Peanut shell (PNS) was used to prepare a novel adsorbent to achieve resource recovery of the agricultural residue. The hydroxyl groups of peanut shell were turned into -C(CH3)(2)-Br pendant groups to initiate polymerization of acrylonitrile. Graft copolymer peanut shell/polyacrylonitrile (PNS-g-PAN) was modified by hydroxylamine hydrochloride to transform the cyano groups into amidoxime (AO) groups. The modified copolymer of AO-PNS-g-PAN was used as adsorbent. The maximum adsorption capacity for Hg(II) was 4.45 mmol g(-1). The adsorption process fitted well the Freundlich isotherm model and followed pseudo-second-order model. The modified copolymer demonstrated its potential as an efficient adsorbent to solve the problem of Hg(II) contamination. The peanut shell (PNS) macroinitiator was obtained by acylation of hydroxyl groups on the cellulose backbone of the peanut shell and initiated by Cu(0)-mediated RDRP of acrylonitrile. PNS-g-PAN was modified by NH2OH center dot HCl and used to remove heavy metal ions. The maximum adsorption capacity of Hg(II) was 4.45 mmol g(-1).