Chromatographic Purification of Lithium, Vanadium, and Uranium from Seawater Using Organic Composite Adsorbents Composed of Benzo-18-Crown-6 and Benzo-15-Crown-5 Embedded in Highly Porous Silica Beads.

The use of the composite adsorbents composed of benzo-15-crown-5 (abbreviated as BC15) and benzo-18-crown-6 (BC18) for the simultaneous recovery of vanadium (V), uranium (U), and lithium (Li) from seawater has been proposed for industrial applications. The adsorption and desorption behavior of these elements on BC15 and BC18 has been examined in various types of aqueous solutions over a wide temperature range. As a result, it was shown that BC15 and BC18 have sufficient adsorption ability for the simultaneous recovery of V, U, and Li from seawater. Moreover, it was seen that the distribution coefficients (K d) of V decrease with an increase in [HCl]T (subscript T: total concentration), indicating that the anionic V species such as H2V4O13 4- are exponentially changed into the cationic V species such as V3+, VO2+, and VO2 + under the condition [HCl]T = 1.0 M, and the complexation reactions between BC15 (or BC18) and the initial V structures are inhibited. Besides, it was reasonably shown that the adsorption mechanism is the path through the electrostatic interaction between the anionic V species such as H2V4O13 4-, and the -C-O-C- single bond that the electron density is eccentrically located in ether functional groups in crown ether rings in BC15 and BC18 (or the -C-OH single bond that the electron density is eccentrically located in bisphenol A in BC15 and BC18). Then, the chromatography experiment of V, U, and Li on BC15 (or BC18) at 298 K was carried out by flowing seawater, 1.0 × 10-2 M HCl, and 1.0 M HCl in sequence. The first peak of V can be separated from the plateau of Li and the first and second peaks of U in the case of the BC15 system. The recovery ratios of V and U were more than 80%. On the other hand, entirely overlapping chromatograms were obtained in the case of the BC18 system, and accordingly, the recovery ratios of V and U were much lower. In short, the separation efficiency of V with BC15 is more pre-eminent than that with BC18. Judging from these results, the durability of BC15 was finally assessed for industrial applications, that is, the aforementioned chromatography experiment was repeatedly carried out to check whether V, U, and Li were stably and mutually separated from seawater or not. The evidence that the recovery performances of V, U, and Li from seawater do not decrease at all after at least five cycle tests was provided. This indicates that this information will be valuable for the development of a practical chromatographic technology to simultaneously recover V, U, and Li from seawater.

Indocyanine green fluorescence to ensure perfusion in middle segment-preserving pancreatectomy: a case report.

BACKGROUND: Middle segment-preserving pancreatectomy (MSPP) is an alternative to total pancreatectomy that allows for the preservation of the endocrine and exocrine functions of the pancreas. However, maintaining perfusion to the pancreatic remnant is of critical importance. We describe the first case to our knowledge in which indocyanine green (ICG) fluorescence was used to confirm perfusion to the pancreatic remnant during MSPP. CASE PRESENTATION: A 79-year-old man with diabetes mellitus was referred to our hospital for treatment of a pancreatic tumor. Computed tomography revealed a hypovascular mass in the uncus of the pancreas and dilatation of the main pancreatic duct, measuring 13 mm in the tail of the pancreas. He was diagnosed with cancer of the pancreatic uncus via endoscopic ultrasound and fine-needle aspiration revealed a mixed-type intraductal papillary mucinous neoplasm (IPMN), along with high-risk stigmata in the tail of the pancreas. We performed MSPP and the length of the pancreatic remnant was 4.6 cm. The dorsal pancreatic artery was preserved and perfusion to the pancreatic remnant was confirmed by ICG fluorescence. Histopathological examination showed a pancreatic ductal adenocarcinoma in the uncus (pT1cN1M0, pStage 2B) and IPMN in the tail of the pancreas. The postoperative course was complicated by a grade B pancreatic fistula, but this was successfully treated with conservative management. The patient was transferred to a hospital 33 days after surgery. Insulin administration was necessary, but C-peptide was detectable and blood glucose was relatively well-controlled. He did not exhibit any exocrine dysfunction when pancreatic enzyme supplementation was administered. CONCLUSION: ICG fluorescence can be used to evaluate perfusion to the pancreatic remnant during MSPP.

Removal of lithium and uranium from seawater using fly ash and slag generated in the CFBC technology.

Fly ash and slag were produced as a result of the incineration of municipal sewage sludge using the circulating fluidized bed combustion (CFBC) technology and were examined for the simultaneous recovery of lithium and uranium from seawater in batch adsorption experiments. These waste materials have been characterized in terms of their physicochemical properties using several research methods including particle size distribution, bulk density, SEM-EDS analysis, thermogravimetry, SEM and TEM morphology, BET, specific surface area, pore volume distribution by the BJH method, ATR FT-IR, and zeta potential. The fly ash and slag waste materials showed the following research results for Li-ion recovery: adsorption efficiency 12.1% and 6.8%, adsorption capacity 0.55 mg g-1 and 0.15 mg g-1, respectively. Better results were reported for U ion recovery: adsorption efficiency 98.4% and 99.9%, adsorption capacity 21.3 mg g-1 and 56.7 mg g-1 for fly ash and slag, respectively. In conclusion, the conducted research revealed that CFBC fly ash and slag are promising low-cost adsorbents for the effective recovery of Li and U ions from seawater.

Combined use of tannic acid-type organic composite adsorbents and ozone for simultaneous removal of various kinds of radionuclides in river water.

Tannic acid-type organic composite adsorbents (PA316TAS, AR-01TAS, PYRTAS, WA10TAS, WA20TAS, and WA30TAS), combined with hydrolyzed and sulfonated tannic acid (TAS) and porous-type strongly basic anion-exchange resin (PA316), benzimidazole-type anion-exchange resin embedded in high-porous silica beads (AR-01), pyridine-type anion-exchange resin (PYR), acrylic-type weakly basic anion-exchange resin (WA10), or styrene-type weakly basic anion-exchange resins (WA20 and WA30) for simultaneous removal of various kinds of radionuclides in river water were successfully synthesized. The adsorption behavior of twelve kinds of simulated radionuclides (Mn, Co, Sr, Y, Ru, Rh, Sb, Te, Cs, Ba, Eu, and I (I- and IO3-)) on these composite adsorbents has been studied in real river water at room temperature. PA316TAS adsorbents showed much higher distribution coefficients (Kd) for all metal ions. TAS structure has more selective adsorption ability for Mn, Co, Sr, Y, Cs, Ba, Eu, and IO3-. On the other hand, Y, Ru, Rh, Sb, Te, Eu, I (I- and IO3-) were adsorbed on both PA316 and TAS structures. To evaluate the validity of these mechanistic expectations, the respective chemical adsorption behaviors of Mn, Co, Sr, etc. and PA316TAS adsorbent were examined in river water ranging in temperature from 278 to 333 K. As was expected, one adsorption mechanism for Mn, Co, Sr, Cs, and Ba systems and two types of adsorption mechanisms for Y, Ru, Rh, Sb, Te, Eu, I (I- and IO3-) systems were observed. On the other hand, the precipitation of Mn, Co, Y, Ru, Rh, Te, and Eu was formed by ozonation for river water, that is, ozone can transform Mn, Co, Y, Ru, Rh, Te, and Eu ions into the insoluble precipitates. Hence, one straight line for Sr, Cs, Ba systems and two types of straight lines for Sb, I (I- and IO3-) systems were obtained in river water treated with ozone. The chromatography experiments of Cs, Sr, I (I- and IO3-) were carried out to calculate their maximum adsorption capacities. The obtained maximum adsorption capacities of Cs, Sr, and I- mixed with IO3- were 1.7 × 10-4 (Cs), 1.8 × 10-3 (Cs/O3), 7.8 × 10-5 (Sr), 5.6 × 10-4 (Sr/O3), 5.4 × 10-2 (I- and IO3-), 3.1 × 10-2 (I- and IO3-/O3) mol/g - PA316TAS. It was discovered that the maximum adsorption capacities of I- and IO3- for the composite adsorbent is unprecedented high and the capacity become much greater than an order of magnitude, compared with those of previous reports. This phenomenon suggests the formation of electron-donor-acceptor (EDA) complexes or pseudo EDA complex. Based on these results, it was concluded that the combined use of tannic acid-type organic composite adsorbents and ozone made it possible to remove simultaneously and effectively various kinds of radionuclides in river water in the wide pH and temperature ranges.

Effective use of elderberry (Sambucus nigra) pomace in biosorption processes of Fe(III) ions.

Elderberry (Sambucus nigra) pomace obtained as a result of processing in the food industry was examined for the bioremoval of Fe(III) ions from aqueous solutions in batch experiments. Several physicochemical properties of the biomass were analyzed using a variety of analytical methods, such as particle size distribution, elemental composition (SEM-EDS), X-ray diffraction analysis (XRD), thermogravimetry (TGA, DTG), specific surface area and average pore diameter (BET adsorption isotherms), volume of pores and pore volume distribution (BJH), morphology (SEM), mid-infrared analysis FT-IR. The impact of adsorbent dosage, initial concentration, pH and contact time on the process efficiency was studied. The calculated maximum adsorption efficiency and capacity was estimated at 99.5% and 33.25 mg/g, respectively. The biosorption kinetic analysis indicated that the removal process fits better to the pseudo-second order equation and the Langmuir model. Summing up, the biosorbent is a promising low-cost material for the highly effective iron recovery from effluents and improvement of water quality.