Non-conventional Adsorbents for Dye Removal - Green Chemistry for Dyes Removal from Wastewater - page 374

although the adsorption capacities reported were low (Table 10.6).
Netpradit et al. [146-148] studied the capacity and mechanisms of metal
hydroxide sludge in removing azo reactive dyes. The sludge is a dried
waste from the electroplating industry, which is produced by precipi-
tation of metal ions in wastewater with calcium hydroxide. It contains
insoluble metal hydroxides and other salts. The authors demonstrated
that metal hydroxide sludge was an effective positively charged adsorbent
with maximum adsorption capacities for azo reactive dyes. The charge of
the dyes is an important factor for the adsorption due to the ion exchange
mechanism. Similar interesting results were reported by Santos et al. [83],

Table 10.6 Reported adsorption capacities q max (mg g -1 ) for industrial
byproducts (selected papers).

Adsorbent Dye q max Reference

Activated red mud Reactive Blue 19 454.54 [160]

Activated red mud Acid Blue 113 83.33 [161]

Activated red mud Reactive Black 5 35.58 [161]

Boron waste Astrazon Red 74.73 [162]

Chrome sludge Basic Blue 9 0.51 [163]

Fe (III)/Cr (III) hydroxide Basic Blue 9 22.8 [164]

Fly ash Alizarin Sulfonic 11.21 [98]

Fly ash Rhodamine B 10 [165]

Fly ash Basic Blue 9 5.57 [166]

Fly ash Basic Blue 9 5.52 [149]

Fly ash Basic Blue 9 4.6 [167]

Leather waste Reactive Red 163 [158]

Leather waste Basic Blue 9 80 [158]

Metal hydroxide sludge Reactive Blue 19 91 [168]

Metal hydroxide sludge Reactive Red 2 62.5 [148]

Metal hydroxide sludge Reactive Red 141 56.18 [148]

Metal hydroxide sludge Reactive Red 120 48.31 [148]

Palm oil mill sludge Basic Blue 9 50.7 [169]

Red mud Basic Blue 9 2.49 [155]

Red mud Direct Red 28 4.05 [156]

Sewage sludge Basic Blue 9 114.9 [47]

Sludge waste Bomaplex Red CR-L 192.31 [170]