Collecting carpets

The plant faced many of the same issues that the Evergreen facility did, except that it could handle 100% of the collected carpet. The system was hampered by the differences in construction of European carpet compared to US carpet, which yielded a much lower amount of nylon 6 per lb of collected carpet. 

Ny lon-6 (108 g) carpet backed with calcium-carbonate-filled latex and polypropylene was charged to a 1000-mL three-neck round-bottom flask (equipped with a condenser) with 6 mL of 85% phosphoric acid. Superheated steam was injected continuously during a 45-min period. The vapor temperature of the reaction medium was 250-300°C. The volume of distillate collected was 1065 mL. The distillate contained 1.9% e-caprolactam (as determined by GC), which corresponded to a crude yield of 37.5%. The distillate was fractionated in a distillation column and the nonaqueous phase removed. The remaining aqueous phase was treated with 2% potassium permanganate at 40-50°C for 2 h. Evaporation of... 

This paper describes DuPont s very successful progress in the chemical recycling of nylon carpets by a patented ammonolysis process. Each stage of the process is described, from the collection of old and dirty used carpets, right through to the production of high-purity monomers. 

Traditionally carpet tile backings have been made from bitumen, PVC or polyurethane. There are problems with the environmental impact of these materials and they are difficult to recycle. Shaw industries developed their EcoWorx carpet tile backing using a polyolefin resin. This has superior environmental profile to PVC and is easier to recycle than bitumen and the cross-linked polyurethane backings. EcoWorx has lower toxicity, better adhesion and good dimensional stability. It is easy to recycle and can be separated from any fibre type used in the carpet tile. It works particularly well with nylon-6 fibres. EcoWorx tiles contain 40% recycled content and Shaw have established a collection and return scheme to close the loop. 

Shaw selected a combination of polyolefin resins as the base polymer of choice for its substitute, EcoWorx . Due to the low toxicity of its feedstocks, superior adhesion properties, dimensional stability, and its ability to be recycled, EcoWorx meets all of the design criteria necessary to satisfy the needs of the marketplace from a performance, health, and environmental standpoint. Research also indicated that the post-consumer carpet tile had a positive economic value at the end of its useful life. The cost of collection, transportation, elutriation, and return to manufacturing processes is less than the cost of using virgin raw materials. This is a truly recyclable (or Cradle to Cradle) product and is a good example of how substitution through innovation can make economic as well as environmental sense. ... 

In contrast, PET end-use markets have been developing for at least 10 years. When the PET bottle was introduced in 1978 and was collected in states with deposit laws, the industry for recycling them and reusing them began to develop. PET resins can be reused to make polyols for insulation and unsaturated resins for bathtubs, shower stalls, boat hulls, and auto panels. Reclaimed PET is also used for strapping, paint brushes, geotextiles, fibers for fiberfill and carpets, and other textile applications. 

Natural materials can be found in many forms in museum collections. The items in this photograph include wool, cotton, wood, leather, dried plant materials, paints, and metal alloys. Rug/carpet kurdish mid-twentieth century wool on cotton, naturalpigments/dye. Basket Hopi piki-bread tray, wicker, early twentieth century. Kachina c. 1970 cottonwood root with water-based (poster) paint, fabric, wool, feathers, yarn, fur ruff, unsigned (cloth "cape is also painted). Books calfskin, marbled paper, gold. Baseball leather, linen cord, pen ink. Glove leather, metal (grommets). Gun wood, metal (brass, steel). 

For sample collection, the hand was pressed ten times on the carpet, progressing from one end to the other of a 10-cm x 100-cm area framed by the template (total area sampled, 640 cm ). The PUF roller was used to sample adjacent areas of similar size. After pressing in each of three areas of the carpeted room, the hand was carefully rinsed with 70 mL of pesticide-quality 2-propanol, which was collected in a clean sample bottle. Only one hand press was performed per day. 

Several other types of hand-held vacuum samplers have been used to collect dust from residential surfaces. One of these, the Baltimore Repair and Maintenance Study Cyclone Sampler (BRMCS) (Farfel et al 1994), has been evaluated against the HVFS. The BRMCS uses the same cyclone and catch bottle assembly as the HVS3, but a different nozzle and vacuum source. The vacuumed dust is sucked into the cyclone via a semi-rigid Tygon hose (2.54-cm o.d.) that is notched on the sampling end to simulate a nozzle. Suction is provided by a small, hand-held vacuum device (Royal Hand Vac , Model 553, 2 A). The collection efficiency for the BRMCS was determined to be 44.1 % n =6, s = 3.8) for plush uylou carpet, 61.1 % (n = 6, = 6.7) for level loop carpeting, 71.8-87.8 % n =6, s = 3.5) for upholstery and 84.7 % n = 3, s = 2.3) for wood surfaces (USEPA, 1996b). 

This has been used on carpets, bare floors, window sills and furniture, typically collecting 1.4 to 12 g (mean, 4.5 g) of bulk dust in 45 to 90min sampling periods. 

Coupons have also been used to estimate dissipation rates. For such use, it is best if the coupons are made of materials representative of honsehold furnishings, flooring or other residential surfaces (i.e. fabrics, carpet, wood and Formica), and they shonld be placed on or near the surfaces they represent. Replicate coupons (e.g. three) shonld be placed at each location for best characterization, and field spikes are particnlarly important. Coupons shonld be exposed pre-application and at several time intervals post-application to provide snfficient measnrements to project residne half-lives . The same measnres to prevent or limit the evaporative losses given above shonld also be exercised in order to assnre that the coupons reflect the residnes remaining on the snrfaces being evalnated at the time of collection. 

Colt, J.S., S.H. Zahm, D.E. Camann and P. Hartge (1998). Comparison of pesticides and other compounds in carpet dust samples collected from used vacuum cleaner bags and from a high-volume surface sampler. Environ. Health Perspec., 106, 721-724. 

USEPA (1997a). Round-Robin Testing of Methods for Collecting Dislodgeable Residues from Carpets, Report No. 600/R-97/119, National Exposure Research Laboratory, Research Triangle Park, NC, USA. 

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