銅鐵雙金屬奈米顆粒結合Fenton反應接續礦化移除四溴雙酚A

Removal of tetrabromobisphenol A by Cu/Fe bimetallic nanoparticles and sequential mineralization with a Fenton reaction

郭進順(Chin-Shun Kuo)

指導教授 ： 施養信

國立臺灣大學/生物資源暨農學院/農業化學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201700450

摘要

四溴雙酚A (Tetrabromobisphenol, TBBPA)是最被廣泛使用的溴化阻燃劑，由於不當的貯存和處置，導致TBBPA已經在多種環境基質，甚至是人體中被偵測到。此外，許多前人研究顯示，TBBPA可能會對人體造成負面的影響，因此，開發出一個有效的TBBPA整治方法是非常重要的。奈米零價鐵已經成功地被應用於處理含鹵有機汙染物，而藉著第二種金屬當催化劑，形成的雙金屬顆粒能更有效地處理含鹵有機汙染物。然而TBBPA降解的副產物具有類似內分泌干擾素的能力，在此研究中，也將進一步探討Fenton 反應對於TBBPA脫溴副產物移除之效率。銅鐵雙金屬奈米顆粒能快速及有效地使TBBPA脫溴。在銅添加量上，4.0 % 的銅在銅鐵奈米顆粒上，具有最高的移除效率99.8 %，其擬一階速率常數為0.229 min-1。此外，當銅鐵雙金屬奈米顆粒劑量增加及TBBPA初始濃度下降時，TBBPA反應動力隨之上升。在TBBPA初始濃度為5.0 mg/L，銅鐵雙金屬奈米顆粒劑量為2.0 g/L時，TBBPA在30分鐘內會被完全移除，在反應期間，較低溴數的副產物和溴離子會被偵測到。銅鐵雙金屬奈米顆粒移除TBBPA之反應速率隨溫度增加而增加，並計算出活化能為35.64 kJ/mole，顯示此反應為表面控制之作用。在水溶液pH值的影響上，銅鐵雙金屬奈米顆粒較偏好在酸性環境下移除TBBPA。當pH值從9.0降低到5.0時，反應速率常數從0.191 min-1增加到 0.228 min-1，pH值持續地下降到3.0時，反應速率常數則會下降至0.162 min-1。另外，在pH 3.0 到pH 9.0間，其TBBPA的移除效率無顯著差異，皆高於98.5 %。然而，在pH 11.0時，其移除效率及反應速率常數則分別只有77.0 % 和0.063 min-1。Cu/Fe 雙金屬奈米顆粒可將TBBPA完全脫溴，藉由其脫溴副產物：三溴雙酚A、二溴雙酚A、一溴雙酚A及雙酚A (BisphenolA, BPA) 推測出其降解途徑。原則上，藉由銅鐵雙金屬奈米顆粒反應後鐵氧化生成的鐵離子及額外添加的H2O2，使TBBPA脫溴最終副產物BPA可利用Fenton 反應移除。在BPA溶液中，增加H2O2或Fe2+濃度，會增加BPA的移除速率；然而，過高的H2O2或Fe2+濃度，會降低BPA的移除速率，分別為從0.015 min-1降到0.0107 min-1及0.015 min-1降到0.0004 min-1。合成的銅鐵雙金屬奈米顆粒對於處理TBBPA有相當高的潛力，且結合H2O2能有效地礦化大部分的TBBPA與其脫溴副產物。

關鍵字：四溴雙酚A、雙酚A、銅鐵雙金屬奈米顆粒、脫溴

關鍵字

四溴雙酚A ； 雙酚A ； 銅鐵雙金屬奈米顆粒 ； 脫溴

並列摘要

Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardant. Due to its extensive usage and then improper storage and disposal, it has been detected in various environmental matrices and even human bodies. Moreover, many previous studies showed the results that TBBPA could cause many negative effects on human bodies. Thus, exploiting an effective method for TBBPA treatment is important. Nanoscale zero-valent iron has been successfully applied for treating halogenated organic pollutants. With a secondary metal as the catalyst, bimetallic nanoparticles (BNPs) become more efficient. However, the byproducts of TBBPA degradation have the ability like endocrine disruptor. In this study, we further investigated Fenton reaction for final TBBPA debrominated byproducts.
The results showed that Cu/Fe BNP aggregates demonstrated a fast and effective debromination of TBBPA. For copper doping, Cu/Fe NPs in 4.0 % copper ratio had the highest removal efficiency with a pseudo-first order rate constant of 0.229 min-1. Furthermore, reaction kinetics increased as the decreased initial TBBPA concentrations and the increased dosages of Cu/Fe BNPs. At the initial TBBPA concentration of 5.0 mg L-1, TBBPA could be completely removed within 30 min by a Cu/Fe NPs dosage of 2.0 g L-1, and less brominated byproducts and bromide ions were detected during the reactions. The activation energy of the TBBPA removal with Cu/Fe BNPs was 35.64 kJ/mole, indicating that the removal of TBBPA by Cu/Fe BNPs is surface-control mechanism. For the effect of aqueous pH, TBBPA removal by Cu/Fe NPs favored acid and neutral conditions. The removal rate constant increased from 0.191 to 0.228 min-1 with the decrease of pH from 9.0 to 5.0. The removal rate constant decreased to 0.162 min-1 with continuously dropped the pH to 3.0. Besides, the removal efficiencies were over 98.5 % and have no obvious difference at pH 3.0 to 9.0. However, at pH 11.0, the removal efficiency only 77.0 % with removal rate constant of 0.063 min-1. The complete debromination pathways of TBBPA with Cu/Fe were also presented by the identified byproducts: tribromobisphenol A, dibromobisphenol A, bromobisphenol A, and bisphenol A (BPA). In principle, the removal of the final debrominated byproduct, BPA, can be degraded by Fenton reaction through residual iron ions and additional H2O2. In BPA solutions, the increase of either H2O2 or Fe2+ concentration increased the BPA removal rate. However, a higher concentration of H2O2 or Fe2+ (both are 2.5mM) cause the BPA removal rate constant drop from 0.015 min-1 to 0.0107 min-1 and from 0.015 min-1 to 0.0014 min-1, respectively. The results demonstrated that our synthesized Cu/Fe bimetallic nanoparticles have a high potential for TBBPA treatment and combine with H2O2 to degrade most TBBPA debrominated byproducts effectively.

Keyword: tetrabromobisphenol A (TBBPA), bisphenol A (BPA), Cu/Fe bimetallic nanoparticles (Cu/Fe BNPs), debromination

並列關鍵字

tetrabromobisphenol A (TBBPA) ； bisphenol A (BPA) ； Cu/Fe bimetallic nanoparticles (Cu/Fe BNPs) ； debromination

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