Application of cross-linked chitosan for nitrate nitrogen (v) removal from aqueous solutions

This study was aimed at determining the possibility of applying non-cross-linked chitosan (CHs) as well as chitosan cross-linked with glutaraldehyde (CHs-GLA) and epichlorohydrin (CHSECH) for the removal of nitrates (V) from aqueous solutions. The scope of the study included determinations of: optimal pH value of nitrates sorption (from pH range of 2-11), equilibrium time of sorption process, and maximum N-NO3 sorption capacity of the analysed chitosan sorbents. Kinetics of nitrates sorption was described with pseudo-first and pseudo-second order equations, and with the intraparticle diffusion model. Sorption capacity analysis was conducted with the heterogeneous Langmuir model, the double Langmuir model and the Freundlich model. The optimal pH value of N-NO3 sorption onto CHs-GLA and CHs-ECH was pH 3, whereas onto CHs this was pH 4. The equilibrium time of sorption reaction was the same for all chitosan sorbents and reached 120 min. The maximum sorption capacity of CHs, CHs-GLA and CHs- ECH accounted for 12.71 mg N-NO3/g, 34.99 mg N-NO3/g and 38.47 mg N-NO3/g.