CD var/Includes CD:Removal of Methyl Orange, Remazol Brilliant Blue Reactive, Allura Red Dyes and Binary Mixture by CoAl and CoFe Layered Double Hydroxides (LDHs)

Includes references(92-104 p.)

'Abstract CoAl and CoFe- Layered Double Hydroxides with Co2+/Al3+ Co2+/Fe3+ molar ratio of 4:1 were synthesized using Co-precipitation method. The LDHs were characterized using X-Ray Diffraction and Fourier Transform Infra-Red Spectroscopy before and after sorption, Scanning Electron Microscopy analysis of the LDHs was also conducted before the sorption experiments. The uncalcined and calcined LDHs were used to investigate their adsorption efficiency of Remazol brilliant blue reactive, Methyl orange, Allura red and binary mixture of Remazol brilliant blue and Methyl orange. The effects of contact time, initial dyes concentrations were investigated. The sorption kinetics was investigated using the two equations pseudo first order and pseudo second order kinetics. The studies revealed that the experimental data results of all the LDHs against the respective dyes fitted well with the pseudo second order kinetics with R2 = 0.999 in some cases. The equilibrium sorption isotherm was also investigated using the two linear isotherm models Langmuir and Freundlich isotherm models, the Langmuir isotherm fitted the experimental data for RBBR onto CoAl and CoFe-LDHs with Qmax of 167 mg/g and R2 = 0.999 and AR with Qmax of 96.98 and R2 = 0.999. On the other hand the experimental results for MO adsorption showed that for the two LDHs the results fitted the Freundlich sorption isotherm with R2 = 0.988 and Qe of 801 mg/g at C0 = 200 mg/L. In binary experiment RBBR and MO data also fits pseudo second order both and Langmuir and Freundlich models respectively with maximum capacity of about 120 and 400 mg/g respectively. Therefore the LDHs will be promising low cost adsorbents for the removal RBBR, MO AR and the binary mixture. Key words: Adsorption, Layered Double Hydroxides, Remazol Brilliant blue Reactive, Methyl Orange, Allura Red, Cobalt Aluminum, Cobalt Iron'