Thermal Desorption of Contaminated Marine Sediments: Analysis of Performance Under Low-Temperature Process Conditions

Sediments play a crucial role in the marine ecosystem by serving as both a sink for pollutants from human activities and a medium of exchange with aquatic environments and organisms. Chemical contaminants such as heavy metals and hydrocarbons pose significant risks due to their potential for bioaccumulation. As a result, treating marine sediments is often necessary. The present study reports the results of the experimental activities aimed at evaluating the removal performance achievable with a Low-Temperature Desorption Treatment (LTDT) on contaminated marine sediments. An LTDT was simulated by means of a lab-scale plant, with the aim of optimizing recalcitrant organic pollutant removal, evaluated by the analysis of the residual concentration of total petroleum hydrocarbons (TPH) in the sediments by varying the treatment temperature (200, 350, and 500 °C) and contact time (10, 15, and 20 min). The evolved vapors were recovered by means of an off-gas condenser system that allowed mass balances to be performed and the volatile organic compound recovery efficiency to be evaluated. Two different biochars were tested as innovative adsorbent materials, achieving a contaminant removal between 97 and 99%.