Key Laboratory of Industrial Ecology and Environmental Engineering (China Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology , # 2 Linggong Road, Dalian 116024, People's Republic of China.
Environ Sci Technol. 2014 Nov 4;48(21):12876-85. doi: 10.1021/es5039084. Epub 2014 Oct 23.
Cr(VI) biotreatment has attracted a substantial amount of interest due to its cost effectiveness and environmental friendliness. However, the slow Cr(VI) bioreduction rate and the formed organo-Cr(III) in solution are bottlenecks for biotechnology application. In this study, a novel strain, Acinetobacter sp. HK-1, capable of reducing Cr(VI) and immobilizing Cr(III) was isolated. Under optimal conditions, the Cr(VI) reduction rate could reach 3.82 mg h(-1) g cell(-1). To improve the Cr(VI) reduction rate, two quinone/graphene oxide composites (Q-GOs) were first prepared via a one-step covalent chemical reaction. The results showed that 2-amino-3-chloro-1,4-naphthoquinone-GO (NQ-GO) exhibited a better catalytic performance in Cr(VI) reduction compared to 2-aminoanthraquinone-GO. Specifically, in the presence of 50 mg L(-1) NQ-GO, a Cr(VI) removal rate of 190 mg h(-1) g cell(-1), which was the highest rate obtained, was achieved. The increased Cr(VI) reduction rate is mainly the result of NQ-GO significantly increasing the Cr(VI) reduction activity of cell membrane proteins containing dominant Cr(VI) reductases. X-ray photoelectron spectroscopy analysis found that Cr(VI) was reduced to insoluble Cr(III), which was immobilized by glycolipids secreted by strain HK-1. These findings indicate that the application of strain HK-1 and NQ-GO is a promising strategy for enhancing the treatment of Cr(VI)-containing wastewater.
六价铬的生物处理因其成本效益和环境友好性而引起了广泛关注。然而，六价铬的生物还原率缓慢以及溶液中形成的有机铬（III）是生物技术应用的瓶颈。在本研究中，分离到了一株能够还原六价铬并固定铬（III）的新菌株不动杆菌 sp. HK-1。在最佳条件下，六价铬的还原率可达 3.82 mg h−1 g 细胞−1。为了提高六价铬的还原率，首先通过一步共价化学反应制备了两种醌/氧化石墨烯复合材料（Q-GOs）。结果表明，与 2-氨基蒽醌-氧化石墨烯相比，2-氨基-3-氯-1,4-萘醌-氧化石墨烯（NQ-GO）在六价铬还原中表现出更好的催化性能。具体而言，在 50 mg L−1 NQ-GO 的存在下，获得了 190 mg h−1 g 细胞−1 的最高六价铬去除率。还原率的提高主要是由于 NQ-GO 显著增加了含有主要六价铬还原酶的细胞膜蛋白的六价铬还原活性。X 射线光电子能谱分析发现，六价铬被还原为不溶性的铬（III），由菌株 HK-1 分泌的糖脂固定。这些发现表明，应用菌株 HK-1 和 NQ-GO 是增强含铬废水处理的有前途的策略。
