Determination of the apparent rate constants of the degradation of humic substances by ozonation and modeling of the removal of humic substances from the aqueous solutions with neural network

In this study, the degradation rate constants of humic substances by ozonation under the different empirical conditions such as ozone-air flow rate, ozone generation potential, pH, temperature, powdered activated carbon (PAC) dosage and HCO(3)(-) ions concentration were determined. The ozonation of humic substances in the semi-batch reactor was found to fit pseudo-first-order reaction. The values of apparent rate constant of humic substances degradation increased with the increase of initial ozone-air flow rates, ozone generation potential, pH, temperatures and PAC dosage, but decreased with the increase of HCO(3)(-) concentration of the solution. Using Arrhenius equation, the activation energy (E(a)) of the reaction was found as 1.96 kJ mol(-1). The reaction of ozonation of humic substances under the different temperatures was defined as diffusion control according to E(a). The model based on artificial neural network (ANN) could predict the concentrations of humic substances removal from aqueous solution during ozonation. A relationship between the predicted results of the designed ANN model and experimental data was also conducted. The ANN model yielded determination coefficient of (R(2)=0.995), standard deviation ratio (0.065), mean absolute error (4.057) and root mean square error (5.4967).     

Effect of humic substances on Cu(II) solubility in kaolin-sand soil

The type and amount of organic matter present in industrially contaminated soils will influence the risk they pose. Previous studies have shown the importance of humic and fulvic acids (FAs) (important components of soil organic matter) in increasing the solubility of toxic metals but were not carried out using toxic metal levels and the pH range typical of industrially contaminated soils. This study investigated the influence of three humic substances (HSs: humates, fulvates and humins) on the solubility of copper(II) ions in kaolinitic soil spiked with Cu at levels representative of industrially contaminated soil. Humates, fulvates and humin were extracted from Irish moss peat, and controlled pH batch leaching tests were conducted on an artificial kaolin-sand soil that was spiked with each. Further leaching tests were conducted on soil spiked with each HS and copper nitrate. Dissolved organic contents were determined by titration and total and free aqueous copper concentrations in the leachate were measured using AAS and ion selective electrode (ISE) potentiometry respectively (dissolved complexed copper levels were determined by difference). It was found that humates and fulvates are partially sorbed by the soil, probably by chemisorption on positively charged gibbsite (Al-hydroxide) sites in the kaolinite. The addition of 340 mg/kg Cu(II) ions did not significantly affect the amount of humate or fulvate sorbed. Dissolved humates and fulvates form soluble complexes with copper over the pH range 3-11. However, in the presence of kaolinite, soluble copper humates and fulvates are unable to compete with the kaolinite for Cu ions at pH 6-7. Above pH 8, humate and fulvate complexes are the only forms of dissolved Cu. Humin is largely insoluble and has little effect on Cu mobility between pH 2 and 12. The implication of this study is that measurement of total soil organic content and water leaching tests should be a standard part of contaminated site investigation.     

Sorption of metal ions on lignite and the derived humic substances

The study presents results of sorption of metal ions (Pb2+, Zn2+, Cu2+, and Cd2+) onto lignite mined in South Moravia, Czech Republic, and solid humic substances (humin and humic acid) derived from it. The efficiency of these sorbents has been studied as a function of contact time, solution pH, and metal concentration. The sorption efficiencies were higher for humin and lower for humic acid samples than for the original lignite. With its high sorption capacities of several mmol/g, particularly for Pb2+ and Cd2+, the South Moravian lignite can provide a cheap source material for preparation of sorbents utilizable in removal of toxic metals from wastewaters.     

超滤膜分离渗滤液腐植物质的压力影响研究

超滤处理渗滤液膜生物反应器(MBR)出水,考察操作压力(0.3～0.7 MPa)对分离腐植物质(HS)的影响.结果表明,0.6MPa时浓缩液中TOC随体积因数Fv的增加幅度最大,0.4～0.6 MPa时浓缩液中HS浓度均大幅升高,但0.7 MPa时浓缩液HS浓度仅小幅上升,且HS占总TOC的百分比低于进料液;0.3MPa、0.4 MPa时透过液中TOCC随Fv的增加幅度明显高于其他压力条件;各压力下无机盐离子的截留情况比较相似,Fv=5时,Na、K、Mg离子的截留率约为30%,Fe离子约为50%,Ca离子约为15%;重金属离子的变化情况在低压下基本一致,在0.7 MPa时有所不同;0.6 MPa时HS与盐分的分离效果最好,在本实验条件下0.6MPa为最佳操作压力.压力对TOC和HS的浓缩、透过液中TOC的变化以及HS与盐分的分离效果有明显影响,对无机盐离子和重金属离子的变化影响不明显.     

Assessment of removal of components containing hazardous substances from small WEEE in Austria

Minimum treatment requirements for waste electrical and electronic equipment (WEEE) established by Directive 2002/96/EC provide for the removal of specific components containing hazardous substances. To date, no comparative analysis of removal rates has been undertaken. The present paper examines the state of de-pollution of sWEEE in Austrian treatment plants. The mass of selected components removed and the corresponding mass of hazardous substances is compared to estimated values for sWEEE input material. The results obtained reveal that components are only partly removed, featuring a high variation between components and plants assessed. The overall rate of removal ranged from 72% of the estimated value for batteries to 21% of the estimated value for liquid crystal panels. This implies the forwarding of substantial quantities of hazardous substances to mechanical treatment processes, particularly relevant in terms of dispersion of pollutants. Furthermore, easily releasable pollutants, such as Hg from LCD-backlights, Cd from batteries or highly contaminated dust in general, pose substantial health risks for plant workers. Low removal rates of printed circuit boards, batteries and toner cartridges also lead to a reduction in quantities of valuable recyclable materials (precious metals, plastics).     

浊度和腐植酸对超滤膜污染过程的研究

对超滤膜污染的两种数学模型－滤饼层过滤模型和膜孔窄化模型进行了理论分析，结合用国产中空纤维超滤膜对浊度和腐植酸混合液进行直接过滤试验的结果，证明两种模型均可描述超滤膜污染过程，并说明腐植酸是造成膜污染的主要物质，但膜孔污染主要发生在膜过滤的初期，而膜表面沉积污染发生在膜过滤的中期。     

Integrated system of databases on the properties of inorganic substances and materials

An integrated system of databases on the properties of inorganic substances and materials has been developed, currently combining the database of the A.A. Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, and an AtomWork database on the properties of inorganic substances, developed at the National Institute for Materials Science (Japan). This system is developed as an information service for specialists and for computer-aided design of new inorganic compounds, which was supported by an elaborate information-analytical system. The results of application of this system for compound design that have not yet been synthesized are presented.     

Volume dependence of the bulk modulus of inorganic substances

An equation describing the change in the bulk modulus with the variation of the volume under high pressure or temperature is derived. It is shown that the derivatives ∂B/∂V for 56 metals and 120 ionic crystals MX (X = H, F, Cl, Br, I) vary from 4.2 to 5.4. Original Russian Text ? S. S. Batsanov, 2009, published in Neorganicheskie Materialy, 2009, Vol. 45, No. 4, pp. 509–512.     

瓜环对部分腐殖酸模型物去除的规律研究

根据腐殖酸的结构特点选取适当模型物,采取紫外-可见分光技术研究瓜环的投加量、时间、温度及pH值对腐殖酸模型物去除的规律。研究表明,模型物的结构是影响瓜环对腐殖酸模型物去除的最主要因素,其中羧基和芳环是影响瓜环对模型物吸附效果的主要基团;瓜环对腐殖酸及其模型物的吸附主要为物理吸附,并且吸附有较宽的pH值范围;瓜环对腐殖酸模型物去除作用的较优条件为瓜环投加量1.8g/L,初始浓度20mg/L,平衡时间5h。在此条件下,瓜环对腐殖酸模型物苯甲酸、2-萘酚、萘、苯甲醚及腐殖酸的去除率分别为94.52%、98.24%、81.52%、85.66%和99.85%。     

Key issues in the targeted synthesis of inorganic substances

Chemistry is a science concerned with conversion of substances. From the chemical point of view, a substance is an assemblage of interacting particles, which is characterized by four properties: composition, structure, type of chemical bonding, and particle size. A conversion of a substance is a change in one or several of its properties. Targeted synthesis is a way of controlling a conversion of a substance. This paper considers thermodynamic and kinetic issues in targeted synthesis that are associated with control over the composition, structure, characteristic features of chemical bonding, and particle size and, hence, with the identification of conditions for the preparation of a substance with tailored properties. The concept of pure substance is discussed, which is an important issue for materials research and inorganic chemistry. It is pointed out that the composition of compounds should be characterized not only by their stoichiometry and impurity concentration but also by the related concentrations of native defects and impurities. In connection with this, a defect classification is presented and defect formation processes and techniques for controlling the defect composition are analyzed. Statistical criteria for assessing the compositional homogeneity of a pure substance are considered.     

机械力化学效应对煤矸石物理性能的影响

用高能行星磨对煅烧后煤矸石进行机械力化学活化,通过XRD、SEM和FI-IR分析,研究了粉磨过程中煤矸石的粒度、密度、形貌和显微结构的变化情况.结果表明:煤矸石属于易磨性物质,极易细化,球磨处理后的煤矸石,颗粒表面光滑,高岭土晶相消失,α-石英结晶程度降低,Al-O键和Si-O键键能和键结构发生了明显的变化,煤矸石活性提高.     

机械力化学效应对锅炉底渣理化特性的影响

为了考察机械力化学效应对锅炉底渣理化特性的影响,采用高能球磨机对锅炉底渣进行球磨,并使用粒度测试、密度测试、XRD、SEM、FI-IR及DSC检测手段,分析其粒度、密度、矿物性能、显微形貌及热力学性质在不同球磨时间下的变化.结果表明:随着球磨时间的增加,锅炉底渣的粒度减小,密度增加;形貌明显改变,颗粒趋于球形,且分布均匀;锅炉底渣中的莫来石、石英等晶相遭到破坏;Al—O—Si、Si—O—Si键断裂,非晶态Al2O3、SiO2增加,有利于提高锅炉灰渣的活性.并确定了在实验条件下最佳球磨时间为9 h.     

On-the-fly fluorescence lifetime detection of humic substances in capillary electrophoresis

On-the-fly fluorescence lifetime detection was investigated as a tool for studying humic substances in capillary zone electrophoresis (CZE). Humic substances are complex, heterogeneous mixtures of natural products that tend to migrate in a single, broad CZE peak. The intrinsic fluorescence lifetime of five humic substances from the International Humic Substances Society (IHSS) was monitored using excitation at 488 or 364 nm to produce intensity-lifetime electropherograms for each of the substances. Each frequency-domain lifetime measurement, collected at subsecond intervals during the CZE run, contains the equivalent of a complete decay profile. Lifetime analysis of each decay profile was used to construct a lifetime-resolved electropherogram for each lifetime component, from which the variation in relative intensity contributions of each lifetime across the broad CZE peak could be determined. Absorption spectra, fluorescence excitation-emission spectra, and lifetime profiles of batch solutions of the samples were determined as well. It was found that, whereas absorption and fluorescence spectral characteristics tended to discriminate between humic acids and fulvic acids, the batch solution lifetime profiles discriminated instead between samples from different sources, regardless of fraction. On-the-fly lifetime detection provided a more detailed view of the fluorescence decay of the samples, including greater resolution of lifetimes for two of the fulvic acids and greater discrimination among samples based on lifetime profiles across the CZE peaks.     

Influence of mechanochemical pretreatment on leaching of silver in cyanide and non-cyanide medium

The leaching of silver from a mechanochemically pretreated silver-bearing complex sulphide concentrate of Peruvian origin (Casapalca) has been studied. The results with as-received concentrate have shown very low extraction of silver (up to 5.7%) in all cases of leaching. The mechanochemical pretreatment has caused 85% amorphization of tetrahedrite as silver-bearing mineral and an increase in the specific surface area of the concentrate from 0.3 m² g^?1 to a maximum value of 15.7 m² g^?1. This fact manifested itself in the subsequent process of silver extraction. By application of thiosulphate and thiourea leaching 99% recovery of Ag was reached already after 3-5 min of leaching.     

含腐殖酸类有机物模拟废水超滤过程研究

研究了用中空纤维超滤膜组件净化含腐殖酸类有机物模拟废水的过程.考察了料液中Ca2 浓度、离子强度和pH值对超滤过程的影响.实验结果表明,由于Ca2 与腐殖酸分子发生络合反应,随着料液中Ca2 浓度的增大,膜污染程度加剧;料液离子强度的变化改变了腐殖酸分子的构型和溶质分子之间以及溶质分子与膜面之间的相互作用,随着溶液离子强度的增大,膜通量下降程度增大;料液pH值的降低减少了腐殖酸分子链上官能团中H 的离解度,随着pH值的降低,膜污染程度增大;同时,随着料液中Ca2 浓度、离子强度的增大以及pH值的降低,膜对腐殖酸的脱除率降低.     

无机组分对聚酰亚胺杂化薄膜电性能的影响

初步探讨了聚酰亚胺薄膜在电场作用下的电学行为,采用溶胶-凝胶工艺制备了聚酰亚胺/二氧化硅纳米杂化薄膜,并对薄膜进行浸水24 h处理,利用原子力显微镜对制备的薄膜进行表面形貌表征,讨论了无机组分SiO2和水对薄膜电性能的影响.结果表明:无机组分的引入及两相间的界面形态将对杂化薄膜的电学性能产生重大的影响;偶联剂的引入使得两相间产生紧密的微相结合,并对电性能产生一定的影响.     

Separation factors for the crystallization of inorganic substances from aqueous solutions

A method is proposed for evaluating separation factors for the crystallization of inorganic substances from aqueous solutions. The method allows the interaction between components of mixed electrolyte solutions to be assessed using basic data for binary solutions of the impurity and major component.     

ACF阳极氧化法去除水中腐殖酸的研究

以活性炭纤维毡为阳极,不锈钢片为阴极,采用电化学氧化法处理了含腐殖酸的水溶液.结果显示,该方法可有效去除水中的腐殖酸,对于初始浓度为50mg/L的腐殖酸溶液,在适宜条件下电解120min后,腐殖酸和COD去除率可分别高达93.81%和92.60%.实验考察了溶液pH值、电流密度、支持电解质浓度、腐殖酸的初始浓度和阳极材...