Activated carbon has been prepared from sewage sludge of the municipal wastewater treatment plant using chemical activation method. Porous structure of activated carbon was characterized by nitrogen adsorption and scanning electron microscopy. It was also characterized by its surface area and porosity. Its surface is an irregular and porous structure. Then it was used as an adsorbent for the removal of nickel ions from aqueous solution. The effects of parameters such as contact time and initial nickel ion concentration were investigated. The adsorption kinetics of nickel ions in aqueous solution onto activated carbon was investigated through experimental data. The results showed that the adsorption process was perfectly fitted to the pseudo-second order model with very high regression coefficient. It may be evaluated as an environmental friendly and extra economic treatment of nickel ions in aqueous solution.

For many years, especially in emerging nations like India, the environment has been threatened by the increased output of industrial wastes and heavy metal toxicity. The usage of inexpensive adsorbents has recently attracted a lot of attention in studies on the removal of heavy metals like nickel from industrial wastewater. The use of agro-based adsorbent is an alternative to conventionally used activated charcoal. In this research, adsorption experiments were carried out using agro-based adsorbent prepared from rice husk, wheat husk, and soybean husk to reduce nickel from industrial wastewater. The adsorption process is simple, economical, and effective is the most preferred method used for the removal of toxic metals like nickel from industrial wastewater. Adsorbents prepared from these husks can be effectively used for adsorption due to low cost & high availability. Characterization of agricultural material by various tests like XRF, proximate analysis, bulk density, and iodine number was conducted on agro-based adsorbents to know the co-relation between removal efficiency and adsorption capacity. The effect of turbidity and pH parameters on Ni removal efficiency is also studied. Results indicated that wheat husk adsorbent appeared to be the most effective for the adsorption of Ni from wastewater as compared to soybean husk and rice husk adsorbent. Wheat husk, soybean husk, and rice husk have removal efficiency in the range of 62.50 to 73.33. Composite absorbents CA-2 with the proportion of 50% wheat husk, 33% soybean husk, and 17% rice husk have 82.50% efficiency, and CA-3 has 80.83% efficiency in removing Nickel. Wheat husk adsorbent, CA-2, and CA-3 are more effectively and sustainably used for the treatment of industrial wastewater to remove heavy metals.