新疆夏子街膨润土的柱撑化改性及吸附性能研究

以新疆夏子街钠基膨润土为原料,制备了无机柱撑膨润土和无机—有机柱撑膨润土,考察了溶剂及配比等对柱撑膨润土的影响。无机柱撑膨润土的合成条件为[OH-]/[Al3+]=2.2,Al3+/土=15mmol/g。膨润土应用于城市污水的吸附研究结果表明:膨润土原矿对废水中COD去除率为38.5%,无机柱撑膨润土在最优吸附条件下对废水中COD去除率达到91.85%,无机—有机柱撑膨润土在最优吸附条件下对废水中COD去除率达到97.12%。     

膨润土的铝酸脂表面改性研究

为提高无机膨润土与有机塑料的相容性,强化两者的复合效果,研究了铝酸脂对膨润土的偶联改性行为。以沉降体积和粘度为评价指标,考察了单次物料用量、改性温度、改性剂用量及改性时间等对膨润土改性效果的影响,并利用红外光谱分析探讨了铝酸脂对膨润土的改性机理。结果表明：铝酸脂偶联剂对膨润土的改性效果明显,较佳改性条件为改性温度110 ℃,改性剂用量3.0%,改性时间30 min;铝酸脂偶联剂对膨润土的改性同时存在化学吸附和物理包覆作用。     

我国膨润土资源概况及开发利用现状

葫芦岛市位于锦西-哈尔套膨润土成矿带的最南端,为探究葫芦岛膨润土的特性,对葫芦岛的6个膨润土矿进行了研究,通过测定试样的膨胀容、亚甲基蓝吸收量、阳离子交换容量和X射线衍射分析,对葫芦岛膨润土的表观特性、矿物组成、膨胀性能和阳离子交换性等性能进行了评价和表征。研究表明：葫芦岛膨润土矿均为钙基膨润土矿,总体质量较好,大部分膨润土的粒度均匀、自然白度较高,蒙脱石平均含量接近或高于70%。葫芦岛膨润土矿的石英、长石、方解石是主要脉石矿物,矿物组成比较简单,阳离子交换性能较好,在辽西地区膨润土矿中处于中上等地位,具有较强的代表性。然而,辽西膨润土普遍含有方石英,限制了产品的应用范围。     

钒钛铁精矿润磨试验研究

针对川威集团自产的钒钛铁精矿,在钒钛铁精矿、膨润土理化性能测定结果基础上,进行了钒钛铁精矿的润磨、成球试验研究,探究了该钒钛铁精矿较佳的润磨工艺参数。     

超细膨润土/环氧树脂复合材料的结构与热性能

采用TG-DTA、IR、SEM、马丁耐热和Daniel流动点测定等方法,研究了有机胺改性超细膨润土与环氧树脂的固化体系的结构及其性能。结果表明,有机胺改性膨润土与环氧树脂固化复合后,可形成由层问固化与层外固化相结合的结构,所得复合材料的耐热性能、分散性均有提高,其中活化有机膨润土／环氧树脂复合体系的分散效果和马丁耐热特性改善更加显著。     

Utilisation of waste clay from boron production as a landfill liner material

The objective of this study was to investigate the potential utilisation of waste clay from boron production in sanitary landfills. The waste clay (CW) was mixed with bentonite (B) and waste tyre (TW) at different ratios. Results show that, any of the CW-TW mixtures were not acceptable to use in landfills because of insufficient bearing capacity values. On the other hand, CW and 2B/98CW mixtures have sufficient values from the point of experimental tests. As a conclusion, it has been concluded that CW can be used as a liner material for landfills without an addition.     

Arsenic (V) removal from aqueous solutions using natural clay ceramic monoliths

Abstract

An adsorbent material arranged in a ceramic monolith (CM) obtained by extrusion technique using natural bentonite and alumina (as raw materials) is presented. Ceramic and raw materials were characterized by X-ray fluorescence, thermal analysis, X-ray diffraction, and textural analysis (with N₂ adsorption–desorption at 77?K and Hg intrusion–extrusion porosimetry) to determine their chemical and physical properties. Then, As (V) adsorption capacity of the CM at different pH (3–9) using arsenic aqueous solution (with 2000?µg As (V) L^?1) was evaluated. Additionally, studies of kinetics and equilibrium of As (V) adsorption on CM were performed. It was found that: (i) the As (V) removal capacity is favored at acidic pH, reaching an average value of 15?µg As (V) per gram of CM; (ii) from kinetic studies, As (V) adsorption on CM occur in two stages, the first of them reaching a lower As uptake in a short time period, followed by an slow second stage with a subsequent higher As uptake, which continued for a longer time period, reaching equilibrium conditions in approximately 24?h; and (iii) the As (V) adsorption isotherm is a type-Langmuir, indicating that the CM present an homo quantity of fixed sites to adsorb the As (V).     

Investigating the mechanism of downslope bentonite erosion in GCL liners using X-Ray CT

Exposed composite GMB-GCL liners are at risk of downslope bentonite erosion caused by the release of low ionic strength condensed water onto the top surface of the GCL following daily solar heating. This paper investigates the use of X-ray computed tomography (X-ray CT) to quantify the thinning of the bentonite layer and the application of X-ray diffraction techniques (XRD) to investigate the changes in clay chemistry (if any) of the bentonite from the virgin GCL to the eroded bentonite. The effect of specimen size and scanning orientation was investigated resulting in a revised testing procedure in which the CT scanning orientation was changed from horizontal to vertical to permit a longer test specimen which was also sealed at the bottom edge to minimise the edge boundary condition. The X-ray CT results provide highly visual evidence that a) bentonite thinning immediately under the upper cover geotextile is the initial location of erosion, and b) the bentonite core erodes at a significantly higher rate when not covered by a geotextile than when covered by a geotextile. These observations indicate that the upper geotextile of the GCL plays a significant role in controlling the rate of bentonite erosion. Finally, a comparison of the virgin and runoff bentonite properties was conducted to investigate potential changes in swell index, X-ray diffraction results, and concentration of Na and Ca cations. The runoff bentonite was observed to had a significantly higher swell index (40?ml/2?g) than the virgin bentonite (28?ml/2?g) and lower Na and Ca concentrations. This finding is consistent with the observation from XRD analyses of the runoff bentonite which illustrate that the clay fraction of the bentonite is preferentially eroded by the application of DI water.     

Bentonite deposits of Northern Patagonia

Some Argentine North Patagonia bentonite deposits have been characterised by chemical and differential thermal analysis (DTA), X-ray diffraction and Isoelectric Point (IEP), Cation Exchange capacity (CEC) and specific surface area (S) determinations.Samples with high degree of tetrahedral isomorphic substitution, and consequently high interlayer cation charge compensation, would be used as organic pollutant adsorbent when the adsorption was a cation exchange mechanism.     

Elemental sulfur fertilizers and their use on crops and pastures

This paper reviews the use of elemental sulfur (S°) as a fertiliser and its efficacy in different pastoral and cropping situations. The effect of S° particle size on rate of oxidation is critical to the effectiveness of S° fertilisers. Emphasis is therefore centred on the issue of how particle size of S° affects the rate of oxidation in different environments and cropping systems, and the size of S° in different S° fertiliser products. Rate constants of S° oxidation offer the opportunity to generalise particle size relationships needed in S° fertilisers for different crops in different environments, or alternatively, to calculate the agronomic effectiveness of different S° fertilisers available on the market. Conversely they offer a technique to set specifications as to S° particle size requirements, which together with dispersion rate specifications provide the basis for the design of S° fertilisers for specified crops and environments.