| Summary: | 碩士 === 國立高雄第一科技大學 === 環境與安全衛生工程研究所 === 103 === Recently the fabric dyeing business tends to use more chemicals to manufacture rather diversified products, and in returns the treatment of its wastewater becomes a great challenge. Traditional biological treatment process was not a popular alternative due to the toxicity of dyes in the wastewater. To alleviate the COD loading to the biological unit of the dyeing wastewater treatment system, allocation of a dye adsorption unit is feasible and deserves to attest. Rice husk was chosen as a raw material for making rice husk carbon (RHC) for dye adsorption. Rice husk contains a great amount of silica and is an agro-waste makes it a suitable resource to use. Thus the objectives of this study include: (1) to study the suitable conditions for manufacturing rice rusk adsorbent, (2) to determine the optimal treatment conditions for regenerating the dye-adsorbed rice husk, and (3) to investigate the operational mean of dye adsorption and rice husk regeneration using column test. Reactive Black-5 (RB-5), and Acid Red-114 (AR-114) were two target dyes tested for adsorption, and were analyzed by UV-spectrophotometric mean. Rice husk was pre-treated with base submerging (0.1 N NaOH) for two hours followed by high temperature (85 oC) submerging (1 N KOH) for three hours, and finished by 800 oC combusting for four hours and water rinse. The RB-5 adsorption capacity of the self-made RHC reached 671 mg/g, which was greater than the commercial activated carbon of 467 mg/g. Furthermore, the RB-5 riched RHC could be regenerated at 5 mM EDTA-Fe and 5.55% H2O2 solution at the presence of UV light (wavelength= 300 nm) for 3 hours. 90% of the adsorption capacity was restored. Finally, the column test with actual dyeing wastewater was conducted. The results showed that even at an insufficient hydraulic retention time of 19 minutes, 25% of the incoming COD was consistently removed for 8 hours. It implied that the self-made RHC worked as expected and will be tested in actual dyeing treatment facility soon.
Keywords: rice husk carbon (RHC), dyeing wastewater, peroxide oxidation, activated carbon regeneration, adsorption column test.
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