南京大学学报(自然科学版) ›› 2017, Vol. 53 ›› Issue (5): 831.
张翰林,李 艳,鲁安怀*,丁 聪,刘菲菲,丁竑瑞,王长秋
Zhang Hanlin,Li Yan,Lu Anhuai*,Ding Cong,Liu Feifei,Ding Hongrui,Wang Changqiu
摘要: 以水钠锰矿为代表的锰氧化物在地表环境中广泛存在,其日光催化作用是驱动地表锰元素价态循环的重要途径之一.在合成并系统研究不同结构锰氧化物半导体矿物学性质的基础上,重点开展了其光催化还原反应及其影响因素的对比实验研究,探讨了矿物晶体结构、电子结构与介质条件对光催化还原效果的影响机制,提出了光催化反应过程中光电子的转移途径.实验结果表明:不同结构锰氧化物在可见光照射下均可发生自光催化自还原从而释放锰离子,其中层状的单斜水钠锰矿自还原效率最高,光照5 h可释放11.65%锰离子,孔道状的锰钾矿自还原效率最低(3.58%);锰氧化物的光催化反应速率随pH的降低而升高,其中单斜水钠锰矿在pH为6.5条件下的锰离子溶出率是pH为9.5中的2.66倍;锰氧化物的光催化反应速率受有机电子供体的影响,其中腐殖酸做空穴捕获剂时锰的还原量是甲醇时的1.78~4.46倍;焦磷酸根可迅速络合光催化反应中产生的三价锰而显色,其中δ型二氧化锰与六方水钠锰矿光照5 h可持续产生0.058 mg·L-1三价锰,表明锰氧化物的光还原是单电子转移方式,三价锰是主要的中间产物.
[1] Glasby G P.Manganese in the marine environment.Oceanography & Marine Biology:An Annual Review,1984,22:169-194. [2] McKenzie R M.The synthesis of birnessite,cryptomelane,and some other oxides and hydroxides of manganese.Mineralogical Magazine,1971,38(296):493-502. [3] Risse J A,Bailey G W.Spectroscopic study of surface redox reactions with manganese oxides.Soil Science Society of America Journal,1992,56:82-88. [4] Matocha C J,Elzinga E J,Sparks D L.Reactivity of Pb(Ⅱ)at the Mn(Ⅲ,Ⅳ)(oxyhydr)oxide-water interface.Environmental Science & Technology,2001,35(14):2967-2972. [5] Majcher E H,Chorover J,Bollag J M,et al.Evolution of CO2 during birnessite-induced oxidation of 14C-labeled catechol.Soil Science Society of America Journal,2000,64(1):157-163. [6] Narsito N,Santosa S J,Lastuti S.Photo-reduction kinetics of MnO2 in aquatic environments containing humic acids.Indonesian Journal of Chemistry,2008,8(1):37-41. [7] Messinger J,Robblee J H,Bergmann U,et al.Absence of Mn-centered oxidation in the S2→S3 Transition:Implications for the mechanism of photosynthetic water oxidation.Journal of the American Chemical Society,2001,123(32):7804-7820. [8] Paul E A,Clark F E.Soil Microbiology and biochemistry.San Diego,CA:Academic Press Inc.,1989,159-177. [9] Sherman D M.Electronic structures of iron(Ⅲ)and manganese(Ⅳ)(hydr)oxide minerals:Thermodynamics of photochemical reductive dissolution in aquatic environments.Geochimica et Cosmochimica Acta,2005,69(13):3249-3255. [10] Marafatto F F,Straderb M L,Gonzalez-Holguera J,et al.Rate and mechanism of the photoreduction of birnessite(MnO2)nanosheets.Proceedings of the National Academy of Sciences of the United States of America,2015,112(5):4600-4605. [11] Matsunaga K,Ohyama T,Kuma K,et al.Photoreduction of manganese dioxide in seawater by organic substances under ultraviolet or sunlight.Water Research,1995,29(2):757-759. [12] Sunda W G,Huntsman A,Harvey G R.Photoreduction of manganese oxides in seawater and its geochemical and biological implications.Nature,1983,301(5897):234-236. [13] Hsu Y K,Chen Y C,Lin Y G,et al.Birnessite-type manganese oxides nanosheets with hole acceptor assisted photoelectrochemical activity in response to visible light.Journal of Materials Chemistry,2012,22:2733-2739. [14] 姜 君,徐仁扣,赵安珍.用酸碱滴定法测定酸性红壤的pH缓冲容量.土壤通报,2006,37(6):1247-1248.(Jiang J,Xu R K,Zhao A N.Determination of pH buffer capacity of acid red soils by acid- base titration.Chinese Journal of Soil Science,2006,37(6):1247-1248.) [15] 张耀丹,邱琳琳,杜文超等.土壤环境基准的研究现状及展望.南京大学学报(自然科学),2017,53(2):209-217.(Zhang Y D,Qiu L L,Du W C,et al.Current research and prospect of soil environmental criteria.Journal of Nanjing University(Natural Science),2017,53(2):209-217.) [16] Xu Y,Schoonen M A A.The absolute energy positions of conduction and valence bands of selected semiconducting minerals.American Mineralogist,2000,85:543-556. [17] 卢晓英,鲁安怀,陈 洁等.单斜与六方磁黄铁矿处理含Cr(Ⅵ)废水过程中pH值变化规律.高校地质学报,2000,6(2):271-277.(Lu X Y,Lu A H,Chen J,et al.Characteristics of pH variation in the Cr(Ⅵ)-bearing wastewater disposed by clino-pyrrhotite and hexa-pyrrhotite.Geological Journal of China Universities,2000,6(2):271-277.) |
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