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It is a vital technical challenge to extract lithium from salt-lake brine which has very high Mg2+ / Li+ mass ratio via green and low-cost methods, as these two cations have quite similar ionic hydration radius. Positively charged nanofiltration membranes can separate Li+ and Mg2+ through Donnan exclusion. In this work, a kind of hollow fiber nanofiltration membrane with positively charged skin layer was successfully fabricated via interfacial polymerization followed by a surface modification with branched polyethyleneimine (BPEI). The resultant membrane has a large number of amine groups, and thus shows positively charged surface with high rejection for divalent cation ions via Donnan exclusion. This gives it very high selectivity for the separation of Li+ ions from salt-lake brine. Under optimized conditions, it achieves a water permeance of up to 126.2 L m-2 h-1 MPa−1 at a transmembrane pressure difference of 4 bar, and a MgCl2 rejection of 94.6% with 2000 mg L-1 aqueous MgCl2 solution as feed. Meanwhile, it achieves a Mg2+ / Li+ selectivity of nearly 24 for MgCl2 and LiCl salt mixture solution with an overall concentration of 2000 mg L-1 and a Mg2+ / Li+ mass ratio of 150 : 1 as feed, which is high as compared with most of the literature, demonstrating its potential in the practical application of Mg2+ and Li+ separation.

Positively charged nanofiltration (NF) technology is considered a green and low-cost method for mono/divalent cation separation. Nevertheless, the separation rejection mechanisms of these NF membranes have yet to be extensively investigated. In this work, we fabricated a thin-film composite (TFC) hollow-fiber (HF) NF membrane with a positively charged surface via modification of the nascent interfacial polymerization layer using a branched polyethyleneimine (BPEI)/ethanol solution. Then, we extensively investigated its selective separation mechanism for mono/divalent cations. We proposed and proved that there exists a double-charged layer near the membrane surface, which helps to repel the divalent cations selectively via Donnan exclusion while promoting the fast penetration of monovalent cations. Meanwhile, the membrane skin layer is loose and hydrophilic due to the loose BPEI structure and the abundance of amine groups, as well as the changed fabrication conditions. In this way, we achieved very good mono/divalent cation selectivity and relatively high water permeance for the as-prepared HF NF membrane. We also obtained good anti-fouling, anti-scaling, and acid resistance, and long-term stability as well, which are urgently needed during practical application. Furthermore, we successfully amplified this HF NF membrane and proved that it has broad application prospects in mono/divalent cation separation.

Organic solvents take up 80% of the total chemicals used in pharmaceutical and related industries, while their reuse rate is less than 50%. Traditional solvent treatment methods such as distillation and evaporation have many disadvantages such as high cost, environmental unfriendliness, and difficulty in recovering heat-sensitive, high-value molecules. Organic solvent nanofiltration (OSN) has been a prevalent research topic for the separation and purification of organic solvent systems since the beginning of this century with the benefits of no-phase change, high operational flexibility, low cost, as well as environmental friendliness. Especially, hollow fiber (HF) OSN membranes have gained a lot of attention due to their high packing density and easy scale-up as compared with flat-sheet OSN membranes. This paper critically reviewed the recent research progress in the preparation of HF OSN membranes with high performance, including different materials, preparation methods, and modification treatments. This paper also predicts the future direction of HF OSN membrane development.

Objective: The aim of this study was to evaluate oxycodone versus dezocine for postoperative analgesia in patients with cervical cancer treated with radical surgery.Materials and Methods: Fifty-one cases of cervical cancer treated with radical surgery were included in the present study and divided into oxycodone group (n = 26) and dezocine group (n = 25). Patients in the oxycodone group were given with oxycodone 1 mg/kg plus tropisetron 0.1 mg/kg diluting to 100 ml by 0.9% saline for patient-controlled intravenous analgesia (PCIA) after surgery. Moreover, patients in the dezocine group were given with dezocine 0.6 mg/kg plus tropisetron 0.1 mg/kg diluting to 100 ml by 0.9% saline for PCIA after surgery. The visual analog scale (VAS) and Ramsay sedation score of the two groups were recorded in the time point of 4, 8, 12, 24, and 48 h after surgery. The adverse event-related drugs were recorded and compared between the two groups.Results: The VAS score was significantly lower in oxycodone group compared to dezocine group in the time point of 4, 8, 12, 24, and 48 h (Pall < 0.05). The Ramsay score at time point of 4, 8, 12, 24 h, and 48 h were obviously higher in oxycodone group than those in dezocine group (P < 0.05) which indicated that the sedative effect in oxycodone group was superior to dezocine. For oxycodone group, there were six cases (23.08%) with nausea and one case (3.85) with vomiting in the treatment procedure. Moreover, for dezocine group, there were one case (4.00%) with nausea, two cases (8.00%) with vomiting, and two cases (8.00%) with dizzy in the treatment procedure. There was no statistical difference of adverse event risk between the two groups (P > 0.05).Conclusion: Oxycodone postoperative analgesia is superior to dezocine for patients with cervical cancer treated with radical surgery. [ABSTRACT FROM AUTHOR]