Page 391 - Industrial Wastewater Treatment, Recycling and Reuse

Phenolic Wastewater Treatment: Development and Applications of New Adsorbent Materials 363

and bimetallic oxides for the removal of three industrially important pollut-
ants, phenol, 4-CP, and 4-NP, indicate:
1. The adsorption capacity of the adsorbents is significantly lower when
used in untreated form than in their charred or activated forms. The car-
bonaceous adsorbents showed greater efficiency than the synthesized
binary mixed oxide of Fe-Al because of greater porosity and the presence
of certain functional groups that facilitated the adsorption process.
2. The order of the adsorption follows: phenol<4-CP<4-NP.
3. Most of the adsorption processes can be described by the Freundlich and
Langmuir isotherm model.
4. The activated adsorbents have a high surface area, generally above
2
1
1000 m g . The pore size for most of the adsorbents is in the micro-
porous to mesoporous range.
5. The cost of the adsorbents is believed to be substantially lower than for
commercial activated carbon and hence they have the potential to com-
pete with commercial products.
The development of new adsorbents can provide better opportunities for
commercial applications. The synthesis of porous materials from zeolite,
the preparation of AC fibers, and the fabrication of nanomaterials can also
be considered in the future scope of this research. Growth can be seen in
the area of the synthesis of new porous materials with tailored structural
and surface properties. Thus, there is an immense potential for creating func-
tional structures to meet specific requirements. In this regard, the potential
use of the biomass-derived new materials remains largely unexplored.
The low-cost adsorbents used in the present study may also be effective
in removing other harmful phenolics, organics, and metal ions present in
industrial effluents.
Nomenclature

4-CP 4-chlorophenol
4-NP 4-nitrophenol
AAJSC acid activated jute stick chars
Ad i % individual adsorption in %
AES activated egg shells
Langmuir’s theoretical adsorption capacity
a L
ANL activated neem leaf
AOPs advanced oxidation processes
APPC activated potato peel chars
ATW activated tea waste
BET Brunauer-Emmett-Teller
BJH Barret-Joyner-Halenda