Environmental Engineering Reference
In-Depth Information
100
Gra
MGNCs
80
60
40
20
0
0.0
0.5
1.0
Adsorbent concentration (g l -1 )
1.5
2.0
2.5
3.0
figure 4.10 Cr(vI) removal percentage based on different loadings of Gra and MGNCs. ([Cr(vI)] = 1000 µg/l, pH 7, treatment time:
5 min). Adapted with permission from Ref. [25]. © ACS.
8
25
20
6
15
4
10
2
5
0
0
0
20
40
60
80
100
120
t , min
figure 4.11 Adsorption kinetic behavior of As(III) by MGNCs: As(III) removal rate q t versus time t (curve with squares) and the trans-
formed rate plot t / q t versus t (curve with triangles). (MGNC concentration: 0.2 g/l [As(III)] = 4 ppm, pH = 7, room temperature). Adapted with
permission from Ref. [77]. © eCS.
others methods, adsorption has the advantages of low cost and low technology demand for operation and maintenance. As for
chromium removal, MGNCs with core-shell Fe-Fe 2 O 3 NPs also showed great potential in the remediation of arsenic species
[77]. As can be seen in Figure 4.11, the removal rate of arsenic reached 7 mg/g after a 2-h interaction at room temperature when
the starting concentration of As(III) was 4 ppm and the pH 7.
4.4.4
Wastewater treatment—residual dye removal
Dyes are commonly used in many industries such as paper, textile, pulp, pharmaceutical, and bleaching. Residual dyes discharged
into natural water resources consist of serious organic pollutants, posing health and environmental concerns. The textile industry
is a major source of dye pollutants in significant amounts. As the degradation products of those dyes, such as benzidine, naphtha-
lene, and other aromatic compounds, are potentially carcinogenic or mutagenic to life forms, treatment of dye-polluted water is
 
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