A straw fiber adsorption material, its preparation methods and applications

A preparation method for a straw fiber adsorption material capable of efficiently adsorbing heavy metal and antibiotic composite pollutants is described. The method includes pretreating corn straw cellulose, etherification with epichlorohydrin, crosslinking with ethylenediamine, and grafting of diethylenetriamine pentaacetic acid. Preferably the pretreatment includes crushing and sieving corn straws, soaking in 1mol/L NaOH solution for 24hours, respectively filtering and washing to neutrality, and drying. Etherification may include etherifying 2-5g of pre-treated corn straw with 70-100ml of epichlorohydrin and 60-100ml of N-N dimethylformamide at 70-100ºC for 1-3hours. Crosslinking can include adding 8-15ml ethylenediamine after the etherification has finished, then carrying out crosslinking at 70-100ºC for 1-3hours. Preferably, grafting includes adding 5-15g of diethylenetriamine pentaacetic acid after crosslinking has finished, then grafting at 70-100 ºC for 1-3hours. After grafting, the material can be washed with N-N dimethylformamide, deionized water, saturated sodium bicarbonate and deionized water in turn to neutrality, and then dried. The adsorption material has amino, carboxyl and hydroxyl groups which have been introduced into the fiber surface, as evidenced by SEM-EDS and FTIR. Adsorption experiments show that the modified materials have strong adsorption performance for single and mixed systems of heavy metal cadmium (Cd) and sulfamethoxazole (SMZ) in water.