Effect of modifying agents on the preparation and properties of the new adsorbents from wheat straw

Three different types of new adsorbents modified from wheat straw were synthesized after the reaction between epichlorohydrin and triethylamine by using ethylenediamine (EDA), diethylenetriamine (DETA) and triethylenetetramine (TETA) as modifying agents. The performance of the modified wheat straws (MWS) was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and elemental analysis. Results showed that the optimal dosages for the three modifying agent (EDA, DETA and TETA) were 3, 4 and 3 ml. The optimum synthesis temperature for the three MWS was 80, 85 and 95 °C, respectively. The IR spectra of the three MWS were analogical, and nitrogen contents of the MWS were found to be consistent with their adsorption capacity. The pseudo-second-order equation generated the best agreement with the experimental data for adsorption systems. In addition, the adsorption process of the three MWS reached equilibrium at 10–15 min. MWS (EDA) demonstrated the largest phosphate capacity than the other MWS.