Investigation of the adsorption capacity of olive-waste cake activated carbon for removal of metribuzin from aqueous solutions

• DOI: 10.1007/s13762-021-03728-x
• Publication Date: 2021-10-19T02:51:21Z
• Authors: D. Angin; A. Ilci
• Keywords: Langmuir adsorption model; Endothermic process; BET theory; Carbon fibers; Specific surface area; Physisorption

In the first step of this study, activated carbon was produced from the olive-waste cake, which is a solid waste of the olive oil industry, at different activation temperatures by the chemical activation method. The effect of activation temperature on the surface and chemical properties of activated carbon was investigated. For this purpose, the porous structure and surface chemical composition of obtained activated carbons were characterized by proximate analysis, BET surface area, elemental analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The highest surface area of activated carbon was found as 1418 m2 g−1 at 800 °C activation temperature. The elemental and fixed carbon contents of activated carbon obtained at this temperature were 87 wt% and 86 wt%, respectively. In the second stage, adsorption potential of the activated carbon having the highest surface area was investigated for metribuzin removal from aqueous solutions. Metribuzin adsorption experiments showed the best removal performance at the original pH of 9.20 using an adsorbent dosage of 0.2 g for 100 ml solution. Experimental data of metribuzin adsorption on activated carbon fits the pseudo-second-order kinetic model with a maximum adsorption capacity of 144.93 mg g−1 at 318 K. It was defined as homogeneous and monolayer adsorption in accordance with the Langmuir isotherm model. Thermodynamic parameters showed that the adsorption was suitable, spontaneous, and endothermic. This study showed that activated carbon produced from the olive-waste cake by chemical activation could be used as an effective adsorbent for the removal of herbicide from aqueous solutions.