ONP精筛渣处理回收技术

采用高频疏解及气浮组合技术对ONP(旧新闻纸)制浆精筛渣进行处理研究。结果显示:经过高频疏解处理可以有效分离纤维及胶黏物,高频疏解可将精筛渣中大胶黏物从纤维上剥离并碎解,气浮可进一步将游离的大胶黏物分离排出系统,大胶黏物总含量降低80%左右,而大面积(≥0.8 mm~2)胶黏物去除率可达90%左右;同时尘埃度可降低53.0%;残余油墨去除率可达25%;此外,该工艺对纸浆的物理强度由显著的改善作用,可使纸浆抗张强度、撕裂度及耐破度分别提升95.4%、16.3%和84.3%。     

浮选设备在OCC制浆系统杂质去除中的应用

介绍了在废瓦楞箱纸板(OCC)制浆生产过程中增加浮选设备,用于去除OCC浆料中的胶黏物等杂质,以减轻胶黏物等杂质对后续生产运行及成品纸张质量的负面影响。结果表明:OCC浆料经浮选后胶黏物去除率约为39%,灰分去除率约为34%;精筛处理后浮渣的胶黏物去除率约为71%,可以进行纤维回收。说明本制浆系统改造对OCC浆料中胶黏物和灰分都有较好的去除效果,是解决废纸制浆杂质去除问题的有效途径。     

浆料浮选技术的创新性应用

主要介绍了浮选技术在OCC制浆工艺中创新应用的成功案例,借助浮选技术可进一步改善和提高OCC制浆中胶黏物的去除效率。OCC浮选技术应用的主要目标和挑战有:单一的浮选法对于纤维中杂质的去除率必须足够高,否则没有应用意义,这些杂质包括胶黏物、尘埃点、原料中夹杂的废旧报纸中的油墨等;浮选法会产生一定量的浆渣排出,由此会造成6%~8%纤维流失,这很难让制浆造纸企业接受,如何能在保证OCC浮选法杂质去除率的同时又能最大限度地减少纤维流失,也是本次应用要研究解决的重点。     

热分散处理条件对胶黏物分散与后续去除的影响

研究了热分散处理温度、齿盘间隙以及进浆浓度对浆中胶黏物的分散作用,同时检测了后浮选过程中胶黏物的去除效果。研究结果表明,热分散处理使大胶黏物和细小胶黏物得到了有效的分散,微细胶黏物以及胶体与溶解物质含量有所增加。提高处理温度、减小齿盘间隙或增加进浆浓度,都将促进大胶黏物和细小胶黏物的分散。在温度为100℃、齿盘间隙为0.3 mm、进浆浓度为30%的条件下,大胶黏物可降低大约92%,细小胶黏物可降低大约81%。由于大胶黏物被分散成为尺寸更为细小的成分,促进了胶黏物在后续浮选过程的有效去除,细小胶黏物的去除率达到25%~26%,微细胶黏物的去除率达到68%~70%。     

第1部分大胶黏物、细小胶黏物和微细胶黏物的分散与去除

研究了热分散处理温度、齿盘间隙以及进浆浓度对浆中胶黏物的分散作用,同时检测了后浮选过程中腔黏物的去除效果.研究结果表明,热分散处理使大胶黏物和细小胶黏物得到了有效的分散,微细胶黏物以及胶体与溶解物质含量有所增加.提高处理温度、减小齿盘间隙或增加进浆浓度,都将促进大胶黏物和细小胶黏物的分散.在温度为100℃、齿盘间隙为0.3mm、进浆浓度为30％的条件下,大胶黏物可降低大约92％,细小胶黏物可降低大约81％.由于大胶黏物被分散成为尺寸更为细小的成分,促进了胶黏物在后续浮选过程的有效去除,细小胶黏物的去除率达到25％～26％,微细胶黏物的去除率达到68％ ～70％.     

脱墨剂对胶黏物和油墨去除影响的研究

选取3种不同种类的脱墨剂,研究它们在旧报纸(ONP)脱墨过程中对油墨和胶黏物去除的影响。结果表明,油墨的去除方面,以非离子表面活性剂为主要成分的脱墨剂A的洗涤脱墨效果最优,但浮选脱墨效果最差,浮选时纤维流失较低;以无机质为主要成分的脱墨剂C的浮选脱墨效果最优,但洗涤脱墨效果最差,同时,浮选纤维流失最低;以皂类为主要成分的脱墨剂B的浮选和洗涤脱墨效果居中。胶黏物的去除方面,脱墨剂A有利于较大尺寸的胶黏物颗粒的形成,胶黏物的浮选去除效果最好,去除效率为82.8%;脱墨剂B和C对胶黏物颗粒尺寸的影响不大,浮选去除效果较差,尤其是脱墨剂B的胶黏物去除效率仅8.42%。因此,在去除ONP浆中的油墨和胶黏物时,要综合杂质、脱墨剂和处理流程各自的特点,综合考虑各方面因素选取适宜的脱墨剂,以有效提高杂质去除率,提升ONP浆品质。     

旧新闻纸油墨和胶黏物在弱碱性条件下的去除特性

在弱碱性条件下,添加不同用量的Na_2SiO_3和Na_2SO_3碎浆,研究这两种化学药品对旧新闻纸中的油墨以及胶黏物去除的影响,并与碱性条件下的脱墨效果进行比较。结果表明,在弱碱性条件下,在碎浆阶段,Na_2SiO_3对油墨的剥离作用比Na_2SO_3的要好;但在浮选阶段,Na_2SO_3的脱墨效果比Na_2SiO_3的脱墨效果好。从胶黏物的去除方面看,Na_2SO_3用量的改变没有导致胶黏物去除量发生较大的波动,而Na_2SiO_3用量的改变却引起胶黏物去除量发生较大的波动,当用量均为2%时,胶黏物浓度的去除率最大。碱性条件下,虽然在白度、胶黏物方面表现效果好,但是浮选脱墨效率低于Na_2SO_3的脱墨效果。总体来看,碱性脱墨还是有一定的优势;在弱碱性条件下,使用Na_2SiO_3的脱墨效果优于使用Na_2SO_3的脱墨效果。     

表面活性剂对旧新闻纸胶黏物和油墨去除效果的研究

选取三种不同类型的表面活性剂,对其在废旧报纸浮选过程中去除胶黏物以及油墨的影响进行了研究,并初步探讨了染色法对浮选过程中混合杂质的评价方法,取得了一定进展。结果表明,皂类表面活性剂用量在0.4%时,油墨去除率最高,为47.34%;阴离子表面活性剂用量在0.15%时,大胶黏物去除率最高为83.4%;非离子表面活性剂用量在0.15%时,混合杂质去除率最高为78.75%。综合整体浮选效果来看,选取0.15%的阴离子表面活性剂较其它两类表面活性剂具有较大的优势。     

纳米TiO2在废纸浆浮选脱墨中的应用

将纳米TiO2胶体溶液直接用于废纸浆浮选脱墨过程中,主要考察了纳米TiO2用量、温度以及pH值对浮选脱墨效果的影响,并对其在胶黏物去除方面做了研究。实验发现,随纳米TiO2用量的增加,脱墨效果呈现先提高后降低的趋势;在其用量为0.06%时,残余油墨的降低量最大可达773mg/kg,白度提高量最高可达9.4%。提高温度、碱性环境更有利于纳米TiO2浮选脱墨。浮选中纳米TiO2对胶黏物有良好的去除效果,胶黏物去除率最高可达66.8%,与空白样相比,胶黏物去除率最高可提高50.3个百分点。     

实验室浮选柱脱墨系统的初步研究

介绍了一种用于废纸脱墨的实验室浮选柱装置。利用这套系统初步考察了浮选柱用于浮选时的一些特点和性能,如不同的空气流量以及浆料流量下脱除胶黏物和灰分的能力。实验发现,即使在空气贮藏量较低、浮选柱气体流量0.4m3/h时,胶黏物去除率也能够达到83.4%、灰分去除率在50%以上。实验证明这套浮选系统对胶黏物去除具有较好的选择性。     

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.     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the