Preparation Of Spongeous Adsorbents Composed Of Polypyrrole/Corncob-Corefor Cr(Ⅵ) Removal In Water

As a kind of natural renewable resources, the corn core is a kind of polymer, which has a certain number of active groups, and which can be used as an adsorption site for the complexation of metal ions.As one of the famous conducting macromolecules, Polypyrrole is applied extensively in water treatment, This should be attributed to its large adsorption capacity and selectiⅥty.In this paper, we prepared poly-pyrrole/corncob granular materials,and the application of PPy/Corncob Granular Materials for Cr（Ⅵ） ions removal in aqueous solution is also explored.In this experiment, Polypyrrole was prepared by FeCl₃ oxidation method,and Polypyrrole was fully grown on the core of corn. The material was characterized by SEM, XPS, FTIR and other analytical methods, the surface morpHology of the adsorbent was observed, the composition of the adsorbent andon the phase composition was studied. The results showed that the adsorbent could be successfully modified by using the modified corn core. In this experiment, we investigated the factors that affect the preparation of the composite adsorbent and determined the optimum preparation conditions of the composite adsorbent. It show’s that: the best conditions for the preparation of Polypyrrole modified corn core was that the corn cob particle diameter is greater than or equal to 5mm, the mass ratio of the monomer to the corn core was 1:1, and the molar ratio of FeCl₃ to the monomer was 1:1.The prepared adsorbent will be used for the adsorption of Cr（Ⅵ） in water. We examine the different conditions such as the effect of Cr（ Ⅵ） solution initial concentration, initial pH value, different concentrations of equilibrium time, temperature and coexisting ions on the adsorption properties of the composite adsorbents.The results showed that when the dosage of adsorbent was 3.0g/L, the initial pH=3.5, and the normal temperature, the adsorption process was most economical and efficient, and the maximum adsorption capacity was 84.7mg/g.The experimental data were fitted with the kinetic（the quasi first order kinetics, the quasi two level dynamics and the particle diffusion） and isothermal model（Langmuir isotherm model and Freundlich isotherm model respectively）.The results showed that the adsorption process is monolayer adsorption process, and the chemical adsorption. It not only has the ion exchange but oxidation reduction process. The Cr（Ⅵ） is reduced to trivalent chromium by some functional groups of the adsorbent, and then the trivalent chromium is formed by the complexation with a functional group.We simulated electroplating wastewater containing chromium, and adsorption experiments were carried out,also we carried out the experiment of desorption and regeneration to study the performance of the adsorbent.Results showed that the adsorption agent has good selective adsorption of Cr（Ⅵ） in water and the adsorption capability of Polypyrrole Modified Corn Cob core to Cr（Ⅵ） almost did not change after recycling three times.It’s repeatability is very good. The adsorption agent has good engineering application prospect.