Nanoscale Porous Materials for Water Treatment: Advances and Challenges - Nanotechnologies for Water Environment Applications - page 323

variety of pollutants. Among different silicates, the characteristics of mesoporous
silicate molecular sieves are attractive due to their large surface areas and narrow pore-
size distribution. A variety of silica materials has been synthesized and used for wide
range of contaminants removal (Table 11.4). The higher surface area of the adsorbent(s)
leads to a higher the adsorption capacity (Figure 11.3). Among different contaminants
tested, Hg and TCE have very promising results, which signifies great promise of using
silica-based NPM for water and wastewater treatment.

Table 11.4 Summary of applications of Si-mesoporous compounds for different
contaminant treatment.

Maximum
Adsorption
Capacity
(mM/g)

Surface
Area
(m 2 /g)

Target
Compound

Si-Compound Ref.

Mesopores Si Functionalized
with 3-
Mercaptopropyltrimethoxysilane
Ligands

(Nooney et
al., 2001)

1184 Mercury 1.26

Phosphonic Acid Functional
Adsorbent

(Nam and
Tavlarides,
2005)

437 chromium(III) 1.58

NH2-MCM-41 750 (Lam et

al., 2007a)

Cd 0.71

NH2-MCM-41 750 (Lam et

al., 2007a)

Ni 1.45

(Sawicki
and
Mercier,
2006)

Cyclodextrin-Silica
Nanocomposites (with 0.8%
Cyclodextrin)

235 p-nitrophenol 0.36

Actinides
effectively
removed

Hydroxypyridinone-
Mesoporous-Silica

U(VI), Pu(IV) and
Np(V)

(Lin et al.,
2005b)

~ 900

trichlorethylene
and
tetrachloroethylene

Hexagonal (MCM-41)
Mesoporous Materials

1200 100%

removal

(Zhao et
al., 2000)

11.2.1.3 Alumina-Based Nanoporous Material

Aluminum oxide is an amphoteric oxide of aluminum with the chemical formula
Al 2 O 3, generally referred as alumina. Activated alumina (AA) is one of the most widely
used materials for water treatment. AA is a porous form of aluminum oxide,
manufactured from aluminum hydroxide by dehydroxylating it to produce high surface