超临界CO2萃取在环境样品预处理中的应用

阐述了超临界流体萃取的原理和特点，分析了温度、压力、流体流速、改性剂、络合剂等因素对萃取过程的影响，介绍了超临界CO2萃取技术的优点及其在萃取土壤中的有机污染物、非固体介质中的污染物、环境样品中的金属离子等方面的应用，对该技术的应用前景作了展望。     

Lipid-Filled semipermeable membrane devices and mussels as samplers of organochlorine compounds in lake water

Semipermeable membrane sampling devices (SPMDs) and caged lake mussels (Anodonta piscinalis) were simultaneously deployed at four lake watercourse sites in Central Finland four weeks in August 1992. This study was part of the regular annual monitoring of the organochlorine compounds (OCC) in pulp-mill recipient watercourses of Finland with bivalves. Chlorohydrocarbons (CHCs), chlorophenol compounds (PCPs), chloroanisoles (PCAs) and chloroveratroles (PCVs) were analyzed from lipid extract of mussels and from the synthetic triolein lipid of the SPMDs. Hexane-diethyl ether (9:1, v/v) dialysis using polyethylene membrane was applied in dean up of the SPMD lipids and, for comparison, to six sets of the mussel fat. Dialysis recovered CHCs but not PCPs from the mussel fat. CHCs, PCPs, PCAs and PCVs were all recovered in dialysis of the SPMD lipid. Handling of SPMDs in the transport and deployment operations caused significant OCC contamination for the blank SPMDs. Similar trends were revealed in the OCC profiles for mussels ans SPMDs. An exception was the lack of PCPs appearing in SPMDs that did appear in mussels and in a complementary manner the appearance of the PCAs and PCVs in SPMDs.     

超临界乙醇流体制取活性炭-TiO2光催化剂复合材料的研究

研究表明：在超临界乙醇流体介质下钛酸异丙酯能有效地分解成具光催化活性的锐钛矿型TiO2粒子，同时产生的TiO2粒子可与活性炭融合成一体，形成的活性炭－TiO2光催化剂复合材料具很好的光催化活性与吸附作用，而且具有的协同效应优于活性炭与TiO2样品的物理混合形式。     

化学萃取技术在重金属污染土壤修复中应用的研究

用HCl、Na2 EDTA、柠檬酸作为萃取剂在不同的萃取条件下对湘潭锰矿污染土壤进行萃取实验 ,研究 3种萃取剂对土壤中 3种重金属Mn、Pb和Cd的萃取效率。该研究表明 ,浓度是影响重金属萃取效率的主要因素     

Life cycle greenhouse gas emissions, fossil fuel demand and solar energy conversion efficiency in European bioethanol production for automotive purposes

Crop derived biofuels such as (bio)ethanol are increasingly applied for automotive purposes. They have, however, a relatively low efficiency in converting solar energy into automotive power. The outcome of life cycle studies concerning ethanol as to fossil fuel inputs and greenhouse gas emissions associated with such inputs depend strongly on the assumptions made regarding e.g. allocation, inclusion of upstream processes and estimates of environmentally relevant in- and outputs. Peer reviewed studies suggest that CO₂ emissions linked to life cycle fossil fuel input are typically about 2.1–3.0 kg CO₂ kg⁻¹ starch-derived ethanol. When biofuel production involves agricultural practices that are common in Europe there are net losses of carbon from soil and emissions of the greenhouse gas N₂O. Dependent on choices regarding allocation, they may, for wheat (starch) be in the order of 0.6–2.5 kg CO₂ equivalent kg⁻¹ of ethanol. This makes ethanol derived from starch, or sugar crops, in Europe still less attractive for mitigating climate change. In case of wheat, changes in agricultural practice may reduce or reverse carbon loss from soils. When biofuel production from crops leads to expansion of cropland while reducing forested areas or grassland, added impetus will be given to climate change.     

Role of NADH-dependent chromium reductases,exopolysaccharides and antioxidants by Paenibacillus thiaminolyticus PS 5 against damage induced by reactive oxygen species

ABSTRACT

Cr (VI) being used in various activities of industries and its improper treatment lead to contamination of environment. Among different methods, biological is the most efficient method to control pollution from soils affected with metals. Present study was designed to assess the role of Paenibacillus thiaminolyticus PS5 for adsorption, Cr (VI) reduction and mechanism of reduction. Sorption of chromium (VI) by strain PS5 was obtained by batch equilibrium method. Cr (VI) reduction in both free and immobilised cells were evaluated by 1,5-Diphenyl Carbazide method. The formation of biofilm by Paenibacillus thiaminolyticus PS5 was observed for colour change as well as quantified spectrophotometrically. Analysis kits were used to measure the amount of eDNA, superoxide and malondialdehyde (MDA). Metal resistant strain PS5 was characterised as P. thiaminolyticus using 16S rRNA gene sequence. Maximum biosorption of Cr (VI) by strain PS5 was found at pH 6–8 and 100–400 µgCr/mL within 24 hours of incubation. Complete reduction of Cr (VI) by strain PS5 was achieved at pH 6–8 and100–300 µg/mL Cr (VI). Paenibacillus thiaminolyticus PS5 immmobilisation on sodium alginate and polyvinyl alcohol facilitated complete reduction of Cr (VI) within 18 hours due to the formation of more biofilm under metal stress conditions. Strain PS5 reduced almost all Cr (VI) into Cr (III) in supernatant, most of which was immobilised by cell debris. Experiments confirmed the reduction of Cr (VI) by cytosolic cell-free extracts which is a mechanism of detoxification. The release of exopolysaccharides and antioxidants by strain PS5 played a protective role against cell damage by Cr (VI) as Cr (VI) could not release the significant amount of eDNA, superoxide and MDA. The present study proved strain PS5 to be a super bioinoculant which has great capacity for adsorption, biotransformation and can activate cytosolic reductases, exopolysaccharides and antioxidants against oxidative damage.     

萃取色层-原子吸收法测定废水中痕量铅和镉

萃取色层-原子吸收法测定废水中痕量铅和镉采用吸附树脂GDX-301,粒度60～80目为支持体,以双硫腙0.2%四氯化碳溶液;甲基异丁基酮(MIBK)混合为萃取剂的萃取色层柱分离富集废水中痕量铅、镉,用0.5N盐酸20 ml分4～5次洗脱,流速为1 ml/min,洗脱液承接于25 ml容量瓶中,用去离子水定容后与标准系列同时在原子吸收分光光度计上分别进行铅、镉含量的测定.方法用于一般工业废水和生活饮用水中微铅、镉的测定.     

First in vitro use of the phenylphosphate carboxylase enzyme in supercritical CO2 for the selective carboxylation of phenol to 4-hydroxybenzoic acid

A new biotechnological synthetic approach to 4-hydroxybenzoic acid is reported. Thauera aromatica cells produce the phenylphosphate carboxylase enzyme that selectively carboxylates phenylphosphate in the para position, without any formation of the ortho isomer. Here we show that the enzyme also works in supercritical carbon dioxide, opening a new technological solution to the recovery of the products that is a key problem when aqueous media are used. The enzyme shows an activity comparable with that shown under CO₂ pressure in aqueous media and does not require the presence of NaHCO₃.     

Production of biodiesel from macroalgae by supercritical CO2 extraction and thermochemical liquefaction

We compare two different techniques for the extraction of biodiesel from macroalgae: the thermochemical liquefaction and the extraction using supercritical carbon dioxide (sc-CO₂). The first allows to use wet material, while sc-CO₂ requires dry material and uses moderate temperature and pressure so that it can be useful for the extraction of thermolabile compounds which may decompose at the temperature at which thermal methos are carried out. In both cases the extracted oil was characterized quantitatively and qualitatively. The novelty of the work is that in the literature the use of macroalgae for the production of biodiesel has not so far been described, while they are used mainly as food or other purposes.     

活性污泥好氧异养菌群平板分离培养方法的改进

自然温度(12~21℃)、贫营养、活性污泥提取物等目前提高菌群可培养性的方法用于培养活性污泥好氧异养菌群的结果显示,这些方法均能显著提高平板培养基的分离培养能力.含活性污泥提取物的贫营养培养基ASEⅡ培养细菌的数量可占细菌总数的23.2%,在所有培养基中最高,而营养最丰富的培养基MRS培养细菌的数量只占细菌总数的8.82%,在所有培养基中最低.图1表4参14