Method for preparing heavy metal adsorbent

The invention discloses a method for preparing a heavy metal adsorbent. The method comprises the following steps: firstly carrying out alkali treatment on bagasse to prepare bagasse cellulose; carrying out ultrasonic activation on the bagasse cellulose, and sequentially adding an initiating agent, N,N'-methylene bisacrylamide and acrylic acid for grafting reaction to prepare a graft copolymerization product, wherein the N,N'-methylene bisacrylamide and the acrylic acid are neutralized by an NaOH solution; sequentially washing by using distilled water and absolute ethyl alcohol, drying and crushing to obtain a crude product of the heavy metal adsorbent; and carrying out acetone extraction to obtain the purified heavy metal adsorbent. Compared with the prior art, the preparation method disclosed by the invention has the beneficial effects of crushing and removing the outer layer of a cell wall of a bagasse fiber by carrying out ultrasonic activating treatment on the bagasse fiber, so that the chemical reaction activity of the bagasse fiber is enhanced, the grafting ratio of the grafting reaction is increased and the adsorption property of a product is improved.