Chromium (VI) is environmentally mobile owing to its high solubility in water. Its pollution is largelyrnattributed by discharge of inadequately treated effluents of chrome utilizing industries. Discharges ofrnsuch effluents pose a potential threat to human health unless are treated properly before its disposal.rnAdsorption using activated carbon prepared from biomaterials is a new technology for the treatment ofrnheavy metals rich industrial effluents. Opuntia Ficus Indicus (OFI) activated with H3PO4 (45%) wasrnevaluated for Cr (VI) removal capability from both synthetic and tannery waste water. The present workrnwas aimed at assessing the biosorbent capability of OFI in removal of Cr (VI) from synthetic aqueousrnsolution and tannery waste water. OFI was activated with H3PO4 (45%) and carbonized at 450rnornC in rnmuffle furnace for 1hr and its different physical properties such as bulk density and moisture contentrnwas determined. Besides; the sorbent characterized by FTIR spectroscopy test analysis before and afterrnadsorption processes, suggested possible key contributions of hydroxyls and carboxyls in thernsequestering of Cr(VI) on OFI. Maximum Cr(VI) removal efficiency of 99.5% was achieved by OFIrnunder different study parameters. The percentage removal of Cr (VI) ions increased with increase of thernamount of sorbent concentration for which the Optimum removal of Cr (VI) was observed at sorbentrndose of 125 mg. The adsorption efficiency of Cr (VI) on OFI was increased at low pH values between 2rnand 3, attending its optimum at pH of 2. Percentage removal was observed to increase, while decreasingrnthe initial concentration of Cr (VI) to which 6mg/l was the minimum of adsorption system. Whereas; thernremoval was increased with increasing the agitating speed and its corresponding contact time, whereby;rnthe optimal adsorption reached at 60 minutes at 150rpm agitating speed. Both Langmuir and Freundlichrnmodels and followed adsorption process with high regression correlation coefficient (Rrn2rn) values of 0.999 rnand 0.956 respectively. But, Langmuir isotherm with higher Rrn2rnwas best fitted to the experimental values, rnwith monolayer adsorption capacity of 4.587mg/l. Besides; the RL values were obtained in range of 0