Development of a new compound based on low-density polyethylene degraded with zeolite waste for the removal of diesel from water.

A new adsorbent composite has been developed based on low-density polyethylene and zeolite. This material was used to remove diesel as pollutant in an aqueous system. In the synthesis of the composite and diesel removal were combined these effects: capacity of the zeolite to degrade polyethylene, partial filling of the zeolite with the polyethylene degradation products, favorable thermodynamic interactions between composite-diesel and porosity of the composite (imbibition effect). The term composite is used in the sense that partially degraded-polyethylene oligomers (waxes) are introduced into the zeolite pores in intergranular positions, insuring a good cohesion of waxes and zeolite. The material was synthetized easily by mixing low-density polyethylene and zeolite (1:1) and degraded at 200 °C at three different times: 2, 4 and 6 h. Several techniques as Differential Scanning Calorimeter, Thermogravimetric analysis, Size Exclusion Chromatography and X-Ray Diffraction are combined to study the steps of synthesis and the mechanism of diesel adsorption. The molecular weight obtained at different degradation time varied between 8470 and 99,100, while the molecular weight of the original LDPE was 136,300 g/mol. Diesel removal capacity was determined by TGA through the difference of weight loss at diesel evaporation temperatures (115-275 °C). All the prepared materials presented buoyancy in water and swelling of diesel. Highlighting among them the material prepared at 2 h with a weight loss of 39%, meanwhile the materials prepared for 4 and 6 h presented a weight loss of 29% and 23% respectively, that corresponded to the diesel removed from the water.