The distributions of nickel adsorbed on peat and the effect of pH were studied using sequential extraction procedures proposed by Tessier and Yang Chongjie respectively.It's indicated by Tessier's sequential extraction procedure method that the nickel adsorbed on peat exits as exchangeable speciation mostly

which means that the peat adsorbs nickel mainly by ion exchange.And it's indicated by Yang Chongjie's sequential extraction procedure that the nickel adsorbed on peat exits as exchangeable and presentable speciation mostly

which means that the nickel and peat are combined with ion exchange and complexation.Analysis shows that the adsorption mechanism changes with the variance of pH value.