Abstract

KINETICS OF HEAVY METAL (Cr & Ni) REMOVAL FROM THE WASTEWATER BY USEING LOW COST ADSORBENT

T. Brahmaiah, L. Spurthi, K. Chandrika, S. Ramanaiah, and K. S. Sai Prasad*

ABSTRACT

Heavy metal toxicity due to industrial wastewater has been a threat to the environment for the past many decades, especially in the developing countries such as India, China and Thailand where cost effectiveness of the removal process is a major factor. In this research, the effectiveness of two natural adsorbents, untreated and treated rice straw (RS), which are cheaply available in these countries for the removal of Chromium metal from synthetic wastewaters were studied. Adsorption experiments were carried out using rice straw as an agricultural residue to adsorb some heavy metals like Cr and Ni from aqueous solution. Rice straw was treated with two different methods like acid treatment and alkali treatment in order to increase their metal- binding capacity. The adsorption process is affected by various parameters such as such as adsorbent dose, pH and contact time are of vital importance. Adsorption equilibrium data was well fitted with Lagergren second order kinetics for both untreated and treated rice straw as adsorbents. This indicates that the rate limiting step may be chemical sorption rather than diffusion.

Keywords: Rice Straw (RS), Adsorption, Sodium Hydroxide, Kinetics.