Synthesis And Application Of Polyamine Grafted Chitosan Copolymer

In order to further improve coordination ability of chitosan (CS) and synthezize novel chitosan material with two functions of adsorbing heavy metal ion and inhibiting metal corrosion, CS was grafted with polyamine group of complex function, ethylene diamine grafted CS copolymer (CS-MAA-EN) and triethylene tetramine grafted CS copolymer (CS-MAA-TN) were synthesized. The CS grafting copolymer were characterized by FTIR spectra. The adsorption performance of Cu(II) in industrial wastewater and anticorrosive performance for Q235 carbon steel in dilute hydrochloric acid medium were studied, respectively.The study of CS-MAA-EN and CS-MAA-TN for removal of Cu(II) ion from aqueous solutions are as follows:firstly, the effect of pH, adsorbent dosage and initial metal concentration and so on were investigated to study adsorbing effect of adsorbing effect of CS-MAA-EN and CS-MAA-TN for removal of Cu(II) ion from aqueous solutions, the data was fitted to the Langmuir and Freundlich isotherm model at temperatures of 25℃. The Langmuir model gave the best fit for both adsorbent, which belonging to adsorption of single molecule layer surface. Sencondly, Equilibrium absorption capacity of CS-MAA-EN and CS-MAA-TN were 85.91mg/g and 102.67mg/g, respectively. The adsorption isotherm types were better described by second-order Lageren equation than first-order Lageren equation. Thirdly, two adsorbents have excellent desorption and regeneration rate, CS-MAA-EN desorption rate and regeneration rate was 95.2% and 89.35%, respectively, CS-MAA-TN desorption rate and regeneration rate were 92.73% and 83.25%, respectively. Lastly, the competitive adsorption order of two adsorbents in mixed metal ions followed by Fe(Ⅲ),Cu(Ⅱ),Cr(Ⅵ), Ni(Ⅱ) and Zn(Ⅱ), which indicating that they still have a high selectivity for Cu(Ⅱ) in mixed metal ions aqueous solutions.The method of weight loss and electrochemical test were used to analyzed the anticorrosive performance for Q235 carbon steel in dilute hydrochloric acid medium.Firsrly, in static coupon experiments, CS-MAA-EN had the best inhibition efficiency among CS, CS-MAA-EN and CS-MAA-TN at the mass fraction of 0.1%, the corrosion rate of CS-MAA-EN was 90.34%,Sencondly, electrochemical tests found that CS-MAA-EN had the minimum corrosion current density and maximum charge mobile resistance in Tafel polarization curve and alternating-current impedance (EIS) tests, respectively, which coincided with the conclusion of weight loss experiment. In addition, concentration of corrosion inhibitor for carbon steel was investigated to corrosion performance by EIS test. The results discovered that inhibition efficiency fluctuated with concentration of corrosion inhibitor, this showed that concentration of corrosion inhibitor in corrosion inhibitor performance had certain extreme value, when exceeding a certain concentration range, the inhibition efficiency was descending.