Coffee grounds waste was used to prepare activated carbon with particle size between 1.18 and 2 mm by
chemical activation with sulphuric acid. The influence of impregnation ratio on physical properties of
activated carbon and removal efficiency of total iron and orthophosphate (PO4–P) was studied. Impregnation
ratio of 0.5 was found optimum for preparing activated carbon with high pore surface area (224.7 m2/g) and
micropore volume (0.07986 cm3/g). Batch experiments were conducted to study the effects of contact time,
pH, particle size and adsorbent dosage. Impregnation ratios of 2.5 and 0.5 were found to be optimum for the
adsorption of total iron and PO4–P, respectively at doses of 10 g and pH 8.1. pH 13 was optimum for iron
removal while pH b5 and N11 was optimum for PO4–P removal. The adsorption capacity increased with
increasing adsorbent dosage for total iron. However, this trend was exceptional for PO4–P with fluctuating
adsorption capacity. The smaller particle size yielded larger adsorption capacity