Tegoprens in anaerobic digestion of a mixture of cheese whey,poultry waste,and cattle dung for improved biomethanation

To obtain enriched methane content and improve the anaerobic digestion of a mixture of cattle dung, poultry waste, and cheese whey, the effect of various doses of Tegoprens: T-3012, T-3022, T-5842, T-5843, T-5851, T-5852 has been studied, in bench-scale digesters. Among them, Tegoprens 3022 showed more than a 45% increase in gas production with higher methane content.     

Effect of HF addition on the microwave-assisted acid-digestion for the determination of metals in coal by inductively coupled plasma-atomic emission spectrometry

The microwave-assisted acid-digestion for the determination of metals in coal by ICP-AES was investigated, especially focusing on the necessity of adding HF. By testing five certified reference materials, BCR-180, BCR-040, NIST-1632b, NIST-1632c, and SARM-20, it was found that the two-stage digestion without HF (HNO₃ + H₂O₂ was used) was very effective for the pretreatment of ICP-AES measurement. Both major metals (Al, Ca, Fe, and Mg) and minor or trace metals (Co, Cr, Cu, Mn, Ni, Pb, and Zn) in coal gave good recoveries for their certified or reference values. The possibility of ‘HF-memory effect’ was cancelled by the use of a set of vessels which had been never contacted with HF. Twenty-four Japanese standard coals (SS coals) were analyzed by the present method, and the concentrations of major metals measured by the present method provided very high accordance with those from the authentic JIS (Japanese Industrial Standard) method.     

Macroscopic mass and energy balance of a pilot plant anaerobic bioreactor operated under thermophilic conditions

Intensive poultry production generates over 100,000 t of litter annually in West Virginia and 9×10⁶ t nationwide. Current available technological alternatives based on thermophilic anaerobic digestion for residuals treatment are diverse. A modification of the typical continuous stirred tank reactor is a promising process being relatively stable and owing to its capability to manage considerable amounts of residuals at low operational cost. A 40-m³ pilot plant digester was used for performance evaluation considering energy input and methane production. Results suggest some changes to the pilot plant configuration are necessary to reduce power consumption although maximizing biodigester performance.     

微波在分析化学及有机合成中的应用

综述了近10年来微波技术在分析化学和有机合成中的应用，着重介绍了微波消解在分析化学和微波辐射在有机合成反应中的应用进展。     

Probing in vitro digestion at oil–water interfaces

Interfacial layers have been widely applied to study the formation and stability of emulsion-based systems. However, the application of isolated interfaces to address digestibility of emulsions is often limited because of the complexity of experimental methods and results. This review summarizes the latest developments in analytical methods and literature data on effects of digestion on interfacial layers. Particular emphasis is given to understand the changes on interfacial magnitudes during oral, gastric, and duodenal digestion, either applied separately or sequentially. Limitations of interfacial aspects and key factors that influence emulsion microstructure in bulk and lipid digestion are identified. Understanding the behavior of interfacial layers upon gastrointestinal digestion promotes an accurate tracking of the physiological fate of emulsions.     

微波消解凯氏定氮法快速测定酱油中全氮

研究了凯氏定氮法测定酱油中全氮时样品的微波消解方法，进行了微波消解条件的选择及消解结果精密度试验，并与国家标准方法对比，验证了方法的准确度。试验结果表明，消解完全仪需20min，相对标准偏差均小于2%（n=7），回收率范围为96%～103%，经t检验，微波溶样法与国家标准凯氏定氮法的测定结果无显著性差异。     

Determination of selenium, zinc and cadmium in antidandruff shampoos by atomic spectrometry after microwave assisted sample digestion

Microwave assisted pre-treatments for atomic spectrometric determination (inductive coupled plasma-optical emission spectrometry, ICP-OES or flame atomic absorption spectrometry, FAAS) of metallic elements, usually present in antidandruff shampoos, are proposed. They are based on the digestion of the sample with HNO₃ into a closed reactor, which is irradiated at 800 W for a few minutes. Selenium was determined by ICP-OES. The limit of detection was 0.11 mg l⁻¹; the relative standard deviation (R.S.D.) for the selenium content in the samples was in the 0.6–3.6% range. The results obtained were in agreement with the label contents and the recovery of the proposed method was in the 100–106% range. Zinc and cadmium were determined by FAAS. The limit of detection for zinc determination was 0.078 mg l⁻¹; the R.S.D. for zinc contents was in the 0.8–8.6% range. A limit of detection of 0.09 mg l⁻¹ was obtained for cadmium determination; the R.S.D. for cadmium contents was in the 0.7–2.7% range. The determinations were performed after two different sample mineralization pre-treatments — dry ashing (in an electric furnace) and wet mineralization (in a microwave oven). Both methodologies provided comparable results for zinc and cadmium determination in shampoos. The proposed microwave assisted digestion procedures allow a precise and accurate determination of selenium, zinc and cadmium in commercial antidandruff shampoos, and the sample pre-treatment is less time-consuming than the classic methods.     

A new procedure for bovine milk digestion in a focused microwave oven: gradual sample addition to pre-heated acid

Milk samples can be efficiently digested using a focused microwave oven, however the conventional procedure of addition of concentrated acids to the liquid sample leads to digestates with elevated acidity and residual carbon concentrations. In this work a focused microwave oven was applied for acid digestion of bovine milk samples using a conventional and an alternative procedure based on gradual sample addition to hot and concentrated acids. A two-level 2³ full factorial design experiment with eight runs was carried out to evaluate the optimum experimental conditions for reducing both the residual carbon and the final acidity of digestates. The three studied parameters were: temperature of the digestion medium for sample addition, addition of sulfuric acid before the sample or during the first step, and number of aliquots of the sample gradually added. The best conditions were attained by adding small aliquots of milk (ten-fold a volume of 0.5 ml added during 5.0 min) to a digestion mixture containing 3.0 ml nitric acid plus 1.0 ml sulfuric acid heated at 105 °C. It was demonstrated that the digestion efficiency of the alternative procedure was better than the conventional procedure, i.e. 98 and 80%, respectively. The alternative procedure was applied for determination of Ba, Ca, Cu, K, Mg, Na, P, and Zn in whole and non-fat bovine milk. The accuracy was proved using two certified reference materials (whole and non-fat milk powder).     

Optimization of inoculum to substrate ratio for enhanced methane yield from leather fleshings in a batch study

One of the most significant issues of the last few decades has been tracing for renewable energy sources. Animal fleshing (ANFL) is the most common proteinaceous solid waste accured during the production of leather and it must be disposed of in an environmentally responsible manner. This paper is attempts to assess the biogas production from solid waste originating from the chrome based tannery. Anaerobic digestion of these wastes will be a viable option for waste stabilization and energy production in the form of biogas to be utilized in the industry. The bio-methane potential of the wastes were examined by mixing these wastes with various sources of inoculum and different inoculum to substrate (I/S) ratio considered. The batch experiments were carried out in 2.5 l glass reactors with a various source of inoculumviz., Cow Dung (CD), Elephant Dung (ED) and Bio-Digested Slurry (BDS) with varied inoculum to substrate (LFs) ratios for a retention time of 50 days with replications. The results obtained from the experiments showed that BDS:LF (25:75) had the highest gas production of 14505 ml (651.85 ml CH₄g^?1 VS) followed by CD:LF (50:50) produced 12072.5 ml (789.36 ml CH₄g^?1 VS) and ED:LF (75:25) produced 11252.5 ml (1492.08 ml CH₄g^?1 VS)with a methane content of 63.77, 61.92 and 62.72%, respectively.     

矿区植物重金属元素测定的两种前处理方法比较

分别采用酸消解法和干灰化法处理16种矿区植物,并用原子吸收分光光度法测定其中的Mn、Cd、Cr和Zn的含量。结果表明:除Cd外,两种处理方法对Mn、Cr、Zn的测定结果有明显影响。测定植物组织Cd时,两种处理方法都可采用;测定Mn、Cr元素,采用酸消解法较为合适;测定Zn则宜采用干灰化法,并可适当延长木质部分(根、茎)的灰化时间。