我們提出了一種快速的方法，利用太陽光或是可見光，以氧化石墨烯(GO)作為光催化劑將毒性很高且具有致癌性的六價鉻[Cr (VI)]還原成三價鉻[Cr (III)]。GO是一種新興且二維的奈米材料，組成的元素在地球上都很豐富。光催化是一種具有吸引力且相對簡單的方法，它將毒性很高的Cr (VI)還原成毒性更低的Cr (III)。與傳統方法相比，減少了許多廢棄污泥的產生，以及排放到環境中的影響。本研究的目的是探索GO將Cr (VI)光催化還原成Cr (III)的能力。結果顯示GO可以有效地在30分鐘內光催化還原六價鉻(0.32 mM)。草酸鹽作為電子提供者可以顯著地加速光催化反應，而且在化學計量比中草酸鹽與Cr (VI)的比例約為1.5，也就是一個分子的草酸會提供兩個電子還原Cr (VI)。在光還原Cr (VI)的過程中會抑制過氧化氫(H2O2)的生成，因為在GO的光催化反應中氧氣與Cr (VI)會有搶奪光電子的情況，此外在此篇研究中還將介紹pH值、電子提供者，氧氣扮演的角色，鉻的質量平衡以及實驗最佳化的參數等等。

We present a new, rapid method to photocatalytically reduce the highly toxic hexavalent chromium [Cr (VI)] to relatively non-toxic trivalent chromium [Cr (III)] by graphene oxide (GO) photocatalyst using renewable sunlight or visible light. GO is an emerging two-dimensional nanomaterial consisting of earth-abundant elements. The new method is an attractive and relatively simple method, as it photoreduces toxic Cr (VI) with minimized sludge generated comparing to conventional reduction and precipitation processes, leaving reduced environmental footprints. We found that GO can efficiently photocatalyze the reduction of Cr (VI) (0.32 mM) in 30 min. Oxalate as an electron donor can significantly accelerate the photoreduction and the stoichiometric ratio of oxalate to Cr (VI) is about 1.5. The photoreduction of Cr (VI) inhibits the photoproducton of H2O2, a process that involves photoelectron reduction of O2 in GO photocatalysis. The effects of pH and electron donors, O2 level, a mass balance disclosure of Cr transformation and optimization will also be presented.

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