Transport of Cu(II) ions through charged cation‐exchange membranes

Transport of Cu(II) ions through polysulfonated cation‐exchange membranes under Donnan dialysis conditions was studied as a function of the pH gradient. The used charged membranes are homogeneous (polysulfone composition) and heterogeneous (polysulfone with polyester support) structures which are strongly acidic cation‐exchange microporous‐type membranes. The flux increases with decreasing of the pH gradient, which is influenced by the transport of copper ions. The quantitative relations were obtained which describe the time dependence of the transport system with the equilibrium distribution and the results were correlated with the flux data as well as with the membrane structure. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 421–427, 2001     

用碳酸氢铵法制备硫酸亚锡的研究

通过实验和生产实践，提出用碳酸氢铵法制备试剂硫酸亚锡，研究结果表明这种方法比传统的用碳酸钠法制备硫酸亚锡更经济、实用，从而证明用碳酸氢铵法制备硫酸亚锡是可行的。     

盐析效应对卤水制纯碱的影响

卤水和固体碳酸氢铵复分解反应得碳酸氢钠沉淀和氯化铵溶液,碳酸氢钠经煅烧得纯碱。采用BaCl2-Na2CO3-NaOH法净化卤水,使其中主要杂质Ca2 、Mg2 、SO42-降低到20 ppm,达到反应要求。研究了盐析效应对复分解反应的影响,盐析剂的加入使碳酸氢钠结晶率从70%~79%提高到90%以上。煅烧碳酸氢钠得纯碱,产品符合GB210.1—2004Ⅱ类一等品要求。     

Antibiotic lock: In vitro stability of gentamicin and sodium citrate stored in dialysis catheters at 37 °C

Catheter‐related bacteremia (CRB) is a major cause of morbidity and mortality especially among patients receiving hemodialysis. Antibiotic lock therapy represents a promising technique in the treatment of CRB. Several studies have evaluated antibiotics in combination with heparin as an interdialytic locking solution for prophylaxis of CRB. The objective of this study was to evaluate the stability of gentamicin and sodium citrate in hemodialysis catheters as an interdialytic lock. Solutions containing gentamicin 2.5 mg/mL and sodium citrate 40 mg/mL (4%) were prepared individually and in combination. The solutions were instilled into dialysis catheters and stored at 37 °C for 96 h. Samples were withdrawn randomly from catheter lumens at 24‐hour intervals for 4 days and stored at ?20 °C until analysis. The samples were analyzed with validated, stability‐indicating HPLC assays. The luminal concentration of gentamicin 2.5 mg/mL, sodium citrate 40 mg/mL (4%), and the combination was determined on study days 0, 1, 2, 3, and 4. When gentamicin was combined with sodium citrate and stored at 37 °C in dialysis catheters, the solution showed no decrease in either the gentamicin or the sodium citrate concentrations over the 96‐hour study period. The percent of the original concentration at 96 h was 102.4±1.03 for gentamicin and 102.9±1.25 for citrate (P=0.5556). The combination of gentamicin 2.5 mg/mL and sodium citrate 40 mg/mL (4%) can be retained in hemodialysis catheters for at least 96 h at 37 °C with no evidence of degradation.     

The path to a paradigm shift in hemodialysis

About 1 out of 4 American conventional dialysis patients die in the first year and 3 out of 5 die within 5 years with no favorable trend in sight. Largely ignored in practice is the evidence accumulated over decades that longer, more frequent dialysis can immediately slash this grim result in half or more. Pierratos has called for a paradigm shift—a disruptive change—in dialysis practice from conventional treatment to daily nocturnal dialysis, performed at home, to realize this dramatic improvement. We examine here how such a paradigm shift might be brought about and suggest that changes in 3 perspectives must occur. First, new dialysis guidelines must be recast from the old goal of minimally adequate to a new goal of best possible . Second, the body of dialysis research must be interpreted through the lens of best possible patient survival and well being, and the near-impossibility of demonstrating dialysis survival advantage through randomized clinical trials must be acknowledged. Finally, dialysis modality must be seen as, most importantly, a survival and well-being choice, not merely a Lifestyle choice; hence, it must be the nondelegatable responsibility of the physician, not dialysis center personnel, to advise and prescribe. Many old perspectives, which might stand in the way of this sorely needed paradigm shift are also examined. These old perspectives make up a fabric of excuses that has delayed—and, if not discarded, will continue to delay—progress toward a survival and well-being outlook for dialysis patients just as favorable as might be achieved through kidney transplant.     

Volume-Independent Sodium Toxicity in Peritoneal Dialysis: New Insights from Bench to Bed

Sodium overload is common in end-stage kidney disease (ESKD) and is associated with increased cardiovascular mortality that is traditionally considered a result of extracellular volume expansion. Recently, sodium storage was detected by Na23 magnetic resonance imaging in the interstitial tissue of the skin and other tissues. This amount of sodium is osmotically active, regulated by immune cells and the lymphatic system, escapes renal control, and, more importantly, is associated with salt-sensitive hypertension. In chronic kidney disease, the interstitial sodium storage increases as the glomerular filtration rate declines and is related to cardiovascular damage, regardless of the fluid overload. This sodium accumulation in the interstitial tissues becomes more significant in ESKD, especially in older and African American patients. The possible negative effects of interstitial sodium are still under study, though a higher sodium intake might induce abnormal structural and functional changes in the peritoneal wall. Interestingly, sodium stored in the interstial tissue is not unmodifiable, since it is removable by dialysis. Nevertheless, the sodium removal by peritoneal dialysis (PD) remains challenging, and new PD solutions are desirable. In this narrative review, we carried out an update on the pathophysiological mechanisms of volume-independent sodium toxicity and possible future strategies to improve sodium removal by PD.     

对辊式造粒机在复混肥生产中的应用

对辊式造粒机生产粒状 ( 5 .5 m m)复混肥的原理及特点 :过程无温升 ,不需干燥 ,故采用原料广泛 ;该机可用含硝态氮的氮肥生产喜硝态氮的的作物专用肥 ;还可生产颗粒磷肥及颗粒碳铵。该机的主要消耗为对辊外壳 ,一对对辊外壳价值 80 0 0元 ,可生产 30 0 0 t肥料 ,每吨肥料的设备机物料损耗约 3元     

Branched Polyvinyl Alcohol Hybrid Membrane for Acid Recovery via Diffusion Dialysis

A branched polymer was prepared by grafting allyltrimethylammonium chloride onto polyvinyl alcohol (PVA) via free‐radical polymerization. Afterwards, a series of hybrid membranes were prepared by sol‐gel cross‐linking between quaternary ammonium‐PVA and tetraethoxysilane. The obtained membranes were characterized in terms of infrared spectroscopy, ion exchange capacity, water uptake, linear expansion ratio, and acid resistance. The thermal properties of the membranes were investigated as well. The diffusion dialysis performances of the membranes were tested by using a simulated feed solution containing HCl and FeCl₂. The diffusion dialysis coefficients and the separation factors were much better than those of the commercial DF‐120 membrane.     

合成氨变换出现的问题及处理

本文针对在实际生产过程中出现的一些问题进行处理。合成氨变换装置在接气和正常生产时,变换催化剂床层出现不同程度的超温现象,严重影响变换装置的安全平稳运行,因此在变换炉前增加放空管线,并在正常生产时增加气化水汽比,使催化剂床层温度控制在正常范围内。对粗煤气做带液处理时,由于V1501液位较高,容易将水带入变换炉使催化剂粉化,因此在V1501液相新增管线去气化澄清池,带液问题得到有效控制。由于系统中氨含量较高, E1506容易形成碳铵结晶,针对这个问题将去气化磨煤的尿素废液改成去气化除氧器,同时对内漏的尿素废液换热器进行更换。经过改造确保了装置平稳运行。     

重碱加压过滤的研究探索

在化工领域偿试使用加压过滤技术处理重碱，使重碱水份由真空过滤的１８～２０％降为加压过滤的１２％，可使生产厂家降低能耗；节约返碱