Page 235 - Materials Chemistry, Second Edition

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Sustainable Industrial Design and Waste Management
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softening temperature between 93 and 110°C, which is much higher than
the expected service temperature of 60°C.
Environmental related test
The health hazards of the investigated waste material will be determined
according to the water leaching test DIN 38414-S 4 (Kourany and El-Haggar,
2001). Fresh deionized water media were used to determine the heavy met-
als content and leaching characteristics of the produced bricks. In this test,
three specimens measuring 50 50 50 mm from the selected mixes were
immersed in 300 ml of deionized water media for 28 days. At the end of the
immersion period, the media were analyzed for chromium, cadmium, and
lead concentrations using a Perkin Elmer SIMAA 6000 spectrometer. A
blank sample of the deionized water was also tested to determine the exist-
ence of any background levels of heavy metals.
Table 6.9 lists the results of the leaching tests by water for 28 days
together with the World Health Organization (WHO) guideline values
(Kourany and El-Haggar, 2001) for heavy metal content in drinking water. The
results indicate very low concentrations of heavy metals for the various mixes
which are expected since most of the wastes are plastic rejects with only minor
potential sources of heavy metal contamination from the garbage dumpsites. It
is obvious that the samples are nearly free from any cadmium (Cd) and contain
very small amounts of lead (Pb) and chromium (Cr). The only exception was
mix 12 which revealed high concentrations of 2.2 µg/L and 3.2 µg/L, for lead and
chromium, respectively. Nevertheless, all mixes showed concentrations far
below the WHO guideline values, which proves the safety of using recycled
plastic waste composite material.
In conclusion, the morphological analysis of the composite material
reveals a general intact structure with the presence of polymer segregation
phases and particle filler (sand) clustering phases. The tendency of polymer

TABLE 6.9
Heavy Metal Content by Water Leaching for 28 Days (Abou Khatwa et al., 2005)
Element concentration (µg/L)
Mix no. Lead (Pb) Chromium (Cr) Cadmium (Cd)

Mix 4 0.1 0.2 0
Mix 5 1.4 1.5 0
Mix 6 0 0 0
Mix 10 0.4 0 0
Mix 11 0.1 0 0
Mix 12 2.2 3.2 0.1
Blank sample 0.2 0.8 0
WHO guidelines 10 50 3