Syntheses of magnetic GO @ melamine formaldehyde resin for dyes adsorption

Melamine formaldehyde resin based on graphene oxide (GO@MF) was successfully prepared, then, Fe3O4 was introduced to synthesis a magnetic composite, which used for the adsorption of anionic dyes. The Fe3O4/GO@MF was characterized by SEM, FTIR, XRD and VSM. Adsorption behaviors affected by concentration, contact time, pH and ionic strength of the as-prepared composites for Congo red (CR) and methyl blue (MB) were systematically explored and discussed. The equilibrium adsorption data of CR and MB accorded better with the Langmuir model and the Freundlich model, respectively, while there kinetics adsorption data both fitted the pseudo-second-order model. The kinetic and equilibrium parameters were also calculated. The maximum adsorption capacities calculated by Langmuir model of CR and MB were 257.07 mg g (-1), 418.41 mg g(-1), respectively and the equilibrium adsorption capacities calculated by pseudo-second order were basically same to the experimental results. The adsorption capacities of CR and MB affected by the pH were significant which may due to the protonation or deprotonation of amino and secondary amino groups. In addition, the introduction of Fe3O4 into GO@MF composited endued it with excellent magnetic separation property.Fe3O4/GO@MF exhibited well adsorption selectivity on anionic acid dyes and stabilized regeneration performance.