Wood processing by-products treated with the lignin-based conditioner as mulch for soil protection

Wood processing by-products such as bark of different wood species and hydrolysis lignin were applied as soil mulch. The lignin-based soil conditioner (LSC) representing a lignin-based polyelectrolyte complex with the different composition (a lignin/polymer mass ratio) was obtained under laboratory conditions and was intended to protect sandy soil from erosion by simultaneous application of a soil conditioner as an adhesive, mulch and plant seeds by hydroseeding. The study revealed the pronounced dependence of the properties of the treated wood-originated mulch on the wood species as well as on the composition, the applied concentration and the application rate of LSC. A comparison of the obtained results showed that the treated hydrolysis lignin was characterised by higher compressive strength, higher water resistance and lower moisture losses from sandy soil for a given LSC composition and application rate than the bark-based mulch. The conditioner concentrations don't have negative impact on the germination of seeds plants of the coastal dune zone. First published online: 21 Oct 201

Use of 2-ethylhexyl nitrate for the slow pyrolysis of plastic waste

Plastics are widely used and are part of modern life. Recycling of plastic waste can be achieved by pyrolysis. Conventional pyrolysis of plastic waste takes place at temperatures higher than 450 °C, because the oil yield is higher. In this study, we examined if an initiator for radical reactions can achieve the conventional pyrolysis of HDPE and PP even at low temperatures. To support the onset of decomposition of HDPE and PP at low temperatures, 2-ethylhexyl nitrate (2-EHN) was added. 2-EHN forms radicals already at about 150 °C and can thus initiate the pyrolysis process at lower temperatures. Pyrolysis oil yields increased, especially for HDPE pyrolysis, at the expense of the gaseous (minus 50%) and especially the solid fraction (minus 80%). For PP and HDPE pyrolysis oil, the proportion of carbon compounds shifted toward shorter-chain, less cyclic compounds, and there was an improvement in the physicochemical property profile: the heating values of both oils were slightly higher and the pour point significantly lower, in line with the shift toward shorter-chain compounds. The diesel content and, to a lesser extent, the gasoline content increased at the expense of waxes and other high-boiling compounds

Vertical distribution of polycyclic aromatic hydrocarbons in the brackish sea water column: ex situ experiment

Background Oil spills can cause severe damage within a marine ecosystem. Following a spill, the soluble fraction of polycyclic aromatic hydrocarbons is rapidly released into the water column. These remain dissolved in seawater over an extended period of time, even should the insoluble fraction be removed. The vertical distribution of the aromatic hydrocarbon component and how these become transferred is poorly understood in brackish waters. This study examines the vertical distribution of polycyclic aromatic hydrocarbons having been released from a controlled film of spilled oil onto the surface of brackish water. Methods The study was undertaken under controlled conditions so as to minimize the variability of environmental factors such as temperature and hydrodynamics. The distribution of polycyclic aromatic hydrocarbons was measured in the dissolved and suspended phases throughout the 1 m water column with different intensity of water sampling: 1, 2, 4, 7, 72, 120, 336, 504 and 984 h. Results The total concentration of polycyclic aromatic hydrocarbons ranged from 19.01 to 214.85 ng L–1 in the dissolved phase and from 5.14 to 63.92 ng L–1 in the suspended phase. These hydrocarbons were released immediately following a controlled spill attaining 214.9 ng L–1 in the dissolved phase and 54.4 ng L–1 in the suspended phase near the cylinder bottom after 1–2 h. The 2–3 ring polycyclic aromatic hydrocarbons dominated in the dissolved phase (60–80%), whereas the greater amount of 4–6 ring polycyclic aromatic hydrocarbons (55–90%) occurred in the suspended phase. A relatively low negative correlation (rS = –0.41) was determined between the concentration of phenanthrene and suspended matter, whereas a high negative correlation (r = − 0.79) was found between the concentration of pyrene and suspended matter. Despite the differences in the relationships between the concentration ratio and amount of suspended matter the obtained regressions allow roughly to predict the concentration of polycyclic aromatic hydrocarbons

Rūgščių kritulių poveikis aliuminio išplovimui iš kalkinto dirvožemio

Acid precipitation accelerates acidification process in the soil and facilitates nutrient leaching. The study aimed to explore the effects of long-term liming on aluminium (Al) leaching by comparing a limed soil with an unlimed soil at different acidity (pH) levels of simulated acid rain (SAR). The columns of unlimed and limed soil were watered with SAR at 5.4, 4.7 and 4.0 pH levels. Aluminium was extracted from the solid phase with the following solutions: ammonium oxalate (non-crystalline Al), sodium pyrophosphate (organically bound Al), copper chloride (organo-Al complexes of low and medium stability), lanthanum chloride (the most labile organo-Al complexes) and ammonium chloride (exchangeable Al). The total Al in the leachate was also determined. Long-term liming had a significant influence on the soil acidity and reduced all Al compounds in the in solid phase. The Al concentrations determined in the leachate of the limed soil were 0.12–0.92 mg L-1 and in that of the unlimed soil – 1.63–2.62 mg L-1. Leaching losses of Al from limed and unlimed soil increased with decreasing acidity of the simulated acid rain. The losses were found to be high when the pH of SAR was 4.0. Al in the leachate was positively correlated with all Al fractions in a solid phase and showed this to be one of the reasons for increased Al leaching from acid soils. Al leaching from the soil depended not only on the pH of simulated acid rain, but also on the soil properties: acidity, Al saturation in the exchange sites (effective cations exchange capacity) and Al compounds in the solid phase of the soil. Limed soil, characterised by a higher buffer capacity (more Ca and Mg), is able to neutralize the effects of acid precipitation and reduce the solubility of Al-containing compounds

Use of polypropylene pyrolysis oil in alternative fuel production

In this study, polypropylene (PP) was recycled in a non-stirred batch reactor by slow pyrolysis at low temperature. Virgin PP and waste PP as well as mixed material of equal amounts of virgin PP plus virgin PP pyrolysis oil (ratio 1:1 w/w) were used as raw material. The highest yields of liquid product were obtained at 350°C and 400°C (82.0 and 82.3 w/w%, respectively). The density, viscosity and calorific value of the gasoline and diesel fractions of the obtained pyrolysis oils comply with EN228 and EN590 standards, respectively. The flash point corresponded to the standard only for some of the oils, but the cold filter clogging point, the pour point and especially the oxidation stability were far above the stated reference values of the standards. The pyrolysis oils as products of thermal decomposition were determined by the methods of 1 H and 13 C and two-dimensional-heteronuclear single quantum coherence nuclear magnetic resonance (2D-HSQC NMR) spectra. Spectral analysis showed that only very little aromatic compounds were present in the oils, but they contained many unsaturated compounds, which is presumably consistent with the measured oxidation stability and limits their use in the production of alternative fuels. The research octane number (RON) calculated from the NMR analyses corresponds to the lower limit of gasoline