Abstract
This research paper presented the optimization of activation Kutigi clay for the adsorption of Cu2+ from aqueous solution using response surface methodology. The Kutigi clay sample was activated with H2SO4 by varying acid concentrations, activation temperature and activation time. X-ray fluorescence (XRF) analysis was carried out before activation in order to know the chemical composition of the clay sample. Response surface methodology was adopted to optimize the activation conditions, with percentage removal of Cu2+ set as the response. Fourier-transform infrared spectroscopy (FT-IR) and Brunauer-Emmett-Teller (BET) surface area analyses were conducted on the clay sample before and after the activation procedure. A total of twenty experimental runs were carried out and the optimal clay activation conditions obtained was 2.5 M acid concentration at 50oC and 75 minutes contact time using Cu2+ percentage removal as the response. At the optimum conditions, a BET surface area of 170.80 m2/g of the activated micro porous adsorbent gives good adsorption capacity of 238.095 mg Cu2+/g adsorbent. The effects of contact time, initial Cu2+ concentration, adsorbent dosage and pH on the activated Kutigi clay adsorption capacity also examined. Freundlich isotherm and pseudo-second-order models best described adsorption of Cu2+ onto the activated Kutigi clay when compared to Langmuir isotherm and pseudo-first order model respectively.

Key words: Adsorption, clay, response surface methodology, optimization, isotherm