Congratulations to Mr Mohd Alamgir Kabir who has completed his MSc research in my laboratory at Universiti Kebangsaan Malaysia. Mr Kabir is a Bangladesh Geology officer who was sent to Malaysia for higher education. He was supervised by me and Dr Krishna.
Photo of Mr Alamgir Kabir in the Laboratory
Abstract: Natural
zeolite has net negative charge on their surface. This net negative charge is
the prime factor that restricts the use of zeolite for the adsorption of
cationic dyes. So, zeolite was modified with cationic surfactant to increase
its anionic adsorption capacity. Natural zeolite used in the present work was
obtained from Indonesia. In the present study natural zeolite has been modified
with cetyltrimethylammonium bromide (CTAB) to increase the positive charge on
the zeolite simultaneously to remove anionic dye Acid blue 25(AB25) from waste
water. The adsorption equilibrium and kinetic studies of anionic dyes were
carried out .The adsorption of reactive dyes on zeolite and modified zeolite
(zeolite-CTAB) was investigated by batch adsorption experiments. The effects of
adsorbent dosage, pH, temperature, time and the initial dyes concentrations
were investigated.The
modification effect on the surface of zeolite was analyzed using Fourier
transform infrared spectroscopy (FTIR), Scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy
(EDX), X-ray fluorescence (XRF) and X-ray Diffraction (XRD). All the methods
support the modification of zeolite by CTAB was done. The maximum removal of dye was obtained under
acidic conditions; in particular at pH 2.The percentage removal of dye
initially increases with increase in dye concentration and with time. After
that the dye removal percentage decreases. The kinetic experimental results imply that the
adsorption of AB25 onto these adsorbents nicely followed the second order
kinetic model. Equilibrium isotherms were analyzed by Langmuir and Freundlich isotherms.
From the concentration effect it is indicated that due to modification of
zeolite with CTAB the adsorption capacity of zeolite for AB25 increases
36.84%. The maximum adsorption capacity
was found to be 43.48 mg/g for zeolite at 300C
(3030 K) and 71.43 mg/g for
zeolite-CTAB at 400C (3130 K).
However, it follows an increase and decrease trend with increase in
temperature. The adsorption of AB25 onto zeolite-CTAB better fitted using
Langmuir model and onto zeolite better fitted with the Freundlich model. A
decrease in AB25 adsorption on zeolite-CTAB has been observed with an increase
in temperature. This decrease in AB25 adsorption on zeolite-CTAB indicates that
the preferential adsorption may occur at low temperature. The negative value of
enthalpy indicating the process was exothermic and the presence of possible
physisorption phenomenon.
The negative values of entropy both for zeolite and zeolite-CTAB indicate the
decrease in randomness at the adsorbent and solution interface. The results of the present study substantiate
that zeolite modified by CTAB material are promising adsorbents for the removal
of the dye AB25.
Zeolite
and zeolite-CTAB were produced in the laboratory during Mr Kabir's research
Adsorption test of Zeolite and zeolite-CTAB on Acid Blue 25
