Optimized photocatalytic regeneration of adsorption-photocatalysis bifunctional composite saturated with Methyl Orange

Photo-responsive adsorption-photocatalysis nanocomposites are generally used in water and wastewater decontamination; however, the prolonged adsorption capacity of composites and the role of adsorption in concomitant photocatalysis are typically neglected. These composites can be regenerated under light irradiation as their adsorption capacity decreases. Herein, a novel adsorption-photocatalysis bifunctional nanocomposite, Bi-doped TiO₂ supported on powdered activated carbon (Bi₂O₃/TiO₂/PAC), was prepared using the sol-impregnation-hydrothermal procedure. Bi₂O₃/TiO₂/PAC with a secondary calcination temperature of 700°C under a nitrogen atmosphere was selected for maximum adsorption capacity on Methyl Orange (MO). The composite displayed an excellent adsorption capacity and was easily separated and recycled. The results demonstrate that 71.2% photocatalytic regeneration efficiency could be attained under visible light irradiation for 1 hr at an intensity of 750?W/m² and pH 7. Characterization of the as-prepared Bi₂O₃/TiO₂/PAC nanocomposite (700°C) indicates that it possesses a highly specific surface area and great optical properties, showing bifunctional adsorption-photocatalysis characteristics. The p-n heterojunction of the composite played a dominant role in the photocatalytic regeneration process, and effective degradation of MO could be achieved along with composite regeneration.     

Strong enhancement of methylene blue removal from binary wastewater by in-situ ferrite process

Dye wastewater containing heavy metal ions is a common industrial effluent with complex physicochemical properties.The treatment of metal–dye binary wastewater is difficult.In this work,a novel in-situ ferrite process(IFP) was applied to treat Methylene Blue(MB)–Cu(II)binary wastewater,and the operational parameters were optimized for MB removal.Results showed that the optimum operating conditions were OH/M of 1.72,Cu~(2+)/Fe~(2+)ratio of 1/2.5,reaction time of 90 min,aeration intensity of 320 mL/min,and reaction temperature of40°C.Moreover,the presence of Ca~(2+)and Mg~(2+)moderately influenced the MB removal.Physical characterization results indicated that the precipitates yielded in IFP presented high surface area(232.50 m2/g) and a multi-porous structure.Based on the Langmuir model,the maximum adsorption capacity toward MB was 347.82 mg/g for the precipitates produced in IFP,which outperformed most other adsorbents.Furthermore,IFP rapidly sequestered MB with removal efficiency 5 to 10 times greater than that by general ferrite adsorption,which suggested a strong enhancement of MB removal by IFP.The MB removal process by IFP showed two different high removal stages,each with a corresponding removal mechanism.In the first brief stage(5 min),the initial high MB removal(~95%)was achieved by predominantly electrostatic interactions.Then the sweep effect and encapsulation were dominant in the second longer stage.     

Highly cited articles (2014-2015)

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A Yin‐Yang approach to education policy regarding health and the environment: early‐careerists' image of the future and priority programmes

Since the inception of sustainable development (SD), there has been a somewhat ignored contradiction between paradigms that are ecosystem‐based and paradigms that are human‐based or purely economic. We suggest that this contradiction can be unified through a balance of the two. The Chinese Yin‐Yang philosophy is applied as a tool or approach to seeking balance between these ecocentric and anthropocentric paradigms. Priority education policy design for the merging of ecology and health are projected through an Ecohealth lens in response to increasing SD challenges and the intention of the international Ecohealth organization to contribute to SD goals. Meeting SD goals along the nexus of health and environment is further considered through early‐careerist cultural assessments and projections. The groups considered for their professional image of the future are: members of the Ecohealth Association Student Section and Chinese early‐careerists participating in a related conference. In response to SD goals, a problem‐based learning design is suggested as an education policy priority. Rather than approaching SD as a boolean concept, for example, by either focusing on ecosystem sustainability or economic development, we suggest education policy for programmes and curriculums that will help emerging professionals balance these paradigms, so as to best address national and global challenges.     

Advanced treatment of biologically pretreated coal gasification wastewater by a novel heterogeneous Fenton oxidation process

Sewage sludge from a biological wastewater treatment plant was converted into sewage sludge based activated carbon(SBAC) with Zn Cl2 as activation agent, which was used as a support for ferric oxides to form a catalyst(Fe Ox/SBAC) by a simple impregnation method.The new material was then used to improve the performance of Fenton oxidation of real biologically pretreated coal gasification wastewater(CGW). The results indicated that the prepared Fe Ox/SBAC significantly enhanced the pollutant removal performance in the Fenton process, so that the treated wastewater was more biodegradable and less toxic. The best performance was obtained over a wide p H range from 2 to 7, temperature 30°C, 15 mg/L of H2O2 and 1 g/L of catalyst, and the treated effluent concentrations of COD, total phenols,BOD5 and TOC all met the discharge limits in China. Meanwhile, on the basis of significant inhibition by a radical scavenger in the heterogeneous Fenton process as well as the evolution of FT-IR spectra of pollutant-saturated Fe Ox/BAC with and without H2O2, it was deduced that the catalytic activity was responsible for generating hydroxyl radicals, and a possible reaction pathway and interface mechanism were proposed. Moreover, Fe Ox/SBAC showed superior stability over five successive oxidation runs. Thus, heterogeneous Fenton oxidation of biologically pretreated CGW by Fe Ox/SBAC, with the advantages of being economical, efficient and sustainable, holds promise for engineering application.     

镜泊湖流域浮游植物群落及其功能类群的时空演替特征研究

为了解镜泊湖流域浮游植物群落的时空变化特征,于2013年对镜泊湖流域进行了采样调查.共检测出浮游植物7门81种(属),以硅藻和绿藻为主,分属17个功能类群.时间上,春季浮游植物丰度、叶绿素含量和功能类群丰度均高于秋季.空间上,春季镜泊湖流域浮游植物丰度和叶绿素含量湖泊区＞汇水区＞出水区,秋季汇水区＞湖泊区＞出水区.多维尺度分析表明,镜泊湖流域不同区域之间浮游植物群落组成存在显著的空间差异.     

Nitrogen removal from coal gasification wastewater by activated carbon technologies combined with short-cut nitrogen removal process

A system combining granular activated carbon and powdered activated carbon technologies along with shortcut biological nitrogen removal （GAC-PACT-SBNR） was developed to enhance total nitrogen （TN） removal for anaerobically treated coal gasification wastewater with less need for external carbon resources. The TN removal efficiency in SBNR was significantly improved by introducing the effluent from the GAC process into SBNR during the anoxic stage, with removal percentage increasing from 43.8%49.6% to 68.8%-75.8%. However, the TN removal rate decreased with the progressive deterioration of GAC adsorption. After adding activated sludge to the GAG compartment, the granular carbon had a longer service-life and the demand for external carbon resources became lower. Eventually, the TN removal rate in SBNR was almost constant at approx. 43.3%, as compared to approx. 20.0% before seeding with sludge. In addition, the production of some alkalinity during the denitrification resulted in a net savings in alkalinity requirements for the nitrification reaction and refractory chemical oxygen demand （COD） degradation by autotrophic bacteria in SBNR under oxic conditions. PACT showed excellent resilience to increasing organic loadings. The microbial community analysis revealed that the PACT had a greater variety of bacterial taxons and the dominant species associated with the three compartments were in good agreement with the removal of typical pollutants. The study demonstrated that pre-adsorption by the GAC-sludge process could be a technically and economically feasible method to enhance TN removal in coal gasification wastewater （CGW）.     

SoundPLAN在交通噪声对住宅小区影响评价中的应用

采用实测法对小区内的代表性点位进行噪声监测,并记录主要道路的车流量,将实测的车流量及道路相关参数输入到SoundPLAN预测软件中进行预测,计算预测值与实测值的差值。结果表明,偏差在2.8 dB(A)以内说明该软件可以用于交通噪声对住宅小区的噪声影响预测。用SoundPLAN预测软件绘制了住宅小区的平面和横截面声等值线图,形象的表达了交通噪声对住宅小区的影响。     

学科视角：环境教育与可持续发展教育对比分析及其启示

环境教育与可持续发展教育不是对立的,而是相互联系的,各有侧重点.环境教育关注的焦点是以自然保护价值为中心,强调看得见的某些环境问题,往往被简单处理为环境问题的研究,从而朝向技术主义的解决途径.可持续发展教育则是对教育进行重新定位和创新,从而有利于促进经济、社会的可持续发展,兼顾了内部和外部的问题.通过搜索国内文献对于环境教育和可持续发展教育的关注度情况,以期能够在各学科教学中更好的融入环境教育和可持续发展教育.     

铁氧化物与电子供体基质交互作用对红壤性水稻土中DDT还原脱氯影响

铁氧化物与电子供体基质交互作用对电子转移及具有脱氯功能的铁还原菌生长有重要影响,进而可能影响土壤中多氯代有机物的还原脱氯降解.本研究采用土壤厌氧培养实验,分析铁氧化物(针铁矿)和电子供体基质(正丁酸和乙醇)及其交互作用对红壤性水稻土中DDT脱氯的影响及其机制.结果表明,由于DDT脱氯降解,DDT及其降解产物与土壤形成结合态残留,厌氧培养6周后,土壤中DDT可提取态残留量仅为初始量的1.29%~2.01%.DDT厌氧脱氯降解的主要产物为DDD.在培养前期,加入正丁酸和乙醇使反应体系的pH降低Eh增加,进而不利于DDT还原脱氯降解.添加针铁矿或者同时添加针铁矿和电子供体基质均使反应体系的pH增加Eh降低,并且增加土壤中二价铁的量,从而促进DDT还原脱氯降解.正丁酸和铁氧化物对DDT还原脱氯无显著交互作用,而乙醇和铁氧化物对DDT还原脱氯具有拮抗作用.本研究结果对于制定DDT污染土壤的高效原位修复技术方案具有重要意义.