Removing lignin model pollutants with BiFeO3–g-C3N4 compound as an efficient visible-light-heterogeneous Fenton-like catalyst

BiFeO_3–g-C_3N_4 nanoscaled composite was prepared with a hydrothermal method and evaluated as a highly efficient photo-Fenton like catalyst under visible light irradiation. The BiFeO_3–g-C_3N_4 composite exhibited much stronger adsorption ability to lignin model pollutant(guaiacol) than that of BiFeO_3, which may be due to the higher specific surface area(BiFeO_3–g-C_3N_4: 35.59 m~2/g BiFeO_3: 7.42 m~2/g) and the adsorption form of π–π stack between g-C_3N_4 and guaiacol. The composite exhibited excellent visible light-Fenton like catalysis activity, being influenced by the solution pH value and the proportions of BiFeO_3 and g-C_3N_4 nanosheets. Under optimal conditions with visible light irradiation, the BiFeO_3–g-C_3N_4 composite yielded fast degradation of guaiacol with an apparent rate constant of 0.0452 min~(-1), which were 5.21 and 6.80 folds of that achieved by using BiFeO_3 and the mixture of BiFeO_3 and g-C_3N_4 nanosheets, respectively. The significantly enhanced visible light-Fenton like catalytic properties of the BiFeO_3–g-C_3N_4 composite in comparison with that of BiFeO_3 was attributed to a large surface area, much increased adsorption capacity and the semiconductor coupling effect between BiFeO_3 and g-C_3N_4 in the composite.     

全氟辛酸对酿酒酵母细胞毒性作用

全氟辛酸(PFOA)广泛应用于工业生产中,具有高度的生物毒性及生物蓄积性,然而PFOA对环境微生物的毒性影响仍有待深入开展.通过流式细胞术测定了酵母菌在不同浓度PFOA胁迫下细胞膜通透性、ROS、线粒体跨膜电位的变化,并且测定了MDA含量和Na+K+-ATPase、Ca2+Mg2+-ATPase活性变化.结果显示PFOA可使PI染色细胞比例增高,酿酒酵母细胞膜通透性增大、ROS和MDA含量升高、线粒体跨膜电位降低,且ROS含量、MDA含量与线粒体跨膜电位降幅均与PFOA胁迫浓度和时间呈正相关.Na+K+-ATPase、Ca2+Mg2+-ATPase活性先上升后降低,表明酿酒酵母在PFOA胁迫下,其生理活性受到抑制甚至发生细胞凋亡.证明PFOA对酿酒酵母具有生物毒性,100 mg·L-1PFOA对酿酒酵母具有即时毒性.该结果可为PFOA的影响评价提供更多依据.     

深圳荔枝湖富营养化综合治理工程效果研究

分析和比较了深圳荔枝湖综合治理工程运行9个月内不同湖区水体的叶绿素a、总磷、总氮及透明度的变化,探讨了综合治理工程对城市富营养化湖泊荔枝湖的水质改善情况.结果表明,治理工程运行期间全湖湖水营养水平控制在较低水平(总磷＜0.1 mg·L-1,总氮＜1.5 mg·L-1),四湖区藻类水平北湖区(16.77μg·L-1)和东湖区(21.45μg·L-1)较低,南湖区(35.83μg·L-1)、西湖区(32.69μg·L-1)相对较高,全湖水体透明度提高(全湖平均＞0.5 m);治理工程将湖水水质由劣Ⅴ类改善为Ⅳ类,由重富营养化水平改善为富营养化水平.     

低强度超声波辐射对污泥生物活性的影响机制

通过测定超声辐射前后污泥性质的变化,不同处理方式对污泥活性影响以及自由基清除剂NaHCO3加入对超声作用效果影响,初步探讨了低强度超声波辐射对污泥生物活性的影响机制.研究结果表明,低强度超声辐射的机械作用和空化作用,使污泥絮体破碎,强化了固-液对氧的传质,提高了酶活性以及增加了溶液中可利用基质,从而强化了污泥的生物活性;不过,超声辐射同时也产生大量自由基,会对污泥生物活性产生抑制或破坏.因此,低强度超声辐射对污泥活性影响是促进效应和抑制效应共同作用的综合表现.     

KIO_4光催化脱色甲基橙的研究

以KIO4为催化剂,对甲基橙进行了光催化脱色研究。结果表明甲基橙的脱色率随着催化剂量的增加而增加,但是没有一个最佳的量。当甲基橙浓度低于16mg/L时,反应为拟一级动力学反应,但是反应不符合Langmuir-Hinshewood动力学模型。脱色率在酸性条件下比碱性条件较高。高碘酸钾光催化脱色甲基橙的机理不完全是羟基自由基进攻。     

重度富营养化水培条件下烟草的生长特性及其净化效果的研究

研究了烟草在重度富营养化水培条件下的生长特性、根的解剖结构,对其净化效果进行了观测,并对烟草在重度富营养化水中的生长特性变化原因、适应机理进行了探讨.     

Cattle manure biochar and earthworm interactively affected CO2 and N2O emissions in agricultural and forest soils: Observation of a distinct difference

• Earthworms increase CO₂ and N₂O emissions in agricultural and forest soil. • 10% biochar suppresses CO₂ and N₂O emissions in forest soil. • Biochar interacted with earthworm to significant affect CO₂ and N₂O emissions. The application of manure-derived biochar offers an alternative to avoid the direct application of manure to soil causing greenhouse gas emission. Soil fauna, especially earthworms, can markedly stimulate carbon dioxide (CO₂) and nitrous oxide (N₂O) emissions from soil. This study therefore investigated the effect of cattle manure biochar (added at rates of 0, 2%, or 10%, coded as BC0, BC2 and BC10, respectively) application, with or without earthworm Aporrectodea turgida, on emissions of CO₂ and N₂O and changes of physic-chemical properties of agricultural and forest soils in a laboratory incubation experiment. The BC10 treatment significantly enhanced cumulative CO₂ emissions by 27.9% relative to the untreated control in the agricultural soil. On the contrary, the BC2 and BC10 treatments significantly reduced cumulative CO₂ emissions by 16.3%–61.1% and N₂O emissions by 92.9%–95.1% compared to the untreated control in the forest soil. The addition of earthworm alone significantly enhanced the cumulative CO₂ and N₂O fluxes in agricultural and forest soils. Cumulative CO₂ and N₂O fluxes were significantly increased when BC2 and BC10 were applied with earthworm in the agricultural soil, but were significantly reduced when BC10 was applied with earthworm in the forest soil. Our study demonstrated that biochar application interacted with earthworm to affect CO₂ and N₂O emissions, which were also dependent on the soil type involved. Our study suggests that manure biochar application rate and use of earthworm need to be carefully studied for specific soil types to maximize the climate change mitigation potential of such management practices.     

青岛市生态环境质量动态变化研究简

以2011年Landsat TM遥感影像为基础数据源,利用遥感与GIS技术对青岛市生态环境状况进行了监测,依据《生态环境状况评价技术规范（试行）》（HJ/T 192-2006）对2000-2011年生态环境质量动态变化趋势进行了评价,在此基础上对地市级单位进行生态环境质量评价中存在的主要问题进行了分析。指出使用归一化系数评价不同区域同一时期的生态环境状况是有效的,但同一区域不同时期的同一指标却不具有可比性;地市级单位在应用规范的过程中发现,不能将“区”作为和“县”同级的评价单元; COD对环境的污染影响应与区域降水的总量负相关,在对COD负荷进行评价时,应考虑的是区域的降水总量。     

赤水河流域仁怀市生态保护态度与行为研究

通过调查问卷的形式探索了仁怀市赤水河两岸的村民在生态保护中的态度与行为。结果表明:沿赤水河两岸居住的部分村民的环保意识相对较低,居民的环保意识与所受教育程度有关,且居民了解环保知识的渠道单一,需要加强多渠道宣传;居民的日常生活和农耕对赤水河的污染较小,周围酒厂及小工厂的污染"贡献"较大。当地环保部门应该加强宣传,提高两岸居民的环保知识水平,减少生活污染,严格控制企业污染排放,减少工业污染,从而维护赤水河流域生态安全。     

2010～2019年雅鲁藏布江中游植被变化及其对气候因子的响应——以拉林铁路段为例

基于2010~2019年MOD13Q1/NDVI数据,结合研究区地形、1∶100万植被类型图和气象数据,采用趋势分析法、相关分析方法,探讨在气候变化背景下雅鲁藏布江拉林铁路段植被覆盖的时空演变规律及植被与气温、降水的相关性研究。结果表明,2010~2019年研究区生长季NDVI值呈波动上升趋势,增速为0.2%/10a; NDVI值呈四周高中部低,区域植被覆被改善面积(65.66%)大于退化面积(34.34%);植被覆盖变化与同期的降水呈正相关关系,与气温呈负相关;研究区植被生长对降水较气温更敏感,且西部冲积平原、山南宽谷及米林宽谷的灌丛、草原、高山植被和少量的针叶林对水热条件响应较强。