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In the present study, feasibility of the selective surface hydrophilization of polyvinyl chloride (PVC) by microwave treatment was evaluated to facilitate the separation from automotive shredder residue (ASR), by the froth flotation. The combination of 60 sec microwave treatment with PAC, a sharp and significant decrease about 16.5° contact angle of PVC was observed in ASR plastic compared with other plastics. The microwave treatment with the addition of PAC resulted in a synergetic effect for the froth flotation, which may be a result of the 90% selective separation of PVC from ASR plastics, with 82% purity. While, simple mixing with a nanometallic Ca/CaO/PO4 dispersion mixture immobilized 95-100% of heavy metals in ASR soil/residues. The quantity of heavy metals leached from thermal residues after treatment by nanometallic Ca/CaO/PO4 was lower than the Korean standard regulatory limit for hazardous waste landfills. Microwave treatment can be a simple and effective method for PVC separation from ASR plastics., {"references":["Solving the E-Waste Problem (StEP) Initiative, StEP E-waste World\nMap. (2014) http://www.step-initiative.org/step-e-waste-worldmap.\nhtml","C. P. Balde, R. Kuehr, K. Blumenthal, S. Fondeur Gill, M. Kern, P.\nMicheli, E. Magpantay, J. Huisman (2015), E-waste statistics: Guidelines\non classifications, reporting and indicators. United Nations University,\nIAS - SCYCLE, Bonn, Germany. (2015)","Y. C. Jang, Waste electrical and electronic equipment (WEEE)\nmanagement in Korea: generation, collection, recycling systems, J.\nMater. Cycles Waste. Manag. 12 (2010) 283–294.","Korea Ministry of Environment (Korea MOE) (2007) The Act on the\nResource Recycling of Waste Electrical Electronic Equipment (WEEE)\nand End-of-life Vehicles (ELVs), The Ministry, Gwacheon.","T. Takoungsakdakun, S. Pongstabodee, Separation of mixed\npost-consumer PET-POM-PVC plastic waste using selective flotation,\nSep. Purif. Technol. 54 (2007) 248-252.","S. Moriwaki, M. Machida, H. Tatsumoto, Y. Otsubo, M. Aikawa, T.\nOgura. Dehydrochlorination of poly(vinyl chloride) by microwave\nirradiation. Applied Thermal Engineering 26 (2006) 745–750.","M. Ito, K. Ushida, N. Nakao, N. Kikuchi, R. Nozaki, K. Asai, M. Washio.\nDechlorination of poly (vinyl chloride) by microwave irradiation I:A\nsimple examination using a commercial microwave oven. Polymer\nDegradation and Stability 91 (2006) 1694e1700.","Bacalogulu R., Fish MH, Kaufhold J., Sander H. J. In: Zweifel H., editor.\nPlastics additives handbook. Cincinnati: Hanser Gardner Publications;\n2001. p. 427 (chapter 3).","D. A. Jones, T. P. Lelyveld, S. D. Mavrofidis, S. W. Kingman, N. J.\nMiles. Microwave heating applications in environmental engineering—a\nreview. Resources, Conservation and Recycling 34 (2002) 75–90.\n[10] J. A. Menéndez, A. Arenillas, B. Fidalgo, Y. Fernández, L. Zubizarreta,\nE. G. Calvo, J. M. Bermúdez. Microwave heating processes involving\ncarbon materials, Fuel Processing Technology 91 (2010) 1–8.\n[11] Y. Mitoma, S. R. Mallampati, H. Miyata, M. Kakeda, Decomposition of\nPolychlorinated Biphenyls in Soil With a Dispersion Mixture of Metallic\nCalcium and Calcium Oxide, Arch. Environ. Contam. Toxicol. 64 (2013)\n180–186.\n[12] Mallampati S. R., Mitoma Y., Okuda T., Sakita S., Kakeda M. (2012a)\nHigh immobilization of soil cesium using ball-milling with nano-metallic\nCa/CaO/NaH2PO4: implications for the remediation of radioactive soils.\nEnviron Chem Lett 10:201–207.\n[13] Mallampati, S. R., T. Okuda, Y. Mitoma, S. Sakita, and M. Kakeda.\n2012b. Enhanced heavy metal immobilization in soil by grinding with\naddition of 595 nanometallic Ca/CaO dispersion mixture. Chemosphere\n89:717–723. doi:10.1016/j.chemosphere.2012.06.030.\n[14] M. S. Reddy, T. Okuda, K. Kurose, T. Y. Tsai, S. Nakai, W. Nishijima,\nM. Okada, Surface ozonation of polyvinyl chloride for its separation from\nwaste plastic mixture by froth flotation, J. Mater. Cycles. Waste., 12\n(2010) 326-331.\n[15] T. Okuda, K. Kurose, W. Nishijima, M. Okada, Separation of polyvinyl\nchloride from plastic mixture by froth flotation after surface modification\nwith ozone, Ozone-Sci. Eng., 29 (2007) 373-377.\n[16] Regulatory of waste management (Ministry of Environment Report,\nSeoul, Republic of Korea) (2000) 2-5."]}

Wet gravity separation technique has been regularly practiced to separate the polypropylene (PP) and polyethylene (PE) (light plastic films) from chlorinated plastic films (CP films) (heavy plastic films). The CP films including poly vinyl chloride (PVC) and poly vinylidene chloride (PVDC) would float in water even though its density is more than 1.0g/cm(3). This is because films are twisted in which air is sometimes entrapped inside the twisted CP films in real existing recycling plant. The present research improves the current process in separating the PP and PE from plastic packaging waste (PPW), by reducing entrapped air and by increasing the hydrophilicity of the CP films surface with ozonation. The present research also measures the hydrophilicity of the CP films. In ozonation process mixing of artificial films up to 10min reduces the contact angle from 78° to 62°, and also increases the hydrophilicity of CP films. The previous studies also performed show that the artificial PVDC films easily settle down by the same. The effect of ozonation after the wet gravity separation on light PPW films obtained from an actual PPW recycling plant was also evaluated. Although actual light PPW films contained 1.3% of CP films however in present case all the CP films were removed from the PPW films as a settled fraction in the combination process of ozonation and wet gravity separation. The combination process of ozonation and wet gravity separation is the more beneficial process in recovering of high purity PP and PE films from the PPW films.

Selective surface modification of polyvinyl chloride (PVC) by ozonation was evaluated to facilitate the separation of PVC from other heavy plastics with almost the same density as PVC, especially polyethylene terephthalate (PET), by the froth flotation process. The optimum froth flotation conditions were investigated, and it was found that at 40°C, 90% of PVC and PET plastics floated. The bubble size became larger and the area covered with bubbles on the plastic surface was reduced with increasing temperature. Optimum PVC separation was achieved with the flotation solution at 40°C and mixing at 180–200 rpm, even for sheet samples 10 mm in size. Combined treatment by ozonation and froth flotation is a simple, effective, and inexpensive method for PVC separation from waste plastics.

This study describes the possible separation of chlorinated plastic films (PVC and PVDC) from other heavy plastic packaging waste (PPW) by selective twist formation and gravity separation. Twists formation was mechanically induced in chlorinated plastic films, whereas twist formation did not occur in PS and PET films. After twist formation, all the films had the apparent density of less than 1.0 g/cm{sup 3} and floated in water even though the true density was more than 1.0 g/cm{sup 3}. However, the apparent density of the PS and the PET films increased with agitation to more than 1.0 g/cm{sup 3}, whereas that of chlorinated plastic films was kept less than 1.0 g/cm{sup 3}. The main reason would be the air being held inside the chlorinated plastic films which was difficult to be removed by agitation. Simple gravity separation after twist formation was applied for artificial film with 10 wt.% of the chlorinated films and real PPW films with 9 wt.% of the chlorinated films. About 76 wt.% of the artificial PPW films and 75 wt.% of real PPW films after the removal of PP and PE were recovered as settling fraction with 4.7 wt.% and 3.0 wt.% of chlorinated plastic films, respectively.more » These results indicate that simple gravity separation process after twist formation can be used to reduce the chlorinated plastic concentration from mixed heavy PPW films.« less

Many industrial effluents contain occasionally various toxic elements. Many a time, bromide forms a constituent of the effluents especially originating from coastal regions. Plant materials have been effectively employed as tools to remediate this situation. Some halophytes are the best choice for reducing the toxic levels from affected salanised soils. This paper deals with the bromide uptake and its accumulation effect on the growth of Salicornia brachiata, Suaeda nudiflora, and Salvadora persica, the common halophyts of Indian coast. The species were grown with NaBr solution along with other essential nutrients. The growth in S. brachiata, S. nudiflora, and S. persica was more or less same except for some apparent morphological differences in NaBr grown plants as compared to that in NaCl-fed plants. The bromide present in various parts of these plants was determined by simple and eco-friendly techniques for the first time. A reliable spectrophotometric method was developed and employed to estimate the bromide composition in all plant extracts. The bromide levels were about 0.086–0.2 g in the root, 0.175–0.443 g in stem and 0.287–0.432 g in leaves per g of dry plant material and at higher levels it affected the photosynthetic activity. Cultivation of these plants for reclamation of bromide affected soils has been advocated as an alternative.

The present study focused on the selective recovery of poly(vinyl chloride) (PVC)-free polymers from automobile shredder residue (ASR) polymers by ozonation and froth flotation. Three different heavy ASR polymer samples were used. Appropriate alkaline washing was done as a pretreatment for the removal of the pollutants from the ASR polymer surface. The samples grinded by two different methods (two-shaft shear shredder and single-shaft rotary grinder) were compared for the behavior of PVC in the froth flotation. Ozonation with pre-washed by alkaline solution of PVC polymer in ASR has been found to significantly modify the hydrophilicity when compared to PVC polymer without pre-washing with alkaline solution. Whereas, alkaline washing did not change the surface hydrophobicity of other heavy polymers. It is found from the results that ozonation (with alkaline washing) has changed the contact angle of PVC from 80.7° to 55.7°, 82.4° to 59.1° and 82° to 59.6°, whereas little decrease of the contact angle was observed on other heavy ASR polymers. This result indicates that 93.5–96.4% PVC-free ASR polymer was successfully recovered with less than 0.1–0.2% of PVC by the froth flotation after ozonation in different ASR compositions. Ozonation with pre-washed by alkaline solution of ASR has significantly improved the PVC purity.

The purpose of this study is to develop froth flotation to separate polyvinyl chloride (PVC) from automobile shredder residue (ASR) plastic mixtures of variable composition. Some polymers in ASR polymer mixtures have similar density and hydrophobicity with PVC and thus selective flotation of PVC from ASR polymer mixtures cannot be achieved. The present study focused on the surface modification of PVC with ozonation, and then the modified PVC can be separated from other polymers by the following froth flotation. The results of this study indicate that the selective recovery of PVC from real ASR polyethylene tetra pethelate (PET), polymethyl methacrylate (PMMA), polybutyl methacralate (PBMA), ethyl acrylate (EA), polycarbonate (PC) and rubber mixtures can be accomplished in a three-step process involving a gravity separation, ozonation and froth flotation. The rubber was removed from other heavy ASR (PVC, PET, PMMA, PBMA, EA and PC) polymers by froth flotation without mixing. It was found that ozonation process produced the desired difference in contact angle required (from 89.5 to 73.0 degrees ) for separation of PVC from other heavy ASR polymers, whereas the contact angles of other polymers was slightly decreased. The most of the load ASR, i.e. about 72.4% is floated away and 27.6% was settled down. The highest component 96.7% of PVC was recovered in the settled fraction. As a result of this research effort, the surface modification of PVC with ozonation can be efficiently useful to separate the PVC from other similar density ASR mixed polymers.

In recent years, environmental nanotechnology has risen to the forefront and the new properties and enhanced reactivates offered by nanomaterial may offer a new, low-cost paradigm to solving complex environmental pollution problems. This study assessed the synthesis and application of multi-functioned nano-size metallic calcium (nMC) composite for detoxification of hazardous inorganic (heavy metals (HMs)/organic chlorinated/brominated compound (CBCs) contaminants in automobile shredder residue (ASR). ASR residues ball milled with nMC composite can achieve about 90-100% of HMs immobilization and CBCs decomposition. The results highlight the low quantity of HMs leached from ASR residues after treatment with nMC, which was found to be lower than the standard regulatory limit for hazardous waste landfills. The use of nMC composite in a mechanochemical process to treat hazardous ASR (dry conditions) is a simple and innovative approach to remediate hazardous inorganic/organic cross-contaminates in ASR., {"references":["L. Ciacci, L. Morselli, F. Passarini, A. Santini, I. Vassura: Inter. J. Life Cycle Ass. 15 (2010) 896–906.","G. Mancini, P. Viotti, A. Luciano, D. Fino: Waste Manag. 34 (2014) 448–457.","S. R. Mallampati, Y. Mitoma, T. Okuda, S. Sakita, C. Simion: Environ. Sci. Pollut. Res. 21(2014) 9270-9277.","J. Boisson, A. Ruttens, M. Mencha, J. Vangronsveld: Environ. Pollut. 104 (1999) 225 - 233.","R. X. Cao, L. Q. Ma, M. Chen, S. P. Singh, W. G. Harris: Environ. Pollut. 122 (2003) 19 - 28.","S. Raicevica, T. K. Radoicicb, A. I. Zouboulisc: J. Hazard. Mater. 117 (2005) 41 - 53.","A. Polettini, R. Pomi, P. Sirini, F. Testa: J. Hazard. Mater. 88 (2001) 123 - 138.","H. Okuno, B. Yim, Y. Mizukoshi, Y. Nagata, Y. Maeda: Ultrason Sonochem. 7(2000) 261–264.","K. Miyoshi, T. Nishio, A. Yasuhara, M. Morita, T. Shibamoto: Chemosphere 55 (2004)1439–1446.\n[10]\tC. H. Lee, N. T. T. Truc, B. K. Lee, Y. Mitoma, S. R. Mallampati: J. Hazard. Mater. 296 (2015) 239–247.\n[11]\tS. R. Mallampati, B. H. Lee, Y. Mitoma, C. Simion: Environ Sci Pollut Res, 2016: DOI 10.1007/s11356-016-7458-7.\n[12]\tS. R. Mallampati, C. H. Lee, N. T. T. Truc, B .K. Lee: International Scholarly and Scientific Research & Innovation, 9 (2015) 1414-1417."]}