海藻酸锌纤维

海藻酸锌纤维是一种具有优良生物活性的功能性纤维材料,可以通过湿法纺丝直接制备,也可以通过对海藻酸钙纤维进行离子交换间接制备。在间接法制备海藻酸锌纤维的过程中,可以通过控制海藻酸钙纤维与锌盐的质量比例得到含不同浓度锌离子的纤维。由于纤维中含有对伤口的愈合有促进作用的锌离子,海藻酸锌纤维通过持续释放锌离子在医用敷料的生产中有特殊的应用价值。试验结果表明:海藻酸锌纤维在释放锌离子的过程中可以起到抑制细菌增长的作用,在医疗卫生领域具有特殊的应用价值。     

海藻酸纤维对碱性品红的吸附性能研究

以自制海藻酸纤维为吸附剂,考察了吸附剂用量、溶液温度、吸附时间和溶液pH值等因素对海藻酸纤维吸附碱性品红的吸附效果的影响。结果表明:脱色率随海藻酸纤维加入量的增加而提高,随着溶液温度升高而迅速下降;加酸或加碱都不利于海藻酸纤维对碱性品红的吸附;对于40 mg/L的碱性品红溶液,当海藻酸纤维的加入量为5 g/L,室温下振荡40 min既能达到吸附平衡,脱色率可达96%;Freundlich等温方程能很好地描述海藻酸纤维对碱性品红的吸附,其吸附行为是物理吸附,吸附过程为熵减过程;海藻酸纤维经过8次再生后,对碱性品红的脱色率仍可达到93%以上,可重复利用。     

羧甲基甲壳胺纤维对铜离子的吸附性能

为了提高甲壳胺纤维对重金属离子的吸附性能,用氯乙酸对纤维进行改性处理,在纤维的结构中引入羧甲基团后使纤维同时具有能结合重金属离子的胺基和羧酸基团。研究了改性后纤维在不同的改性程度、添加量、时间、温度、pH值等条件下对铜离子的吸附性能。结果表明:羧甲基化改性后的甲壳胺纤维对铜离子有很好的吸附性能。在同样的条件下,未改性的纤维对铜离子的吸附值为41.3mg/g,而改性后的纤维为79.4mg/g。经过羧甲基化改性的甲壳胺纤维对铜离子的饱和吸附容量可以达到148.1mg/g。     

基于“蛋盒”结构高电化学性能活性炭的制备

与陆生植物不同,海藻中通常含有大量的海藻酸和海藻酸盐,其中海藻酸盐主要以海藻酸钙、海藻酸镁等形式存在于细胞壁中。本文利用海带中海藻酸钙的“蛋盒”式结构,对海带炭化产物进行盐酸酸洗处理,除去海藻酸钙中的钙离子,形成“蛋盒”式初始孔结构,然后采用KOH活化法制备海带基活性炭,研究海带基活性炭的孔结构特性以及电化学性能。实验结果表明：基于“蛋盒”结构制备的海带基活性炭拥有丰富的孔隙结构,其比表面积高达3027m²/g,其中73.3%由中孔比表面积提供,且中孔孔径分布比较集中,几乎全部分布在2～10nm。海带基活性炭在碱性电解液中展现出优秀的电化学性能,当电流密度为0.1A/g时,其比电容高达366F/g,即使在电流密度为10A/g的条件下,活性炭比电容仍然高达329F/g,显示出良好的比电容性能和倍率性能。     

海藻酸纤维的性能与应用

海藻酸纤维是一种具有优良生物活性的功能性纤维材料。海藻酸可以与许多种类的金属离子结合后形成富含金属离子的纤维材料,使纤维具有优良的阻燃及屏蔽电磁波的性能。以海藻酸钙纤维为原料制备的医用敷料在与伤口渗出液接触后,可以在吸收大量的渗出液后形成具有促进伤口愈合的水凝胶体,在医疗卫生领域具有特殊的应用价值。     

海藻酸钙/壳聚糖复合纤维的制备及性能研究

以海藻酸钙纤维为主体,壳聚糖为整理剂,采用交联整理的方法制备一种新型的海藻酸钙/壳聚糖复合纤维;探讨了整理过程中壳聚糖溶液p H值、壳聚糖浓度及海藻酸钙纤维用量对复合纤维吸湿性能的影响,并测定了复合纤维的抗菌性能、力学性能、表面结构及红外光谱。结果表明:相比海藻酸钙纤维,海藻酸钙/壳聚糖复合纤维表面沟槽较小,较为圆润,截面呈现腰子形;当壳聚糖溶液质量浓度为0.5 g/L,溶液p H值为7,海藻酸钙纤维用量为1.2 g时,复合纤维在蒸馏水、生理盐水、人造血浆中吸湿率分别为94.1%,695.0%,680.0%;相比海藻酸钙纤维,复合纤维具有良好的抗菌性能,断裂强力及断裂强度变化不大,断裂伸长率降低了11.14%,性能可达到应用要求;复合纤维的红外光谱表明壳聚糖已交联整理到海藻酸钙纤维上。     

海藻纤维应用研究进展

海藻酸是一种从褐藻提取的天然线性多糖,文章简单介绍了海藻纤维的特殊结构及其制备方法,并且重点描述了海藻纤维在重金属离子和染料吸附材料、阻燃材料、医用材料、电磁屏蔽材料领域的最新研究进展。     

用于去除多种污染物的新型藻酸钙磁吸附剂的合成

已经利用静电挤压技术制备了一种新型藻酸钙磁吸附剂。该吸附剂以藻酸钙作为生物聚合物壳，氧化铁作为磁核。其具有多功能特性：在通过磁力分离中使用简单，可以有效吸附砷（V）和铜离子。发现铜和砷的平衡时间可以在分别少于3h和25h时间内获得。铜和砷的最大吸附能力分别是6．75mg／g和60．24mg／g，其明显高于那些普通的吸附剂。     

SAS/AA吸附材料的制备与性能研究

通过溶液聚合法来制取功能高分子材料,并研究了引发剂、交联剂、单体用量等对材料吸附性能的影响,研究结果表明:交联剂用量在0.3％时,材料的吸附水和铅离子或铜离子的性能相对较好,对溶液中铜离子的吸附率达到95.2％,吸附量为143 mg/g,对铅离子的吸附率达到84.8％,吸附量为85 mg/g;引发剂用量在0.5％时,材料的吸附水和铅离子或铜离子的性能相对较好,对溶液中铜离子的吸附率达到94.8％,吸附量为142 mg/g,对铅离子的吸附率达到87.9％,吸附量为88 mg/g;当SAS用量为20％时,材料的材料的吸附水和铅离子或铜离子的性能相对较好,对溶液中铜离子的吸附率达到94.7％,吸附量为142 mg/g,对铅离子的吸附率达到87.8％,吸附量为88 mg/g.     

海藻酸凝胶性质对蛋白质扩散的影响

通过观察冷冻干燥海藻酸凝胶的断面扫描电镜(SEM)照片与卵清蛋白从海藻酸凝胶中的释放试验,分析了海藻酸凝胶性质对蛋白质在凝胶中扩散的影响。凝胶的SEM照片可见,海藻酸钙的冷冻干燥颗粒内为较大的圆孔,海藻酸锌凝胶内为较小的长孔,表明海藻酸锌高分子链在凝胶颗粒中的体积分率相对较大同时刚性较强;卵清蛋白从海藻酸凝胶颗粒中释放的试验结果表明,由于上述海藻酸锌凝胶的特性,导致海藻酸锌对卵清蛋白扩散阻滞作用相对较强;根据试验数据计算得卵清蛋白在海藻酸钙、海藻酸锌凝胶颗粒中的扩散系数分别为1.19×10-7、0.07×10-7cm2/s,利用阻滞模型计算得海藻酸锌高分子链在凝胶颗粒中体积分率约为海藻酸钙高分子链在凝胶颗粒中体积分率的1.7倍。     

Absorption and release of zinc and copper ions by chitosan fibers

Chitosan fibers were treated with aqueous solutions of ZnCl₂ and CuSO₄·5H₂O to prepare zinc and copper containing fibers, respectively. Significant weight gains were obtained as the zinc and copper ions were absorbed onto the fibers through chelation with the primary amine groups. The fibers were then placed in contact with aqueous solutions containing NaCl and water soluble proteins, respectively, to assess the release of zinc and copper ions. Results showed that the release of zinc and copper ions were affected by the treatment temperature, time, and the composition of the contacting media. More metal ions were released when the fibers were in contact with aqueous protein solutions than in NaCl solution, indicating the binding abilities of the protein molecules for zinc and copper ions. The zinc and copper containing fibers were tested for their antimicrobial effects against several species of bacteria commonly found in wound and skin. Results showed that these metal containing chitosan fibers had much stronger antimicrobial properties than the original chitosan fiber. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Adsorptions of Some Heavy Metal Ions in Aqueous Solutions by Acrylamide/Maleic Acid Hydrogels

Abstract

In this study, acrylamide—maleic acid (AAm/MA) hydrogels in the form of rod have been prepared by γ-radiation. They have been used for adsorption of some heavy metal ions such as uranium, iron, and copper. For the hydrogel containing 40 mg of maleic acid and irradiated at 3.73 kGy, maximum and minimum swellings in the aqueous solutions of the heavy metal ions have been observed with water (1480%) and the aqueous solution of iron(III) nitrate (410%), respectively. Diffusions of water and heavy metal ions onto hydrogels have been found to be of the non-Fickian type of diffusion. In experiments of uranyl ions adsorption, Type II adsorption has been found. One gram of AAm/MA hydrogels sorbed 14–86 mg uranyl ions from solutions of uranyl acetate, 14–90 mg uranyl ions from solutions of uranyl nitrate, 16–39 mg iron ions from solutions of iron(IV) nitrate, and 28–81 mg copper ions from solutions of copper acetate, while acrylamide hydrogel did not sorb any heavy metals ions.     

胺基接枝纤维的制备及其对铜离子吸附的应用研究

以漂白蔗渣浆纤维素为基体,二乙烯三胺为单体,硝酸铈铵为引发剂,制备胺基接枝纤维,得到高效重金属吸附剂。研究了单体用量、引发剂用量、温度、时间等反应因素对胺基接枝纤维制备的影响。采用红外光谱、X射线衍射和扫描电镜分析表征胺基接枝纤维的结构。从温度、时间、pH值、接枝纤维加入量和铜离子溶液初始浓度方面对胺基接枝纤维吸附二价铜离子进行研究,探究较好的吸附条件。结果表明,当绝干蔗渣纤维∶单体二乙烯三胺=1∶1（质量比）,硝酸铈铵的用量为25%,温度为70℃,时间为2h时,可以获得较高的吸附量,其吸附量可以达到12.8 mg·g-1。通过红外光谱和扫描电镜分析手段对接枝纤维的结构进行表征。胺基接枝纤维对铜离子溶液吸附的较优条件为：时间20min,温度为30℃,pH值为4.5,初始浓度为400mg·L-1。对吸附过程进行动力学研究,拟合得到Lagrange二级动力学方程y=0.0116x＋0.021。     

Batch and Column Adsorption of Cu(II) on Unmodified and Oxidized Coir

Abstract

The potential of coir, a low cost lignocellulosic material, was assessed for the removal of Cu(II) ion from aqueous solutions of copper sulphate. The coir fiber was also modified by an oxidative treatment, whereby the maximum uptake of Cu(II) increased to 6.99 mg/g as compared to 2.54 mg/g for the unmodified coir. A Langmuir type of adsorption was followed by oxidized coir fiber. A second order rate equation was observed for the Cu(II) uptake. The lowering of pH adversely affects adsorption on both the materials. Almost complete desorption of the loaded Cu(II) was possible using 0.25 N hydrochloric acid. The materials retained the adsorptive capacity up to three cycles when an intermediate regeneration step was given with dilute sodium hydroxide solution. In a fixed column packed with oxidized coir fibers, it was observed that the breakthrough time decreased with an increase in inlet Cu(II) concentration. The desorption level in the fixed bed column was around 90% and the column was regenerated and used up to eight cycles. The fixed bed column packed with oxidized coir was used to remove Cu(II) from an electrochemical industrial effluent. An ion exchange mechanism has been proposed for uptake of Cu(II) on the oxidized coir fiber.     

海藻酸钙/纳米TiO_2共混纤维的制备与表征

将含固体质量分数为5%的海藻酸钠纺丝原液与纳米二氧化钛(TiO2)水分散液均匀混合,制得海藻酸钠/纳米TiO2混合纺丝原液,采用湿法纺丝,通过氯化钙凝固浴,经拉伸、水洗,制备了海藻酸钙/纳米TiO2共混纤维,研究了纳米TiO2含量对共混纤维结构及性能的影响。结果表明:纳米TiO2的加入,提高了共混纤维的力学性能;加入质量分数为0.5%的纳米TiO2,海藻酸钙大分子链上的红外特征吸收峰峰形明显变宽,共混纤维的力学性能最佳,断裂强度为2.93 cN/dtex,断裂伸长率为7.34%,优于海藻酸钙纤维;添加纳米TiO2质量分数为3%时,纳米TiO2在共混纤维中仍能较好的分散,且纤维表面光滑。加入纳米TiO2后,共混纤维的热稳定性提高。     

Gel swelling properties of alginate fibers

This article described a study on the gel‐forming abilities of a number of different types of alginate fibers. The gelling abilities were assessed through the measurement on the release of calcium ions from the fibers and the absorption capacities in water and 0.9% saline solution. The effects of the chemical compositions of the alginate and the calcium and sodium contents of the fibers on the gelling abilities were studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1641–1645, 2004     

Modification of Sodium Alginate for the Removal of Cd(II) from Aqueous Solutions

Sodium alginate was protonated using HCl in ethanol: H₂O mixture (30:70). The modified sodium alginate (MSA) was characterized by determination of carboxyl content and solubility percent. The modified sample acquires of 450 meq-COOH/100 g sample and exhibits the complete insolubility in water. The MSA was utilized as adsorbent material to remove Cd(II) ions from aqueous solutions. Factors affecting adsorption process, such as agitation time and adsorbent concentration and pH of the adsorbate, were examined. The adsorption data show that the maximum adsorption capacity, Q_max, of Cd(II) onto MSA is 769.23 mg/g. The adsorption data also showed that the adsorption of Cd(II) onto MSA obeys Langmuir and Freundlich isotherms.     

Low cost adsorbents obtained from ash for copper removal

We investigated the utilization of ash and modified ash as a low-cost adsorbent to remove copper ions from aqueous solutions such as wastewater. Batch experiments were conducted to determine the factors affecting adsorption of copper. The influence of pH, adsorbent dose, initial Cu²⁺ concentration, type of adsorbent and contact time on the adsorption capacity of Cu²⁺ from aqueous solution by the batch adsorption technique using ash and modified ash as a low-cost adsorbent were investigated. The optimum pH required for maximum adsorption was found to be 5. The results from the sorption process showed that the maximum adsorption rate was obtained at 300 mg/L when a different dosage of fly ash was added into the solution, and it can be concluded that decreasing the initial concentration of copper ion is beneficial to the adsorption capacity of the adsorbent. With the increase of pH value, the removal rate increased. When the pH was 5, the removal rate reached the maximum of over 99%. When initial copper content was 300 mg/L and the pH value was 5, the adsorption capacity of the zeolite Z 4 sample reached 27.904 mg/g. The main removal mechanisms were assumed to be the adsorption at the surface of the fly ash together with the precipitation from the solution. The adsorption equilibrium was achieved at pH 5 between 1 and 4 hours in function of type of adsorbent. A dose of 1: 25 g/mL of adsorbent was sufficient for the optimum removal of copper ions. For all synthesized adsorbents the predominant mechanism can be described by pseudo-second order kinetics.