Recycling of Tetra pak wastes via pyrolysis: Characterization of solid products and application of the resulting char in the adsorption of mercury from water

Abstract

This paper provides a detailed analysis of the recycling of Tetra Pak waste via pyrolysis to recover the most valuable solid products within its composition, char and aluminum, and the subsequent application of the char in the adsorption of mercury in aqueous solutions. The impact of the Tetra Pak pyrolysis conditions on the char and aluminum yields and their associated properties have been analyzed using a variety of physico-chemical techniques. Tetra Pak-derived chars showed outstanding mercury adsorption properties (up to 215.7 mg/g) that can be attributed to the heterogeneous surface chemistry composed mainly by oxygenated functional groups associated to C, Ca, Al and Si. Tetra Pak pyrolysis allowed an effective recovery of aluminum at pyrolysis temperatures of 600 and 800 °C. Higher temperatures, up to 1000 °C, promote its oxidation to aluminum oxide and hydroxide. These findings contribute to increase the versatility in the Tetra Pak reuse to develop new adsorbents with promising performance for water treatment and the associated recovery of aluminum for further industrial applications. • New adsorbents for mercury removal were obtained from Tetra pak pyrolysis. • Tetra pak pyrolysis produced aluminum with different composition of oxide and hydroxyde. • Tetra pak-derived chars are outstanding adsorbents for mercury removal.