Biofuels for diesel engines are produced mainly from rapeseed oil in Lithuania and the Member States of the European Union. In order to minimise an adverse impact of biodiesel fuel on the food sector, it is necessary to look for alternative feedstocks for producing biodiesel fuel including the potential utilisation of the new kinds of oilseed crops and various fatty waste. Camelina (Camelina sativa) could be one of the kinds of such oilseed crops, and therefore the physical and chemical parameters of Camelina sativa oil and biodiesel fuel produced from this oil were determined and the conformity of quality parameters with the requirements of biofuel standard was evaluated. It was found that fatty acid methyl esters made from Camelina sativa oil had a high iodine value (164.6÷169.6 g I2 / 100 g oil), and therefore could be used as fuel for diesel engines only in the mixtures with methyl esters produced from animal fat or used for frying oil. It has been established that similar mixtures can contain 50÷60% of Camelina sativa oil methyl esters. The possibilities of increasing oxidation stability as well as improving the cold flow properties of ester mixtures were investigated. The most effective antioxidant – Ionol (optimal dosage of 500 ppm) and the most efficient depressants Wintron XC-30 (optimal dosage – 1500 ppm) and Infineum R-442 (optimal dosage – 1200 ppm) were selected.

Wet-process feasible high triplet energy carbazole type host materials are synthesized. On doping a green emitter into a host carbazole, the device shows an efficacy of 51 lm W¬1 and current efficiency of 52 cd A¬1 at 100 cd m−2.

The current study hypothesizes that false flax (Camelina sativa L.), as a high-value biofuel feedstock, could be grown under humid conditions of western Lithuania and that nitrogen fertilisation could influence its seed yield and oil content. The following objectives were pursued: 1) to determine the optimum nitrogen fertiliser rate for winter (N 0 , N 50 , N 100 , N 150 ) and summer (N 0 , N 30 , N 60 , N 90 , N 120 ) types of false flax, 2) to estimate false flax seed oil content, its composition and feasibility to use it for the production of biodiesel fuel. The experiments were conducted in 2008-2011 at the Vėžaičiai Branch of the Lithuanian Research Centre for Agriculture and Forestry. It was revealed that the highest (1.28 t ha -1 , in 2010) and (1.29 t ha -1 , in 2011) as well as cost-efficient summer false flax seed yield was produced having fertilised with 90 kg ha -1 of nitrogen. Significantly highest (1.2 t ha -1 , in 2011 and 1.6 t ha -1 , in 2010) winter false flax seed yield was obtained having fertilised with N 100 . In our study, the seed oil content of summer false flax amounted to 40.3% and that of winter false flax was lower -37.0%. Nitrogen fertilisation (N 150 and N 120 ) increased protein content in winter false flax seed from 22.98% to 26.97% and in summer false flax seed from 20.53% to 23.23% and did not reduce seed oil content. Methyl esters of false flax oil have a high iodine value and an especially high content of polyunsaturated linolenic acid: it reached 38.2% in winter false flax oil and 34.3% in summer false flax oil. Therefore false flax methyl esters can be used as fuel for diesel engines only in mixtures containing 40-50% of methyl esters of animal origin (used frying oil or pork lard). The most effective antioxidant Ionol BF200 (optimal dosage -500 ppm) as well as the most effective depressants Wintron XC-30 (optimal dosage -1500 ppm) and Infineum R-442 (optimal dosage -1200 ppm) were selected for improvement of oxidation stability and cold flow properties of esters.

The total concentration and the concentrations of individual chemical species of selected heavy metals were estimated in primary and anaerobically digested sewage sludge. The concentration of Zn (1503 mg/kg) was highest and was followed by Cu (201 mg/kg), Cr (196 mg/kg), Pb (56 mg/kg), Ni (44 mg/kg) and Cd (3.6 mg/kg). The metal was divided into 5 fractions (exchangeable (F1), adsorbed (F2), organically bound (F3), bound to carbonates (F4), and residual (F5)) via sequential extraction. The sludge treatment procedure had no significant effect on the fractionation results. In both the primary and anaerobically digested sewage sludge, the heavy metals were ranked according to their mobilities (fractions F1 and F2) in the following order: Ni Zn Cu Cd Pb Cr. Metal stability in the environment was evaluated by the sulphide and residual fraction F5, and the following ranking order was identified: Cr Pb :Ni Cd Zn :Cu. A leaching experiment with low-molecular-weight organic acids (oxalic, acetic and citric acid) revealed that the metal-removal efficiency varied depending on the number of carboxyl groups in the extracting agent, the chemical speciation of the metal (Ni, Zn or Cu) in the sludge and the concentration and pH change of the extracting solution. Acid solutions with a 0.5 M concentration, ranked according to their Zn-removal efficiency, are ranked as follows: citric acid (100%) acetic acid (78%) oxalic acid (71%). In all of the cases, citric acid showed the best capacity for the removal of metal from the sludge, with an extraction efficiency ranging from 30Á100%, while the Ni and Cu removal efficiencies with the acetic and oxalic acid were less than 40%. Keywords: sewage sludge, heavy metals, sequential extraction, heavy metal removal, organic acids. Reference to this paper should be made as follows: Zaleckas, E.; Paulauskas, V.; Sendžikienė, E. 2013. Fractionation of heavy metals in sewage sludge and their removal using low-molecular-weight organic acids, Journal of Environmental Engineering and Landscape Management 21(3): 189Á198. http://dx.

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