海洋石油降解细菌对石油烃降解效果的气相色谱法分析

用毛细管气相色谱法分析评价海洋石油降解细菌对石油烃的降解效果,结果表明,毛细管气相色谱法能够测定出石油降解细菌对石油烃的降解进程和对正构烷烃的总降解率,以及温度对降解速率的影响。石油降解细菌对正构烷烃有明显的降解作用,混合菌株的降解率明显高于单菌株的降解率;在20℃的条件下,经过21 d后,绝大部分的正烷烃被降解,总的降解率为94.93%。     

天然植物纤维增强塑料复合材料降解性能研究进展

近年来,天然植物纤维增强塑料复合材料的产出呈现出激增趋势。产量激增为其废弃物的及时处理带来了难题。材料的有效降解不仅能解决这一难题,也能促进该类复合材料产业的发展。本文介绍了植物纤维增强塑料复合材料的主要降解方法,并从光降解、热降解、化学剂降解、酶降解及微生物降解等方面对其降解性能的研究现状进行综述,提出了该类复合材料降解亟待解决的难题。     

气氛对尼龙1010热降解的影响

利用ＴＧ和ＤＴＡ研究了尼龙１０１０在Ｎ２气和空气流巾的降解过程和动力学，考察了反应气氛对降解步骤．降解温度、降解率和动力学参数的影响，分析了两者降解机理的可能差别．发现空气中的热氧降解为多步反应，而Ｎ２气中的热降解为一步反应Ｚ降解温度和降解率，Ｎ２气中均高于空气中；表观反应级数Ｎ２气中为１．０，空气中为１．１级．     

聚对二氧环己酮-乙交酯缝合线体外降解研究

用DSC和X ray衍射法对聚对二氧环己酮 乙交酯 (PDG)缝合线的初期体外降解过程进行了研究 ,并使用纤维摄影仪对纤维在降解过程中的表面形态变化进行了观察 .研究结果表明 ,在本工艺条件下得到的PDG缝合线在体外降解过程中分为三个阶段降解 ,即无定形区降解、原纤间非晶区降解和晶区水解 .在体外降解过程中 ,PDS缝合线以横向断裂为主 ,而PDG则通过表面积的大块脱落来完成降解过程     

环境激素邻苯二甲酸二丁酯的光催化降解机理探讨

环境激素邻苯二甲酸二丁酯的光催化降解机理探讨;邻苯二甲酸二丁酯;光催化降解;降解机理;二氧化钛     

微波辅助高效降解木质素转化酚类化合物的研究进展

木质素作为自然界中丰富的可再生芳香族聚合物,可用于生产高附价值的酚类化合物,木质素降解已引起了各界越来越广泛的兴趣,为了高效降解木质素以获得酚类化合物更高得率,各种技术被广泛运用在木质素降解的研究中,其中微波辅助高效降解技术因更具优势而备受关注,微波降解木质素具有环境友好、高效快速、节能省电、易控制、安全、选择性强等特点。为了解微波辅助高效降解木质素转化酚类化合物的现状,并预测未来发展方向,本文在综述其研究进展的基础上,着重回顾了微波辅助高效降解技术的机理、特点及优势,考察了微波辅助条件下不同催化剂高效降解木质素的效果,介绍了微波辅助高效降解与其他物质偶联降解木质素的方法以及效果,同时综述了降解产物的分离检测方法、特点以及优势与应用前景,最后以此为依据,展望微波辅助高效降解木质素转化绿色化学品研究的未来发展方向。     

耐晒大红BBN与表面活性剂双组分光催化降解

以表面活性剂十六烷基三甲基溴化铵(CTAB)和难溶有机颜料耐晒大红BBN(简称BBN)为双组分降解底物, 以TiO2为光催化剂, 研究双组分底物的光催化降解的快慢及规律, 双组分降解的相互影响, 初步建立双组分和催化剂之间的作用模型. 结果表明, pH值及底物的浓度对双组分体系的降解都有显著影响, 碱性条件更适合体系的降解, 在中性(pH=6.8)环境中两种底物的降解效果明显高于单组分的降解. 在碱性条件下(pH=9.2), 加入BBN使CTAB的降解速率略有下降. CTAB的浓度对BBN褪色速率影响较大, 当CTAB 的浓度为1 cmc 时, BBN和CTAB的降解速率都达到最快. BBN在TiO2表面吸附性强, 且被优先降解.     

真菌BFM-X1对聚丁二酸丁二醇酯薄膜的降解过程

对菌株Bionectria sp.BFM-X1(简称BFM-X1)分别利用不同碳源对聚丁二酸丁二醇酯(PBS)薄膜的降解情况及降解后的残留膜进行了观察分析,揭示PBS薄膜的微生物降解过程.结果表明:菌株分别以PBS乳剂、葡萄糖、大豆油及甘油为唯一碳源时均能有效降解PBS薄膜；降解过程表现为表面失去光泽期、裂纹状结构期、破碎期和完全降解期4个阶段,并存在迟滞期,且葡萄糖碳源下的降解速率快于其他碳源的；菌株的菌丝能在PBS膜表面上扩展生长是该菌株降解PBS的前提,真菌的寄生作用是前期降解的主要动力；降解过程中胞外酶的水解作用使聚合物的酯键水解,生成可被菌株同化吸收的小分子；菌株BFM-X1对PBS薄膜的降解首先发生在膜表面,非结晶部分先于结晶部分被降解.     

微生物降解酚类污染物的研究进展

从降解酚类微生物筛选、影响酚类降解的因素、降解机制和降解动力学等方面综述了微生物降解酚类污染物的研究进展。微生物降解苯酚的代谢途径主要为厌氧途径和好氧途径。好氧条件下,苯酚首先被氧化成邻苯二酚中间态,然后在邻位或者间位发生苯环裂解反应。厌氧条件下,苯酚首先被微生物羧基化,然后发生脱羟基还原反应和开环裂解。微生物降解苯酚的霍尔丹方程模型的参数是多变的,所以微生物降解苯酚的动力学方程没有固定常数。     

超声波-二氧化钛光催化耦合法降解高效氯氰菊酯

采用超声波-TiO2光催化耦合法降解高效氯氰菊酯,考察了高效氯氰菊酯初始浓度、降解时间、溶液pH、催化剂用量等对高效氯氰菊酯农药残留的降解效果,并利用水果进行了实物模拟.结果表明:利用超声波-TiO2光催化耦合法能够有效地降解高效氯氰菊酯农药残留.在弱酸环境中,当纳米TiO2投放量为1.2g/L时,经2h超声催化降解,不同浓度的高效氯氰菊酯农药稀释液均被有效降解,降解率最高可达98.3%.     

Indirect Electrochemical Oxidation of 4-Amino-dimethyl-aniline Hydrochloride

Introduction4Amino dimethyl anilinehydrochlorideisoneof themaincomponentsofthewastewaterresultedfrom vanillinproduction[1]whichinhibitsthenormalactivity ofthemicroorganismsofmicrobialpopulation,thereby affectingthebiologicaltreatmentprocessofvanillin.Comm…     

Electroanalysis may be used in the Vanillin Biotechnological Production

This study shows that electroanalysis may be used in vanillin biotechnological production. As a matter of fact, vanillin and some molecules implicated in the process like eugenol, ferulic acid, and vanillic acid may be oxidized on electrodes made of different materials (gold, platinum, glassy carbon). By a judicious choice of the electrochemical method and the experimental conditions the current intensity is directly proportional to the molecule concentrations in a range suitable for the biotechnological process. So, it is possible to imagine some analytical strategies to control some steps in the vanillin biotechnological production: by sampling in the batch reactor during the process, it is possible to determine out of line the concentration of vanillin, eugenol, ferulic acid, and vanillic acid with a gold rotating disk electrode, and low concentration of vanillin with addition of hydrazine at an amalgamated electrode. Two other possibilities consist in the introduction of electrodes directly in the batch during the process; the first one with a gold rotating disk electrode using linear sweep voltammetry and the second one requires three gold rotating disk electrodes held at different potentials for chronoamperometry. The last proposal is the use of ultramicroelectrodes in the case when stirring is not possible.     

Application of Dielectric Barrier Discharge Reactor Immersed in Wastewater to the Oxidative Degradation of Organic Contaminant

Dielectric barrier discharge (DBD) is an effective method available for the production of ozone and ultraviolet light. The wastewater treatment system of this study was designed to utilize both ozone and ultraviolet light produced in the DBD reactor for the degradation of organic contaminant. The DBD reactor consisted of a quartz cylinder and a coaxial ceramic tube inside of which a steel rod was placed. The DBD reactor was immersed in the wastewater that was grounded. In this case, the wastewater acted not only as an electrode but also as the cooling medium for the DBD reactor. An azo dye, Acid Red 27, was used as the organic contaminant. In this system, the organic contaminant was degraded by two oxidation pathways induced by ozone and ultraviolet light. The concentration of ozone, the ultraviolet radiation intensity and the degradation efficiency of the organic contaminant were measured by varying the discharge. The results showed that the present system was very effective for the degradation of the organic contaminant. The energy requirement for the degradation was found to be 0.654 kJ/mg, which is much smaller value than those obtained with an ultraviolet/photocatalytic process.     

Optimization of environmental friendly process for removal of cadmium from wastewater

Simple, efficient and eco-friendly electrochemical method for removal and recovery of Cd(II) from wastewater has been studied. Experiments were carried out in a batch electrochemical reactor with iron electrodes. The removal was examined at different pH values and electrical potentials. It was observed that the experiments carried out at 20 V and at pH 9 were sufficient for the maximum removal of Cd(II). This method is highly efficient in removal of Cd(II) from wastewater containing up to 1000 mg L^?1. The removal is faster in comparison with the adsorption on activated carbon, which is one of the most important requirements for practical application of this treatment method. In this process, the use of different electrical potentials can provide a wide range of pH values for performing this process. The removal data were used to determine the adsorption kinetics by using the first-order adsorption kinetics model. The data can be analyzed in terms of various adsorption models. The results of Cd(II) removal from real samples indicate that the method used in this study can provide an efficient and cost-effective technology for the treatment of Cd(II)-containing wastewater. The parameters can be used for designing a plant for an economical treatment of Cd(II)-rich water and wastewater.     

Electrochemical nitrate reduction to produce ammonia integrated into wastewater treatment: Investigations and challenges

Nitrate (NO₃⁻) is widely found in wastewater, which is harmful to human health and water environmental. Electrochemical reduction can convert NO₃⁻ to high value-added ammonia (NH₃)/ammonium (NH₄⁺) for pollutant removal and resource recovery. Currently, electrochemical nitrate reduction to produce ammonia (ENRA) is mostly focused on the preparation of high-performance catalysts, while ignoring the prerequisite for industrial application as the stable operation and optimal regulation of the process. Therefore, the review focused on wastewater treatment, based on the mechanism of electrochemical nitrate reduction for ammonia production and reactor construction (reactor, power supply system), then summarized the operation control strategies (such as reduction potential, nitrate concentration, inorganic ions, pH) that should be noted for ENRA. Finally, the challenges (system structure, economy) and prospects (ammonia recovery process, construction of large-scale ENRA system, application of real wastewater) of the field as it moves towards commercialization were discussed. It is hoped that this review will facilitate the scaling up of ENRA in the wastewater treatment field.     

Mathematical modeling and simulation of the reaction environment in electrochemical reactors

An electrochemical reactor, enabling controlled flow and capable of including a varied range of forms of electrodes, is important in the studies of electrochemical processes, such as energy production and storage, electrosynthesis of chemicals, electrowinning of metals, purification of water, wastewater treatment, remediation of soils, and so on, before the process development and scale-up. Here, we reviewed recent advances in modeling and simulation of the reaction environment in many electrochemical reactors used in multiple applications. The importance of computational fluid dynamics simulations to study existing reactors and to design novel reactor geometries and some components of existing cells is discussed. Aspects include the effect of electrolyte velocity on the flow dispersion, mass transport rates, and current distribution.     

Performance of anaerobic sequencing batch biofilm reactor submitted to different influent volume feeds and cycle time periods maintaining organic loading

The stability and efficiency of an anaerobic reactor containing biomass immobilized on polyurethane foam were assessed. The reactor with mechanical stirring of 500 rpm and maintained at 30+/-1 degrees C treated synthetic wastewater with a concentration of approx 500 mg of chemical oxygen demand/L and was fed with different influent volumes and cycle times maintaining organic load. Operation was in batch mode with renewal of only part of the volume of wastewater to be treated; that is reactor discharge was not complete, but partial. The main operational characteristic investigated was the ratio of the volume of wastewater fed per cycle (VA) to the volume of wastewater in the reactor (VA) maintaining the same volumetric organic load. This way, operating flexibility could be verified in relation to the volume of treated wastewater at each cycle and the cycle time for the same organic load. The results indicated that the reactor was able to operate with different VA/Vu ratios with no significant loss in performance, thus allowing increased operational flexibility. For conditions in which VA was >or=50% of VA, removal efficiencies of filtered and nonfiltered organic matter were about 84 and 79%, respectively, whereas at conditions of higher initial influent dilution, these efficiencies were slightly lower, about 80 and 74%, respectively. At higher initial influent dilutions, it became difficult to maintain a constant reactor medium volume, owing to a high formation rate of viscous polymer-like material, likely of microbiologic origin.     

Self-regeneration of activated carbon modified with palladium catalyst for electrochemical dechlorination

Catalyst regeneration and the retention of high catalytic activity are still the critical issues in environmental application.A novel fluidized gas-liquid-solid electrochemical reactor was developed to simultaneously remove chlorinated pollutants and in situ regenerate the spent catalyst.Activated carbon modified with palladium catalyst (AC-Pd) was prepared for electrochemical dechlorination.For the 4-chloropbenol wastewater of initial concentration 200 mg L~(-1),the removal efficiency could nearly reach 100% in less than 30 min.Catalytic activity of AC-Pd catalyst was preserved effectively even in consecutive cycling run without special regeneration.OH radicals,generated by electrochemical reaction,played a critical role in self-regeneration of AC-Pd.High catalytic activity of spent AC-Pd catalyst provided an attractive alternative in wastewater treatment.     

电化学生物传感器在污水分析及污水流行病学中的应用进展

近年来,污水流行病学（wastewater-based epidemiology, WBE）已被证明是用来监测社区毒品滥用和公共健康的一种有效评估方法,该方法通过定量分析指定社区污水回收站中污水的药物残留或者代谢物来反推社区中人们对毒品的消耗量并结合指定社区的人口数量对其进行归一化处理. 电化学生物传感器具有响应时间快、成本低、分析样品需求量小、数据分辨率高以及能够现场快速测试等特点,已被广泛应用于疾病快速诊断、环境污染监测、食品安全以及毒品检测等领域. 液相色谱-质谱联用是分析污水中的毒品及其代谢物的主要方法,但随着传感技术尤其是电化学传感器近来的快速发展,也开始被用于研究污水传染病学并可实现现场快速测量. 本文综述了电化学生物传感器在污水中无机污染物（如重金属）、有机污染物（如农药、毒品）、生物分子（如 DNA）以及细菌等微生物分析中的最新进展,同时还论述了目前电化学传感器技术在污水流行病学领域的应用和未来所面临的主要挑战.     

AnSBBR Applied to the Treatment of Metalworking Fluid Wastewater: Effect of Organic and Shock Load

An investigation was performed regarding the application of a mechanically stirred anaerobic sequencing batch biofilm reactor containing immobilized biomass on inert polyurethane foam (AnSBBR) to the treatment of soluble metalworking fluids to remove organic matter and produce methane. The effect of increasing organic matter and reactor fill time, as well as shock load, on reactor stability and efficiency have been analyzed. The 5-L AnSBBR was operated at 30?°C in 8-h cycles, agitation of 400 rpm, and treated 2.0 L effluent per cycle. Organic matter was increased by increasing the influent concentration (500, 1,000, 2,000, and 3,000 mg chemical oxygen demand (COD)/L). Fill times investigated were in the batch mode (fill time 10 min) and fed-batch followed by batch (fill time 4 h). In the batch mode, organic matter removal efficiencies were 87%, 86%, and 80% for influent concentrations of 500, 1,000, and 2,000 mgCOD/L (1.50, 3.12, and 6.08 gCOD/L.d), respectively. At 3,000 mgCOD/L (9.38 gCOD/L.d), operational stability could not be achieved. The reactor managed to maintain stability when a shock load twice as high the feed concentration was applied, evidencing the robustness of the reactor to potential concentration variations in the wastewater being treated. Increasing the fill time to 4 h did not improve removal efficiency, which was 72% for 2,000 mgCOD/L. Thus, gradual feeding did not improve organic matter removal. The concentration of methane formed at 6.08 gCOD/L was 5.20 mmolCH₄, which corresponded to 78% of the biogas composition. The behavior of the reactor during batch and fed-batch feeding could be explained by a kinetic model that considers organic matter consumption, production, and consumption of total volatile acids and methane production.