Ag+-TiO2/AC复合材料的可见光吸附-光催化协同作用

采用水热法制备活性炭负载银掺杂纳米TiO2复合材料(Ag+-TiO2/AC),对样品进行了TEM、XRD、FT-IR和UV-Vis表征,分析了Ag+-TiO2/AC的微结构、吸收谱特性和掺杂银离子后的半导体带隙变化,并研究了其在可见光下对甲基橙溶液(MO)的降解性能。结果表明,水热法不需要高温处理即可得到高活性的锐钛矿相纳米TiO2,Ag+掺杂和AC负载均明显提高TiO2光催化剂的光催化活性,在可见光下光照180 min,0.2 g/L的Ag+-TiO2/AC对10 mg/L的甲基橙溶液的降解率为73.7%,主要由于存在持续的活性炭局域强吸附-TiO2光催化降解协同作用,明显提高了甲基橙的降解效率。     

微波辅助生物淋滤废旧碱性电池锌锰的溶出

以氧化硫硫杆菌为淋滤菌株对废旧碱性电池电极材料中Zn、Mn进行生物淋滤,考察了生物淋滤、化学浸提和微波辅助处理对Zn、Mn浸出率的影响。实验结果表明,在能源底物单质硫浓度20 g/L、初始pH值1.0、淋滤培养温度35℃、固液比为1%条件下,经过9 d生物淋滤,微波辅助处理的生物淋滤体系Zn、Mn浸出率均达到49%左右,优于其他淋滤体系。溶出动力学研究表明,Zn的溶出动力学符合化学反应控制模型,Mn的溶出则表现较为复杂。此外,SEM-EDS、XRD分析可知,原样经过微波辐照,部分ZnMn2O4分解为MnO,促进了Mn的溶出。     

烟气参数对细颗粒湍流聚并的影响

细颗粒湍流聚并技术是控制燃煤烟气中细颗粒排放的有效措施之一。为了研究烟气参数对湍流聚并效果的影响,在一种细颗粒湍流聚并器中分别对烟气流速、烟气温度、颗粒物浓度以及烟气含湿量进行实验测试。结果表明：烟气流速能显著增大聚并器内湍流强度,提高飞灰颗粒的聚并效率,烟气流速为16 m·s-1时,PM2.5聚并效率为44.51%;烟气温度在酸露点以上时,其对飞灰颗粒聚并效率的促进作用有限;颗粒物浓度越大,则烟道内单位体积的颗粒物数量越多,从而增加了颗粒间的碰撞概率,飞灰颗粒聚并效率明显提高,颗粒物浓度为35 mg·L-1时,PM2.5的聚并效率达到52.48%;烟气含湿量较低时对飞灰颗粒聚并过程影响不大。     

基于HHT的干散货港区大气TSP浓度时频特征分析

为探究干散货港区粉尘污染演化的时间效应,该文应用希尔伯特-黄变换(HHT)对2019年8-12月镇江港兴隆作业区范围内总悬浮颗粒物(TSP)浓度时间序列进行研究。获得不同时间尺度上的本征模态函数(IMF)并提出一种自适应港区的IMF重构分类标准。研究表明,HHT方法于揭示隐含在TSP浓度数据中的物理意义方面具有良好的适用性,利用经验模态分解方法(EMD)可以从数据中剥离出小时、天、周等周期性变化的IMF分量,对于颗粒物污染总体的贡献占到90%以上。同时研究发现,各分量颗粒物浓度呈正偏态分布。结果表明,HHT方法所获得的不同IMF分量可以明晰港区大气颗粒物污染的多尺度特性,对于码头前沿作业区应注重粉尘浓度即时检测值的变化,而堆场区域则应注重较长期的变化值。     

固体废物有价资源机械力化学清洁提取技术的研究进展

有价资源是固体废物循环利用的主要经济驱动力之一,而有价资源的清洁提取一直是固体废物资源化领域的研究重点。简述了机械力化学技术的反应原理,通过文献计量形式重点呈现了机械力化学技术在固体废物有价资源清洁提取方面的研究动态。针对机械力化学技术在多源固体废物,如电子废物、废汽车催化剂、飞灰、含金废渣等有价资源清洁提取方面的研究进展进行了总结和分析,并系统讨论了该技术应用于固体废物有价资源清洁提取的产业优势和技术限制。结果显示,机械力化学技术适用于固体废物中有价金属的清洁提取与绿色再生,而能量利用及转化问题限制了该技术目前的进一步工业化应用。随着研究的持续深入和配套产业的不断进步,机械力化学技术有望成为新一代的固体废物有价资源清洁提取及绿色再生技术。     

Sensorized waste collection container for content estimation and collection optimization

The concurrent effects of a fast national growth rate, of a large and dense residential area and a pressing demand for urban environmental protection create a challenging framework for waste management in Pudong New Area, Shanghai. The complexity of context and procedures is indeed a primary concern of local municipal authorities due to problems related to the collection, transportation and processing of residential solid waste. In order to design and implement a suitable urban solid waste system, the first task is to forecast the quantity and variance of solid waste as it relates to residential population, consumer index, season, etc. The system here discussed addresses exactly these issues, by means of an intelligent, sensorized container. The container has been prepared and tested in the Pudong New Area, Shanghai.     

Superior pillared clay catalysts for selective catalytic reduction of nitrogen oxides for power plant emission control

Fe(3+)-, Cr(3+)-, Cu(2+)-, Mn(2+)-, Co(2+)-, and Ni(2+)-exchanged Al2O3-pillared interlayer clay (PILC) or TiO2-PILC catalysts are investigated for the selective catalytic reduction (SCR) of nitric oxide by ammonia in the presence of excess oxygen. Fe(3+)-exchanged pillared clay is found to be the most active. The catalytic activity of Fe-TiO2-PILC could be further improved by the addition of a small amount of cerium ions or cerium oxide. H2O and SO2 increase both the activity and the product selectivity to N2. The maximum activity on the Ce-Fe-TiO2-PILC is more than 3 times as active as that on a vanadium catalyst. Moreover, compared to the V2O5-WO3/TiO2 catalyst, the Fe-TiO2-PILC catalysts show higher N2/N2O product selectivities and substantially lower activities (by approximately 85%) for SO2 oxidation to SO3 under the same reaction conditions. A 100-hr run in the presence of H2O and SO2 for the CeO2/Fe-TiO2-PILC catalyst showed no decrease in activity.     

高比表面积掺氮多孔炭的制备及其对金霉素的吸附性能研究

以煤沥青为碳源,三聚氰胺为氮源,MgO模板耦合KOH活化一步法热解制备具有高比表面积的掺氮多孔炭MCC_x,其中x代表不同的氮源添加含量。采用比表面积及孔径分布(BET)、扫描电子显微镜(SEM)、傅立叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)等表征方法对MCC_x进行了表征分析,并考察了MCC_x对金霉素的吸附性能。结果表明,当煤沥青与三聚氰胺的质量比为0.5时,制得的MCC_0.5表面富含大量孔道,且伴随堆积褶皱片层,其微孔比表面积可达到2 042 m²·g⁻¹。傅立叶变换红外光谱图表明MCC_x出现了芳香族化合物的C＝N键的伸缩振动。XPS分析结果表明三聚氰胺的添加成功为材料引入氮元素,MCC_0.5吡啶N含量最高。Langmuir吸附等温线模型能很好的描述MCC_0.5对金霉素的吸附过程,最大理论吸附量达到1 056 mg·g⁻¹。     

LANDSCAPE ATTRIBUTES AS CONTROLS ON GROITHD WATER NITRATE REMOVAL CAPACITY OF RIPARIAN ZONES1

ABSTRACT: Inherent site factors can generate substantial variation in the ground water nitrate removal capacity of riparian zones. This paper examines research in the glaciated Northeast to relate variability in ground water nitrate removal to site attributes depicted in readily available spatial databases, such as SSUIRGO. Linking site‐specific studies of riparian ground water nitrate removal to spatial data can help target high‐value riparian locations for restoration or protection and improve the modeling of watershed nitrogen flux. Site attributes, such as hydric soil status (soil wetness) and geomorphology, affect the interaction of nitrate‐enriched ground water with portions of the soil ecosystem possessing elevated biogeochemical transformation rates (i.e., biologically active zones). At our riparian sites, high ground water nitrate‐N removal rates were restricted to hydric soils. Geomorphology provided insights into ground water flowpaths. Riparian sites located on outwash and organic/alluvial deposits have high potential for nitrate‐enriched ground water to interact with biologically active zones. In till deposits, ground water nitrate removal capacity may be limited by the high occurrence of surface seeps that markedly reduce the time available for biological transformations to occur within the riparian zone. To fully realize the value of riparian zones for nitrate retention, landscape controls of riparian nitrate removal in different climatic and physiographic regions must be determined and translated into available spatial databases.