Comparison of Activated Carbon and Pyrolyzed Biomass for Removal of Humic Acid From Aqueous Solution

Abstract

The pyrolysis of sewage sludge (SS) and olive mill waste (OMW) was carried out under nitrogen atmosphere and analyzed thermogravimetric and scanning electron microscopy micrographs. Removal capacity of pyrolyzed cokes was measured by humic acid solution. Humic substances can react with chlorine to produce carcinogens in drinking water. Activated carbon can be used as an effective treatment method to remove humic substances from water to prior to disinfection by chlorination. Olive mill waste, an agricultural byproduct and sewage sludge were used to produce activated carbon by pyrolysis with the addition of zinc chloride to enhance the reaction. Activated carbon was also produced using olive mill waste and sewage sludge. Both of them were compared to a commercially-available activated carbon product. Optimum pyrolysis conditions and concentration of the activating agent were identified. The equilibrium parameter model of the Freundlich isotherm and Langmuir isotherm was applied to the adsorption data, and the efficiency of py-rolyzed coke was determined. Activated carbon produced from olive waste material had a lower specific surface area (437.92 m 2 /g) than activated carbon produced from sewage sludge (814.48 m 2 /g). While both of these were lower than the surface area of a commercially activated carbon, the latter fell within the expected range of commercial products, thus suggesting an effective means of producing activated carbon while reducing sewage waste disposal costs.