1. 70 gm of grinded kaolin of granular size 53 μm was weighed and placed in a Beaker (capacity of 500 ml).

2. 35 gm of Urea was weighed and then added to the clay on the same Beaker.

3. The mixture was mixed by an electrical mixer in its dry form.

4. Suitable amount of water then added to the mixture with keeping continuous stirring, till getting a solution of kaolin-urea.

5. The mixture then placed at a porcelain crucible and heat in an oven at 90˚C till dryness.

6. The products, finally was grinded and became ready to the required tests (FTIR, XRD and Adsorption of methylene blue (MB).

7. Same procedure was used on kaolin (partical size 106 µm).

1 gm of MB dye was dissolved in one liter of double distilled water to obtain 1000 ppm MB dye solution. UV- Vis spectra of this solution appeared an absorption band at λ_max = 660 nm.

- 0.5 gm of the prepared organoclay was weighed, each alone and placed at 25 ml volumetric flask.

- 10 ml of methylen blue solution dye of the required concentration was added and stirred, very well to the clay.

- The flasks were placed at shaker water bath at different temperatures (10˚C, 30˚C, 40˚C and 50˚C) and stirred for 1 hour each.

- The solutions were filtered.

- The absorption was measured for each filtrate at 660 nm.

- The adsorption required calculation according to (Langmuir and Freundlich isotherms), from which the ther- modynamic constant can be obtained (ΔG, ΔH and ΔS).

Vibrational spectroscopy is a key technique in the study of formation and structural characterization of kaolinite intercalates [13] .

FTIR of kaolin, urea and kaolin-urea complex are shown in Figure 1 and Figure 2. From these figures, one could observed that kaolin show two sharp bands at 3694 cm⁻¹ and 3625 cm⁻¹. The literature however shows con- flicting assignment of these bands [14] , band at 3694 cm⁻¹ belong to hydroxyl group in specific lattice sites in the layer and resulting from vibrational coupling of three surface of hydroxyl in the primitive cell and the dipole oscillation in perpendicular to the layer, while band at 3625 cm⁻¹ in belong to hydroxyl group lie within lamellae

in plane common to both the tetrahedral and octahedral sheets. Upon intercalation with urea, the intensity of these two bands decrease and shifted to lower frequency, Also a new bands at 3503 cm⁻¹ appeared due to the breaking of some hydrogen bonds between the kaolinite layers and formation of new band, which usually involve the inner surface OH group and change are observed in the intensities of bands assigned to vibrations of these groups [13] .

Bands at 3440 and 3444 cm⁻¹ in the Figure 1 and Figure 2 (Chart C) which appear in the results intercalation of kaolinite 53 and 106 µm with urea respectively are attributed to formation H-bond between NH₂ group from urea and Oxygen group of tetrahedral sheet for kaolinite.

The newly formed bands at 3384 and 3503 cm⁻¹ in the intercalation of kaolinite 53 µm with urea confirmed the asymmetric and symmetric NH₂ stretching frequencies involved in weak H-bonding with the inner hydroxyls [15] - [18] .

Band at 2352 cm⁻¹ in urea chart and kaolinite 53 and 106 µm started disappear when intercalated urea with kaolinite 106 µm and happened shifted in this band to the 2356 cm⁻¹ when intercalate urea with kaolinite 53 µm.

Also same effect appeared for the band at 1673 cm⁻¹, which assigned for the C?O group of urea, upon interaction with kaolin, formation a bond between C?O and OH group in Gibbsite-like layer so it shifted to 1658 and 1666 cm⁻¹ whene kaolinite 53 and 106 µm interactions with urea respectinely (Chart C in Figure 1 and Figure 2). CN stretching of free urea appeared at 1461 cm⁻¹, upon interaction with kaolinite shifted to 1457 and 1454 cm⁻¹ in the Figure 1 and Figure 2 Chart C respectively, and a new band at 1403 cm⁻¹ appeared. This suggest urea in this system would then be considered to exist in two forms anionic and complex (ion dipole) as shown in Figure 3.

The XRD curves of raw kaolin chart (A), and kaolin-Urea complexes charts (B and C) are shown in Figure 4.

From this figure one could observe that the strongest three peaks and their values are recorded in Table 2.

From this table:

Peaks at 2θ = 12.3044, d(Å) = 7.18765, intensity = 403 and 2θ = 24.9208, d(Å) = 3.57009, intensity = 362 are attributed to kaolinite and 2θ = 26.6345, d(Å) = 3.34415, intensity = 286 is due to SiO₂.

Peak in Chart B at 2θ = 22.4669, d(Å) = 3.95417, intensity = 1019 is attributed to urea, and peaked at 2θ = 268558, d(Å) = 3.31709, intensity = 247 is due to SiO₂. Band at 2θ = 25.1508, d(Å) = 3.53796, intensity = 227 is due to kaolinite.

These peaks in Chart C at 2θ = 22.3047, d(Å) = 3.98256, intensity = 2249, 2θ = 29.3554, d(Å) = 3.04008, intensity = 371 and 2θ = 24.6676, d(Å) = 3.60616, intensity = 370 are assigned to urea, SiO₂ and kaolinite respec- tively.

From the results in Table 2 and make comparison between these values, on could concluded that strong intercalation between kaolinite layers and urea as a result of appearance high intensity of peaks are due to urea and

in the same time happened shifted and decrease in the intensity of kaolinite and SiO₂ when the intercalation is event. The intercalation caused the destruction of the hydrogen bonding between the kaolinite layers [14] . And from results in this table show decreasing in intensity of peaks when the kaolin 53 µm-urea intercalated with urea compared with other complex this indicates that this kaoline a granular size 53 µm is the best.

Effects of temperature on the equilibrium adsorption of methylene blue from aqueous solution using kaolin (par- tical size 53 and 106 µm) and kaolin-urea complex were studied.

The equilibrium adsorption data were analyzed using two widely applied isotherms: Langmuir and Freundlich. The results were shown in Table 3 and Table 4. Non-linear method was used for comparing the best fit of the isotherms. Best fit was found to be Langmuir isotherm.