Application of ash from bio-power plant for color adsorption in brine recovery system

Name: Chaiwat Ngasan

LCSH: Kasetsart University -- Dissertations. Ph.D. (Biotechnology) 2020

Classification :.LCCS: TD758.5.C65

LCSH: Kasetsart University. -- Department of Biotechnology -- Dissertations

LCSH: Sewage -- Purification -- Color removal

LCSH: Fly ash

LCSH: Bagasse

LCSH: Carbon activated

Abstract: Brine effluent recycling is a challenging task for many sugar refineries in Thailand. The effluent is a high concentrated sodium chloride with an intense brown coloration which is obtained from the regeneration process of resin after decolorization of sugarcane syrup. The adaptation of an efficient and cost-effective method to recycle brine effluent served as the premise of this research. In this study, the adsorption process of decolorization was used to recycle the brine effluent using the fly ash from bioelectric power plants (named as A, B, C, D and E). The fly ashes were characterized and applied as a low-cost adsorbent for decolorization of brine effluent. The activation processes to improve the fly ash properties and calorific value of the spent adsorbents (fly ash) were investigated. The microscopic observation of treated fly ash (TFA) identified carbon as the principal element and revealed a porous structure which resulted from the original rectangular shape of the plant cells. The Brunauer-Emmett-Teller (BET) surface area analysis indicated that the TFA originating from the factories B, C and E exhibited high surface areas of 307, 251 and 247 m2 /g, respectively, and the adsorption isotherms corresponded to those of mesoporous adsorbents. The percentages of color removal from brine effluent in the batch test at an adsorption time of 24 h were of 80%, 48%, 85%, 87%, 96% and 96% for TFA from factories A, B, C, D, E and commercial granular activated carbon (GAC), respectively. The lowest decolorization efficiency of the TFA from factory B found in the batch and fixed bed column experiments were as a result of the low mesopore proportion. In addition, the functional group of -O-Si-O- shown by FTIR, and the proportion found in total inorganic matter (TIM) measured by X-ray fluorescence spectrometry was greatly found in this sample. The adsorption isotherm of colorants from brine effluent by TFA was studied using melanoidin as a model adsorbate and fitted with Freundlich model. Thermodynamic parameters for TFA indicated that the adsorption process was endothermic and spontaneous process. Furthermore, the activation methods were studied with TFA originating from factory B and the chemical activation produced activated carbon (AC) with the highest surface area (474 m2 /g), with a high mesoporosity ratio of 0.52 which were higher than that found in AC of steam and CO2 methods, respectively. The activation process improved the property and efficacy of TFA, with the steam activation method chosen as environmentally friendly. The percentage of color removal was improved to be 76% at room temperature and 79% at 60 C. The minimum dosage of AC to achieve a target decolorization value was 40 g/L for 20 h of equilibrium time. In addition, the dry spent carbon has a high calorific value (>19 MJ/kg), demonstrating its potential to be used as fuel for power plant. In conclusion, TFA and activated-TFA were promised adsorbent for color removal of brine effluent in sugar refinery plant as well as zero waste processes.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Ulaiwan Withayagiat

Role: Thesis Advisor

Name: Chinnathan Areeprasert

Role: Thesis CO-Advisor

Created: 2020

Modified: 2025-07-11

Issued: 2025-07-11

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2563/chaiwat-nga-all.pdf

CallNumber: TD758.5.C65 .C43

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degraee

Descipline: Biotechnology

Grantor: Kasetsart University

©copyrights Kasetsart University

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