“…Alternative adsorbents were investigated in search for an effective low-cost technology for the treatment of Cr (VI). Bioadsorbents, e.g., brewers draff, grape waste, peat moss, sawdust, fruit peel [4,5] and nature materials, such as akadama clay, sawdust, and parthenium hysterophorus weed [6][7][8] were used due to low-cost, local availability and minimal pre-treatment requirements but the efficiency for Cr (VI) removal is relatively low with equilibrium adsorption capacity smaller than 50 mg L À1 ; Modified natural materials, e.g., modified lignocellulosic materials, activated alumina, organo-bentonite and chitosan [9][10][11][12], are common Cr (VI) adsorbents as well. Active carbon is a widely utilized absorbent in Cr (VI) adsorption for its large volume of micropores and mesopores, providing a high surface area and having high chemical and thermal stability [13][14][15].…”