利用吸附技术提取盐湖卤水中锂的研究进展

综述了无机吸附剂提取盐湖卤水中锂的研究进展。详细叙述了铝基吸附剂,层状离子交换吸附剂,钛基、锑基和锰基锂离子筛的提锂原理及发展现状,并根据物质结构特点指出了各类吸附剂的优势以及在提锂过程中存在的不足,提出了相应的改进方向。作为一种新型、高效、绿色的提锂剂,锰基吸附材料的发展前景被普遍看好,重点讨论了锰基吸附材料制备手段及掺杂改性研究,并对其发展进行了展望。     

Vacuum membrane distillation of seawater reverse osmosis brines

Seawater desalination by Reverse Osmosis (RO) is an interesting solution for drinking water production. However, because of limitation by the osmotic pressure, a high recovery factor is not attainable. Consequently, large volumes of brines are discharged into the sea and the flow rate produced (permeate) is limited. In this paper, Vacuum Membrane Distillation (VMD) is considered as a complementary process to RO to further concentrate RO brines and increase the global recovery of the process. VMD is an evaporative technology that uses a membrane to support the liquid-vapour interface and enhance the contact area between liquid and vapour in comparison with conventional distillation. This study focuses on VMD for the treatment of RO brines. Simulations were performed to optimise the operating conditions and were completed by bench-scale experiments using actual RO brines and synthetic solutions up to a salt concentration of 300 g L⁻¹. Operating conditions such as a highly permeable membrane, high feed temperature, low permeate pressure and a turbulent fluid regime allowed high permeate fluxes to be obtained even for a very high salt concentration (300 g L⁻¹). For the membrane studied, temperature and concentration polarisation were shown to have little effect on permeate flux. After 6 to 8 h, no organic fouling or biofouling was observed for RO brines. At high salt concentrations, scaling occurred (mainly due to calcium precipitation) but had only a limited impact on the permeate flux (24% decrease for a permeate specific volume of 43L m⁻² for the highest concentration of salt). Calcium carbonate and calcium sulphate precipitated first due to their low solubility and formed mixed crystal deposits on the membrane surface. These phenomena only occurred on the membrane surface and did not totally cover the pores. The crystals were easily removed simply by washing the membrane with water. A global recovery factor of 89% can be obtained by coupling RO and VMD.     

Iodinated contrast media oxidation by nonthermal plasma: the role of iodine as a tracer

The oxidation of trace pharmaceutical compounds in wastewater desalination streams by nonthermal plasma (NTP) was evaluated. Brines from a two stage-RO pilot plant process as well as two sources of tertiary effluents, ultrafiltrated secondary effluents and membrane biological reactor effluents, were comparatively tested with ultra-pure water. The non-ionic and ionic iodinated contrast media (ICM) compounds, iopromide (IOPr) and diatrizoate (DTZ), respectively, were used as model compounds. The neurostabilizer drug carbamazepine (CBZ) was used for reference purposes. Based on deiodination profiles, two distinct patterns of initial oxidation could be established for the ICM. The time profile of deiodination and transformation paralleled for DTZ, indicating that transformation of the aromatic ring is the main initial pattern of transformation. For IOPr, a considerable lag phase of deiodination was observed, suggesting that oxidation of the alkyl chains rather than ring oxidation is the main pattern of initial transformation. Although transformation rate of IOPr was higher compared to DTZ, the rate and degree of deiodination was higher for DTZ than IOPr. Both ICM displayed a markedly lower susceptibility to NTP oxidation compared to CBZ. However, the kinetics of IOPr transformation seems to be less affected by the water matrixes, compared to DTZ and CBZ. Whereas NTP mediated oxidation of ICM followed first-order kinetics, a better fit to Harris model was found for CBZ. As a result of the NTP oxidation, treated brines and effluents displayed a substantial increase in biodegradability (measured as BOD).To conclude, NTP displayed a high potential for treating reluctant pharmaceuticals active compounds such as ICM, even at the background of relatively high DOC concentrations, as can be found in treated effluents and desalination brines, and with no need for chemical additives.     

共轭亚油酸高产菌株的分离与鉴定

共轭亚油酸(CLA)因具有抗肿瘤、增强免疫力、抗动脉粥样硬化、减肥、抗氧化等功效,在医药与保健食品领域显示了巨大的应用潜力。目前获得CLA的主要途径是化学合成法,化学合成法产量高,但产物异构体众多,成分复杂,分离提纯困难,生物法因其反应条件温和,产物成分较单一,在食品医药领域展现出了良好前景。为筛选共轭亚油酸高产菌株,本文在有氧条件下,采用MRS培养基从泡菜环境中分离出16株产共轭亚油酸的菌株,其中PC-3菌株具有较高的CLA转化率,且能将亚油酸转化为具有生物活性的c9,t11-CLA和t10,c12-CLA。经形态学特征(扫描电子显微镜)分析、生理生化试验分析(API-50CHL)及16S r DNA序列分析及同源性分析,PC-3菌株被鉴定为植物乳杆菌(Lactobacillus plantarum PC-3),其16S r DNA基因序列长度为1460 bp,该序列Gen Bank的登陆号为JX270774.1。     

Aluminum silicate scale formation and inhibition: Scale characterization and laboratory experiments

Amorphous silica scale enriched in aluminum is deposited from a variety of geothermal brines. Scale deposits examined in the present study are formed by tetrahedrally-coordinated aluminum substitution within an amorphous silica framework. There is no evidence that aluminum in these scales derives from distinct aluminum minerals, such as gibbsite, or from aluminum silicate minerals transported in brine from the reservoir. The formation of aluminum-rich amorphous silica scale is dependent on brine pH, temperature and aluminum concentration. Silica and aluminum exhibit concentration minima in brines at near-neutral pH. Aluminum-rich silica scales dissolve more slowly than pure amorphous silica in water and brine. Lowering brine pH below 5 or increasing it above 9 retards the kinetics of silica polymerization and the formation of aluminum-rich silica. Laboratory studies demonstrate that sequestering agents such as citric acid, acetic acid, and ethylenediaminetetraacetic acid (EDTA) may inhibit aluminum silicate scale formation.     

Extraction of Lithium Using TBP and the Noncoordinating Cation Exchanger Tetraphenylborate: Principles of Selectivity from Sodium and Higher-Valent Cations

Extraction of lithium, calcium, and some other metal cations using tetraphenylborate/tributyl phosphate mixtures has been studied. The possibility of a qualitative change in the cation exchange extraction series towards the preferential recovery of lowly-charged (singly-charged) metal cations was shown for these systems. A change in the separation factors for singly- over multiply-charged cations in this system, compared to the known commercially available extractants such as alkylphosphoric, carboxylic, and other organic acids, is several orders of magnitude and increases when passing from doubly- to triply-charged metal cations, reaching, for example, values of 10³ and more for the lithium/yttrium couple. It was assumed that the change in the extraction series was caused by the instability of the salts of the multiply-charged metal cations compared to that for the singly-charged cations due to the ionic character of the bond with the extracted metals and structural problems caused by the large volume of the tetraphenylborate anion. The investigated system can serve as a model for the development of a new class of extractants having a higher selectivity for singly-charged metal cations, in particular, for lithium.     

Chemical thermodynamics in geothermal operations

Chemical thermodynamics of geothermal brines are important in every aspect of geothermal development, starting from initial stages of exploration to the final stages of utilization. Yet there are serious gaps in the knowledge of high temperature thermodynamics of aqueous fluids. The critical areas of chemical thermodynamics that need serious evaluation include: (1) chemical and physical characteristics of aqueous solutions at high temperatures, (2) solubility and phase behaviour of numerous inorganic solids in aqueous media at high temperatures, (3) solubility and flash behaviour of gases in equilibrium with aqueous media at high temperatures and (4) cement, metal and other material resistivity to any mechanical and/or chemical degradation in various high temperature aqueous environments. The present paper reviews the status of the various aspects of chemical thermodynamics. The emphasis is placed in reviewing the various methodologies used in predicting scale formation and gas flashing during the production of geothermal brines. Various well-known models used in obtaining the chemical thermodynamic information are also critically reviewed. The general lack of knowledge on the data bases related to solubility of various species in high temperature brine is clearly pointed out. Based on the critical review of chemical thermodynamics of geothermal brines, the following conclusions are made: 1. The basic chemical thermodynamics of aqueous systems at high temperatures are not well known. 2. There is a lack of a thorough and reliable data base related to the phase behaviour of inorganic solids and their solubilities in aqueous media at high temperatures. 3. The solubilities and flash behaviours of gases in equilibrium with aqueous media at high temperatures and high pressures are not well known.     

D403树脂从盐湖卤水中提取硼酸的探索试验

中国很多的盐湖卤水中都富含大量的硼矿资源，使用硼特效离子交换树脂从中提取硼酸是利用盐湖卤水中硼矿资源的一条重要途径。针对D403型硼特效离子交换树脂从盐湖卤水中提取硼酸的性能进行了探索试验，考察了该树脂对卤水中硼的吸附性能、洗脱性能，以及对卤水中钙镁等杂质离子的吸附洗脱性能。结果表明，D403树脂对卤水中硼的吸附量较低，但其在盐酸中的洗脱性能较好；对卤水中钙镁等杂质离子的吸附量不大，较易被去离子水洗脱。     

下辽河平原南部盐卤水资源开发现状及利用规划

下辽河平原南部拥有较丰富的盐卤水资源,普遍储存于第四系含水层中,在一定的范围内已有地方百姓进行开采利用,主要应用于制造工业盐。近几十年来,辽宁省、盘锦市、辽河油田等部门为了不同目的在本地区分别开展过地质和水文地质工作,对区域地层、岩性结构、地质构造、地下水特征、成因等方面积累了一些资料。本文对盐卤水的工业利用品位进行评价,为下一步开发利用盐卤水资源、确定合理的布井和综合开发方案以及防止盲目的开发打下了基础。