交联氧化铝-壳聚糖新杂化吸附剂的制备及去除废水中Cu(Ⅱ)(英文)

A novel biosorbent was developed by coating chitosan,a naturally and abundantly available biopolymer,on to activated alumina based on oil shale ash via crosslinking.The adsorbent was characterized by various techniques,such as Fourier transform infrared spectroscopy,scanning electron microscopy,thermogravimetric-differential thermal analysis,and X-ray photoelectron spectroscope.Batch isothermal equilibrium adsorption experiments were condcted to evaluate the adsorbent for the removal of Cu(Ⅱ) from wastewater.The effect of pH and agitation time on the adsorption capacity was also investigated,indicating that the optimum pH was 6.0.The equilibrium adsorp-tion data were correlated with Langmuir and Freundlich models.The maximum monolayer adsorption capacity of chitosan coated alumina sorbent as obtained from Langmuir adsorption isotherm was found to be 315.46 mg·g-1 for Cu(Ⅱ).The adsorbent loaded with Cu(Ⅱ) was readily regenerated using 0.1 mol?L?1 sodium hydroxide solution.All these indicated that chitosan coated alumina adsorbent not only have high adsorption activity,but also had good stability in the wastewater treatment process.     

原料粒度对煤矸石烧结砖结构和性能的影响

将煤矸石粉碎至三种不同的粒度,经过陈腐、压制成型、干燥、烧成后制得煤矸石烧结砖。利用X射线衍射仪、扫描电子显微镜研究烧结砖的物相组成和显微结构,并对其抗压强度和吸水率等性能进行了研究。结果显示,煤矸石原料的粒度和烧结保温时间对烧结砖的吸水率和抗压强度有较大影响。利用粒度小于0.15mm的煤矸石原料制备的烧结砖综合性能较好,1100℃烧结3h时,吸水率为17.63%,抗压强度达到22.47MPa,符合普通烧结砖的有关国家标准要求。     

污泥含炭吸附剂的制备及其吸附模拟烟气中汞蒸汽的应用(英文)

The carbonaceous adsorbent was prepared from mixtures of dewatered sludge and sawdust with enhanced ZnCl2 chemical activation.Characteristics of the adsorbent were studied using scanning electron microscope(SEM) ,Fourier transform infrared spectroscopy(FT-IR) ,and adsorption of nitrogen.The surface analysis showed that the carbonaceous adsorbent had good specific surface and porosity(394 m 2 ·g-1of BET surface,0.12 and 0.10 ml·g-1of microporous and mesoporous volume,respectively) .The oxygen functional groups such as OH,C O and C O were found on the surface by FTIR and XPS(X-ray photoelectron spectroscopy) .The adsorption of elemental mercury(Hg0) on the carbonaceous adsorbent was studied in a fixed bed reactor.The dynamic adsorption capacity of carbonaceous adsorbent increased with influent mercury concentration,from 23.6μg·g-1at 12.58μg·m-3to 87.9μg·g-1at 72.50μg·m-3,and decreased as the adsorption temperature increased,from 246 μg·g-1 at 25°C to 61.3μg·g-1 at 140°C,when dry nitrogen was used as the carrier gas.The carbonaceous adsorbent presented higher dynamic adsorption capacity than activated carbon,which was 81.2μg·g-1and 53.8μg·g-1respectively.The adsorption data were fitted to the Langmuir adsorption model.The physical and chemical adsorption were identified on the adsorbent.     

孔隙尺寸、盐度和气体组分对水合物相平衡的影响(英文)

An experimental device was set up to study the hydrate formation conditions. Effects of pore size, salinity, and gas composition on the formation and dissociation of hydrates were investigated. The result indicates that the induction time for the formation of hydrates in porous media is shorter than that in pure water. The decrease in pore size, by decreasing the size of glass beads, increases the equilibrium pressure when the salinity and temperature are kept constant. In addition, higher salinity causes higher equilibrium pressure when the pore size and temperature are kept constant. It is found that the effects of pore size and salinity on the hydrate equilibrium are quite different. At lower methane concentration, the hydrate equilibrium is achieved at lower pressure and higher temperature.     

原料粒度对高压干法成型机成型效果的影响

介绍了兖矿洁净煤厂的主要生产设备--立磨系统、烘干锤式破碎机系统和高压对辊成型机系统的工作原理;试验分析了煤粉粒度对型煤成型效果的影响,结果表明,细粒煤粉成型样品的冷压强度、跌落强度均较高。     

粉煤灰粒度对泡沫混凝土性能的影响

选取5个不同细度及粒度分布的粉煤灰试样,试验研究了不同粒度粉煤灰掺入对泡沫混凝土抗压强度,导热系数,吸水率性能的影响,研究结果表明,泡沫混凝土的性能与5μm,5μm~10μm含量有密切关系,小颗粒越多,泡沫混凝土的抗压强度值越高,但是其吸水率不断下降与导热系数不断升高的趋势。     

粉煤灰粒度分布对水泥性能的影响

主要研究了不同粉磨时间的粉煤灰密度、比表面积、粒度分布等颗粒特性的变化规律,以及研究了将不同粉磨时间的粉煤灰按30％比例掺人硅酸盐水泥中的水泥性能变化情况.结果表明：随着粉磨时间的增加,粉煤灰颗粒的密度、比表面积和粒度分布都呈有规律的变化;其中粉磨60 min时的粉煤灰水泥性能达到最佳.     

碱-磷渣-粉煤灰胶凝材料的性能与硬化浆体结构

为充分利用磷渣和粉煤灰两种工业废渣生产高性能胶凝材料,研究了不同磷渣/粉煤灰配合比的碱-磷渣-粉煤灰胶凝材料性能,并用扫描电子显微镜和压汞仪分析了硬化浆体的细观结构和孔结构.结果表明:碱-磷渣-粉煤灰胶凝材料的凝结时间正常,在粉煤灰掺量为0～30 %(质量分数)范围内,随粉煤灰的掺量的增加,碱-磷渣-粉煤灰胶凝材料的凝结时间略有延长.与普通硅酸盐水泥相比,碱-磷渣胶凝材料的抗压强度较高,其3d和28d抗压强度分别可达到30.9MPa和98.8MPa,但其抗折强度相对较低.掺加粉煤灰后碱胶凝材料的抗压强度降低,而抗折强度提高.碱-磷渣-粉煤灰胶凝材料的耐蚀性和抗冻性能均显著优于硅酸盐水泥,其干缩比硅酸盐水泥的大.用部分粉煤灰取代磷渣粉可一定程度减小干缩.碱-磷渣-粉煤灰胶凝材料硬化浆体的结构非常致密,其孔隙率和平均孔径均小于普通硅酸盐水泥硬化浆体.     

赤泥原料及其对吸附剂吸附性能的影响

赤泥的堆放会对环境造成污染,但其具有较高的吸附性能,因此研究制备赤泥吸附剂能达到以废治废的目的。实验分别采用平果和德保赤泥制备吸附剂,研究了赤泥原料及赤泥吸附剂的物相组成,采用除氟及除铜实验研究了赤泥产地及赤泥堆放时间对吸附剂吸附性能的影响。结果表明,以平果、德保赤泥制备的吸附剂,在焙烧温度500℃、焙烧2 h、溶液p H值为6的条件下,氟浓度可分别从19 mg/L降低到0.21、0.19 mg/L;铜浓度可分别从64 mg/L降低到0.32、0.51 mg/L。对氟的吸附容量均可达0.94 mg/g;对铜吸附容量分别可达3.18、3.17 mg/g;对氟、铜的去除率分别在99%、98%以上。     

钢渣作为铁质校正原料对水泥熟料性能的影响(英文)

探讨了钢渣作为一种铁质校正原料在水泥生料配料中的应用,通过掺加不同含量的钢渣,对其易烧性进行了研究,并对不同钢渣掺量的熟料进行了力学性能研究。用X射线衍射和扫描电子显微镜等对水泥水化进程和水化产物进行了分析。结果表明:钢渣作为一种铁质校正原料,在水泥熟料中的掺量可以达到6%～10%,3组不同钢渣掺量、不同率值的水泥生料在1450℃烧成30min后,熟料抗折强度和抗压强度分别达到9.0MPa和58MPa以上。     

Structure and properties of forming adsorbents prepared from different particle sizes of coal fly ash

In this paper, different particle sizes of coal fly ash FA-R (D50=15.75μm), FA-A (D50=3.61μm) and FA-B (D50=1.73μm) were treated with NaOH solution to prepare the forming adsorbents FFA-R, FFA-A and FF...     

Effect of particle size and alkali activation on coal fly ash and their role in sintered ceramic tiles

We focus on fly ashes of different sizes and their alkali-activation on ceramic products. Backscattered electron imaging-energy dispersive X-ray spectroscopy was used to classify coal fly ash particles according to particle size and to study the pre-activation of particles with different sizes. Secondary electron imaging-energy dispersive X-ray spectroscopy was used to study the role of coal fly ash particles of different sizes in ceramic bodies before and after alkali-activation. Ash particles can be divided into three classes based on size: clay-, quartz- and feldspar-like particles, which act as clay, quartz and feldspar, respectively, in ceramic bodies. The pre-activation process contributes to the plasticity of ash particles, the crystal skeleton role of clay-like particles and the fluxing agent role of feldspar-like particles, so preprocessing can improve the performance of ash-based ceramic tiles significantly. This research provides a new pretreatment method for coal fly ash in ceramic fields.     

Effects of particle size on microstructure and mechanical strength of a fly ash based ceramic membrane

Recycling fly ash for ceramic membrane fabrication not only reduces solid waste discharge, but also decreases the membrane cost. Now, fly ash is becoming a promising substitute material for ceramic membrane preparation. A significant difference between fly ashes from different plants is the particle size, which makes performances of fly ash membranes unpredictable. The novelty of this work is to clarify the effects of the particle size of fly ash on ceramic membranes, thereby giving practical suggestions on fly ash selection for ceramic membrane preparation. Ceramic membranes were fabricated with different sizes of fly ashes. Effects of particle size on porosity, pore size, microstructure, mechanical strength and gas permeability of the membrane were investigated. Results indicate that a broader particle size distribution of fly ash leads to a denser structure of membrane with a lower porosity. Pore size and gas permeability of membrane increase while bending strength decreases with the particle size increasing. Bending strength of a fly ash membrane is largely determined by large particles in the fly ash because the large particles lead to cracks in the membrane. This work provides experimental bases for developing high performance ceramic membranes from fly ash.     

Hydrothermal synthesis of zeolites from coal fly ash

The fly ash, from the combustion of coal to produce energy and heat, is an industrial waste, in which large accumulations represent a serious environmental threat. To reduce the environmental burden and improve the economic benefits of energy production, the science and industry focus on the transformation of coal combustion byproducts into new functional materials. The fly ash was studied by modern analytical methods. As a result of the hydrothermal reaction, several types of zeolites were synthesised from the fly ash: analcime, faujasite (zeolite X) and gismondine (zeolite P). It was shown that the experimental conditions (temperature, reaction time and alkali concentration) have a significant influence on the type of zeolite and its content in the reaction products. The series of experiments resulted in building approximate crystallisation field of zeolites and other phases as the first stage of the formation of ceramic membrane and other materials.     

粉煤灰在酸性废水处理中的应用

粉煤灰是燃煤电厂排放的固体废弃物。近年来,人们开始致力于粉煤灰在环境保护方面的开发利用,其处理废水已经成为研究的热点之一。本文综述了近年来国内粉煤灰处理工业酸性废水的研究进展,并介绍了粉煤灰处理酸性废水的机理、存在的问题及其应用前景。     

Adsorptive removal of thiophene and benzothiophene over zeolites from Mae Moh coal fly ash

Zeolites have been hydrothermally synthesized using Thai coal fly ash from Mae Moh Power Plant as silica and alumina sources. The synthesis conditions, i.e., SiO₂/Al₂O₃ ratio, amount of water, amount of base, and aging temperature, were varied to prepare different topologies of zeolitic products. The zeolites attained were sodalite (SOD), gismondine (GIS), and cancrinite (CAN). The zeolites have been applied to adsorption of thiophene and benzothiophene in n-hexane solution. It was found that GIS with higher specific surface area and average pore volume had superior performance to other synthesized materials. Adsorption capacity of our developed zeolites was compared to those of commercial zeolites, i.e. NaY, HUSY, beta, and ZSM-5 obtained via the conventional synthesis methods. The results suggested a potential of zeolites derived from Mae Moh coal fly ash for removal of refractory sulfur compounds, such as benzothiophene.     

Investigations on Cr mobility from coal fly ash

Coal fly ash, which is a source of metals emission to environment, was researched. Investigations on Cr chemical fractions and their environmental mobility in ash-solution system were carried out. In order to obtain results repeatedly, the conditions of sequential extraction of Cr from coal fly ash were optimized. It was found that Cr in coal fly ash occurs in the following fractions (mg kg⁻¹): exchangeable (2.5), associated to carbonates (4.0), associated to organic matter and sulfides (8.5), associated to Fe-Mn oxides (16.0), and residual (41.6). Mobility fractions of Cr contain 8.2% of its total concentration in the fly ash in environmental conditions. The obtained results indicate that coal fly ash is a source of environmental contamination by Cr especially, in soils where its utilization is inadequate.     

分选与磨细粉煤灰对水泥胶砂性能的影响

研究了分选与磨细粉煤灰的颗粒分布与形貌的差异及对水泥胶砂性能的影响。研究结果表明:当勃氏比表面积相近,磨细粉煤灰的中位粒径大于分选细粉煤灰,其圆珠状颗粒较少,表面较为粗糙。在相同水胶比的条件下,掺分选粗粉煤灰的水泥胶砂流动度及强度均低;分选粗粉煤灰磨细后,不仅减少了颗粒的粘连,增加了比表面积,而且提高了粉煤灰的反应活性和水泥胶砂流动度及强度,虽其水泥胶砂流动度仍小于掺分选细粉煤灰的水泥,3d水泥胶砂强度也略低,但其28d水泥胶砂强度略高于掺分选细粉煤灰的水泥;在相同水泥胶砂流动度的条件下,掺磨细粉煤灰配制的水泥胶砂3d强度低于掺分选细粉煤灰的水泥,但随着水化龄期的增长,其差距逐步缩小,至60d时可超过后者。     

Production of glass from coal fly ash

The coal fly ash from a Chinese thermal power plant was vitrified after the addition of ∼10 wt% Na₂O. The glass products have suitable viscosity at 1200 °C and displayed a good chemical durability. The heavy metals of Pb, Zn, Cr and Mn were successfully immobilized into the glass as determined by the toxicity characteristic leaching procedure method. Results indicate an interesting potential for the coal fly ash recycling to produce useful materials.     

Influence of trace metal distribution on its leachability from coal fly ash

The risks associated with the reuse of coal fly ash in natural environmental settings in terms of their mobility and ecotoxicological significance is largely determined by: (1) the physicochemical conditions the fly ash is placed under; (2) the total leachable metal content in fly ash and; (3) the distribution or mineralogical fractionation of metals. In this study, we report the mobility of As, Cr, Pb, Fe, Cu and Zn from a single Class F fly ash (CFFA). The influence of pH on metal release was compared to the total leachable metal content, as determined by single and sequential chemical extractions. The results show that the CFFA sample is environmentally safe under natural pH conditions, with metal leaching less than the mandated RCRA limits. The elements Fe, Pb and Cr were moderately soluble at acidic pH and sparingly soluble beyond neutral pH. Arsenic release from CFFA was higher under aggressive pH conditions (pH < 4 and pH > 9) and consistent with its oxyanionic behavior. Partial dissolution of the acid soluble (exchangeable) fraction at acidic pH; desorption of oxyanions at alkaline pH; adsorption and or co-precipitation of metals with iron (hydr) oxides at neutral pH appeared to be the probable mechanisms controlling metal release. While simple EDTA extractions provided good indications of the total leachable amounts, a direct correlation with pH leaching data was impossible as the mineralogical distribution of the metals in the fly ash appeared to play a significant role in their leachability. In the case of Class F fly ash, metal association with Fe-oxide appeared to play a more dominant role in metal release.