新穎材料農業：友善環境農業新穎材料研發與安全評估【土壤環境科學系/鄒裕民特聘教授、劉雨庭特聘教授】
| 論文篇名 | 英文：Cross-redox and simultaneous removal of Cr(VI) and As(III): Influences of Fe(II), Fe(III), oxalic acid, and dissolved organic carbon 中文：交互氧化還原同時移除Cr(VI)及As(III): F(II), Fe(III), 草酸及可溶性有機碳的影響 |
| 期刊名稱 | ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY |
| 發表年份,卷數,起迄頁數 | 2022, 245, 114084 |
| 作者 | Ng, Kim Hoong; Hsu, Liang-Ching; Liu, Yu-Ting(劉雨庭); Hsiao, Chuan-Yen; Chiang, Po-Neng; Teah, Heng Yi; Hung,Jui-Ting; Tzou, Yu-Min(鄒裕民)* |
| DOI | 10.1016/j.ecoenv.2022.114084 |
| 中文摘要 | 六價鉻(Cr(VI))及三價砷(As(III))皆為對人體及環境有害之物質。當兩者的交互氧化還原反應發生並減少兩者毒性時，充斥在其中的鐵離子(二價及三價鐵)及有機化合物(草酸及土壤可溶性有機碳(DOC))對其反應的影響卻甚少被討論，也激發對此研究的調查。結果縣市，在缺乏干擾物質下，交互氧化還原反應只發生在六價鉻及三價砷濃度分別為0.676及0.783的pH≤ 2.0酸性環境。模擬反應之常數k’為0.087m1.377/ (mmol0.459 min)。在添加亞鐵離子(Fe(II))，六價鉻的反應速率會協同加速三價砷的氧化反應。提升環境酸鹼值到pH 6.0，六價鉻會因被亞鐵離子吸附亦或共沉澱而減少。然而，三價砷的移除率較低，約為36%，這是因為三價砷較不易被吸附或產生共沉澱而被移除。三價鐵(Fe(III))不像二價鐵，並不會參與六價鉻及三價砷的交互氧化返原反應路徑，其主要是作為觸發其吸附或共沉澱來移除90%鉻及砷。相對而言，兩個有機化合物參與的系統都顯示三價砷的氧化，但兩者機制不同：在交互氧化還原作用中草酸與三價砷相互競爭，而可溶性有機碳則是將五價砷還原成三價砷。其中可溶性有機碳會與金屬離子錯合或者被佔據吸附位或者共沉澱等作用，進而降低鉻及砷的沉澱。此篇研究解開了六價鉻及三價砷的共移除反應中充斥的干擾物質的影響，並提供重金屬汙染復育的有用的方法。 |
| 英文摘要 | Hexavalent chromium [Cr(VI)] and arsenite [As(III)] are hazardous to both human and ecosystem. While their cross-redox reaction decreases both their toxicities, the interferences from ubiquitous substances like Fe (Fe(II) and Fe(III)) and organic compounds (oxalic acid and soil-extracted dissolved organic carbon (DOC)) on such interaction are rarely reported; thence, inspires the investigation in this study. Results showed that the cross-redox, in the absence of interfering substances, only occurred at pH≤2.0, with reaction orders of 0.676 and 0.783 in respect to the concentration of Cr(VI) and As(III). The pseudo-reaction constant, k′ , of such reaction was recorded at 0.087 m1.377/(mmol0.459 min). With the addition of Fe(II), the rate of Cr(VI) reduction is promoted in conjunction with suppressed As(III) oxidation. Upon neutralizing to pH 6.0, such reduced Cr can be entirely removed via Fe(II)-assisted adsorption and/or co-precipitation. Meanwhile, the elimination of aqueous As is relatively inferior (36 %), attributed to the largely preserved As(III), which is less susceptible to adsorptive/co-precipitative removal. Unlike Fe(II), Fe(III) did not alter Cr(VI)-As(III) cross-redox path, but triggered high adsorptive and/or co-precipitative removals of Cr and As (90 %). In contrast, both organically-altered systems exhibits plummeted As(III) oxidation, under distinctive mechanisms: oxalic acid competes with As(III) in the redox interactions while DOC reduces As(V) into As(III). Also, DOC would undergo complexion with metals and/ or block the adsorption or co-precipitation sites, leading to even lower Cr and As precipitation. This study unravelled the interference from ubiquitous species in the co-removal of Cr(VI) and As(III), which provides insightful remediation for heavy metal contaminations. |
| 發表成果與本中心研究主題相關性 | 六價鉻及三價砷為環境中常見的致癌物, 此篇研究解開了環境中六價鉻及三價砷發生氧化還原反應時所產生的自淨行為, 本研究除了釐清自淨反應如何受到環境中干擾物質的影響, 也建議如何減輕干擾物質而達到最大的移除效率, 並提供環境中重金屬汙染復育有用的方法, 有利於環境永續發展。 |
