Utilization of Activated Carbon for the Removal of Ni Metal from Industrial Liquid Waste

Abstract

Environmental pollution caused by toxic metals seems to occur globally. Metal intoxicated wastewater can be challenging to health safety. The high concentration of pollutants is required to be removed before the discharge of wastewater into open waste streams. The present study relates the monitoring of heavy metals in the industrial waste coming from Shairshah, Lyari SITE industrial area and control sites selected from Clifton beach of Karachi (Pakistan). Concentrations of selected trace metals, Cr, Fe, Hg, Na, K, Cd, Pb, Ni, Zn, Mo, Mn and Cu were estimated by using Atomic Absorption Spectrophotometer, Flame Photometer and 200 Multi parameter Ion Specific Meter under standard analytical conditions. Statistical methods of relevance were applied to check the accuracy of the system. Selective removal of Ni metal from waste water was carried out by adsorption process using activated carbon prepared from agricultural waste. The effectiveness of the adsorption process has been tested under the optimized conditions of temperature, concentration, stay time and amount of adsorbent. Adsorption isotherm models like Freundlich and Langmuir were applied to determine the feasibility of process by finding the values oftheir respective constants. The R values show that Langmuir model was the best fitted adsorption model. The feasibility of adsorption process was determined by RL factor. Thermodynamic parameters such as free energy (ΔG ), enthalpy (ΔH ) and entropy (ΔS ) of the system were calculated. The sorption free energy (Es) was also estimated. The pHpzc of adsorbent was also estimated by adopting pH drift method. The percentage removal and distribution coefficient (KD) values for Ni removal were also determined. The present system represents that Ni and other metals can be effectively removed by employing adsorption method using low cost natural adsorbents.