焚烧飞灰预处理工艺及其无机氯盐的行为研究

研究表明WCCB(水洗+烧结)预处理工艺能更高效更节能地去除飞灰中的氯化物,以利于其作为水泥原料的使用.水洗工艺条件为两次水洗、水固比均为3∶1,搅拌速度均为150 r.min-1,第一次水洗时间5 min,第二次水洗时间10 min;利用原焚烧炉进行烧结处理,温度为1 000℃,10%氧气含量,停留时间1 h.本研究尝试了3种焚烧飞灰:节煤器出来的飞灰、石灰干法中和酸性气体后布袋收集的飞灰、NaHCO3中和酸性气体后布袋收集的飞灰.经该工艺处理后,焚烧飞灰残渣量减少20%以上,氯减少94%以上,尤以NaHCO3中和得到的飞灰削减量为最,分别达到了72.1%和99.8%.采用同步辐射的X射线吸收近边精细结构(X-ray absorption near edge structure,XANES)和普通X射线衍射(X-ray Diffraction,XRD)相结合的方法研究分析无机氯盐在工艺过程中的行为,发现焚烧飞灰中主要的氯盐主要有NaCl、KCl和CaCl2.焚烧炉烟气净化系统的酸中和剂会影响无机氯盐的生成.焚烧飞灰中难溶性无机氯盐的结构与Friedel’s盐相似,并且与CaCl2有关系.     

Fate of pharmaceuticals--photodegradation by simulated solar UV-light

The fate of pharmaceuticals in surface waters under solar irradiation was investigated. Photodegradation of pharmaceuticals caused by sun irradiation may be of major significance in the natural elimination process. Based on a data compilation from the literature, the lipid lowering agent metabolite clofibric acid, the iodinated X-ray contrast media iomeprol, which contribute to the adsorbable organic halogen compounds, and the antiepileptic drug carbamazepine were selected. The irradiation experiments were carried out in batch experiments with simulated UV–sunlight. The photodegradation of the pharmaceuticals showed a pseudo-first-order kinetics. The objective of this investigation was to demonstrate that the extent of photoinduced degradation of pharmaceuticals can vary significantly for the different pharmaceuticals and it strongly depends on the water constituents present in solution. The influences of different initial pharmaceutical concentrations, the presence of other pharmaceuticals like carbamazepine or clofibric acid and the presence of natural organic matter on the photochemical degradation rate of pharmaceuticals in aqueous solutions were investigated. Analyses of the pharmaceuticals and their photodegradation products were carried out by high performance liquid chromatography with diode-array and fluorescence detection.     

TiO2/Ag modified penta-bismuth hepta-oxide nitrate and its adsorption performance for azo dye removal

A modified hydrophilic penta-bismuth hepta-oxide nitrate (Bi₅O₇NO₃) surface was synthesized via a precipitation method using TiO₂ and Ag as modified agents. The synthesized product was characterized by different analytical techniques. The removal efficiency was evaluated using mono-and di-sulphonated azo dyes as model pollutants. Different kinetic, isotherm and diffusion models were chosen to describe the adsorption process. X-ray photoelectron spectroscopy (XPS) results revealed no noticeable differences in the chemical states of modified adsorbent when compared to pure Bi₅O₇NO₃;however, the presence of hydrophilic centres such as TiO₂ and Ag developed positively charged surface groups and improved its adsorption performance to a wide range of azo dyes. Dyes removal was found to be a function of adsorbent dosage, initial dye concentration, solution pH and temperature. The reduction of Langmuir 1,2-mixed order kinetics to the second or first-order kinetics could be successfully used to describe the adsorption of dyes onto the modified adsorbent. Mass transfer can be described by intra-particle diffusion at a certain stage, but it was not the rate limiting step that controlled the adsorption process. Homogenous behavior of adsorbent surface can be explored by applying Langmuir isotherm to fit the adsorption data.     

Recovery of phosphorus as struvite from sewage sludge ash

Phosphorus (P) is an element vital for all living organisms, yet the world's reserves of phosphate rock are becoming depleted. This study investigated an effective P recovery method from sludge ash via struvite precipitation. Results showed that more than 95% of the total P content was extracted from sludge ash by applying 0.5 mol/L HCl at a liquid/solid ratio of 50 mL/g. Although heavy metal leaching also occurred during P extraction, cation exchange resin efficiently removed the heavy metals from the P-rich solution. Orthogonal tests showed that the optimal parameters for P precipitation as struvite would be a Mg:N:P molar ratio of 1.6:1.6:1 at pH 10.0. X-ray diffraction analysis validated the formation of struvite. Further investigations revealed that the harvested precipitate had a high struvite content (97%), high P bioavailability (94%), and low heavy metal content, which could be considered a high quality fertilizer.     

国内外体内X射线荧光骨铅检测系统比较研究

血铅生物半衰期较短,只能反应人体短近铅中毒状况,存在一定局限性;骨铅生物半衰期较长,能够反应人体铅负荷的累积效应,有必要进行检测。体内X射线荧光骨铅检测系统从发明至今已有30多年的历史,文章根据激发源的不同将其分为三类系统进行分析讨论,作为国内开展相关研究工作的借鉴。     

铅蓄电池企业废气中铅及其化合物便携式XRF检测方法

在企业污染源现场实现污染物排放浓度水平的快速判定和超标风险筛查,对生态环境管理部门提高执法效率、企业提高环境管理水平意义重大。铅是一种对人体危害极大的有毒重金属,目前缺少含铅废气中铅及其化合物的便携式直读检测设备和检测方法。探索性地将X射线荧光光谱(XRF)法应用于铅蓄电池企业含铅废气中铅及其化合物的便携式快速、直读检测。研究结果表明,基于XRF的面密度法适用于铅蓄电池企业含铅废气处理设施后铅及其化合物的快速、直读检测,相对国标方法具有快速、直读、对样品无损、便于复测等特点,可用于铅及其化合物排放浓度水平的快速判定和超标风险筛查。     

重构土壤垂直剖面重金属Cd赋存形态及影响因素

针对矿业废弃地高背景值-历史矿业源相叠加区下土壤重金属Cd污染问题,以西南地区某历史硫磺矿业废弃地重构土壤为研究对象,采集剖面土壤共30个样品,分析测试土壤样品中镉(Cd)、铬(Cr)、镍(Ni)、砷(As)和汞(Hg),利用电镜扫描-能谱分析(SEM-EDS)和重金属形态连续提取的BCR方法,分析不同土层厚度下Cd的赋存形式,运用风险评价编码法(RAC)和次生相与原生相分布比值法(RSP)对其进行有效性评价,以及对不同理化性质下Cd各形态的变化规律进行了初步探讨.结果表明,研究区5种重金属中Cd全量的富集系数最高,达4以上;通过形貌特征可以发现,样品中存在较多的次棱角状、棱角状颗粒,不同深度下的能谱特征显示结果相似,均含有Cd、Fe、S和As等元素,Cd元素是以类质同象形式存在;对Cd进行潜在风险评价,RAC结果显示为中等风险及以下,RSP结果主要为重度污染;重金属全量是影响Cd各形态含量分布的最主要因素,其次pH、有机质和CEC,对垂直深度的土壤Cd赋存形态也表现出不同程度的影响.该研究结果可为进一步了解Cd在剖面土壤的活性、迁移规律、生物毒性和赋存形式提供科学依据.     

钙质闪石11种阳离子占位度的X射线衍射测定

本义对前期[1][2]的理论分析成果进行修改和验证。前期曾用大量文献上的晶体结构参数仅演为理论的X射线树木图，从中选出若干条特征峰，用逐步回归方法对其强度比与钙质闪石的11种阳离子占位度问，建立一系列经验公式，用以估算未知的钙质冈石样品阳离子占位度，精度在85％－98％之间，多数阳离子精度超过90％．在闪石晶体化学研究上具有重要意义的阳离子如M1、M3位中Mg、Fe2＋、A位的K、三缺值Em及万位的Si等精度均超过90％；晶体化学类型定名的准确度达85％。成果表明，利用X射线衍射法估算闪石的阳离子占位在理论上是可能的。但还有待于用实测数据检验其可行性。本次工作的日的，便是以实测数据来验证前期理论成果并确定其可靠性。通过反复改变衍射圈上特征反射的选择和改变样本数，以实测结果验证各种组合建立的线性模型，所估算的各品位各种阳离子占位数的准确度在78％－96％之间，大多数大于80％，接近或超过90％的有八位的K、空缺值Em、位的Mg、Fe没＋及T位的Si等。晶体化学类型定名的准确度可达80％。但在建立线性模型时，必须将理沦计算的粉末国与实测阁一起进行统计。所选用的实测样品愈多，该族矿物种后愈广泛，则建立的模型的代表性也愈广泛，可靠程度愈高。这一成果证实了用此类方式建立的     

闪石X射线衍射谱上特征峰强度测定的实验研究

本文为《闪石族类质同象及晶体化学的X射线研究》这一专题的系列论文之二，阐述实验方法中的关键问题。通过用特殊的磨样及采用毛玻璃压样，结合计算拟合修正衍射强度等方法，研究了如何减轻乃至消除闪石族样品X射线图中310择尤取向问题，得出较为理想的结果。并讨论了如何判断在制样过程中可能产生的诸如水化、轻度蚀变及键定无序等影响强度测定精度的问题。提出了可行的实验方案。所提方法，对其他涉及修正强择尢取向的X射线衍射图的许多问题均可资借鉴。     

Study on activated carbon in chromium-containingwastewater treatment by XPS

Ｓｔｕｄｙｏｎａｃｔｉｖａｔｅｄｃａｒｂｏｎｉｎｃｈｒｏｍｉｕｍ－ｃｏｎｔａｉｎｉｎｇｗａｓｔｅｗａｔｅｒｔｒｅａｔｍｅｎｔｂｙＸＰＳＹａｎｇＪｕｎ；ＷａｎｇＹｕｎｘｉｕ（ＳｈａｎｄｏｎｇＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ，Ｊｉｎａｎ２５０...