Study on Pre-irradiation Grafting Acrylic Acid and Acrylamide Onto Ramie Fiber and Its Adsorption Performance for Copper Ions

Acrylic acid (AA) and acrylamide (AM) were synergistically grafted onto ramie fiber by pre-irradiation for improving grafting rate. Adsorption performance of the grafted ramie fiber for copper ions was studied. The results with Fourier infrared spectroscopy (FT-IR) surface analysis show that AA and AM are successfully grafted onto ramie fiber. The grafting rate attains 151% under the absorbed dose of 35 kGy with AA and AM concentration ratio 1∶1. And the results with adsorption condition experiment analysis show that at beginning of the adsorption reaction, the copper ions adsorption capacity of grafted ramie fiber increases rapidly, between 20 and 30 min decreases, after 30 min the adsorption reaction tends to saturation. Adsorption capacity increases rapidly with temperature, but when the temperature is higher than 40 ℃, the adsorption capacity no longer increases. The adsorption capacity increases with the initial concentration of CuSO₄. In the solution of the initial concentration of 1 000 mg/L of CuSO₄, the copper ions adsorption capacity of the grafted ramie fiber reaches 14.40 mg/g.