Using of Adsorbents Produced from Waste Polyethylene Pyrolysis Char in Adsorption of Some Aromatic Hydrocarbon Gases and Recoverability of Waste Adsorbents as Fuel

Abstract

Pyrolysis process is an important process used in the disposal of waste in recent years. The pyrolysis products can be recovered and used in different areas. In addition, the purification of gaseous products is important from an environmental point of view. Within the scope of this study, pyrolysis of HDPE and LDPE-type plastic wastes was carried out. Solid product (char), which has a developed surface structure, was used in the purification of the gas product formed from the same pyrolysis process by adsorption. The pyrolysis chars obtained at 500 ?, 600 ?, and 700 ? temperatures were used as adsorbent with and without chemical activation. According to the results of the BET analysis, the surface area of the cokes with the activation method increased 18 times in HDPE and 70 times in LDPE compared to their non-activated state. Adsorption efficiencies of 60-80% and 40-90% were obtained with HDPE and LDPE cokes. In the adsorption columns formed from pyrolysis chars, the components that HDPE-type activated chars adsorbed with the highest efficiency in the adsorption of pyrolysis gases were toluene, styrene, and ethylbenzene, respectively, at 500 ?, 600 ?, and 700 ?. In LDPE, these components were pentane, octane, and benzene, respectively. With this study, an alternative way to the use of char, which is one of the by-products after the disposal of plastic wastes by the pyrolysis method, was presented, and the purification of pyrolytic gas, another pyrolysis product with known toxic properties, was provided by adsorption method. It is also important to recover the adsorbents (waste adsorbents) used in the adsorption process in accordance with the zero waste approach. The calorific values of these waste adsorbents were investigated and their usability as an alternative fuel to coal was investigated.