Physiochemical Properties of Gamma-Irradiated Tri-iso-amyl Phosphate–Dodecane System: Effect of Aqueous Phase Acidity

ABSTRACT

Tri-iso-amyl phosphate (TiAP) in dodecane (DD) is emerging as a potent alternative for the extraction of suitable actinides from nitric acid solutions comprising various metal ions. A detailed investigation on the evolution in physicochemical properties upon gamma irradiation of TiAP-DD system has been carried out. Physical properties, such as density, viscosity, phase disengagement time, interfacial tension, etc., were measured for neat as well as irradiated solvent phases. Effect of aqueous phase acidity, which is an important parameter during extraction, on the hydrodynamic properties of the solvent during radiolysis was compared. ATR–FTIR spectroscopy of the irradiated phase was compared to find out the formation of new classes of compounds, if any.     

TPE and RE Extraction during Long-lived Radionuclide Partitioning in Combination with PUREX-process Using a Single TBP-Based Solvent

ABSTRACT

Extraction of ²⁴¹Am and ¹⁵⁴Eu by 50% tributyl phosphate (TBP) in C13 fraction from nitric acid solutions containing 6 mol L^?1 nitrate-ion of ammonium, aluminum, and iron salts has been investigated. Rig trials with transplutonium elements (TPE) and fission rare earth (RE) recovery from the evaporated raffinate of reprocessed WWER-1000 spent fuel were carried out in hot cells using mixer-settlers. The HLW feed acidity was adjusted by dissolving metallic iron up to 1 mol L^?1 Fe(NO₃)₃. TPE and RE were recovered by 99.98% with DF from ¹³⁷Cs > 7500. The combined extraction-partitioning cycle of a Modified Purex-process is proposed using 50% TBP as the single solvent.     

填料塔中磷酸钠缓冲溶液吸收低体积分数SO2的体积传质系数

为满足磷酸一钠和二钠缓冲溶液脱硫设计开发的需要,采用磷酸钠缓冲盐溶液为吸收剂,测定和计算了在鲍尔环填料塔中磷酸钠溶液吸收模拟烟气中SO2的体积总传质系数KYa.在常温常压下,考察了空塔气速、喷淋密度、入口SO2体积分数、吸收液磷酸根浓度和初始pH等工艺参数对KYa的影响.结果表明,KYa随着空塔气速、喷淋密度、初始pH和磷酸根浓度的增加而增大;随着入口SO2体积分数的增加先增加后减小;该体系的传质过程受气膜和液膜共同控制.     

酸性废水在选矿中的应用

根据弱酸性介质环境下H2PO4-对磷矿物有较好的抑制作用,利用磷酸装置、磷酸一铵装置和磷石膏渣场产生的酸性废水（含H2PO4-）作为反浮选调整剂进行选矿,选矿指标平稳,生产周期由5d延长至15d,硫酸与工艺水消耗降低.     

400 kt/a磷酸二铵装置成品冷却系统的节能技术改造

针对磷酸二铵装置成品冷却系统能耗高的问题进行了工艺优化及风机变频调速的技术改造.改造后,成品冷却系统的电耗降低1.422 kW·h/t,煤耗降低3.4 kg/t,且设备维修费用下降,年节能降耗总效益达154万元.     

澄清磷酸工艺在磷铵生产中的应用

阐述磷铵生产中澄清磷酸的目的,介绍红磷分公司采用稀磷酸陈化-沉降工艺、浓磷酸两级沉降和陈化-沉降工艺,以及添加絮凝剂、延长磷酸停留时间等澄清磷酸的控制措施,可将浓磷酸w（固）控制在1％以下.     

磷石膏综合利用现状及分析

介绍磷肥行业磷石膏综合利用现状,分析当前磷石膏综合利用存在的问题及水泥、建材等相关行业石膏制品的发展状况.面对环境保护的严格要求及节能减排的艰巨任务,提出磷石膏综合利用的建议及措施.     

前驱体二水磷酸铁对磷酸铁锂电化学性能的影响

以钛白生产副产物七水硫酸亚铁为铁源,工业磷酸二氢铵为磷源,双氧水为氧化剂,采用共沉淀法合成了不同粒径和形貌的二水磷酸铁,并以此为前驱体,通过碳热还原法制备了粒径不同的LiFePO₄/C正极材料。经过对样品进行X射线衍射（XRD）、扫描电镜（SEM）以及恒电流充放电测试,研究了二水磷酸铁及LiFePO₄/C的结构、形貌以及电化学性能。结果表明,以较细的二水磷酸铁为铁源,制备得到的LiFePO₄/C颗粒较细,且具有更优异的电化学性能。0.1、0.5、1、2、5、10 C放电比容量分别为154、148、144、140、130、120 mA·h/g。     

Effect of fluoride varnish with added casein phosphopeptide-amorphous calcium phosphate on bond strength to enamel

To investigate the effect of fluoride varnish with added casein phosphopeptide-amorphous calcium phosphate on the shear bond strength (SBS) of two adhesive systems to enamel. Specimens obtained from permanent teeth were randomly distributed among four groups for enamel pretreatment [Control (no treatment, CNT), Duraphat varnish (DV), Clinpro White varnish (CWV), MI Varnish (MIV)], and each group was further divided into two subgroups according to adhesive [Etch&rinse (Adper Single Bond, ASB), self-etch (Clearfil SE Bond, CSE)]. Specimens were stored in distilled water at 37 °C for 24 h. Cylindrical composite specimens (2.3 mm in diameter, 3.0 mm in height) were then bonded to the enamel surfaces. SBS tests were performed and data were analyzed with two-way ANOVA and Tukey’s tests. For both CSE and ASB, SBS values of the CNT groups were significantly higher than those of all the enamel pretreatment groups (p < 0.05). Among the enamel pretreatment groups, SBS values with both adhesive systems were lowest in the MIV groups, followed by CWV and DV groups. In conclusion, pretreatment of enamel surfaces with fluoride-containing varnishes reduced bonding performance of adhesive systems to enamel. MIV appeared to cause greater enamel surface alterations and precipitation, which interfered with adhesive bonding mechanisms.     

Complexes of Silver(I) Ions and Silver Phosphate Nanoparticles with Hyaluronic Acid and/or Chitosan as Promising Antimicrobial Agents for Vascular Grafts

Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes.