“…The most widely used methods for removing heavy metals are chemical or electrochemical precipitation, both of which pose a significant problem in terms of disposal of the precipitated wastes [4,5], and ion-exchange treatments, which do not appear to be economical [6]. It has been reported that some aquatic plants [7,8], wood materials [9][10][11], agricultural by-products [12], clay [13], natural zeolite [14], turba (partially decomposed vegetable matter) [15,16], microorganisms [17][18][19], and other low-cost adsorbents [20] have the capacity to adsorb and accumulate heavy metals.…”