新型聚芳醚酰胺超滤膜的结构与性能研究

以杂萘联苯聚芳醚酰胺(PPEA)为膜材料,N,N-二甲基乙酰胺(DMAc)为溶剂通过相转化法制备超滤膜.研究了PPEA浓度、添加剂种类和用量对膜结构和性能的影响.结果表明,PPEA浓度提高,膜孔结构由宽的指状孔向海绵孔转变,膜表层致密化,膜的水通量降低而截留率提高;添加剂乙二醇甲醚(EG-ME)含量增加,膜孔结构趋于疏松,通量上升,截留率先有增加后下降;添加剂乙醚则使膜表面更致密.EGME含量10%时,膜的通量达到480L/(m2·h)左右,对聚乙二醇(PEG)10000截留率约93%;乙醚含量10%时,对PEG6000的截留率达到100%,而通量降低至56L/(mg·h)左右.     

陶瓷膜法处理退浆废水工艺研究及工业化装置运行评价

针对以聚甲基丙烯酸甲酯为主要成分的退浆废水,采用孔径为50nm的陶瓷膜过滤,实现废水的资源化利用.采用两级串联先循环后浓缩的操作方式.循环过滤时,拟稳态通量为423L/(m2·h)和453L/(m2·h).循环结束后进行浓缩,浓缩倍数达到22倍时通量为66L/(m2·h)和54L/(m2·h);膜对COD的截留率为87.5%,产水浊度低于1NTU,废水中的氢氧化钠等小分子物质均透过膜层进入渗透液;膜污染是以聚甲基丙烯酸酯在膜表面形成滤饼为主;碱洗及酸洗膜通量恢复至新膜的95%以上.陶瓷膜出水回用于生产过程;工业化陶瓷膜运行稳定,经济效益显著.     

弯曲板式膜系统在生物发酵澄清除杂中的应用

自主设计了弯曲板式膜系统,优化了膜壳和膜元件,使得系统能够获得稳定的通量和高质量滤液.该系统对赤霉素过滤的通量可以稳定在65 L/(m2·h);对于头孢C的过滤,通量可以稳定在15 L/(m2·h),系统对二者的蛋白截留率超过85％.     

NaA分子筛改性聚砜超滤膜的通量及截留性能

利用溶液相转化法,在铸膜液中加入分子筛NaA和PEG来协同提高聚砜超滤膜的水通量和截留率,研究了分子筛的含量对聚砜超滤膜的形貌结构,表面粗糙度,水通量,蛋白质截留率和亲水性的影响。利用场发射扫描电镜、扫描探针原子力显微镜、膜评价仪和接触角仪分别对该膜的形貌、水通量、蛋白质截留率和亲水性进行表征。结果表明分子筛含量从0g增加到3.0g,聚砜超滤膜的水通量从140L/(m2·h)提高到500L/(m2·h),对胃蛋白酶的截留率从78.8%提高到92.7%,对牛血清蛋白的截留率从97.6%增加到99.0%以上。分子筛NaA可以协同提高聚砜超滤膜的水通量和蛋白质截留率。     

正渗透膜对印染废水中铬的处理特性

利用水通道蛋白正渗透(FO)膜对含铬模拟废水和印染废水进行处理,分别研究了汲取液浓度和原料液pH对FO膜的水通量、盐返混通量及重金属铬截留效果的影响.结果表明,汲取液浓度对通量影响显著,处理模拟废水时,当氯化钠浓度从0.5 mol/L增加到2.0 mol/L时,膜的水通量从9.7 L/(m~2·h)增加到16.9 L/(m~2·h),盐返混通量从4.35 g/(m~2·h)增加到7.65 g/(m~2·h).而在处理印染实际废水的时候,膜的水通量从6.5 L/(m~2·h)增加到13.3 L/(m~2·h),截留率随汲取液浓度的增加而减小;另外随原料液pH的不断提高,对重金属铬的截留率也不断提高,在模拟废水的pH从3.0增加到11.0的过程中,对铬的截留率从98.8%增加到了99.7%,而对印染实际废水的处理中铬的截留率均高于99.5%,此外随着氯化钠浓度的提高,铬的截留率有所下降.这些数据可为FO应用于印染废水和重金属处理提供一定的参考.     

SiO2/PSf杂化超滤膜制备和性能研究

分别以粉末和溶胶-凝胶的方式向聚砜铸膜液中添加不同含量的SiO2,通过L-S相转换法制备SiO2/PSf杂化超滤膜.比较两种体系在不同SiO2含量下铸膜液的稳定性、黏度,及膜的微观结构、平均孔径、孔隙率、渗透性能和机械性能.结果表明,以溶胶-凝胶方式添加SiO2的铸膜液更加稳定,各方面性能更好.粉末添加下SiO2含量为2%时效果较好,水接触角为62°,纯水通量为141 L/(m2·h),对腐殖酸(Mr=370 000)的截留率为83.7%;溶胶-凝胶添加下SiO2含量为8%～10%时效果较好,水接触角为40°,纯水通量为182 L/(m2·h),对腐殖酸(Mr=370 000)的截留率为92%.     

Al2O3含量对PVDF/PVC/Al2O3共混中空纤维膜的影响

以聚偏氯乙烯(PVDF)、聚氯乙烯(PVC)和纳米氧化铝(Al2O3)三元共混,制备中空纤维膜,探讨Al2O3含量对膜性能的影响。结果表明,由于适量Al2O3的加入,中空纤维膜膜孔结构明显改善,大孔减少,微孔增多;亲水性明显提高。Al2O3为最佳含量3%时,水通量和截留率分别达到了289L/(h·m2)和77.2%。     

新型耐高温聚酰胺复合纳滤膜的制备及性能研究

以耐高温的杂萘联苯聚芳醚超滤膜为基膜,通过哌嗪(PIP)与均苯三甲酰氯(TMC)的界面聚合反应制备了复合纳滤膜.研究了界面聚合条件对膜性能的影响;利用扫描电镜(SEM)和原子力显微镜(AFM)分析了膜表面形貌,并用统计法计算了膜表面粗糙度;考察了操作条件对膜性能的影响,及膜对染料和无机盐的分离性能.结果表明,所制备的复合膜具有良好的热稳定性,在1.0MPa,80℃下对Na2SO4的截留率保持在96%以上,而通量高达400L/(m2·h).在1.0MPa,60℃下复合膜对低分子染料的截留率较高,且通量达到180～210L/(m2·h),对NaCl的截留率低于20%.     

活性炭填充对聚砜超滤膜性能的影响

采用相转化法制备聚砜(PSF)超滤膜,通过正交实验确定了较优的制膜条件,并用活性炭填充制备了共混的聚砜超滤膜,考察了活性炭加入量对膜的水通量、牛血清白蛋白(BSA)截留率及孔隙率的影响,以及操作条件对填充膜性能的影响。结果表明,最优化制膜条件为:添加剂聚乙二醇(PEG-400)含量为8%,蒸发时间为60s,纯水作为凝固浴,在此条件下制得的膜水通量达到212.6L/(m2.h),BSA截留率为84.1%。活性炭填充对膜水通量和截留率有明显影响,在活性炭含量为0.5%～1.5%时,膜通量随操作压力增大而增大,而截留率变化不大。     

PVA/PHEMA水凝胶滤膜的制备及其过滤印染废水特性研究

针对印染废水直接排放对环境造成污染的问题,制备PVA/PHEMA水凝胶滤膜对印染废水中的有机废物进行截留.以聚乙烯醇(polyvinyl alcohol,PVA)凝胶膜作为染料处理基体,加入聚甲基丙烯酸羟乙酯(polyhydroxyethyl methacrylate,PHEMA)网络,以强化滤膜对染料组分的吸收.同时,在聚合过程中加入气相二氧化硅并以氢氟酸浸泡刻蚀制孔,从而提高膜的水通量.实验测得该PVA/PHEMA复合水凝胶膜对于亚甲基蓝和刚果红两种染料溶液的截留率分别为89.7％和93.1％,过滤通量分别达到5.8 L/(m2·h)和10.7 L/(m2·h),显示出良好的染料截留作用.     

Comparison of calcium phosphate product values using measurement of plasma total calcium and serum ionized calcium

Calcium phosphate product (Ca x Pi) is a clinically relevant tool to estimate the cardiovascular risk of patients with renal failure. In reports, mostly total serum calcium has been used. As measurement of serum ionized calcium has some benefits and is being used increasingly, we estimated the respective levels of calcium phosphate product using both total (t-Ca x Pi) and ionized calcium (ion-Ca x Pi). Fifty-eight healthy individuals and 180 hemodialysis (HD) patients from 2 centers were studied. Diagnostic accuracies for corresponding values of the t-Ca x Pi and ion-Ca x Pi were calculated using a GraphROC program. Of HD patients, 64% had t-Ca x Pi <4.4 mmol(2)/L(2) regarded as a desirable goal, and 10% had values over 5.6 mmol(2)/L(2) associated with a high cardiovascular risk. Based on GraphROC analysis, t-Ca x Pi of 4.4 mmol(2)/L(2) corresponded to a value of 2.2 mmol(2)/L(2) of ion-Ca x Pi and, respectively, t-Ca x Pi of 5.6 mmol(2)/L(2) corresponded 2.8 mmol(2)/L(2) of ion-Ca x Pi. Owing to the good agreement between the results in the 2 centers, these values for risk levels can be used in both centers. When measurement of ionized calcium is used, Ca x Pi values of 2.2 and 2.8 mmol(2)/L(2) can be used instead of generally used values of 4.4 and 5.6 mmol(2)/L(2) with total calcium.     

Dialysate calcium and calcium/phosphate balance in hemodialysis

The changing pattern of pharmaceutical use in dialysis patients has resulted in several alterations to dialysate calcium concentration over the past 40 years. Non‐calcium–containing phosphate binders and calcimimetics are the most recent examples of drugs that influence the overall calcium balance in dialysis patients. Renal osteodystrophy, vascular disease, and mortality are believed to be linked in patients with chronic kidney disease (CKD), although to date most of the evidence is based only on statistical associations. The precise pathophysiology of vascular calcification in end‐stage renal disease is unknown, but risk factors include age, hypertension, time on dialysis, and, most significantly, abnormalities in calcium and phosphate balance. Prospective studies are required before “cause and effect” can be established with certainty, but it is an active metabolic process with inhibitors and promoters. Serum calcium levels are clearly influenced by dialysate calcium and may therefore play an important role in influencing vascular calcification. Clinical management of hyperphosphatemia is being made easier by the introduction of potent non‐calcium–based oral phosphate binders such as lanthanum carbonate. Short‐term and long‐term studies have demonstrated its efficacy and safety. Vitamin D analogs have been a disappointment in the control of serum parathyroid hormone (PTH) levels, but evidence is emerging that vitamin D has other important metabolic effects apart from this, and may confer survival advantages to patients with CKD. Calcimimetics such as cinacalcet enable much more effective and precise control of PTH levels, but at the cost of a major financial burden. While it is unreasonable to expect that any one of these recent pharmacological developments will be a panacea, they provide researchers with the tools to begin to examine the complex interplay between calcium, phosphate, vitamin D, and PTH, such that further progress is fortunately inevitable.     

放射自显影海藻酸钙栓塞微球的制备

利用乳化-内部凝胶化法,将放射显影剂碘化油包封于海藻酸钙微球中.通过改变机械搅拌速率可以控制微球的粒径分布.碘化油/海藻酸钙微球可以作为栓塞制剂阻断患处血供,还可以兼具放射自显影的作用,有利于减少碘化油所导致的不良反应,方便治疗.     

水化硅酸钙的制备及磷回收性能表征

以电石渣和白碳黑分别作为钙质和硅质原料,采用水热法制备具有磷回收特性的水化硅酸钙。研究了制备条件对水化硅酸钙磷回收性能的影响,采用XRD揭示了水化硅酸钙的磷回收机制。通过BET、SEM表征了水化硅酸钙的微观结构,考察了水化硅酸钙的溶钙供碱能力。钙硅摩尔比为1.6∶1,水热反应温度为170℃,水热反应时间为4.5h,搅拌强度为90r/min的条件下所制备的水化硅酸钙,其磷回收产品中的磷含量达到18.64%。该材料具有多孔结构,比表面积达到113.3572m2/g,能够溶出的Ca2+浓度为3.52mg/g,这些溶钙供碱特性使得该材料能够在pH值=9.0的环境下以羟基磷酸钙的形式从污水中回收磷。     

Calcium waves initiating from the anomalous subdiffusive calcium sparks

The objective of the study is to investigate the propagation of Ca²⁺ waves in full-width cardiac myocytes and carry out sensitivity analysis to study the effects of various physiological parameters on global Ca²⁺ waves. Based on the anomalous subdiffusion of Ca²⁺ sparks, a mathematical model was proposed to characterize the Ca²⁺ waves. The computed results were in agreement with the experimental measurements using confocal microscopy. This model includes variables of current through the Ca²⁺ release unit (CRU; I_CRU), duration of current flow through CRU (T_open), Ca²⁺ sensitivity parameter (K), the longitudinal and transverse spatial separation of CRUs (l_x and l_y, where x denotes longitudinal direction (x-axis) and y denotes transverse direction (y-axis)) and Ca²⁺ diffusion coefficients (D_x, D_y). The spatio-temporal mechanism of the anomalous Ca²⁺ sparks led to results that were different from those based on Fick''s law. The major findings were reported as: I_CRU affected the dynamic properties of Ca²⁺ waves more significantly than T_open; the effect of K on the properties of Ca²⁺ waves was negligible; l_y affected the amplitude significantly, but l_x affected the longitudinal velocity significantly; in turn, the limitation and significance of the study are discussed.     

Heat capacity of fcc calcium

The lattice entropy derived from the measured heat capacity at intermediate and high temperatures is analyzed to yield a weakly temperature dependent entropy Debye temperature. An unusual temperature dependence of this quantity may be a sign of error in the heat capacity data. When this analysis is applied to heat capacity data recommended by Hultgren et al. (1973) for 20 nontransition metals, the result for fcc Ca stands out as anomalous. We have reconsidered heat capacity data of fcc Ca and find that measurements by Eastman et al. (1924), which were given little weight by Hultgren et al., are consistent with a normal behavior of the entropy Debye temperature up to 450 K.     

不同水灰比下无水硫铝酸钙的水化反应

为澄清无水硫铝酸钙的水化反应机理,利用化学试剂Ca CO3、Al2O3、Ca SO4合成纯度达90%以上的无水硫铝酸钙(C4A3)单矿物,研究其在水灰比为0.3、05、0.7条件下的水化反应,包括不同水化时间的水化产物及变化规律,用X射线衍射仪、综合热分析仪和扫描电子显微镜对水化产物进行分析.结果表明:水化产物为含不同摩尔结晶水的2种单硫型水化硫铝酸钙C4AH12(AFm-12)和C4AH1 4(AFm-14)以及无定形状态的铝凝胶(AH3),整个水化过程未生成钙矾石(AFt);随着水化时间的延长,C4AH12(AFm-12)会逐渐转化为C4AH1 4(AFm-14);水化反应主要集中发生在3~12 h,后期C4AH1 4晶体不断长大.     

硫酸钙晶须的研究现状及进展

根据制备原料的不同,对目前硫酸钙晶须的制备方法进行阐述,并介绍了硫酸钙晶须在复合材料、水处理等领域的应用,从而提出了硫酸钙晶须在制备、应用等方面的未来发展方向。     

纳米CaCO3复合涂料研究进展

简述了纳米CaCO3在涂料中应用的意义,详细综述了纳米CaCO3在PVC防石击涂料、聚氨酯涂料、造纸涂料、建筑涂料、防腐涂料以及丙烯酸涂料中应用的研究现状,并对如何加快纳米CaCO3在涂料中的应用提出了建议.