膨脹石墨（expanded graphite，EG）作為一種兼具優異導熱、導電、阻燃及吸附性能之先進碳材料，其高效、綠色且低成本的製備技術是學術界與產業界持續關注的焦點。然而，膨脹石墨之性能高度依賴於昂貴的高純度天然石墨（natural graphite，NG）原料，而對來源於工業固廢之凝析石墨（kish graphite，KG）等二次資源化之原料，其在膨脹石墨之化學氧化法製程中的反應行為，尤其是其內含金屬雜質在反應中所扮演的化學角色，仍未被完全揭示。
本研究旨在闡明金屬雜質於氧化插層反應中的定位。研究首先在化學計量對等之基礎上，系統性地對天然石墨與凝析石墨進行對比，選用過碳酸鈉/硫酸（SPC/H2SO4）與過氧化氫/硫酸（H2O2/H2SO4）兩種代表性氧化系統中作為實驗對象，後採用微波法合成膨脹石墨，並對反應動力學、製程參數影響及膨脹石墨性能差異進行分析比較。接著，針對觀測到之現象，本研究提出並通過與穩定策略優化等一系列實驗，驗證關鍵的催化副反應機制。
研究結果表明，對於天然石墨，過氧化氫/硫酸作為反應激烈的氧化系統，在原料粒徑0.300-0.600 mm、反應溫度50℃及反應時間15分鐘的製備條件下，能將其膨脹體積提升至319 mL‧g-1的峰值，反觀天然石墨於反應相對溫和之過碳酸鈉/硫酸系統，則在原料粒徑0.150-0.300 mm、反應溫度50℃及反應時間60分鐘的製備條件下達其膨脹體積峰值285 mL‧g-1。然而，凝析石墨之膨脹體積在兩種體系下之最佳膨脹體積均被限制在約130 mL‧g-1，未能如天然石墨從強氧化劑中受益。本研究首次將此現象歸因於雙重限制之機制：即凝析石墨自身的物理結構缺陷及其內含之高濃度鐵雜質（3750 mg‧kg-1）在過氧化氫系統中觸發之芬頓（Fenton）與類芬頓（Fenton-like）反應。進一步的實驗證實，該系列反應引發的非均相催化是導致凝析石墨結構在強氧化環境中被破壞的主要原因。
最終，基於所發現並闡明之機制，本研究通過引入氨基三甲叉膦酸（nitrilotris(methylenephosphonic Acid)，ATMP）進行過氧化氫穩定，成功使過氧化氫/硫酸系統中凝析石墨合成之膨脹石墨的膨脹體積由127 mL‧g-1提升至137 mL‧g-1之峰值，更穩定了膨脹體積隨反應時間增加而衰減的情形。
由以上數據支持，本研究可得出結論：提升二次資源石墨原料性能之關鍵，不在於增強氧化劑的活性，而在於對氧化插層反應中之催化性副反應的控制。本研究不僅為凝析石墨合成膨脹石墨的性能瓶頸提供化學上的解釋，更為凝析石墨之高價值化利用開創了經科學驗證的全新路徑。

This study investigates the preparation of expanded graphite (EG) from waste-derived kish graphite (KG), aiming to elucidate its performance bottlenecks and develop a novel enhancement strategy. A systematic comparison between natural graphite (NG) and kish graphite was conducted using a chemical oxidation method with stoichiometrically equivalent (sodium percarbonate/sulfuric acid) and (hydrogen peroxide/sulfuric acid) oxidants, followed by microwave irradiation for expansion. Results revealed that while the H2O2 system significantly enhanced natural graphite’s expanded volume to 319 mL/g, kish graphite exhibited an anomalous performance ceiling of ~130 mL/g, showing no benefit from the stronger oxidant. This failure was identified and verified as a Fenton-catalyzed degradation process, triggered by the high intrinsic iron impurity (~3750 mg/kg) in kish graphite. Consequently, a targeted hydrogen peroxide stabilization strategy using nitrilotris(methylenephosphonic Acid) (ATMP) was developed. This approach successfully suppressed the catalytic side reaction and achieved a breakthrough in kish graphite's performance, raising its expanded volume beyond the original ceiling. The study concludes that the high-value utilization of graphite from secondary resources hinges on a mechanism-based, targeted inhibition of impurity-catalyzed side reactions rather than simply intensifying the process. This work provides a new pathway for valorizing industrial solid waste.

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