In this research project, a “green”method for preparing Fe3O4@ layered double hydroxide@ guargum bionanocomposites (GLF-BNCs) was used. First of all, the LDH coated Fe3O4 nanoparticles was simply synthesized, using ultrasonic irradiation. The citrate coated Fe3O4 nanoparticles which were under negative charging and LDH nanocrystals which were charged positively make electrostatic interaction which formed a stable self-assembly component, and then guargum as a biopolymer were linked onto Fe3O4@LDH via soloution method. Furthermore, these nanocomposites were modified. So, potassium persulfate and the cross-linker N, N'-methylenebisacrylamide (MBA) were used to synthesis the cross-linked bionanocomposites (MLG). The effect of Fe3O4@LDH contents (2, 4 and 8wt.%) on the thermal, physicomechanical, and morphological properties of guargum and modification of GLF nanocomposites were investigated by Fourier transform infrared spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), field emission scanning electron microscopy, transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy and Brunauer–Emmett–Teller (BET) specific surface area techniques. The TEM results indicated that the LDH platelets are distributed within the polymer matrix. TGA results show that the MLG nanocomposites thermal properties has improved in comparision to GLF nanocomposites. In the following, crosslinked MLG and GLF nanocomposites were prepared for the removal of methylene blue from aqueous solution. MLG show more efficient removal in comparison to GLF. Therefore, efficient factors on the adsorption process such as pH, adsorbent dosage, time, initial and concentration of dye were investigated for MLG10. The adsorption process showed a high dependence on the pH value, and the result showed that the interaction between the adsorbent and dye might follow different mechanisms such as hydrogen bonding. Investigating the kinetic models showed that the rate of absorption process was controlled by linear pseudo-second order model. An investigation of the isotherm models showed that the data were more consistent with linear Langmuier isotherm that confirms the chemical adsorption process.
