锂是重要的战略金属和新能源材料,其开发利用受到全球的高度关注。在高盐卤水特别是盐湖卤水和地下卤水中富含巨量的锂资源,在对这些资源进行锂的开发利用过程中,需对锂的含量进行准确测定,然而卤水中共存的高浓度Na+, K+, Ca2+和Mg2+会对微量锂的准确测定产生严重的干扰。电感耦合等离子体发射光谱法（ICP-OES）具有线性范围宽和多元素同步分析能力,针对卤水中锂的快速准确测定,详细开展了高盐样品中锂的ICP-OES分析方法研究。结果表明,锂在610.364 nm处具有较高的信噪比,且Na+, K+, Ca2+, Mg2+和Ar不会对锂的测定产生显著的谱线干扰。然而,样品中大量共存的Na+, K+和Mg2+会对锂的测定产生严重的基体正干扰,而Ca2+产生负干扰。尽管内标法在消除基体干扰方面具有广泛的应用,但传统的以钇和钪为内标元素的内标法不能有效解决该问题。此外,针对标准加入法操作繁琐、不适合批量样品分析问题,以及基体匹配法需多离子匹配,且不适合样品基体组成变化的批量样品分析等问题,考察了采用单一组分进行复杂基体匹配的可行性。由于NaCl广泛存在于卤水中,且对锂的测定具有显著的增敏效应,通过系列研究发现,通过同时向样品和标准溶液中加入10 g·L-1的NaCl,成功解决了总量不超过40 g·L-1的NaCl, KCl和MgCl2所产生的干扰。尽管采用该法或沉淀预分离方式均不能消除Ca2+产生的负干扰,但当样品中Ca2+含量不高于1.8 g·L-1时,对测定不产生显著的影响。通过采用该方法对三种不同基体组成的卤水样品进行加标回收测定,其回收率在96.60%～104.20%范围内。此外,通过与电感耦合等离子体质谱法（ICP-MS）测定结果进行对比,充分论证了该法的准确性和可靠性（相对误差±3.66%）。该法仅以单一的NaCl进行复杂基体匹配,不仅简化了操作,还实现了基体组成变化的批量样品分析,因而在卤水中锂的快速准确测定及锂资源开发利用方面具有重要意义。

With the increasing demands for lithium, the recovery of lithium from liquid minerals has become a research focus worldwide. The green recovery of a low concentration of lithium from geothermal water was carried out in this work based on the LiFePO4/FePO4 technique. The composite LiFePO4 electrode was prepared first and then electrochemically delithiated to obtain a FePO4 electrode. When the LiFePO4 and FePO4 electrodes were used to construct an electrochemical system in an H-type electrolytic cell, it had high response to low concentrations of Li+ at 1.0 V. The electrochemical adsorption capacity was successfully increased by 57.02% which was 17.10 mg g(-1) in the geothermal water by using PEG-6000 as a poregen to obtain pore structures on the surface of electrode. The recovery rate of Li+ reached 90.65% after eight adsorption-desorption cycles. Subsequently, a novel electrochemical device was proposed for the recovery of low concentrations of Li (+) by the LiFePO4/FePO4 technique. Only electrical energy was consumed and no organic solvents or other toxic reagents were used during the recovery process. All these properties make the developed method a green and promising candidate for the recovery of Li+ from geothermal water. (C) 2019 Elsevier Ltd. All rights reserved.

Solubilities, densities and refractive indices of the ternary system (LiCl+SrCl2+H2O) at 273.15K were determined using the isothermal dissolution equilibrium method. The phase diagram of the system consists of two invariant points, three univariant solubility curves and three crystallization areas corresponding to LiCl2H(2)O, SrCl(2)2H(2)O and SrCl(2)6H(2)O. Applying the Pitzer and Harvie-Weare model, the Pitzer mixing parameters and the solubility product constants (K-sp) of solid phases were fitted to the solubility data; then, the solubilities of this ternary system were predicted. A comparison shows that the calculated solubilities agree well with the experimental results. The phase diagram and Pitzer model for the ternary system at 273.15 and 298.15K were then used to conduct a computer simulation of brine separation. Lithium chloride and strontium chloride salts can be separated completely by six steps in the brine separation process. This result of the simulation of brine separation can be used as a theoretical reference guideline for salt separation and purification of brine systems.

柴达木盆地南翼山地区油田卤水属于氯化钙型,富含丰富的锶资源,具有很高的开采价值。本文采用等温溶解法研究了具有油田卤水组成特征的复杂体系子体系CaCl2–SrCl2–H2O 288.15 K稳定相平衡,测定了该体系的溶解度和固溶体组成。研究发现,上述体系形成钙锶固溶体（Ca,Sr）Cl2·6H2O,体系属于固溶体型。采用Pitzer和Harvie-Weare电解质溶液理论[1],结合文献报道卤水体系的溶解度和热力学数据[2,3],构建了SrCl2–H2O体系和CaCl2–SrCl2–H2O体系的多温（273.15～373.15 K）Pitzer化学模型,与文献[4]类似,Pitzer混合离子作用参数为零,固溶体近似为理想固溶体。采用上述模型计算的三元体系溶解度与实验值吻合较好。上述三元体系低温时形成钙锶固溶体,固溶体近似于理想固溶体,高温时不形成固溶体。根据上述三元体系的相图及化学模型研究结果,分析了利用288.15 K的相图及多温相图实现钙锶分离的蒸发结晶路线。根据288.15 K的相图,采用蒸发-溶解-蒸发-溶解类似"重结晶"方法得到纯度为99%的SrCl2·6H2O,母液中剩余锶低于5%。结合288.15K和373.15K的相图,采用"高温蒸发-兑卤降温-低温析盐-高温蒸发"方法可得到纯SrCl2·H2O,母液中锶浓度为0.027。本文可为含固溶体卤水资源综合开发利用工艺路线的确立提供理论参考。

铷、铯及其化合物有着广泛的用途,而我国拥有丰富的卤水（盐湖卤水、地下卤水、油气田水）资源,其中蕴藏着具有开采价值的铷和铯。针对卤水中稀散碱金属铷和铯分析分离困难的问题,本论文首先建立了一种新的电感耦合等离子体发射光谱法（ICP-OES）同步测定高盐卤水中微量铷和铯的分析方法。其次,开展皂化后的萃取体系“t-BAMBP+D80溶剂油”分离提取卤水中铷、铯的工艺研究,并对该工艺进行萃取-洗涤-反萃取实验研究,获得了相关工艺参数,取得如下主要结论:（1）采用ICP-OES测定高盐卤水中微量的铷和铯:铯的测定在894.347 nm处不存在显著的谱线干扰,而铷在780.027 nm附近存在较强的氩干扰谱线,但通过适当的谱线校正可有效解决该问题。卤水中共存的Na+、K+、Ca2+、Mg2+均会对铷、铯的ICP-OES分析检测产生严重的基体正干扰。本文基于共存离子对铷、铯测定干扰的拟合方程,通过在标准溶液中定量加入NaCl,可对一定浓度范围内共存的NaCl、KCl、CaCl2、MgC12进行基体匹配,从而实现高盐卤水中微量铷、铯的标准曲线法快速准确测定。实验对四川达州地下卤水样品中铷、铯的分析结果表明,通过采用NaCl进行基体匹配后,铷、铯的加标回收率分别在106.7%～112.8%和108.0%～112.5%之间,相对标准偏差分别为1.46%和2.47%,检出限分别为0.013 mg/L和0.018 mg/L。（2）采用NaOH溶液皂化后的萃取体系“t-BAMBP+D80”分离提取卤水中的铷和铯,针对模拟卤水（含铷0.8 g/L,铯0.2 g/L）的萃取-反萃取实验,在较优的皂化及萃取-反萃取条件（有机相组成30%t-BAMBP+70%D80,皂化剂NaOH浓度0.6 mol/L,皂化摩尔比t-BAMBP/NaOH=4/1,萃取相比（O/A）=3/1,反萃取HCl浓度0.2 mol/L,反萃取相比（O/H）=5～6/1）下,铷、铯的单级萃取率分别达到85.05%和98.78%,单级反萃取率分别达到86.19%和82.75%。卤水中钾离子的存在对铷、铯的萃取会产生一定影响,必须对萃取后的负载有机相进行钾离子的洗脱;钙、镁离子的存在使得萃取前必须调节卤水pH=5.0左右,避免其在萃取时沉淀析出,影响萃取操作。（3）针对四川达州地下卤水中铷、铯的萃取-洗涤-反萃取实验研究。首先,对铯开展萃取-水洗-反萃取工艺研究,在最佳工艺条件（卤水pH=5.0左右,有机相组成 30%t-BAMBP+70%D80,皂化剂 NaOH 浓度 0.5 mol/L,皂化相比（O/OH）=1/1,萃取相比（O/A）=1/1,水洗相比（O/A’）=2/1,水洗级数2级,反萃取剂HCl溶液浓度0.1 mol/L,反萃取相比（O/H）=5～6/1）下,铯的单级萃取率达到72.78%,而铷、钾的单级萃取率仅为12.06%和7.33%,铯、钾分离系数为33.80;铷、钾的2级洗脱率分别为111.67%和106.84%,铯的2级洗损率为13.70%;铯的单级反萃取率为47.00%。其次,针对铷开展萃取-碱洗-反萃取工艺研究,在较佳的工艺条件（卤水pH=5.0 左右,有机相组成 30%t-BAMBP+70%D80,皂化剂 NaOH 浓度 0.8 mol/L,皂化相比（O/OH）=1/1,萃取相比（O/A）=2/1,洗碱浓度为0.1 mol/L NaOH溶液,碱洗相比（O/A’）=3/1,碱洗级数3级,反萃取剂HCl溶液浓度0.1 mol/L,反萃取相比（O/H）=5～6/1,反萃取级数3级）下,铷的单级萃取率为47.44%,而钾的单级萃取率仅为4.33%,铷、钾分离系数为19.96;钾的3级洗脱率达111.43%,铷的3级洗损率为18.58%;铷的3级反萃取率为77.31%。通过以上实验研究,可实现卤水中铷、铯的分离提取,这对卤水资源的综合开发利用具有重要意义。

Membrane adsorbents made from lithium-ion sieves (LIS) have gained a lot of attention for lithium recovery from geothermal water. Compared with powdery LIS, the membrane adsorbent suffered a severe decline in lithium adsorption efficiency and poor structural stability, making it difficult for use in industrial applications. Here, a novel thin-film nanocomposite (TFN) membrane adsorbent was constructed by incorporating LIS into polyamide film by an interfacial polymerization approach. Accompanied by the membrane-forming process, the LIS achieved in situ functional modification by the synergistic manipulation of dopamine and piperazine and anchored on the surface of the TFN membrane, causing a low shielding effect on LIS, high interfacial compatibility and structural stability. Applied in natural geothermal water at 328.15 K, the well-designed TFN membrane adsorbent exhibited an uncompromising Li+ adsorption capacity of 23.94 mg g-1, and reached equilibrium adsorption in a shorter time of 35 minutes than powdery LIS (QLi = 25.80 mg g-1, t = 45 minutes), even after undergoing a fifth cyclic adsorption-desorption process. The calculated thermodynamic parameters of Delta H degrees, Delta S degrees and Delta G degrees during the Li+ adsorption process indicated its nature of an exothermic and spontaneous process. The structural advantages of the TFN membrane adsorbent shed light on its potential application in lithium recovery from geothermal water.A LIS-doped thin-film nanocomposite (TFN) membrane adsorbent was constructed by an interfacial polymerization technique, showing a comparable Li+ adsorption capacity of 23.94 mg g-1 and a shorter adsorption time of 35 minutes than powdery LIS.

2004年2月发生在沱江的特大水污染事故给沱江流域的生态环境造成了严重的危害,近年来受工农业和沿岸居民生活的影响,沱江的生态环境依然遭受着一定程度的污染,但对沱江流域氮的地球化学研究甚少。沉积物是水环境中污染元素的重要蓄积库或释放源,为揭示沉积物中氮赋存状态迁移转化特征,并评估该地区生态环境修复状况,本文参照Mackin应用的沉积物中吸附态氨氮提取方法和Smart建立的沉积物中总氮提取方法,采用分光光度法针对沱江流域金堂地区冬季沉积物,开展了河流沉积物中总氮（TN）、可交换态氨氮（AN）、有机氮（ON）赋存状态分析,并对比了十年前后该地沉积物中氮赋存状态的变化情况。实验结果表明:TN含量为518.913~4386.899 mg/kg,ON含量为101.531~3793.683 mg/kg。在-3 cm以上,TN和ON含量较高,且ON是TN的主要组成部分;随着深度增加,两者含量迅速减少,AN含量略有降低。与十年前该地区沉积物中氮的相关数据对比,TN含量增加,其中AN含量增加明显;在-3 cm以上,ON、TN在表层沉积物中增加明显。研究认为:沱江流域沉积物中的氮已经作为内源氮释放至间隙水甚至上覆水中,同时存在外源污染,致使沉积物表层有机氮以及总氮含量升高明显。

Ion-selective electrodes directly respond to the activity of target ions without destroying the existing form of the original electrolyte, so ion-selective electrodes have been widely used in various fields. Mean activity coefficient of NaNO3 in the ternary system (NaNO3+CsNO3+H2O) at 298.15K was measured by electromotive force (EMF) with the cell: Na+ ion-selective electrode (Na-ISE)vertical bar NaNO3 (m(A)), CsNO3 (m(B))vertical bar NO3- ion-selective electrode (NO3-ISE) with total ionic strengths from 0.01 to 4.5 mol.kg(-1) at different ionic strength fractions (0, 0.1, 0.2, 0.4, 0.6, and 0.8). The results showed that the Na-ISE and NO3-ISE have a good Nernst response, and the mean activity coefficients of NaNO3 are obtained via the Nernst equation. Based on the data of mean activity coefficients of NaNO3, the relationship diagrams of activity coefficients of NaNO3 against ion strengths in the ternary system were demonstrated, and the Pitzer mixing ion-interaction parameters theta(Na,Cs) and psi Na, Cs, N O-3 were obtained.