离子筛型锂离子吸附剂的制备

采用高温固相法制备锂离子吸附剂。采用正交实验法对影响吸附率的灼烧时间，温度和水热时间等诸因素进行了讨论，确定了最佳制备条件。实验结果显示：用该吸附剂在室温24℃，液相pH=7．2，锂的初始浓度为6mg／L，对锂的吸附率可达93．2％，吸附量为3．78mg／g。     

聚乙烯亚胺磁性改性对刚果红染料废水的吸附

针对刚果红染料废水吸附处理过程中,吸附剂不易回收的问题,采用共价交联法制备出磁性吸附剂Fe_3O_4@SiO_2@PEI,研究该吸附剂对刚果红染料废水的吸附效果,分析pH值、吸附时间、吸附剂用量和初始质量浓度等因素对吸附性能的影响。结果表明:当pH值为4、吸附剂用量为40 mg、吸附时间为90 min时,对刚果红废水的吸附率达到95.6%;再生实验表明,磁性吸附剂经过5次吸附/解吸循环使用后,吸附率仍在90%以上,显示了吸附剂良好的再生性。     

一种球形木质素吸附剂吸附L-天门冬氨酸的性能研究

以硫酸盐木质素为原料,利用反相悬浮技术制备出球形木质素吸附剂。利用球形木质素吸附剂吸附L-天门冬氨酸,并进行吸附条件的优选实验。结果表明,吸附效果取决于吸附时间、吸附质初始质量浓度、吸附质溶液pH值以及盐浓度等。当吸附时间150 min、吸附质初始质量浓度2000 mg/L、吸附质溶液pH值为3时,球形木质素吸附剂的平衡吸附容量可达518 mg/g,最大饱和吸附量达到625 mg/g。此外,无机盐氯化铵对球形木质素吸附剂吸附率的影响大于氯化钠,而且随着盐浓度的增大,吸附率从85.6%降至21.4%。同时进行了解吸再生和对比实验,发现用0.6 mol/L的氨水解吸时,解吸率可达99.3%,且再生后的木质素吸附剂仍具有很好的吸附性能。     

改性煤矸石吸附染料废水中甲基橙性能的研究

采用ZnCl_2对煤矸石进行改性处理,以甲基橙为原料配制模拟印染废水,在恒温振荡条件下进行吸附试验。研究了吸附剂制备中不同混合配比、焙烧时间、焙烧温度、吸附剂添加量、振荡时间、振荡方式对吸附效果的影响。结果表明:将煤矸石与氯化锌固体以1∶1的质量比混合,在400℃下高温焙烧2.5 h为吸附剂最佳制备条件;取0.07 g煤矸石改性吸附剂加入至12 mg/L的甲基橙模拟染料废水当中振荡吸附2 h,静置3.5 h后为最佳吸附条件;改性煤矸石对甲基橙模拟染料废水的吸附率达97.95%。     

改性香芋皮粉末对Cr(Ⅵ)的吸附性能

采用硫酸(1+19)溶液对香芋皮粉末进行改性制备吸附剂,利用静态吸附法,研究吸附剂粒径、投加量、吸附温度、吸附时间和初始废水的p H、Cr(Ⅵ)初始质量浓度对Cr(Ⅵ)吸附效果的影响。结果表明,吸附剂吸附Cr(Ⅵ)的最佳工艺条件为:改性香芋皮粉末的粒径200目,投加量1.0 g、吸附温度30℃、吸附时间360 min,初始废水p H 3以及Cr(Ⅵ)初始质量浓度150 mg/L。在此工艺条件下,改性香芋皮粉末吸附剂对Cr(Ⅵ)具有良好的吸附性能,对Cr(Ⅵ)的吸附量可达到7.491 mg/g,Cr(Ⅵ)的吸附率可达99.88%。用HCl溶液(1+5)对吸附饱和的吸附剂可解吸再生。     

离子筛型钠吸附剂的制备和吸附性能研究

文章采用氧化物常规粉末烧结方法制备了前驱体钠锰氧化物NaMnO2,对不同条件下合成的样品进行了XRD和SEM表征。对前驱体进行酸洗后制得所需的吸附剂,重点研究了此吸附剂对溶液中Na+的吸附性能。结果表明:当pH值=11时,离子筛型钠吸附剂的吸附容量可达26.02 mg/g;当洗脱剂盐酸的浓度为0.50 mol/L时,对吸附剂中钠离子的洗脱率较高,但同时离子筛的溶损率增大;吸附剂循环吸附洗脱时,吸附与洗脱性能较稳定,并可重复使用。     

壳聚糖衍生物对苯胺、亚硝酸盐氮吸附性能的研究

本文了研究壳聚糖衍生物-羟丙基壳聚糖亚铁配合物(HPCS-Fe2+)对苯胺、亚硝酸盐氮的吸附作用。探讨了吸附时间、溶液pH、吸附剂用量等因素对其吸附性能的影响。研究结果表明:羟丙基壳聚糖亚铁配合对苯胺和亚硝酸盐氮的吸附性能均比改性前的壳聚糖强。最佳条件为pH4、吸附时间150min,吸附剂用量为0.2%(g/mL),HPCS-Fe2+对苯胺的吸附量为5.401mg/g,吸附率为26.019%;pH5、吸附时间90min,吸附剂用量为0.2%(g/mL),HPCS-Fe2+对亚硝酸盐氮的吸附量为0.139mg/g,吸附率为19.892%。     

水杨酸改性稻草秸秆对Cu2+的吸附研究

采用水杨酸对稻草秸秆进行改性,研究其对Cu^2+的吸附性能。以制备的吸附剂对Cu^2+的去除率为参考依据,优化吸附剂制备条件,结果显示:稻草秸秆与水杨酸质量比1∶1.5、改性时间120 min、改性温度35℃为最佳制备条件。同时进一步研究吸附剂投加量、吸附温度、吸附时间、溶液初始浓度等因素对吸附效果的影响。当温度为35℃、pH为5.0、吸附时间为90 min时,0.15 g改性吸附剂对15 mg/L的Cu^2+溶液去除率达92.60%。改性稻草秸秆对Cu^2+的吸附过程符合准二级反应动力学方程,用Langmuir和Freundlich吸附等温模型均能描述Cu^2+在改性稻草秸秆上的吸附。     

回收海藻酸钠制备吸附剂对Cu~(2+)的吸附性能

以印花废水中回收的海藻酸钠为原料,制备了海藻酸钙凝胶颗粒吸附剂,考察了吸附剂在不同pH值、时间、用量和初始浓度条件下对Cu~(2+)吸附效果的影响,研究了Cu~(2+)吸附过程中的热力学和动力学。结果表明,采用回收海藻酸钠为原料制备的吸附剂,能有效去除水中Cu~(2+),在吸附剂质量浓度1.2 g/L,pH=5.4,初始质量浓度100 mg/L,吸附时间300 min的条件下,Cu~(2+)去除率可达90%以上。吸附过程符合准二级动力学和Langmuir吸附等温模型。热力学研究表明,吸附剂对Cu~(2+)吸附是吸热发应,且反应能自发进行。     

杂柑生物吸附剂对花青素的吸附特性研究

采用杂柑皮为原料,经醚化胺化改性制备改性生物吸附剂用于葡萄籽原花青素的吸附,考察了pH、吸附温度和吸附时间对吸附率的影响,并通过解吸实验研究改性杂柑皮吸附剂的再生利用性能。结果表明:最佳吸附温度为40℃,最佳吸附pH为6,在90min达到吸附平衡,最大吸附容量qe为126mg/g。改性杂柑皮吸附剂对原花青素的吸附为化学吸附且为一个吸热过程,该吸附过程更符合准二级动力学方程,吸附等温线拟合得到Langmuir等温模型效果优于Freundlich等温模型。解析实验发现p H 4的盐酸溶液有较好解析效果。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.