A facile method was provided by using biopolymers to mediate and synthesize 3D graphene oxide(GO) based gels.Bovine serum albumin(BSA)

chitosan (CS) and deoxyribonucleic acid (DNA) were chosen as bio-polymeric cross-linking agents to approach the gelation

and the gels were freeze-dried to obtain GO/biopolymer gels.The chemical and physical properties of the GO/biopolymer gels were tested by scanning electron microscope (SEM)

atomic force microscopy (AFM) and zeta potential measurements.The results indicate that these obtained gels have well-defined and interconnected 3D porous network

which allows the adsorbate molecules to diffuse easily into the absorbent.Fourier transform infrared (FTIR) spectra confirmed that these biopolymers have been immobilized into the GO gels successfully.Then

the hybrid gels were used for the removal of cationic dyes from waste water.Adsorption experiments showed that the GO-biopolymer gels had good adsorption ability for the cationic dyes; meanwhile

the hybrid gels also presented certain amount of adsorption capability for anionic and nonionic toxic molecules.The influence of contacting time

initial concentration and pH value on the adsorption capacities of the prepared GO-biopolymer gels was also studied

and the desorption ratios were also investigated.The GO-biopolymer gels displayed an adsorption capacity as high as 1100 mg/g for MB dye.Furthermore

the adsorption kinetics and adsorption isotherm of MB on the GO-BSA

GO-CS and GO-DNA gels were studied and discussed in detail.As a result

the experimental data of MB adsorption turned out that it fitted well with the pseudo-second-order kinetic model and the Langmuir isotherm

which indicated that the adsorption process was well-regulated monolayer adsorption.Besides

the initial adsorption process was pore diffusion while the later adsorption process was intraparticle diffusion.