Adsorption studies of trifluralin on chitosan and its voltammetric determination on a modified chitosan glassy carbon electrode

Journal of the Brazilian Chemical Society

Valentim, Iara Barros¹  Melo, Acácia Maria dos Santos¹  Abreu, Fabiane Caxico de¹  Universidade Federal de Alagoas, Maceió, Brazil¹  Goulart, Marilia O. F.¹ 

关键词: adsorption;    trifluralin;    electroanalytical;    chitosan;   

DOI  :  10.1590/S0103-50532008000400014

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

The studies about adsorption of the herbicide trifluralin (TRF), on chitosan, were carried out by batch methods using temperatures from 298 up to 313 K. The adsorption results were well fitted to Langmuir adsorption model. The obtained enthalpic value of -10.2 ± 0.8 kJ mol-1 confirms that the TRF-chitosan interaction is exothermic and that the adsorption process is relative to electrostatic interaction between the ammonium group of chitosan and the negative dipole of the substituent groups of TRF, being dependent on ionic strength. Voltammetric studies showed that TRF exhibited two irreversible, diffusional reduction waves related to the reduction of the nitroaromatic groups. The current of the first reduction peak intensified on the chitosan-modified glassy carbon electrode in comparison with the unmodified one. This was attributed to the adsorption/accumulation of TRF on chitosan. The reduction current, using Differential Pulse Voltammetry, was proportional to the concentration of TRF in the range of 2.49 ×10-7 to 5.79 ×10-6 mol L-1, with a detection limit of 7.45 × 10-8 mol L-1.

【 授权许可】

Unknown