/3) = d003 = 2d110 and a = 2d006. The lattice parameters **c** and **a** are, respectively, 2.38 and 0.31 nm. These values are similar to those reported in the literature [14].

The peak (1 1 0) indicates the intermetallic distance used to calculate a lattice parameter (a = 2d110). Moreover, the values of the parameters **c** and **a** are, respectively, 23.82 and 3.10 A°. These values are similar to those reported in the literature [19].

#### **3.2 Infrared spectroscopy**

FT-IR confirms that the spectra of synthesized Zn3Al-Cl-(NO3 )ads-LDH (**Figure 2**) resemble those of hydrotalcite-like phases [21]. The FT-IR presents a close-up view of the most important regions of the infrared spectra of Zn3Al-Cl- (NO3 )ads-LDH depicted in **Table 1**.

The frequencies of absorbance links in this material are reported in **Table 1**. Indeed the infrared spectra of this material after adsorption at a different time show the increase in the intensity of characteristic link of NO3 ions at 1381 cm<sup>1</sup> as a function of time.

**Figure 1.** *XRD pattern of Zn3-Al-Cl-LDH-blank.*

#### **Figure 2.**

*(a) FT-IR spectra of Zn3-Al-Cl visualized and (b) proposed adsorption mechanism between the adsorbent and nitrate [22].*


adsorption and which is intended for the dielectric analysis. The filtrate is recovered corresponding to each time and fee in 1 mL is put in a 50 mL flask and then the

*Experimental and Theoretical Study of the Adsorption Behavior of Nitrate Ions by Layered…*

The adsorption kinetic studies were carried out by contacting Zn3Al-Cl-LDH

0.4 mg/L, respectively. The adsorption process was agitated at 25°C and a pH of 7.0 for several periods ranging from 5 to 60 min under inert atmosphere (N2). LDH obtained after adsorption was filtered and then washed several times. The concentration of the nitrate ion in the filtrate was determined by spectrophotometer at 415 nm. The nitrate amount *qe* (mg/g) loaded on adsorbents after adsorption

> *qe* <sup>¼</sup> ð Þ� *<sup>C</sup>* � *Ce <sup>V</sup> m*

> > *C*<sup>0</sup> � *Ce C*<sup>0</sup>

where Ce (mg/L) is the equilibrium of nitrate ion concentration in solution, C0 (mg/L) is the initial of nitrate ion concentration in solution, m (g) is the mass of

The equilibrium is reached after 30 min, with a maximum of approximately 59.12% adsorption capacity corresponding to a 295.62 mg/g of an affinity of the adsorbate for the active sites of the adsorbent [23]. From **Figure 3** it is quite clear that the percentage of nitrate ion adsorption calculated by kinetic study and

� solutions (500 ml) of the initial concentration of

� *adsorbed.*

� ions from solutions

� 100 (2)

(1)

following procedure used for the tracing of the calibration curve.

*Curve calibration of spectrophotometer used for determination of NO3*

*DOI: http://dx.doi.org/10.5772/intechopen.90883*

experiments and the percentage removal (removal %) of NO3

ð Þ¼ %

were calculated using the following equations:

adsorbent, and V (L) is the volume of the solutions.

**3.5 Kinetic study**

**Figure 3.**

(Cm = 0.8 g/L) with NO3

and the removal

**117**

#### **Table 1.**

*Frequencies of absorbance bands.*

#### **3.3 Inductively coupled plasma (ICP) spectrometry**

The chemical formula Zn3-Al-Cl-LDH was obtained using the technical ICP analysis, which shows that the theoretical ratio [R = (Zn2+/Al3+)] is close to that of the synthesis. This characterization also suggests that the sample has a homogeneous chemical composition; the approximate chemical formula is (Zn2.93Al (OH)7.86) (Cl─. 1.87 H2O) for the metal ratio of R = 3. Cl─ anion intercalated.
