Mohammadreza Rahmanifard - Department of Chemistry, Payame Noor University, PO Box ۱۹۳۹۵-۳۶۹۷, Tehran, Iran
Nahid Rasouli - Department of Chemistry, Payame Noor University, PO Box ۱۹۳۹۵-۳۶۹۷, Tehran, Iran
Hossein Salavati - Department of Chemistry, Payame Noor University, PO Box ۱۹۳۹۵-۳۶۹۷, Tehran, Iran

In this research, firstly Zn-Al-NO3-LDH layered double hydroxide was synthesized through chemical co-precipitation method and then modified by the anion of ninhydrin. Structure and morphology of the prepared sample were recognized by instrumental analysis methods as Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX). The effects of different parameters as pH, initial concentration of dye and exposure time on the adsorption rate of the anionic dye of congo red (CR) with the modified clay was studied. The results showed that the maximum removal of CR dye using synthesized layered double hydroxide was achieved at pH=10 and an exposure time of 60 min and was equal to 95%. Moreover, the results were analyzed using the pseudo-first-order and pseudo-second-order kinetic models. This kinetic studies showed that the adsorption process obeys of a pseudo-second-order kinetic model

layered double hydroxide, adsorption, congo red dye