• Resources Recycling
• /
• v.20 no.2
• /
• pp.45-53
• /
• 2011

We devised a procedure for the recovery of silicon and tempered glass from waste photovoltaic (PV) modules using optimized conditions. The tempered glass was recovered without any damage using organic solvents. The surface material is removed by applying an acid solution on the surface of the PV cell. Through our proposed method, we offer a much more efficient approach for recycling solar cells with a surfactant than the conventional method. This process, we obtained pure silicon with a yield of 90% by chemical treatment with the surfactant at room temperature for 18 min. The silicon yield was characterized using an inductively coupled plasma-atomic emission spectrometer.

• Resources Recycling
• /
• v.20 no.2
• /
• pp.54-59
• /
• 2011

An investigation on the synthesis of aluminum tartrate, one of the aluminum organic compounds, has been performed using aluminum chloride solution as a raw material. For this aim, the effect of the ratio of ethanol/Al solution and pH on the synthesis of aluminum tartrate has been examined and aluminum tartrate synthesized has also been characterized in terms of the chemical composition, X-ray diffraction pattern, particle size distribution, and SEM analysis. As a result, the synthesis more than 97% could be obtained under the conditions of pH more than 3.0 at the ratio of ethanol/Al solution of 3.0. From the chemical analysis of aluminum tartrate synthesized in this work, the content of $NH_4$, Al and C was found to be 9.10, 4.83 and 25.8%, respectively. In addition, aluminum tartrate synthesized from the aluminum chloride solution was found to be $(NH_4)_3Al(C_4H_4O_6)_3$.

• Resources Recycling
• /
• v.29 no.4
• /
• pp.51-57
• /
• 2020

Separation of Co and Ni over Mg from the sulfuric acid solutions using Cyanex272, PC88A and Versatic acid 10 as an extractant was carried out. From the comparative studies about the extraction behavior of Co, Ni and Mg, Versatic acid 10 was superior to Cyanex272 and PC88A for the selective extraction of cobalt and nickel from the mixed solutions. About 98% of Ni and Co were extracted at equilibrium pH 7.0 and less than 5% of Mg was co-extracted by Versatic acid 10. McCabe-Thiele diagram indicated two stages requirement for Co and Ni extraction by 10% Versatic acid 10 at pH 7.0 and phase ratio (A/O) of 2.0. The loaded Co and Ni in organic phase was stripped effectively the sulfuric acid concentration above 70 g/L. 99.78% of cobalt and 98.42% of nickel were stripped.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.7 no.3
• /
• pp.187-193
• /
• 2019

Regarding physical absorption mechanism for fine particles(Dust), internal pore-bridging is a major parameter in porous media. In this paper, internal bridging pore system is invented through FA-based geopolymer and incorporated PLA (Polylactic Acid) fiber with biodegradability. With various mix proportions, compressive strength over 20MPa is obtained but PLA is little dissolved in the condition of NaOH 5mole and $30^{\circ}C$ of temperature, which was found that temperature rising accelerates PLA solubility. Within 24hours, beads type PLA is completely dissolved under $90{\sim}130^{\circ}C$ and NaOH 5~12mole of alkali. In room condition, geo-polymerization is limitedly occurs so that the internal pore after PLA dissolution is thought to be effective to absorption and storage of fine particles.

• Korean Journal of Plant Resources
• /
• v.12 no.4
• /
• pp.282-288
• /
• 1999

The experiment was carried out to determine the effects of soil condition on the agronomic characters and aromatic substances in cultivated Codonopsis Lanceolata. An increase of planting densities of Codonopsis Lanceolata. from 1 to 5 plant per pot resulted in the smaller root width, but root yield increased from 109.8g to 286.9g per 1/200pot. The width growth as soil water contents were higher in surplus soil water than that of cultivated deficit soil water. The contents of water, reducing sugar, crude protein and malic acid were higher in cultivated wild than in cultivated upland soil. The higher contents of volatile essential oils as 3-rnethylpentanoic acid and squalene was obtained at the normal soil moisture.

• Korean Journal of Plant Resources
• /
• v.13 no.2
• /
• pp.140-146
• /
• 2000

This study was conducted to determine the effect of cutting type, growth regulators and propagation media on the rooting and root growth of Roea davurica $P_{ALL}$. Three type of cutting, hardwood, half-softwood, softwood cutting and root cutting of Rosa davurica $P_{ALL}$, were used to study the rooting ability. There was no rooting in hardwood cutting while root cutting was appeared 100% of callus formation and rooting. The optimum conditions of softwood cutting for rooting were IAA 100ppm and rooton-F at vermiculite+perlite. The rate of rooting in treatment of rooton-F ranged from 10 to 60%, but such a good effect was not appeared in other growth regulators, IAA, NAA and IBA.

• Korean Journal of Plant Resources
• /
• v.22 no.2
• /
• pp.159-179
• /
• 2009

This study was carried out to investigate the distribution of vascular plants and their usefulness in Mt. Ilsan (Hwacheon-gun, Gangwon-do). The vascular plants were summarized as 496 taxa; 91 families, 295 genera, 422 species, 1 subspecies, 58 varieties, and 15 forma. Among the investigated 496 taxa, 17 Korean endemic, nine rare, and one endangered plants were included. Based on the list of the species of specially designated plants by the Ministry of Environment, 66 taxa including Hanabusaya asiatica and Aconitum koreanum were recorded in the investigated area. The naturalized plants were identified as 27 taxa and the percent of naturalized plant species(PN) was 5.4% of all 496 taxa vascular plants. Usage of 496 taxa were consists of 201 taxa(40.5%) of edible plants, 168 taxa(33.9%) of medicinal plants, 69 taxa(13.9%) of pasture plants, 61 taxa(12.3%) of ornamental plants, 17 taxa(3.4%) of timber plants, 16 taxa(3.2%) of fiber plants and 4 taxa(0.8%) of industrial plants.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.9 no.3
• /
• pp.311-321
• /
• 2021

Many studies have been performed on hybrid fiber reinforced concrete for years, which is to improve some of the weak material properties of concrete. Studies on characteristics of hybrid fiber reinforced concrete using amorphous steel fiber and organic fiber, however, yet remain to be done. The purpose of this research is to evaluate the compressive and tensile behaviors and then propose a material model of high performance hybrid fiber reinforced concrete using amorphous steel fiber and polyamide fiber. For this purpose, the high performance hybrid fiber reinforced concretes were made according to their total volume fraction of 1.0% for target compressive strength of 40MPa and 60MPa, respectively, and then the compressive and tensile behaviors of those were evaluated. Also, based on the experimental results of the high performance hybrid fiber reinforced concrete and mortar, each material model for the compressive and tensile behavior was suggested. It was found that the experimental results and the proposed models corresponded relatively well.

• Korean Journal of Medicinal Crop Science
• /
• v.26 no.6
• /
• pp.464-470
• /
• 2018

Background: Ginseng produced by hydroponics can be cultivated without using agricultural chemicals; thus, it can be used as a raw materials for functional foods, medicines, and cosmetics. This study aimed to determine the optimal harvesting time to obtain the highest levels of ginsenoside and ginseng, as this was not previously unknown. Methods and Results: One-year-old organic ginseng seedlings were transplanted and cultivated using hydroponics for 150 days in a venlo-type greenhouse, using ginseng nursery bed soil and a nutrient solution ($NO_3{^-}-N$; 6.165, P; 3.525, K; 5.625, Ca; 4.365, Mg; 5.085, S; $5.31mEq/{\ell}$). Ginsenoside content and fresh and dry weights were higher at 120 days after transplanting than at 30, 60, 90, and 150 days. Total ginsenoside content was 11.86 times higher in the leaf and stem than in the root at 120 days after transplanting. Ginsenosides F1, F2, F3, and F5 were detected in ginseng leaves and stems. These chemical compounds are known to be effective in altering skin properties, including whitening, anti-inflammation, and anti-aging. Conclusions: Optimal harvesting time for ginseng cultivated using hydroponics was 120 days after transplanting when the biomass and ginsenoside content were highest.

• Resources Recycling
• /
• v.31 no.1
• /
• pp.12-20
• /
• 2022

The smelting reduction of spent lithium-ion batteries results in metallic alloys containing Co, Cu, Fe, Mn, Ni, and Si. A process to separate metal ions from the sulfuric acid leaching solution of these metallic alloys has been reported. In this process, ionic liquids are employed to separate Fe(III) and Cu(II). In this study, D2EHPA and Cyanex 301 were employed to replace these ionic liquids. Fe(III) and Cu(II) from the sulfate solution were sequentially extracted using 0.5 M D2EHPA with three stages of cross-current and 0.3 M Cyanex 301. The stripping of Fe(III) and Cu(II) from the loaded phases was performed using 50% (v/v) and 60% (v/v) aqua regia solutions, respectively. The mass balance results from this process indicated that the recovery and purity percentages of the metals were greater than 99%.