Page 362 - Industrial Wastewater Treatment, Recycling and Reuse

334 Industrial Wastewater Treatment, Recycling, and Reuse

has a specifically high surface area, while Fe 2 O 3 is associated with potential
applications in catalytic and adsorption studies. Our aim in preparation of
Fe-Al mixed oxide is to explore the possibility of synthesizing porous media
of a synthetic nature and to provide a comparative view with the rest of the
agro-based adsorbents so prepared in the present study.

8.2.3.1 Binary Mixed Oxide of Al-Fe
The hydroxide of the mixed oxide was first prepared by the co-precipitation
1
method. Equimolar volumes of FeCl 3 and AlCl 3 prepared in 0.01 mol L

HCl were mixed and heated to 60 C. Aqueous ammonia was used as a
precipitating agent, which was added drop-wise with constant stirring until

the pH of the solution was nearly 7. The solution was then aged at 65 Cin a
water bath for 24 h, and the mother liquor was decanted. The solid mass
was then washed repeatedly with double distilled water in order to remove
chloride ions and dried in hot-air oven at 65 C for 2 days. The correspond-

ing product was obtained by calcination at three different temperatures of
600, 800, and 1000 C for 2 h to study the effect of calcination temperature

1

in a muffle furnace at a heating rate of 10 C min . For convenience, the
mixed oxide so prepared was denoted by the acronyms BMO L , BMO M , and
BMO H . The subscripts L, M, and H denote low, medium, and high tem-
peratures for the mixed oxide so prepared.

8.3 ADSORBENT CHARACTERIZATION
Characterization of the adsorbent is a crucial step for adsorption studies. BET
(Brunauer-Emmett-Teller) surface area analysis, FTIR (Fourier transform
infrared) studies, XRD (X-ray diffraction), SEM (scanning electron micro-
graphy), proximate and ultimate analysis, and pH ZPC are some of the
methods used to characterize the adsorbent.

8.3.1 Fourier Transform Infrared
FTIR studies can provide useful qualitative information about the surface
functionality. The FTIR spectrum helps to reveal the various functional
groups present on the adsorbent surface before and after adsorption. The
spectra can therefore help in interpretation of which functional groups
are responsible for adsorption and whether H bonding is involved in the
interaction between the adsorbate and the adsorbent. All these inferences
pertaining to chemisorption can also be drawn from FTIR studies. FTIR
spectra were collected in the transmission mode from 4000 to 400 cm 1