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1.
In flotation, metal ions possess significant roles that are usually fulfilled by either selectively activating or depressing the target minerals. Despite that tremendous efforts have been made to address the roles of metal ions in flotation, it still lacks a comprehensive review, especially to compare various ions instead of focusing on a specific one. This review begins by elaborately categorizing the factors involved in affecting the roles of metal ions in flotation. After that, well-accepted mechanisms are updated and discussed from the ore type. Furthermore, typical approaches to explore the underlying mechanisms are emphasized, including traditional techniques such as micro-flotation, contact angle measurement, zeta potential measurement, and other recent prevailing methodologies, like computational method, solution chemistry calculation, and cyclic voltammetry. This work will pave the way to promote flotations via activities like selectively adding/reducing metal ions, choosing reagents, and regulating the slurry chemistry.  相似文献   
2.
目的 提高缓蚀剂在酸溶液中的缓蚀性能.方法 构建含有2-巯基苯并噻唑(MBT)以及不同浓度Cl–的Fe表面溶液模型,并进行分子动力学计算.观察缓蚀剂分子在Fe表面的吸附构型,考察不同Cl–值下缓蚀剂膜的致密化行为.提取缓蚀剂分子的均方位移(MSD)曲线,评价缓蚀剂膜的稳定性.计算水分子的密度分布和扩散系数,考察不同Cl–值下MBT缓蚀剂膜的驱水能力和水分子的迁移能力.结果 当Cl–值从0增加到25时,MBT膜的厚度(0.42~1.51 nm)和致密度(占有面积0.33~1.31 nm2)增加,缓蚀剂分子的自扩散系数减小(从1.25×10–9 m2/s到接近0),水分子的吸附峰强度(相对密度为72.3~33.9 nm–3)和扩散系数(1.495×10–9~0.627×10–9 m2/s)降低.当Cl–值从25增加到36时,则出现了相反的趋势.结论 缓蚀剂分子与Cl–之间存在协同作用,适当浓度的KCl可以提高MBT缓蚀剂在H2SO4溶液中的缓蚀性能.Cl–值为25时,MBT缓蚀效率最高.  相似文献   
3.
The disintegration of waste active sludge was investigated by photo‐Fenton processes. A batch study was conducted to evaluate parameters, such as Fe2+ and Fe0 ions and H2O2, governing the activated sludge integration by the photo‐Fenton process. Under optimum conditions, the concentration of soluble chemical oxygen demand (SCOD) with the classical Fenton process (CFP) increased very rapidly in the first five minutes due to the sufficient presence of reaction components in the medium, and then the rate of increase declined. In the modified Fenton process (FTP), the SCOD concentration increased more slowly as metallic iron powder must first be dissolved. The photo‐Fenton process proved to be a feasible and efficient process for the disintegration of waste sludge.  相似文献   
4.
Polyvinylidene fluoride (PVDF) has several crystal forms of which the α-form is nonpolar, while the β-form is polar and has the highest piezoelectric constant. α PVDF, when stretched, transforms into the β form, which has wide applications in sensors and actuators. Steered molecular dynamics simulations are used to study the transformation of a single chain of PVDF from a trans–gauche conformation to an all trans one. The Helmholtz free energy change (∆F) is estimated using Jarzynski's equality. The transformation starts at the chain ends followed by the transformation of the remaining chain. The free energy change for the transformation is found to be always positive, indicating that the TGTG' form has higher thermodynamic stability than the all trans form throughout the studied temperature range. With increasing temperature, free energy change for the transformation increases monotonically.  相似文献   
5.
通过辉钼矿单矿物浮选试验,Ca2+, Mg2+的溶液化学计算及辉钼矿表面Zeta电位和XPS检测,对比研究了Ca2+, Mg2+对辉钼矿可浮性影响的差异性。结果表明,Ca2+, Mg2+均会吸附于辉钼矿表面,改变辉钼矿表面Zeta电位并对辉钼矿的可浮性产生抑制作用,且随pH值增大,抑制作用增强;碱性条件下Mg2+对辉钼矿可浮性的抑制强于Ca2+,且pH>9.0时,两种离子抑制作用的差异性更明显;pH=11.0时,Mg2+为800 mg/L的矿浆中辉钼矿的回收率较Ca2+为800 mg/L的矿浆中辉钼矿的回收率下降约34个百分点;Ca2+, Mg2+均能与辉钼矿“棱”上的MoO42–结合形成钼酸盐沉淀,通过化学吸附的形式存在于辉钼矿表面;当pH>9.15时,钙仍以Ca2+, Ca(OH)+的形态存在并吸附于辉钼矿表面,且Ca2+矿浆Zeta电位随pH增大呈上升趋势,但镁则以Mg(OH)2形态沉积于辉钼矿表面,且Mg2+矿浆Zeta电位随pH增大迅速降低,这是两种离子对辉钼矿可浮性抑制作用不同的主要原因。  相似文献   
6.
非水系氧化还原液流电池(NARFB)的广泛应用受制于其较低的性能。在电解液中加入一些金属离子添加剂是一种可能的解决方案。实验研究了Sb3+离子对低共熔溶剂(DES)电解液液流电池电化学性能的影响。结果表明,添加Sb3+离子可以强化V(Ⅲ)/V(Ⅱ)氧化还原离子对的电化学反应动力学(最高可达22.6%)过程,钒离子在DES中的扩散系数提高了63.3%,并且电荷转移电阻降低了11.9%。场发射扫描电子显微镜表明,Sb3+离子电沉积在石墨毡的表面,对电化学反应起催化作用,从而改善了电化学性能。考虑增强的动力学和降低的活性比表面积之间的平衡,确定了Sb3+的最佳浓度为15 mmol·L-1。此外,当使用含有Sb3+的负极电解液液流电池时,液流电池的功率密度提高了31.2%,从含原始电解质的3.08 mW·cm-2到含15 mmol·L-1 Sb3+离子的4.04 mW·cm-2。这些结果为改善NARFB的电池性能提供了一个便捷而有前景的方法。  相似文献   
7.
ZnO rice like nonarchitects are grafted on the graphene carbon core via a rapid microwave synthesis route. The prepared grafted systems are characterized via XRD, SEM, RAMAN, and XPS to examined the structural and morphological parameters. Zinc oxide grafted graphene sheets (ZnO-G) are further doped in β-phase of polyvinylidene fluoride (PVDF) to prepare the polymer nanocomposites (PNCs) via mixed solvent approach (THF/DMF). β-phase confirmation of PVDF PNCs is done by FTIR studies. It is observed that ZnO-G filler enhances the β-phase content in the PNCs. Non-doped PVDF and PNCs are further studied for rheological behavior under the shear rate of 1–100 s−1. Doping of ZnO-G dopant to the PVDF matrix changes its discontinuous shear thickening (DST) behavior to continues shear thickening behavior (CST). Hydrocluster formation and their interaction with the dopant could be the reason for this striking DST to CST behavioral change. Strain amplitude sweep (10−3% -10%) oscillatory test reveals that the PNCs shows extended linear viscoelastic region with high elastic modulus and lower viscous modulus. Effective shear thickening behavior and strong elastic strength of these PNCs present their candidature for various fields including mechanical and soft body armor applications.  相似文献   
8.
Due to the low concentration of silver in water, most of the cellulose adsorbents exhibited low removal efficiency, which greatly limited their practical applications. Herein, a cellulose aerogel modified by thiosemicarbamide (CAT) was fabricated for reducing and adsorbing silver ions from low concentration wastewater. The characterization results concluded that CAT owned a three-dimensional spongy structure with many circular microspheres and a better specific surface area (19.37 m2 g−1), as well as the functional groups of ─C═N+─H and ─(C═S)─N. The static batch adsorption experiments demonstrated that CAT could reached the maximum removal percentage of 94.94% and adsorption capacity of 42.12 mg g−1 under the initial concentration of Ag(I) was 15 mg L−1 and the pH value was 7. Meanwhile, the adsorption of Ag(I) on CAT was second-order reaction, and the Langmuir model could better fit the adsorption process. In addition, CAT exhibited wide pH values (1–9) adaptability and excellent adsorption performance for silver through electrostatic interaction, chelation, and reduction. This study probably provides a new method as well as important experimental data and theoretical reference for the removal of silver ions and other metals.  相似文献   
9.
四种纳滤膜对高盐废水分盐效果分析   总被引:1,自引:0,他引:1  
为了使煤化工零排放高盐废水分盐产出高质量NaCl和Na_2SO_4结晶盐,提高废水处理过程的分盐效率,以宁东某煤化工零排放高盐废水的水质情况模拟配制了无机盐溶液,选取了膜1、膜2、膜3和膜4等4种商用纳滤膜,探讨了其对模拟高盐废水中的常规离子(Mg~(2+)、 Ca~(2+)、 Na~+、 K~+、 SO_4~(2-)、 Cl~-、 NO_3~-)的截留率,并考察了4种纳滤膜的水通量和分盐效果。结果表明,4种膜对阳离子的截留率从高到低依次为Ca~(2+)> Mg~(2+)> K~+> Na~+;对SO_4~(2-)的截留率为95%~99%,对Cl~-和NO_3~-截留率为负值;4种纳滤膜产水侧ρ(Cl~-)/ρ(SO_4~(2-))值由大到小依次为膜1>膜4>膜2>膜3,纳滤膜1表现出更好的无机盐离子截留率和分盐效果。  相似文献   
10.
为开发具有高效过滤性能的膜材料,以超支化季铵盐(HBP-HTC)为枝化促进剂,利用静电纺丝技术一步法制备了聚偏氟乙烯(PVDF)树枝状纳米纤维膜,探讨了纺丝工艺对纤维膜成形结构的影响,分析了树枝状纳米纤维膜的力学性能及其空气过滤性能。结果表明:由于HBP-HTC表面丰富的季铵基团具有对电荷的稳定富集作用,可获得比用小分子季铵盐制成膜更多的树枝状纳米纤维结构,当PVDF质量分数为12%,季铵基团添加量为 0.10 mol/L, 纺丝电压为25 kV时,制得的纤维膜树枝状覆盖率高达78.32%,且具有较好的力学性能;所制备的纳米纤维膜厚度为40 μm时,其过滤效率高达99.995%,而压降为122.4 Pa。  相似文献   
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