Identification of different kinds of plastics using laser-induced breakdown spectroscopy for waste management.

Laser-Induced Breakdown Spectroscopy (LIBS) was applied for the identification of various kinds of plastics for management and recycling of plastic waste. In order to fingerprint these plastics, a laser-produced plasma emission was recorded for spectral analysis of various kinds of plastics. The plasma was generated by focusing a Nd:YAG laser radiation at wavelength = 1064 nm having laser energy = 40 mJ. The 6 main family of plastics tested are: Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE), Polypropylenes (PP), Polystyrene (PS), Polyethylene Terephthalate (PET) and Polyvinyl chloride (PVC). The capability of this technique is demonstrated by the analysis of the major constituents carbon and hydrogen present in polymer matrices. The LIBS signal intensity measured for carbon and hydrogen was detrimental for the fingerprinting of various kinds of plastics. The C/H line intensity ratio was 1.68, 1.51, 1.42, 1.16, 1.01 and 0.91 for HDPE, LDPE, PS, PP, PET and PVC respectively. The detection limits of carbon and hydrogen were found to be approximately 6 micro g/g by applying 20 laser shots. The unique features of LIBS are: it is a simple, rapid, remote, real-time analysis without sampling requirements. The study demonstrated that LIBS could be applied as a best tool for sorting out different kinds plastics on a fast scale for waste management. The health hazards of different kinds of plastics are also described.