壳聚糖-果胶凝胶珠吸附剂的改性及其去除藻蓝蛋白中Pb(Ⅱ)的应用

壳聚糖-果胶凝胶珠(Chitosan-pectin gel beads,CPB)吸附去除食品中重金属具有较高的潜力，为提高其稳定性、再生利用性及吸附能力，本文采用明胶(Gel)和羧甲基纤维素钠(CMC)对CPB进行改性，利用扫描电镜(SEM)、比表面积与孔隙度分析(BET)、傅里叶变换红外光谱(FTIR)、热重分析(TG)、Zeta电位仪、X射线光电子能谱(XPS)及等技术表征其结构特性，优化吸附解析条件，并评估其对藻蓝蛋白中Pb(Ⅱ)的实际去除效果。结果显示，与CPB和Gel-CPB相比，CMC改性的CPB(CMC-CPB)热稳定性高、表面粗糙多孔、比表面积大(20.28±1.35 m2/g)及Zeta电位低，对金属离子吸附能力强，且解析再生利用率高。FTIR图谱分析显示改性前后CPB官能团结构未发生明显变化，其主要结构官能团为羧基、羟基和氨基。TG分析表明改性前后的CMC-CPB的热稳定性显著高于CPB和Gel-CPB(P<0.05)。XPS光谱分析表明三种吸附剂成功吸附了Pb(Ⅱ)，其中CMC-CPB对Pb(Ⅱ)的吸收峰最强。三种吸附剂(CPB、Gel-CPB和CMC-CP...     

丙烯酰胺改性果胶-Fe3O4磁性微球的制备及对水和海产品中Cu2+的吸附性能

采用包埋的方法制备丙烯酰胺改性果胶磁性微粒,分别用红外光谱、扫描电镜、X-射线衍射对样品进行表征。探讨吸附溶液的pH、Cu~(2+)初始浓度、吸附时间、温度和吸附剂用量等因素对改性果胶磁性微球吸附溶液中Cu~(2+)量的影响。试验结果表明,改性果胶磁性微球对水溶液中铜离子的吸附,在pH 4,Cu~(2+)初始质量浓度500 mg/L,吸附时间180 min,吸附温度25℃,吸附剂添加量20 mg时,单位吸附量达到105 mg/g。该吸附剂用于海螺、香螺和黄蚬子酶解液中的Cu~(2+)的吸附,清除率达80%左右,效果良好。     

聚离子液体改性废报纸基纤维素气凝胶及其染料吸附性能研究

采用超声脱墨技术纯化废报纸（WNP）,将得到的脱墨纤维素纤维在碱溶剂体系中溶解并交联再生制备纤维素气凝胶（WNCA）,最后通过化学接枝法制备了聚（1-乙烯基-3-丁基咪唑溴盐）聚合物刷修饰的纤维素气凝胶吸附剂（WNCA-g-PBVIMBr）;研究了WNCA-g-PBVIMBr的化学结构与物理形貌,探索了其对染料酸性橙II（AO II）的吸附性能与吸附机理。结果表明,WNCA表面均匀接枝了平均分子质量为3780 g/mol的PBVIMBr聚合物刷,其对AO II的最大吸附容量为351 mg/g,吸附过程符合准二级动力学模型和Langmuir等温吸附模型,且化学吸附起主导作用。     

聚间苯二胺对宣纸燎草制浆黑液中Na+的吸附性能研究

本研究利用化学方法合成新型导电高分子吸附材料聚间苯二胺,并将其作为宣纸燎草制浆黑液中Na~+吸附剂。采用扫描电子显微镜、傅里叶变换红外光谱仪对吸附剂进行了表征。考察了吸附剂用量、吸附时间、宣纸燎草制浆黑液中Na~+浓度对吸附效果的影响。结果表明,聚间苯二胺粒径为0. 5μm,具有利于吸附的梯形结构。聚间苯二胺用量为10 g/100 mL黑液,对宣纸燎草制浆黑液中Na~+的去除率达73. 3%。Lagergren准二级动力学方程能很好地描述Na~+在聚间苯二胺上吸附的整个过程,吸附以化学吸附为主。     

向日葵盘低酯果胶对水中重金属铜离子的吸附性能

该研究探讨了向日葵盘中的天然低酯果胶对水溶液中重金属铜离子（Cu2+）的吸附性能,检测了果胶用量、果胶溶液的pH值、吸附温度、吸附时间及共存离子的影响作用。结果表明,随着果胶的用量增加,Cu2+的去除率不断升高,但吸附量先增大后降低。而吸附量和去除率均随吸附温度的升高和时间的延长先增大后不变、随果胶溶液pH值的升高先增大后降低,并受共存离子的影响,随二价金属离子含量的增加而降低。Cu2+初始质量浓度在0~200 mg/L范围时,利用Langmuir等温方程拟合得到向日葵盘果胶对Cu2+的最大吸附量为29.94 mg/g。热力学分析表明该吸附反应是自发的、熵值增加的吸热反应。动力学分析证明该吸附过程遵循准二级动力学方程,以静电吸引作用和络合作用为主要驱动力。可见,向日葵盘低酯果胶具有较强的Cu2+吸附性能,可作为一种安全、高效、环保的生物吸附材料应用在Cu2+废水的处理中。     

含硫改性壳聚糖/NCC复合气凝胶的制备及其在废水中应用

本文以纳米结晶纤维素(NCC)和含硫改性壳聚糖为原料,合成含硫改性壳聚糖气凝胶和含硫改性壳聚糖/NCC复合气凝胶。通过扫描电镜(SEM)和比表面积(BET)对两种气凝胶的形貌和结构进行了分析;并通过改变溶液的pH值、初始浓度、吸附时间和吸附剂用量等吸附条件,探究了气凝胶对Hg~(2+)的吸附情况。实验结果表明,与含硫改性壳聚糖气凝胶相比,复合气凝胶的比表面积增大了10.37%;在pH为5、吸附剂用量30.0 mg和Hg~(2+)溶液初始浓度为100mg/L时,复合气凝胶的最大吸附容量达到最大为242.3 mg/g,比含硫改性壳聚糖气凝胶增加了2.02%;并且复合气凝胶对Hg~(2+)的吸附过程符合准二级动力学模型,同时复合气凝胶能用脱附剂EDTA脱附再生。     

羧甲基纤维素钠/己二酸二酰肼水凝胶的制备及其重金属离子吸附性能研究

以羧甲基纤维素钠（CMC）为基材、己二酸二酰肼（ADH）为交联剂,成功制备了具有三维网络结构的CMC/ADH水凝胶,研究了CMC/ADH水凝胶对废水中重金属离子（Cr⁶⁺、Cu²⁺、Pb²⁺）的吸附性能。采用傅里叶变换红外光谱（FT-IR）、扫描电子显微镜（SEM）、X射线能谱分析（EDS）和溶胀性能分析等方法对CMC/ADH水凝胶进行表征;研究了吸附时间、pH值及重金属离子初始浓度对CMC/ADH水凝胶在模拟废水中吸附行为的影响;并对CMC/ADH水凝胶的吸附机理进行分析研究。结果表明,在室温（25℃）、pH值=3、重金属离子初始浓度50 mg/L、吸附时间300 min的条件下,CMC/ADH水凝胶对废水中Cr⁶⁺、Cu²⁺和Pb²⁺的吸附量分别为31.5、75.9和72.0 mg/g;其吸附过程的动力学模型和等温模型的拟合结果表明,CMC/ADH水凝胶吸附重金属离子的过程是单层化学吸附过程。     

氧化石墨烯/壳聚糖复合材料的制备及吸附应用研究进展

氧化石墨烯/壳聚糖复合材料是近年来新发展的新型可生物降解材料,复合材料巨大的比表面积、丰富含氧官能团以及氨基基团使其成为良好的吸附剂.本文综述了近几年氧化石墨烯/壳聚糖复合材料在吸附应用上的研究进展,侧重介绍了该复合材料的常用制备方法以及其污水处理中金属离子和有机染料中的吸附情况,简单讨论了该复合材料的脱附再生性能.     

海藻酸钠基材料的制备及对金属离子的吸附

采用海藻酸钠作为原材料,使用丙烯酰胺进行化学改性制备海藻酸钠交联丙烯酰胺材料(SA-PAM)。使用红外分析、扫描电镜-能谱仪、元素分布特征和热重分析进行表征,并使用SA-PAM材料对水体中铜和铅离子进行吸附。结果表明,当溶液pH对铜和铅离子分别为5和5.5、初始铜和铅离子浓度为100 mg/L和300 mg/L和吸附时间为2 h时,SA-PAM对铜和铅离子的最大吸附量分别为58.84 mg/L和230.706 mg/L。SA-PAM吸附剂的吸附过程符合拟二阶动力学方程和Langmuir等温线模型,表明其吸附以单层化学吸附为主。此外,经过五次循环实验,SA-PAM材料仍能保持较好的吸附能力。     

铜尾矿砂对氧化石墨烯的吸附性能研究

为研究铜尾矿砂（Copper Tailings Sand,简称CTS）对氧化石墨烯（Graphene Oxide,简称GO）的吸附效果,从绍兴平水铜矿尾矿库采取样本,以其作为吸附剂对GO吸附效果进行研究。结果表明,CTS对GO的吸附与pH、吸附剂CTS的质量、GO初始浓度有关,在pH=2、吸附剂质量m=50mg、GO初始浓度为80mg/L的条件附近吸附率达到最大,吸附率R=90%,平衡时的吸附量qe=72.51mg/g;利用Langmuir和Freundlich等温吸附方程在303K条件下对其剩余浓度与吸附量进行拟合,发现Freundlich吸附模型更适合用来拟合CTS对GO的吸附。     

煅烧紫贻贝壳粉对Cd2+和Pb2+的吸附热力学研究

贻贝是我国的重要的海产经济贝类,但由于养殖规模的增大而随之产生的废弃贻贝壳资源成为了关注的热点。研究发现贻贝壳是一种环境友好型的生物吸附剂,本文通过高温煅烧处理,进一步优化了贻贝壳的吸附性能,采用SEM、BET、XRD和IR表征手段对贻贝壳的微结构、孔径及组成进行了分析;同时探讨了贝壳粉吸附剂对Cd2+和Pb2+的吸附热力学性能。结果发现贻贝壳粉经高温煅烧后,其主要成分为CaO,且比表面积显著增大,比表面积达7.8965 m2/g,形成诸多纳米孔径,直径在0.5~1.1 nm,吸附性能提高。贻贝壳吸附剂用量和溶液pH对Cd2+和Pb2+的吸附量影响较大,吸附剂对Cd2+的吸附量明显高于对Pb2+的吸附量,且吸附剂对Cd2+和Pb2+的吸附均符合Freundlich等温吸附模型。由此可知,煅烧后的紫贻贝壳是一种优良廉价的生物吸附剂,可将其开发成一种针对性去除废水中重金属Cd2+的新型吸附剂。     

向日葵盘低酯化果胶对重金属离子Pb2+的吸附性能研究

重金属污染由于缺乏有效的治理方法而对公众健康有严重威胁,为了开发吸附重金属离子的生物新材料,本文以向日葵盘为原料提取天然的低酯化果胶LAHP,并研究LAHP对水溶液中Pb2+的吸附性能、优化LAHP吸附Pb2+的条件。采用草酸溶液80 oC提取、乙醇沉淀的方法获得LAHP,产率为14.68%±0.76%。质量分析显示LAHP符合国家质量标准对食品添加剂果胶的要求,结构分析说明LAHP主要由半乳糖醛酸（GalA,86.34%）组成,甲酯化度为23.93%±1.57%,分子量为257 kDa,是天然的低酯化果胶。LAHP对Pb2+的吸附能力受果胶用量、溶液pH、吸附温度和干扰离子等因素的影响,优化确定了LAHP吸附Pb2+的最佳条件:果胶添加量为30 mg/L（Pb2+浓度为11.0 mg/L）、溶液的pH=8.0、处理温度30 ℃。LAHP对Pb2+的最大吸附量为44.57±2.50 mg/g,二价金属离子会在一定程度上影响LAHP对Pb2+的吸附能力。因此,从向日葵盘中提取的低酯果胶是一种良好的天然重金属吸附剂,具有广阔的应用前景。     

反向成球法制备风味“爆浆”珍珠的工艺

本研究基于果胶与海藻酸钠在钙离子体系中协同形成凝胶的原理,采用反向成球技术制得具有核壳结构的风味"爆浆"珍珠。以最大力值和咀嚼性为主要指标,通过成球性观察和质构仪测试,得到"爆浆"珍珠制作的最佳工艺;以感官评价为标准,通过正交实验得到桂花风味"爆浆"珍珠的最优配方。结果表明,制备桂花风味"爆浆"珍珠的最优工艺条件为:芯液载入量为350μL,成球反应时间10 min,固化液(壳聚糖)浓度0.5%(W/W),芯液的配方为:桂花风味糖浆用量10%(W/W)、白砂糖用量10%(W/W)及黄原胶浓度0.2%(W/W)。得到的"爆浆"珍珠为规则的圆球状,平均粒径9.5 mm、平均膜厚0.47 mm,其最大力值471 g/cm2、硬度2279 g。得到的桂花风味"爆浆"珍珠具有良好的咀嚼性和爆浆感。为奶茶行业"爆浆"珍珠的工业生产提供了参考。     

Isolation and identification of an exopolysaccharide-producing lactic acid Bacterium strain from Chinese Paocai and biosorption of Pb(II) by its exopolysaccharide

Lactic acid bacteria isolated from various traditional Chinese fermented foods were screened for the production of exopolysaccharides (EPS). The strain 70810 from Chinese Paocai, which was identified as Lactobacillus plantarum (HQ259238) by morphological, physiological, biochemical, and 16S rDNA tests, was selected due to its highest EPS production capability (0.859 g/L) for further study. Biosorption of Pb(II) from aqueous solutions by 70810 EPS was studied with parameters of initial pH, contact time, initial Pb(II) concentration, adsorbent dosage, and temperature, respectively. Maximum adsorption of Pb(II) was observed at pH 5, 30 °C, and 6 h, respectively. The adsorption capacity was also found to be dependent upon initial Pb(II) concentration and adsorbent dosage. Surface adsorption of the metal at surface of 70810 EPS was confirmed through scanning electron microscopy. Fourier transform infrared spectroscopy spectra analysis indicated that some functional groups (for example, -OH, COO-, C = O, and -NH) of 70810 EPS were involved in Pb(II) biosorption process. PRACTICAL APPLICATION: Lactobacillus plantarum 70810 can be used as a starter culture for the production of some fermented foods (for example, yoghurt or fermented soybean milk) and the production of EPS that can meet consumer's demand for products with low levels of additives. The EPS may be used as a potential biosorbent for the removal of heavy metal from environment and these fermented foods maybe have the potential effect to excrete lead from human body.     

Efficient removal of heavy metal ions with biopolymer template synthesized mesoporous titania beads of hundreds of micrometers size

We demonstrated that mesoporous titania beads of uniform size (about 450 μm) and high surface area could be synthesized via an alginate biopolymer template method. These mesoporous titania beads could efficiently remove Cr(VI), Cd(II), Cr(III), Cu(II), and Co(II) ions from simulated wastewater with a facile subsequent solid-liquid separation because of their large sizes. We chose Cr(VI) removal as the case study and found that each gram of these titania beads could remove 6.7 mg of Cr(VI) from simulated wastewater containing 8.0 mg·L(-1) of Cr(VI) at pH = 2.0. The Cr(VI) removal process was found to obey the Langmuir adsorption model and its kinetics followed pseudo-second-order rate equation. The Cr(VI) removal mechanism of titania beads might be attributed to the electrostatic adsorption of Cr(VI) ions in the form of negatively charged HCrO(4)(-) by positively charged TiO(2) beads, accompanying partial reduction of Cr(VI) to Cr(III) by the reductive surface hydroxyl groups on the titania beads. The used titania beads could be recovered with 0.1 mol·L(-1) of NaOH solution. This study provides a promising micro/nanostructured adsorbent with easy solid-liquid separation property for heavy metal ions removal.     

Comparison of alginate and pectin based beads for production of poultry probiotic cells

A comparative study on the stability and potential of alginate and pectin based beads for production of poultry probiotic cells using MRS medium in repeated batch fermentation was conducted. The bead cores, made of three types of materials, i.e., ca-alginate, ca-pectinate and ca-alginate/pectinate, were compared. The effect of single and double layer coatings using chitosan and core material, respectively, on the bead stability and cell production were also studied. The pectin based beads were found to be more stable than that of the alginate beads and their stability was further improved by coating with chitosan. The cell concentration in pectin based beads was comparable to that in the alginate beads. On the other hand, pectin based beads gave significantly lower cell concentration in the growth medium for the initial fermentation cycles when compared to the alginate beads. In conclusion, pectin was found to be potential encapsulation material for probiotic cell production owing to its stability and favourable microenvironment for cell growth.     

Preparation of iron-loaded alginate gel beads and their release characteristics under simulated gastrointestinal conditions

The formulation and processing variables affecting the preparation of iron-loaded alginate beads for potential use as controlled release carriers were studied. The effect of alginates with different mannuronic/guluronic acid ratios, calcium concentration, loading of iron (II) and iron (III) compounds, variable iron loading times and incorporation of iron at different stages in the preparation were considered. Two successful strategies for the incorporation of iron into alginate beads involved using a mixed iron/calcium cross-linking bath or taking preformed calcium cross-linked beads and subsequently loading them with iron. Beads with 50–80 mg iron/g dried bead could be made with ferrous gluconate, high guluronic acid alginate and the mixed cross-linking bath method. Beads with higher loading, up to 180 mg iron/g dried bead, could be made by loading ammonium ferric citrate. Under simulated gastrointestinal conditions the beads progressively released iron in nutritionally relevant amounts.     

Highly effective adsorption of heavy metal ions by a thiol-functionalized magnesium phyllosilicate clay

A thiol-functionalized layered magnesium phyllosilicate material (called Mg-MTMS), prepared by a direct and cost-effective co-condensation synthesis, has been investigated as a high-capacity adsorbent for heavy metal ions. Structural characterization by powder X-ray diffraction, infrared spectroscopy, solid-state 13C and 29Si NMR spectroscopies, and elemental analyses confirms the smectite-type structure and the high organic moiety content of this material. Mg-MTMS was found to be highly effective for the adsorption of Hg(II), Pb(II), and Cd(II) ions, exhibiting unprecedented metal ion uptake capacities of 603, 365, and 210 mg of metal/g of adsorbent, respectively. Mg-MTMS shows an equivalent affinity for the three metal ions, removing them from mixed metal solutions with an equal ion uptake capacity (approximately 400 mg of metal/g of adsorbent). Metal-loaded Mg-MTMS can be regenerated by acid treatment without altering the adsorbent properties. The high effectiveness of Mg-MTMS for the capture of metal ions is attributed to both the high concentration of complexing thiol groups (6.4 mmol of SH/g of Mg-MTMS) and the expansion capability of the framework, which facilitates the accessibility of the binding sites.     

Effect of oxide formation mechanisms on lead adsorption by biogenic manganese (hydr)oxides, iron (hydr)oxides, and their mixtures

The effects of iron and manganese (hydr)oxide formation processes on the trace metal adsorption properties of these metal (hydr)oxides and their mixtures was investigated by measuring lead adsorption by iron and manganese (hydr)oxides prepared by a variety of methods. Amorphous iron (hydr)oxide formed by fast precipitation at pH 7.5 exhibited greater Pb adsorption (gamma(max) = 50 mmol of Pb/mol of Fe at pH 6.0) than iron (hydr)oxide formed by slow, diffusion-controlled oxidation of Fe(II) at pH 4.5-7.0 or goethite. Biogenic manganese(III/IV) (hydr)oxide prepared by enzymatic oxidation of Mn(II) by the bacterium Leptothrix discophora SS-1 adsorbed five times more Pb (per mole of Mn) than an abiotic manganese (hydr)oxide prepared by oxidation of Mn(II) with permanganate, and 500-5000 times more Pb than pyrolusite oxides (betaMnO2). X-ray crystallography indicated that biogenic manganese (hydr)oxide and iron (hydr)oxide were predominantly amorphous or poorly crystalline and their X-ray diffraction patterns were not significantly affected by the presence of the other (hydr)oxide during formation. When iron and manganese (hydr)oxides were mixed after formation, or for Mn biologically oxidized with iron(III) (hydr)oxide present, observed Pb adsorption was similar to that expected for the mixture based on Langmuir parameters for the individual (hydr)oxides. These results indicate that interactions in iron/manganese (hydr)oxide mixtures related to the formation process and sequence of formation such as site masking, alterations in specific surface area, or changes in crystalline structure either did not occur or had a negligible effect on Pb adsorption by the mixtures.     

麦秆水凝胶的制备及其对Cu(Ⅱ)、Mn(Ⅱ)的吸附

以麦秆为原料,通过自由基接枝共聚反应制备对Cu(Ⅱ)、Mn(Ⅱ)具有高效吸附性能的麦秆水凝胶。实验中先将麦秆粉碎成粉,用氢氧化钠溶液超声纯化,然后以过硫酸铵为引发剂,以丙烯酸和丙烯酰胺为单体,以N,N-亚甲基双丙烯酰为交联剂,得到麦秆水凝胶。通过傅里叶红外光谱仪（FT-IR）、扫描电子显微镜（SEM）、热重分析仪（TGA）等对水凝胶进行表征,并研究其对Cu(Ⅱ)、Mn(Ⅱ)等重金属离子的吸附性能。结果表明,通过FT-IR和SEM分析显示麦秆水凝胶成功制备;麦秆水凝胶对Cu(Ⅱ)、Mn(Ⅱ)具有良好的吸附性能,吸附过程符合准二级动力学模型,在Cu(Ⅱ)、Mn(Ⅱ)离子浓度分别为500 mg/L和400 mg/L,振荡吸附6 h后吸附量分别达到238.1 mg/g和176.9 mg/g。