不同原料低温生物炭的性质及氨氮吸附性能

本研究以油葵秸秆（SS）、扁桃核（AH）和核桃壳（WS）3种组织结构差异较大的农业废弃物为原料,在低温下（250、300、350 ℃）慢速热解制备生物炭材料,探究其性质与氨氮吸附性能。结果表明,热解温度和原料种类对生物炭的性质影响较大,由SS制备性质稳定的生物炭所需碳化温度低,且C元素含量高。含氧官能团含量与热解温度呈负相关,SS、AH和WS在250 ℃时制备生物炭的含氧官能团含量最高,分别为2.65、2.46和2.47 mmol/g;而300 ℃时制备的生物炭对氨氮的平衡吸附量最大（pH值=7）,分别为0.9512、0.9548和0.6085 mg/g。生物炭与溶液中NH₄⁺吸附时存在静电作用,在酸性或阳离子共存条件下,吸附量降低。生物炭和商业活性炭（AC）的吸附过程均符合伪二级动力学模型与Langmuir模型,属于单层化学吸附,且生物炭对氨氮的吸附量高于AC。     

活性炭对印染废水的吸附性能

以三种不同材质的活性炭(椰壳炭、木质炭、煤质炭)为吸附剂,吸附模拟印染废水中的甲基橙。在对几种活性炭进行表征的基础上,研究活性炭投加量、p H值、温度以及吸附时间等对活性炭吸附性能的影响,并研究甲基橙在三种活性炭上的吸附热力学和动力学。结果表明,煤质炭的吸附效果最好,p H值对煤质炭的吸附影响较小;椰壳炭和木质炭的吸附符合Langmuir吸附等温线,煤质炭的吸附符合Freundlich吸附等温线;准一级吸附动力学模型,能较好地描述三种活性炭对甲基橙的吸附动力学;吸附热力学研究表明,甲基橙在三种活性炭上的吸附是自发吸附行为。     

磷酸活化文冠果果壳生物炭及其对亚甲基蓝的吸附性能

目的：探究文冠果相关产业废弃物处置方法。方法：以文冠果果壳为原料,磷酸为活化剂,在单因素试验基础上,采用Box-Behnken中心组合设计进行生物炭制备条件优化,并将最优制备条件下所得生物炭用于吸附水体中亚甲基蓝,通过考察吸附影响因素,确定磷酸活化制备的文冠果果壳生物炭对亚甲基蓝的吸附特性,并结合动力学分析探讨其吸附机理。结果：磷酸活化制备文冠果果壳生物炭的最优工艺条件为浸渍比（m_果壳粉∶m_磷酸溶液）1∶21,热解温度530 ℃,热解时间75 min。文冠果果壳生物炭吸附水体中亚甲基蓝最优条件为溶液初始pH 12.6,生物炭投加量1.0 g/L,亚甲基蓝初始质量浓度200 mg/L,吸附平衡时间120 min。文冠果果壳生物炭对水体中的亚甲基蓝吸附服从准二级反应动力学关系,吸附过程由液膜扩散控制、孔隙扩散控制和吸附解析平衡3个阶段组成。结论：磷酸活化可显著提升文冠果果壳生物炭比表面积和孔容,进而显著提升其对亚甲基蓝的吸附性能。     

改性方法对辣木籽壳生物炭吸附亚甲基蓝的影响

目的：探究不同工艺条件所制备的辣木籽壳生物炭对亚甲基蓝的吸附性能。方法：以辣木籽壳为原料,采用超声辅助碳酸钾—Fe₃O₄共浸渍热解和KOH浸渍—1 000 ℃高温热解两种方法分别制备磁性辣木籽壳生物炭（Fe₃O₄-MOS）和改性辣木籽壳生物炭（KOH-MOS）,并用XRD、SEM和FTIR对样品表面物化性质进行表征。在此基础上,通过平衡吸附法测定两种生物炭对溶液中亚甲基蓝（MB）的吸附特性,并用动力学、热力学和等温吸附模型分析对MB的吸附机理。结果：在试验所探究的条件下,Fe₃O₄-MOS和KOH-MOS对MB的吸附效率接近100%,且由Langmuir模型所得到最大吸附量分别为116.83,99.37 mg/g。结论：两种材料对MB的吸附是一个自发吸热熵增、化学吸附为主的过程。Fe₃O₄-MOS和KOH-MOS分别展现出了良好的磁分离能力和吸附能力。     

停留时间对污泥基生物炭中部分重金属的影响

文章针对污泥基生物炭中重金属对农用的潜在影响,通过测定污泥基生物炭、污泥中的重金属含量,研究污泥基生物炭中的重金属含量随热解条件的变化规律。结果表明,热解温度为600℃,终温停留时间为3 h时,能够在一定程度上降低污泥中的重金属直接投入环境中所带来的环境风险。     

制革工业污泥的利用

本研究目的在于将制革工业中产生的污泥转化为有用的材料。为了达到此目的，利用热重法（TG）和轴向固定床反应器研究了废弃污泥的热行为。以不同的升温速率升温至温度750oC进行了热重分析，在248—500℃的温度范围内观察了主要的热解分解步骤。固定床反应器中，污泥于氮气气氛中450℃和600℃热解，热解产物为气体、液体及焦炭。温度对产物组分的比例有轻微的影响。热解气有相当大的总热值（23．22MJNm^-3）。尽管热解油有适当的热值，但其含有大量的含氮和含氧化合物。本文还研究了利用污泥作为生产活性炭的一种原材料。为此，通过物理和化学的活化方法从污泥中制备了活性炭。利用所选择的活性炭对亚甲基蓝、苯酚及Cr（Ⅵ）的吸附行为进行了研究，来验证其作为吸附剂的可行性。     

废纸造纸污泥制备泥质炭吸附材料及其特性研究

通过热解法探究了废纸造纸污泥制备泥质炭吸附材料的工艺条件,并对其热解固体产物特性进行了分析,发现造纸污泥经过研磨过筛预处理、ZnCl_2活化、中低温热解炭化、盐酸洗涤、研磨干燥后可制备出内部孔隙结构发达和比表面积高的优良吸附材料。结果表明,热解温度500℃,活化剂ZnCl_2浓度3mol/L,热解时间30 min,固液比为1∶2时可制备出碘吸附值达610.3 mg/g、固体泥质炭得率为73.3%。泥质炭比表面积可达310.81cm~2/g,高于商品活性炭的159.58cm~2/g,中孔和大孔的比例较大,呈蜂窝结构,吸附性能大大增强,可替代商品活性炭用于工业废水的处理。     

沙棘籽渣生物炭对尼泊金乙酯的吸附特性研究

目的研究沙棘籽渣生物炭对尼泊金乙酯的吸附特性。方法以沙棘籽渣为材料,采用慢速热解技术于300、400、500℃条件下制备生物炭吸附剂(BC300、BC400、BC500),研究热解温度、尼泊金乙酯初始浓度、吸附温度和吸附时间对吸附效率的影响。结果生物炭的制备温度显著影响其对尼泊金乙酯的吸附效果,3种温度制备的生物炭对尼泊金乙酯的吸附能力表现为BC500BC400BC300。此外,尼泊金乙酯的初始浓度、吸附温度和时间等因素均能影响吸附效果。35℃下尼泊金乙酯初始浓度为20 mg/L时,BC500对尼泊金乙酯的去除率最高,达84.46%,生物炭对尼泊金乙酯的等温吸附线符合Langmuir模式和Freundlich模式。结论探明了沙棘籽渣制备生物炭吸附剂去除尼泊金乙酯的最适条件,为沙棘籽渣应用于尼泊金乙酯等有机污染物的去除提供了理论依据。     

污泥-稻壳生物炭对水中亚甲基蓝的吸附

以给水污泥与稻壳为主要原料，添加适量聚乙烯醇、磷酸和海泡石，通过真空热解方式制备一种可悬浮的颗粒状吸附材料，并将其用于去除模拟印染废水中的亚甲基蓝（MB）。通过批量吸附实验考察吸附剂用量、溶液pH、污染物初始质量浓度以及吸附时间等参数对吸附效果的影响，通过等温吸附模型和动力学模型研究其吸附行为，并利用BET、XRD、SEM-EDS以及FTIR探索吸附机理。结果表明，在MB初始质量浓度为61 mg/L、颗粒吸附材料用量为8 g/L、pH为8、吸附时间为90 min、吸附温度为25℃的条件下，溶液中的MB达到最大去除率81.66%。等温吸附曲线和吸附动力学结果表明，该吸附过程与Langmuir等温吸附模型、准二级动力学模型的拟合度较好，表明吸附材料对MB的吸附过程主要为单分子层的化学吸附，理论最大吸附量为66.67 mg/g。微观分析表明，吸附材料主要是通过中孔及纤维吸附、羟基取代和π-π相互作用吸附废水中的MB。     

壳聚糖微球的制备及其对甲基橙的吸附研究

以可生物降解的壳聚糖为原料，采用超声乳化-化学交联法制备了具有空腔结构的壳聚糖微球；采用扫描电子显微镜对微球的形貌和大小进行了表征；采用紫外-可见光谱仪和红外光谱仪研究了壳聚糖微球对甲基橙的吸附动力学和热力学，并对吸附机理进行了初步探讨。结果表明，壳聚糖微球外形为比较规整的球形，粒径为1～10μm，粒度分布均匀，具有空腔结构。壳聚糖微球对甲基橙的吸附过程受甲基橙初始浓度、pH值和温度等因素的影响；当pH=7．25、温度为298K时，壳聚糖微球对甲基橙的吸附率达99．34％；该吸附过程为具有化学吸附的自发过程，与Freundlich等温吸附模型相吻合（R=0．9974）。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.