The objective of this study is to extract phenolic compounds from nettle and melissa by using microwave and ultrasound and to compare these methods with conventional extraction and maceration, respectively. Extraction of melissa essential oil was also studied. In extraction of phenolics, effects of extraction time (5-20 min for microwave / 5-30 min for ultrasound) and solid to solvent ratio (1:10, 1:20, 1:30 g/ml) on total phenolic content (TPC) were investigated for microwave and ultrasound extractions. Different powers were also studied for ultrasound extraction. In addition, effect of solvent type (water, ethanol, ethanol-water mixture at 50:50 v/v) was analyzed and water was found as better solvent. Optimum conditions for microwave extraction of phenolics were determined as 10 min and 1:30 solid to solvent ratio for nettle, and as 5 min and 1:30 solid to solvent ratio for melissa. TPC at these conditions for nettle and melissa extracts were 24.6 and 145.8 mg GAE/g dry material, respectively. Optimum conditions for ultrasound extraction was 30 min, 1:30 solid to solvent ratio, and 80% power for nettle and 20 min, 1:30 solid to solvent ratio, and 50% power for melissa. TPC at these conditions for nettle and melissa were 23.9 and 105.5 mg GAE/g dry material, respectively. Major phenolic acids were determined as naringenin in nettle and rosmarinic acid in melissa. Major aromatic compounds in melissa essential oil were found as limonene, citral, and caryophyllene oxide. Yields of essential oil obtained by microwave and hydrodistillation were 4.1 and 1.8 mg oil/g dry sample, respectively.

ABSTRACT This study was aimed to investigate the operational conditions for stabilizing and recycling copper sludge in electronic industry by serially using acid leaching, cementation and ferrite methods. The physical/chemical characteristics of copper sludge were examined, and TCLP (Toxic Characteristics Leaching Process) tests were conducted. Results show that the copper sludge from electronic industry is weakly alkaline and consists of 6-15.8% Cu and 50-75% moisture. The TCLP tests show that copper in the sludge exceeds the regulation standard. Acid leaching tests indicate that the optimal combination of control factor levels yielding more than 99% of copper extraction is: 2.0 N in sulfuric concentration (A3), pH = 1.5 (B3), 90 minutes in treatment time (C3), and 50 oC in treatment temperature (D3). Moreover, the sediment of treated sludge fulfills the standards of the TCLP, and is thus a general industrial waste. Cementation tests indicate that the optimal combination of control factor levels yielding 96.87% of copper recovery and 92% of copper purity is: addition mole ratio of iron element Fe/Cu = 2.0 (A2), pH = 1.0 (B1), agitation speed = 200 rpm (C1), and 50 oC in treatment temperature (D3). Ferrite tests indicate that the optimal combination of control factor levels yielding more than 99% of copper removal is: addition mole ratio of ferrous sulfuric acid Fe2+/Cu = 10.0 (A3), pH = 9.5 (B2), air supply rate = 3.0 L/min (C3), and 80 oC in treatment temperature (D3). The cost analyses indicate that the expenses would be NT $7.45 for the acid leaching-cementation-ferrite process, less expensive than NT $ 8.0 for the solidification process given the same copper sludge. Thus, the proposed method in this study is competitive and feasible. Keywords: Copper sludge, Acid Leaching, Cementation, Ferrite Process, Recycling

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Laboratory soil columns, 0.3 m diameter $ times$ 0.7 m long, and two computer simulation models, LEACHM-N and NTRM, were used to investigate nitrate-nitrogen ($ rm NO sb{3 sp{-}}$-N) leaching in a sandy loam soil. The following treatments were studied: no-till (NT), reduced tillage (RT), and conventional tillage (CT) practices, with residue (R) and without residue (NR). Nitrogen fertilizer was applied at a rate of 180 kg/ha in granular form (experiment I), and in solution form a year later (experiment II). In both experiments, water was applied 5 times over 3 to 4 weeks duration, with each application lasting for 30 minutes. Each column received an average of 24 mm water in experiment I and 32 mm in experiment II. Soil moisture contents were measured and water for $ rm NO sb{3 sp{-}}$-N concentration determination sampled at 0.1, 0.2, 0.4, and 0.6 m depths, following each water application. / In each experiment I, higher nitrate-nitrogen concentrations ($ lbrack rm NO sb{3 sp{-}}$-N)), occurred at the 0.1 and 0.2 m soil layers in RT and CT treatments initially, but less leached to lower layers, while more $ rm NO sb{3 sp{-}}$-N leached to lower depths (below 0.4 m) in the NT treatment. In experiment II, more $ rm NO sb{3 sp{-}}$-N leached below 0.4 m in RT and CT than in NT treatments. Conventional tillage exhibited the lowest drainage rates. Tillage and residue effects were significant only at early stages (4 hours or before) at some depths of experiment I ($P<0.05$). Maximum $ lbrack rm NO sb{3 sp{-}}$-N) occurred at 0.4 m depth in all treatments. / LEACHM-N estimated more $ rm NO sb{3 sp{-}}$-N leaching below 0.4 m in RT and CT treatments than in NT treatment. The model performed poorly only immediately after fertilizer application, showing up to 50% deviation from observed data. Although LEACHM-N overpredicted $ lbrack rm NO sb{3 sp{-}}$-N) in the 0.2 m soil layers in all treatments, estimations remained within standard deviations of observed data. NTRM performed well below 0.4 m depths, but often underpredicted $ rm NO sb{3 sp{-}}$-N leaching at shallower depths. / From both the laboratory experiments and mathematical simulations it was concluded that when fertilizer is applied in granular form, no till practice is undesirable because deeper $ rm NO sb{3 sp{-}}$-N leaching (below 0.4 m) occurs. Reduced tillage may be the preferred choice in such a situation. When fertilizer is applied in solution, reduced and conventional tillage practices are undesirable because deeper $ rm NO sb{3 sp{-}}$-N leaching occurred. No till practice may be a better choice in such a case.

The effect of cover crops on N and weed dynamics was assessed within a pea (Pisum sativum L.) – cover crop – sweet corn (Zea mays L.) rotation. Cover crops of oat (Avena sativa L.), perennial rye (rye) (Secale cereale L.), oilseed radish (OSR) (Raphanus sativus L. var. oleoferus Metzg Stokes), and OSR plus perennial rye (OSR+rye) increased plant available N (PAN) over the cover crop growing season compared to the no cover control at the Bothwell site only. However, at neither site did cover crops result in increased PAN for the sweet corn, indicating that these cover crops will not reduce required N fertilizer applications. Also, cover crops posed neither an increased or decreased need for weed management during sweet corn production. However, OSR may be useful in pesticide reduced programs due to its potential ability to reduce fall herbicide applications, provided it does not set viable seed.

Complementary electrochemical and spectroscopic techniques were used to characterize the behavior and composition of the passive layer formed at the gold-thiosulfate interface in the presence of copper. Raman studies of three different cationic (calcium, ammonium and sodium) thiosulfate leaching solutions showed that the concentrations of sulfate, thiosulfate, trithionate and tetrathionate remained constant. Initial leaching current densities for the three systems were identical, however, significant differences were noted in the open circuit potentials of these systems. Gold nanorod electrodes were employed as substrates for Surface Enhanced Raman Spectroscopy (SERS) studies of the gold-thiosulfate interface. The composition and behavior of the passive layer at the gold- thiosulfate interface greatly differed from that of the bulk solutions. Higher order polythionate species were not observed, and significant differences were noted in the behavior of species common between the three thiosulfate leaching solutions. Passivation levels determined from SERS indicate that in the presence of copper, the cation associated with thiosulfate may play a key role in the extent of passivation on the gold surface. / Barrick Gold Corp., NSERC

Nitrate leaching was studied on a 2.4-ha subsurface-drained corn (Zea mays L.) field in southwestern Quebec. The soil was a sandy loam to loamy sand (mean depth 46 cm) overlying clay. Treatments, begun in fall 1991, consisted of no-till, reduced tillage, and conventional tillage with crop residues either removed or retained at harvest. Drain flow volume and NO$ sb3 sp-$-N concentrations in flow were monitored year-round, and soil NO$ sb3 sp-$-N levels measured in spring and fall. A total of 34 kg NO$ sb3 sp-$-N ha$ sp{-1}$ was recorded in drain flow in 1992 from the site as a whole, equivalent to 20% of applied fertilizer N. In the first 14 months of monitoring, over 70% of water samples had NO$ sb3 sp-$-N levels exceeding Canadian drinking water guidelines (10 mg NO$ sb3 sp-$-N L$ sp{-1}),$ and about 25% had over 40 mg NO$ sb3 sp-$-N L$ sp{-1}.$ Flow-weighted mean concentration for the site as a whole in 1992 was 19 mg NO$ sb3 sp-$-N L$ sp{-1}.$ Unanticipated variations in drain depth significantly affected flow volume and total NO$ sb3 sp-$-N losses, hampering assessment of treatment effects on drain water parameters. In 1992, post-harvest soil NO$ sb3 sp-$-N levels at 0-25 cm were significantly lower in plots with crop residues retained, regardless of tillage system, than in plots with residues removed. In May 1993 (pre-tillage), soil NO$ sb3 sp-$-N levels were similar for all treatments, having dropped in no-residue plots and risen slightly in plots with residues, suggesting immobilization of NO$ sb3 sp-$-N by crop residues in summer-fall and mineralization in spring. The NO$ sb3 sp-$-N measured in drain flow represents a substantial loss of N from the farm system, and has negative implications for water quality. Within the time-frame of the study, crop residues appeared to have a greater effect on soil NO$ sb3 sp-$-N levels, and thus leaching potential, than did tillage system.

A leaching study was undertaken with $ sp{14}$C radio-labelled atrazine in long, intact, soil columns to investigate the fate and transport of atrazine in a Quebec sandy loam soil and to test two contaminant transport models, namely PRZM and LEACHMP. / Results indicated a large variation in atrazine concentration. The maximum levels in the leachate of the soil columns ranged from 0 to 11.2 $ mu$g/L. Deisopropyl-atrazine, the principal metabolite in the soil columns, was detected near the soil surface and did not leach beyond 15 cm depth. The adsorptive and desorptive capacity of atrazine in the soil columns was mainly attributed to organic matter and moisture content. / LEACHMP was found to be superior in predicting hydrologic characteristics in the soil columns as compared to PRZM which required calibration. Both models underestimated levels of atrazine near the soil surface and in the leachate (115 cm depth). The results from first and second order analysis for PRZM and LEACHMP showed considerable uncertainty in atrazine fate and transport. First and second order analyses were found to be useful tools in indicating where efforts to reduce uncertainty can best be directed.