Thermodynamics and kinetics of D-glyceric acid adsorption on ion exchange resin

D-甘油酸是一种重要的甘油衍生物,具有解酒护肝的功能。关于D-甘油酸生产方法的研究已有不少,但对其分离方法及分离机理的研究却鲜见报道。通过静态吸附实验,研究了D-甘油酸在201×7阴离子交换树脂上的等温热力学和动力学特性。结果表明,D-甘油酸在201×7阴离子交换树脂上的最大平衡吸附容量随p H的增加而降低,其吸附等温线符合Freundlich模型。在293~308 K下,吸附焓变为14.77 k J·mol-1,表明该吸附过程为吸热过程。升高温度有利于提高吸附速率,但对最大平衡吸附容量影响不大。同时,采用动边界模型描述D-甘油酸在该树脂上的交换行为,分别考察了料液浓度、树脂粒径和温度对交换过程的影响。交换过程的吸附速率随D-甘油酸浓度和温度的增加而增大,但随树脂粒径的增大而减小。研究表明该离子交换过程的速率控制步骤为颗粒扩散过程,交换过程的反应速率常数k0为1.22×10-3,反应级数a为0.631,表观活化能Ea为14.90 k J·mol-1,并得到了动力学总方程。D-glyceric acid, one of the promising glycerol derivatives, has various biological functions such as accelerating ethanol and acetaldehyde oxidation. Plenty studies on the synthesis but few studies on downstream processes to recover D-glyceric acid were available. A static equilibrium adsorption was performed to study isothermal thermodynamics and kinetics of D-glyceric acid adsorption onto 201×7 strong basic anion exchange resin. The results showed that the adsorption process followed the Freundlich isothermal model at different p H and temperature conditions, which the maximum adsorption capacity decreased with increasing initial p H. The change of adsorption enthalpy was 14.77 k J·mol-1 at 293—308 K, suggesting an endo-thermic adsorption process. Raising temperature improved adsorption rate with limited influence on equilibrium adsorption capacity. The Dynamic Boundary Model was used to investigate adsorption kinetics with a focus on effects of D-glyceric acid concentration, resin particle diameter and adsorption temperature. The results suggested the particle diffusion was rate-limiting step of the adsorption process. The adsorption rate increased with the increase of D-glyceric acid concentration and temperature, but decreased with the increase of resin particle diameter. The general kinetics equation was obtained with the rate constant of exchange(k0), reaction order(a) and the apparent activation energy of reaction(Ea) as following k0=1.22×10-3, a=0.631, Ea=14.90 k J·mol-1.福建省高校产学合作项目(2015N5006);; 福建省教育厅中青年教师教育科研项目(JA15393);; 泉州师范学院青年博士预研基金项目(2015QBKJ04)~

微波辅助萃取-大孔树脂分离纯化芳樟叶黄酮

为了综合利用芳樟叶精油提取过程中产生的大量残渣,该文利用微波辅助萃取和大孔树脂选择性吸附来分离纯化芳樟叶黄酮。采用L9(34)正交试验,考察了萃取剂、微波辐射功率、辐射时间及料液比对黄酮得率的影响,确定了微波辅助萃取的优化工艺条件:以60%乙醇做萃取剂,微波功率320W,间歇辐射2次,每次1min,料液质量体积比1:12,在此条件下,芳樟叶黄酮的提取得率为2.97%,与乙醇热回流提取方法相比,得率提高了6.83%,时间缩短了98.89%;为进一步纯化萃取所得的黄酮提取物,选择6种大孔吸附树脂,测定芳樟叶黄酮在树脂上的吸附量和解吸率,筛选出了吸附剂HPD-450,其对芳樟叶黄酮有较好的静态吸附和解吸效果。经装填有大孔树脂HPD-450的固定床纯化后黄酮纯度由22.49%提高到51.28%,纯化倍数2.3倍

Studies on mechanisms of silver biosorption by Aeromonas SH10

［中文文摘］以气单胞菌SH10为生物吸附材料,从静电吸附作用、离子交换作用、络合作用、沉淀作用几方面研究了SH10吸附Ag+过程可能存在的作用机制.结果表明,气单胞菌SH10吸附银离子依赖于静电吸附作用;吸附Ag+前后溶液中Na+、K+、Mg2+浓度的变化较小,说明吸附过程中离子交换不明显;SH10表面的羧基、氨基和脂类基团经化学屏蔽后,对Ag+的吸附量明显下降,结合红外光谱分析结果,确定酰胺基CO-NH为SH10与银离子发生络合作用的主要官能团;电镜扫描结果表明,SH10在吸附过程中可以和Ag+形成沉淀沉积在细胞表面.［英文文摘］The study on mechanisms of metal biosorption is helpful to improve the biosorption ability of organism. Mechanisms of silver biosorption by Aeromonas SH10 were discussed from several aspects such as electrostatic adsorption, ion exchange, complexation and deposition. Results showed that silver biosorption by SH10 didn't mainly depend on ion exchange duo to only slight increase of the contents of Na~+, K~+, Mg~ 2+ in solution after biosorption, while electrostatic adsorption was found to be responsible for biosorption. Adsorptive capacity of silver ion decreased distinctly after functional groups such as carboxyl, amino and lipid groups on SH10 cell wall were chemicallymodified, respectively. Combined with FTIR spectra, amino groups were confirmed to be the main active groups that could combine with silver ion. SEM illustrated precipitation could take place on the cellwall of SH10.国家自然科学基金(No.20376067

Study on mechanisms of silver biosorption by laminaria japonica

生物吸附金属作用机制的研究,有助于提高生物吸附剂的吸附能力。文章以前期优选出的对银具有较强吸附能力的海带为生物吸附材料,从静电吸附作用、离子交换作用、络合作用、沉淀作用几方面研究了其吸附Ag+过程可能存在的作用机制。结果表明:海带吸附银离子不依赖于静电吸附作用;吸附Ag+前后溶液中Na+、K+、Mg2+质量浓度的变化说明吸附过程中存在离子交换机制;海带表面的羧基、氨基和脂类基团经化学屏蔽后,对Ag+的吸附量明显下降,结合红外光谱分析结果,确定酰胺基CO—NH和离子化羧基COO-为海带与银离子发生络合作用的主要官能团;电镜结果表明海带在吸附过程中可以和Ag+形成沉淀沉积在细胞表面。The study on mechanisms of metal biosorption is helpful to improve the biosorption ability of organism.Mechanisms of silver biosorption by Laminaria japonica were discussed from several aspects such as electrostatic(adsorption,) ion exchange,complexation and deposition.The results show that silver biosorption by Laminaria(japonica) doesn′t depend on electrostatic adsorption,while ion exchange is responsible for biosorption because of(increase) of the mass concentration of Na~+,K~+,Mg~(2+) in solution before and after biosorption.Adsorptive capacity of Ag~+ distinctly decreases after functional groups such as carboxyl,amino and lipid groups in Laminaria japonica cell wall are chemically modified respectively.Combined with FTIR spectra,carboxyl and amino groups are(confirmed) to be the main active groups which can combine with silver ion.Precipitation can take place on the cell wall of Laminaria japonica through SEM characterization.国家自然科学基金资助项目(20376067

生物法制备纳米银溶胶的稳定性

利用生物还原法制备纳米银溶胶,借助于UV-Vis表征技术对其热稳定性和化学稳定性进行考察。结果表明:生物法制备的纳米银溶胶在100℃下加热6h,UV-Vis谱图未发生明显变化;H+和具有高价阳离子的电解质对其稳定性的影响明显;OH-对银溶胶的稳定性影响相对较弱。生物法制备的纳米银溶胶在热稳定性、化学稳定性方面均略优于柠檬酸三钠法制得的银溶胶

Green Synthesis of Potassium Diformate

以甲酸和氢氧化钾为原料,不外加任何溶剂一步合成二甲酸钾。通过单因素实验,考察了原料配比、反应温度和反应时间对产品质量与收率的影响。采用正交实验进一步优化了合成工艺,确定了最佳工艺条件:n(HCOOH)/n(KOH)=2.2、反应温度70℃、反应时间30 m in,在该条件下,二甲酸钾产品收率达98%以上。所得产品经红外光谱分析及熔点测定,其结果与文献报道一致。反应过程绿色化,有很好的原子经济性。Potassium diformate was synthesized without solvent,using formic acid and potassium hydroxide as raw materials.The optimal conditions for the reaction were:molar ratio of HCOOH to KOH 2.2∶1,reaction temperature 70 ℃ and reaction time 30 min.Yield of the process was over 98% under the optimal conditions.The infrared spectrum and melting range of the product were in good agreement with those reported in literature.The technology developed in this study could be an environmentally benign synthesis route with efficient atom economy

Polyphenol Contents in Eight Fruits and Their Antioxidant Activities

[中文摘要]测定了苹果、石榴、橄榄、芒果、香蕉、菠萝、葡萄和龙眼的壳、肉及核中的多酚含量及其抗氧化性。以70%丙酮(v/v)为提取溶剂,室温下超声波辅助浸提样品后得到提取液。采用普鲁士兰(Prussian blue)法测定了提取液中多酚和单宁的含量,利用FRAP法测定其抗氧化性。结果表明:提取液中多酚和单宁的含量均与其抗氧化性成正相关关系;石榴、橄榄、芒果、葡萄和龙眼等水果的壳与核有望成为天然抗氧化剂的新来源。[英文摘要]The contents o f polyphenols of peel pulp and seed fractions of apple, pome granate, olive, mango, banana, pineapple, grape and long an and their to talantioxidant ac tiv ities were studied. A fter ultrasound-assisted extraction w ith 70% aqueous acetone at room temperature, polypheno ls and tann ins in the p lant ce lls w ere separated and their contents were determ ined by Prussian blue assay. Antioxidant activities of the aqueous acetone extracts were evaluated by Ferric Reducing /Antioxidant Power (FRAP) assay. A positive linear correlation between antioxidant activities and phenolic contents was observed. The resu lts show ed that the fru it pee l and seeds o f pom egranate, olive, mango, grape and longan could be conside red as potentia l sources o f antioxidants rather than just discarded as waste

Treatment of Purified Terephthalic Acid Wastewater by Sequencing Batch Reactor

［中文文摘］采用序批式反应器(SBR)处理模拟精对苯二甲酸(PTA)废水,考察了曝气量、沉降时间、进水方式等对对苯二甲酸(TA)生物降解效果的影响。实验结果表明,对于TA质量浓度小于1 500m g/L的废水,采用完全曝气SBR运行4h,TA和COD的去除率均能达到95%以上,TA平均去除速率随TA浓度的增加而增大。TA质量浓度为1 500m g/L时,曝气量、沉降时间和进水方式是影响其降解效果的主要因素。采用SBR处理高浓度PTA废水可克服污泥膨胀和抗冲击负荷能力弱的问题,且系统的稳定性和PTA废水的处理效果较好。［英文文摘］Simulated purified terephthalic acid(PTA)wastewater was treated by sequencing batch reactor(SBR).The effects of aeration rate,settling time,feeding mode on the biodegradation of terephthalic acid(TA)were investigated.When the mass concentration of TA is less than 1 500mg/L,the removal rate of TA and COD are both more than 95% after aerating for 4h in SBR.The average TA removal rate increases with the increasing of TA mass concentration.When the mass concentration of TA is 1 500mg/L,the main factors affec ting degrada tion are aeration rate, settling time and feeding mode. Treating high concentration PTA was tewater by SBR can solve the problems of sludge bulking and lack of shock load resistance cap ability, and the system has a good stability and treatment effect for PTA wastewater.国家自然科学基金资助项目(20076037

Separation and purification of catalpol from Radix Rehmanniae

An ultrasonic extraction technology of preparing catalpol from Radix Rehmanniae was optimized by a uniform experimental design.The optimum conditions for ultrasonic extraction were thus established: 68% (vol) ethanol aqueous solution as extraction solvent,the volume(ml) to mass(g) ratio of extraction solvent to feed of 5∶1,the ultrasonic treatment time of 36 min.The crude catalpol obtained from the optimized ultrasonic extraction technology was further purified by selective adsorption with macroporous resin.The adsorption capacities and desorption yields of ten kinds of macroporous resins for catalpol were investigated.The results showed that H103 resin possessed the best performance.The properties of dynamic adsorption and desorption of H103 resin for catalpol were subsequently investigated on adsorption column.The optimum conditions for adsorption and desorption were determined.The concentration of catalpol in the loaded sample solution was 6.15 mg·ml-1,the flow rate was 1.0 ml·min-1,the volumetric percentage of ethanol in the eluting solvent was 75%,the elution flow rate was 0.5 ml·min-1 and the elution volume was 3.33 BV(bed volume).Under the above conditions,the purity of catalpol product eluted from the column packed with H103 resin reached 62.39% while that of the crude catalpol was only 10.01%

Preparation of Ag/ZrO_2 Catalyst with Microorganism-mediated Biosynthesis method by using Pichia Pastoris for selective oxidation of 1,2-propanediol

将微生物还原法制备银纳米颗粒的技术引入到催化剂的制备当中,以毕赤酵母菌体干粉作为还原剂制备纳米银粉,采用溶胶负载法将银负载获得Ag/zrO2催化剂,利用TEM、Xrd、uV-VIS drS等方法对催化剂进行了表征,并将所制备的催化剂用于1,2-丙二醇选择氧化制备丙酮醛的反应中。研究表明,在1,2-丙二醇的空速为5.2 H-1,反应温度340℃时,450℃下焙烧的银负载量为8%的Ag/zrO2催化剂获得了最佳的催化反应性能,1,2-丙二醇的转化率达到96.8%,丙酮醛的选择性达到78.3%。Ag/ZrO2 catalysts for the selective oxidation of 1,2-propanediol to methylglyoxal with molecular oxygen were prepared by an immobilization method based on the microorganism-mediated biosynthesis process with Pichia pastoris.The catalyst was characterized by XRD, TEM, UV-Vis DRS and TG techniques.The effects of reaction conditions(temperature and space velocity), Ag loading amount and calcination temperature of the as-produced Ag/ZrO2 catalysts on the catalytic performance were investigated.And the results showed that the 8% Ag/ZrO2 catalyst calcined at 450℃ exhibited the best catalytic activity with 96.8% 1,2-propanediol conversion and 78.3% methylglyoxal selectivity.稀贵金属综合利用新技术国家重点实验室开放课题(SKL-SMP-201210