草原退化与恢复过程中土壤有机矿质复合体分组研究

对采自处于不同发展方向和阶段的草原土壤分组提取有机矿质复合体,并对它的质量分数、腐殖质质量分数和组成、Ｃ／Ｎ比值等的变化做了分析,试图从土壤复合体变化的角度去认识草原的退化和恢复过程。研究发现土壤腐殖质绝大部分集中于粘粒和粉粒级复合体;退化草原恢复时,复合体腐殖质质量分数增加,并且组成也发生变化;而草原轻度退化时,复合体腐殖质质量分数会减少,但组成不会变化。     

Prognosis of the spatiotemporal dynamics of ecosystems by means of universal kriging

The use of quantitative data for constructing prognostic maps of the dynamics of ecosystem degradation and restoration by nonlinear simulation methods is a topical field of landscape ecology. This method of dynamic cartography is based on fiberwise comparison of data on the state of Chernye Zemli (the Kalmyk Republic, Russia) in different years and the detailed analysis of the period on which the prognosis was based. For this purpose, materials of repeated aerial and satellite photography obtained during a long period (1954–1993) were used. Comparison of maps characterizing the dynamics of Chernye Zemli between 1958 and 1993 allows prognostic electronic maps for the next 10–15 years (with a five-year interval) to be drawn and land prognosis for the next 20–30 years (1998–2023) to be obtained. Deceased     

Environmental degradation by mud in tropical estuaries

In wet tropical countries, the intense rainfall and the lack of effective restrictions on human activities in the river catchment leads to increased rates of soil erosion. This has increased the sediment loads many times over from the natural level. As a result, estuarine and coastal waters are becoming increasingly muddy with associated losses for society in terms of increased flooding and a degradation of the environment, the fisheries and the economic use of these waters. It is suggested that science-based models be used to predict the fate of mud in estuaries and coastal waters when planning development in river catchments, particularly in wet tropical countries. This would help integrate land and water management. Modelling technology is demonstrated by a combination of field and model studies in four turbid tropical estuaries, namely the Fly River in Papua New Guinea, the Mekong River in Vietnam, the Cimanuk River in Indonesia, and Hinchinbrook Channel in Australia. The final model is adapted to local conditions and extensively uses data assimilation especially for open boundary conditions. There can be a feedback between the hydrodynamics and the mud dynamics when the system silts; in wet tropical countries this can occur rapidly, sometimes in only 30 years. Electronic Publication     

微生物-光-电化学耦合技术降解污染物和回收能源的研究进展

微生物电化学技术能同时实现污染物去除和能量回收,但存在污染物去除种类有限及产能效率低的局限,近几年将可再生的太阳能引入微生物电化学技术的微生物-光-电化学耦合技术应运而生。本文简要介绍了微生物-光-电化学耦合技术的发展背景和研究现状,对该技术现有的耦合形式进行分类,并对各种形式的耦合机理进行详细的阐释,最后对其未来的发展进行了展望。     

过一硫酸盐的活化及其降解水中有机污染物机理的研究进展

基于活化过一硫酸盐（PMS）产生SO₄^-·的新型高级氧化技术,在芬顿和类芬顿催化降解水中有机污染物的研究中占有重要地位。本文从活化PMS方法的特点和用途出发,对目前活化PMS的主要方法进行了论述,并对活化PMS降解水中有机污染物的机理进行了探讨,最后对该领域研究中存在的问题进行了分析。指出,开发高效的协同活化PMS的方法将成为该领域研究的必然趋势。     

废水中甲基橙的电化学降解

以FTO导电玻璃作为阳极、石墨电极作为阴极电解模拟甲基橙废水,优化了工艺条件,并对甲基橙的降解机理进行了初步探究。实验结果表明,在NaCl投加量5 g/L、电压8 V、废水pH 6、初始甲基橙质量浓度6.0 mg/L的优化条件下电解30 min,废水的脱色率达91.3%,COD降低了62%。机理研究结果表明,电解产生的羟基自由基与甲基橙发生氧化还原反应,破坏了甲基橙的显色基团,使其内部某些化学键发生断裂,从而达到脱色的目的。     

A study on oxidative degradation of polyacrylamide in wastewater with UV/FENTON/C4H4O62−

The degradation of polyacrylamide (PAM) in simulate wastewater was studied in UV/Fenton/C₄H₄O₆^2? system. The factors such as molecular ratio of H₂O₂/Fe²⁺/C₄H₄O₆^2?, pH, and the dosage of Fenton reagent that could affect the PAM degradation in the UV/Fenton/C₄H₄O₆^2? system were investigated. The experimental results showed that adding C₄H₄O₆^2? to UV/Fenton system could form photosensitive ferrous complexes, which led to higher degradation efficiency of PAM. The degradation rate of PAM could be up to 95.2% under the following conditions: the concentration of H₂O₂, Fe²⁺, and C₄H₄O₆^2? were 22.5, 2.25, and 2.25 mmol/L, respectively (i.e., molecular ratio of H₂O₂/Fe²⁺/C₄H₄O₆^2? was 10:1:1), the pH value was 3.0.     

负载型颗粒活性炭催化过硫酸钠氧化降解橙黄G

通过在颗粒活性炭(GAC)上负载氧化铁,并以此作为催化剂(Fe/GAC)在常温常压下催化过硫酸钠(PS)产生硫酸根自由基降解偶氮染料橙黄G.研究了体系pH、氧化剂浓度、催化剂浓度对橙黄G去除率的影响,并且对催化剂的重复使用性能进行了测试.结果表明,在Fe/GAC/PS体系中,[OG]0=0.2 mmol/L,[GAC] =1 g/L,[PS]0=2 mmol/L,降解2h后OG去除率为99％,且有较高的矿化率;随着氧化剂浓度和催化剂浓度的增加,OG的去除效率提高;催化剂有较好的重复使用性.利用扫描电镜(SEM)对催化剂进行了表征,可以看出在活性炭上成功负载氧化铁.利用化学分子探针竞争实验鉴定催化反应中的活性物种SO4-·和OH·.     

γ-射线辐照降解水中阿莫西林

研究了60Coγ-射线辐照条件下水中阿莫西林(AMX)的辐照降解,考察了AMX初始浓度、辐照剂量、p H、H2O2、自由基消除剂(碳酸氢钠和正丁醇)以及溶解氧等因素对AMX辐照降解的影响。结果表明,γ辐照可有效降解水中AMX,当AMX初始浓度为10.0 mg/L,辐照剂量为15 k Gy时,降解率达100%,随着AMX浓度增大,其降解率降低。碱性条件有利于AMX的降解,当p H为11,且辐照剂量大于10 k Gy时,AMX的降解率在90%以上。同时,加入H2O2可以促进AMX的降解;·OH自由基消除剂的存在和缺氧条件会明显抑制γ-射线对AMX的辐照降解,分析表明,AMX的降解主要是基于·OH自由基的氧化。     

Pseudomonas sp.fz胞外分离物降解四溴双酚A

四溴双酚A(TBBPA)是全球消耗量最大的溴系阻燃剂。通过活性物质的定位、分离和TBBPA产物的分析等步骤,对Pseudomonas sp.fz胞外分离物降解TBBPA进行了研究。结果表明,存在于胞外的活性物质通过异丙基断裂和脱溴两条途径降解TBBPA。通过超滤,Sephadex G-10分离纯化得到了具有降解活性的小分子物质,分子量约为376~456 Da,初步鉴定为短肽类物质。这种小分子物质具有很好的热稳定性(30~80℃),在弱酸性条件下(2.0~5.0)活性较高,其活性还受金属离子、氧气和抑制剂(Na N3)的影响。此外,部分纯化的小分子物质在一定条件下能够产生羟基自由基(·OH)。