Sumol Nilratnisakorn. Textile Wastewater Treatment by Narrow-leaved cattail. Doctoral Degree(Environmental Technology). King Mongkut's University of Technology Thonburi. KMUTT Library.. : King Mongkut's University of Technology Thonburi, 2553-01-31.
Textile Wastewater Treatment by Narrow-leaved cattail
Abstract:
Current methods for the decolorization of textile wastewaters can be replaced
efficiently with phytoremediation in sustainable, long-term, wastewater treatment. The
savings in both chemicals and energy augment the environmental impact of this technique.
Cattails are widely-dispersed, aquatic, perennial plants that thrive in many wetland
habitats, including those. polluted by industry. Narrow-leaved cattail (Typha angustifolia
Linn) has never been reported yet for the utilized in the removal of textile dyes from
industrial sources. Preliminary study has found that this plant efficiently removes synthetic
reactive dye wastewater (SRDW) containing reactive red 141, an azo reactive dye
containing eight sulfonate groups upon decrease in pH, chemical oxygen demand (COD)
and total dissolved salts (TDS). The response dose or toxicity was approximately 25.33
mgl". The average system pH of both conditions were tended to be decreased from 9 to 8
during the period of 14 days. The maximum color removal was 60% that found at day 14.
The SEM image of narrow-leaved cattail root after treatment with SRDW indicated that
the cortex of root was damaged and the sodium crystalline was deposited in the root cell
that causes decreasing in evaporation and transpiration. The accumulation of sodium in the
root indicated that plant have the avoidance mechanism for prevent the stem from sodium
salt and tried to keep balance of the water potential, osmotic pressure. It should be noted
that narrow-leaved cattail under caustic conditions from SRDW was known to avoid the
textile dye and salt stress condition through some special mechanisms such as the salt
accumulated in roots or by shedding the older leaves or produced metal complexes in the
form of calcium, iron and silicon binding with dye molecules.
The possible mechanism of dye removal from wastewater was studied by using
Transmission Electron Microscopy connected with Electron Dispersive X-ray
(TEMIEDX), X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR)
and X-ray adsorption spectroscopy (XAS). From TEMIEDX study, it was indicated that
the increasing of sulfur, silicon and iron in plant after treatment with SRDW. Moreover,
the evidence from XRD showed the precipitation of silicon (Si), calcium-silicate (CazSi04)
and calcium oxalate (CaCZ04) in the plant tissue. It could be confirmed that dye molecule
might binding with calcium, silicon and iron, then precipitation in the intercellular space of
plant cell. In addition, FTIR spectra of plants showed an increase in peak of sulfur (S)
group. The amide (R(C=O)NHz) and siloxane (Si-O-Si) groups of the plant showed the
peak shifts and absorbance changes. Hence, these functional groups might involve in the
dye removal. The result from Soft-XAS revealed the Sulfur K-edge of dye molecule in
plant. Sulfur; [R-S03t, transport and translocation from root to shoot and finally deposit
the dye component in the root more than in the shoot. [R-S03t in the root have biotransformation
to the form of [R-SOzt. This can be noted here that calcium-silicate,
calcium oxalate, siloxane group and amide group of plant play the major role for textile
wastewater treatment by Narrow-leaved cattail.
King Mongkut's University of Technology Thonburi. KMUTT Library.