A novel resourcezation strategy for the alkylphenol distillation residues: From hazardous wastes to high-valued epoxy asphalt materials

The treatment of industrial organic wastes is always a challenge for both the production companies and the environmental protection organizations due to their complexity and hazardousness. Take the alkylphenol distillation residues (APDRs) as an example, it was largely produced in petroleum industry every year but traditionally disposed by incineration or landfill, leading to not only the waste of resources but also the potentially secondary pollution. Herein, a novel sustainable way has been proposed to convert the APDRs into high-valued asphalt additives to replace the commercial cardanol for road construction. Generally, APDRs was added into asphalt, mixed with curing agent, and then reacted with epoxy resin to produce epoxy asphalt. Results showed that, compared with cardanol, the APDRs performed more evenly in dispersing the epoxy resin and asphalt binder, increasing the compatibility between epoxy and asphalt. According to the measurements by fluorescence microscopy and toluene etching-SEM hybrid tests, it is found that the addition of APDRs would cause the phase transition of the epoxy asphalt materials with different concentrations. Under the optimal addition of APDRs (15%), the most improved mechanical properties (the tensile strength was 2.09 MPa and elongation at break was 261.58%) of the epoxy asphalt system are obtained, much higher than the national standards. The mechanistic studies showed that the alkylphenol distillation residues play important roles in reacting with epoxy and asphalt by alkylation and cross-linking during the curing process of epoxy asphalt. In this way, the epoxy and asphalt could be well mixed and interacted, improving the mechanical properties and thermal stability of epoxy asphalt for the road construction. Finally, the economic evaluation for this strategy has been preliminarily conducted, which further proves the feasibility of conversion of APDRs to high-valued asphalt additives. These findings would also shed lights on the development of reproducible and scalable resourcization methods for other similar industrial organic wastes.