【作者】 王永娟；

【导师】 周安宁；

【作者基本信息】 西安科技大学 ， 应用化学， 2008， 硕士

【摘要】 本论文以神府煤为研究对象,从神府洗煤废水中提取菌株,采用以神府风化煤和光氧化煤为惟一碳源的筛选方式进行菌株优选,以获得高效溶煤菌株;研究光氧化神府煤的生物转化特性及其生物转化产物的结构,为阐明煤的光氧化与生物转化之间的耦合关系提供实验依据。首先,对煤样进行紫外光催化氧化预处理,光氧化时间6h时,腐殖酸含量达到最大值,约为10.19%。元素分析及FTIR分析表明,光氧化预处理使煤中O/C原子比与H/C原子比增加,醚键、羧基和酚羟基官能团含量增加。用3种鉴别培养基(鉴别真菌、放线菌和细菌)从神府煤洗煤废水中分离、纯化出了47株菌株。以神府风化煤为惟一碳源,经无机盐固体平板培养初筛、再以光氧化煤为惟一碳源液体动态培养复筛后,优选出3种菌株,分别为b菌(真菌)、g菌(放线菌)和h菌(细菌)。考察了培养方式对微生物转化的影响,结果表明:无机盐培养的菌株溶煤效果优于有机培养基培养的菌株;动态方法与静置培养相比,前者菌株的溶煤效果较好。动态无机盐培养条件下,最佳溶煤周期为14天,煤生物转化过程中有弱酸性物质产生。光氧化预处理煤样有较高的生物转化率,其中g菌对光氧化预处理煤样的转化率可达22.3%。煤经b菌、g菌和h菌转化后的液体均呈浅黄色,除原煤经b菌转化产物外,所有液体转化产物加碱处理后,均有棕黄色沉淀产生,其中光氧化煤经g菌转化后的液体产物的加碱沉淀生成率可达17.5%。FTIR分析表明,沉淀产物含有羟基、醚键、芳香环等官能团。生物转化残煤的O/C比、H/C比明显增加。g菌转化残煤中醚键官能团含量减少,说明g菌易于转化含醚键物质。上述结果表明,光氧化处理可促进煤的生物转化。采用梯级溶剂抽提法在索氏抽提器中以丙酮和四氢呋喃(THF)为溶剂,研究了光氧化和生物转化对残煤组成结构的影响。结果表明,光氧化使煤的丙酮抽提率下降,但使其丙酮抽提残煤的THF抽提率提高2倍以上;经生物转化后,残煤的丙酮抽提率均有较大幅度增加,丙酮抽提残煤的THF抽提率增加幅度则与菌株种类有较大关系。原煤经g菌转化后,丙酮抽提率提高程度最大,可达14.96%,而光氧化煤经g菌转化后,丙酮抽提率增加幅度较原煤小;与原煤相比,光氧化煤经b菌和g菌转化后其丙酮抽提残煤的THF抽提率提高了近1倍,光氧化煤经b菌转化后丙酮抽提率增加幅度最大,而且其丙酮和THF的抽提率总和最高,达到21.47%,原煤粉的总抽提率仅有2.92%,此外,煤的光氧化处理对h菌的生物转化影响较小。因此,神府煤在b菌和g菌的生物过程中与光氧化预处理具有一定的耦合作用。FTIR分析表明,经生物转化后,残煤丙酮抽提物中羰基和醚键官能团相对减少。更多还原

【Abstract】 Taking Shenfu coal as participarts, strains were extracted from Shenfu coal-washing waste water. In order to obtain highly efficient strains for bioconversion Shenfu coal, weathered coal and photo-oxidazed coal were respectively used as sole carbon source to screen strains. The bioconversional characteristics of photo-oxidazed coal and the structure of bioconversion products were analyzed for clarifying the coupling between photo-oxidation and bioconversion.Firstly, Shenfu coal was pretreated by UV-photocatalytic oxidation. The humic acid content of the coal photo-oxidazed for 6h was maxmum, reached to 10.19%. Photo-oxidazed coal was characterized by FTIR and ultimate analysis. The results showed that the content of oxygen containing groups (ether, carboxyl, phenolic hydroxyl) were increased by UV-photocatalytic oxidation. Meanwhile, the ratio of O/C and H/C were increased.47 strains were isolated and purificated from Shenfu coal-washing water with differential mediums (fungi,actinomycete,bacteria).Weathered coal was used as sole carbon source to primarily screen strains with solid inorganic salt plate culture. And photo-oxidazed coal was used as sole carbon source to further screen strains with liquid culture medium, finally 3 strains with higher performance to shenfu coal bioconversion , which are b strain (fungi), g strain (actinomycete), and h strain (bacteria), were obtained. The effect of different cultivation systems on bioconversion were investigated in detail. The results incidented that inorganic medium was better than organic medium, dynamic culture was better than static culture for coal bioconversion. the best bioconversional cycle was 14 days for coal bioconversion with inorganic medium dynamic culture. The bioconverted solution products was weak acidic.The bioconverial yield of photo-oxidazed Shenfu coals with strains were higher than that of Shenfu raw coal. The bioconversion yield of photo-oxidazed Shenfu coal using g strain was up to 22.3% .The bioconversional solution products were yellow for 3 strains (b, g, h). Their water-soluble products were precipitated by NaOH. The bioconverted precipitate yield of photo-oxidazed coal for g was up to 17.5%. FTIR analysis showed that the precipitate contained hydroxyl, ether, aromatic ring groups. After bioconversion, the ratio of O/C and H/C in remains of Shenfu coal were greatly increased. The ether groups in the bioconverted residual for g strain were decreased. It meaned that g strain was easy to break ether group. The results showed that photo-oxidation can improve bioconversion of Shenfu coal.Graded extraction was used to characterize the effect of photo-oxidation and bioconversion on the structure of bioconversional residuals by Soxhlet extraction apparatus. The solvents were acetone and THF.The results showed that photo-oxidation made the yield of acetone extraction decreased. After acetone extraction, the residuals were further extracted by THF. The yield of THF extraction for photo-oxidized coal was increased by more than 2 times. After bioconversion of the coals with 3 screened strains, the acetone extraction yield were rapidly increased. The THF extraction yield of bioconverted coals was related with the type of strains. The acetone extraction yield of bioconverted Shenfu coal with g strain was highest ,and it was up to 14.96% as compared with Shenfu coal, the acetone extraction yield of bioconverted photo-oxidazed coal with g strain was increased in an small extent. The THF extraction yield of remain of acetone extraction of bioconverted photo-oxidazed coal by b and g strains were increased by 1 times as compared with Shenfu raw coal. Acetone extraction yield of bioconverted photo-oxidazed coal by b strain were increased in a large extent, the total extraction yield was highest. The total extraction yield of Shenfu raw coal was only 2.92%.The effect of photo-oxidation on h strain conversion of Shenfu coal was less than others. So there was some coupling relationship between the photo-oxidation and b or g strain for coal bioconversion. FTIR analysis indicated that after coal bioconversion with 3 strains, the carbonyl group and ether bond in the acetone solule extract were decreased.更多还原