Recovery of Valuable Chemicals from High Density Polyethylene (HDPE) Polymer: a Catalytic Approachfor Plastic Waste Recycling

Abstract

A high density polyethylene (HDPE) polymer was catalytically degraded using two sulfate modified Zirconium catalysts in a fixed-bed reactor at 400OC with the aim of converting plastic wastes to obtain valuable and recyclable liquid products. The TGA results revealed that the onset of degradation was moved from 420OC for HDPE alone to less than 300OC in the presence of the catalysts. The catalysts improved the polymer degradation by achieving high conversion of about 99.8%. The two catalysts appeared to promote different product composition. CAT1 (7%SO3) was more selective to higher gaseous products (68%) and liquid (32%) of mainly aromatics, whereas CAT2 (3.5%SO3) promoted high liquid products (about 53%) of mainly olefinic compounds. It can be concluded that the catalysts can be used for catalytic conversion of plastic wastes to obtain valuable products, most especially CAT2 (3.5%SO3) which gave high liquid content that is composed of mainly olefinic, naphthenic and paraffinic compounds whose carbon number distribution is within the gasoline range. Thus, catalytic conversion using these catalysts may be use as an alternative method for recycling plastic wastes to more valuable and renewable energy sources