• Title, Summary, Keyword: oyster shell

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Investigation on the material properties of Waste Oyster Shell to use as an Adsorbent for Fluoride Ion (불소(弗素) 이온 흡착제(吸着劑)로서의 활용(活用)을 위한 폐(廢)굴껍질의 특성(特性) 분석(分析))

  • Lee, Jin-Suk;Seo, Myung-Soon;Kim, Dong-Su
    • Resources Recycling
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    • v.16 no.3
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    • pp.12-18
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    • 2007
  • The material properties of waste oyster shell, which is largely generated from the treatment of marine products, have been investigated for its possible utilization as an adsorbent for fluoride ion-containing wastewater. The major composition of waste oyster shell was analyzed to be $CaCO_3$ and loss of 46% in weight reduction occurred during its thermal treatment by the emission of moisture and $CO_2$. The surface structure of oyster shell was decomposed by the heating and its surface potential was negatively increased with pH. As the pH of wastewater was increased, the adsorbed amount of fluoride ion onto oyster shell was decreased and the wastewater was found to be neutralized during adsorption process by ${CO_2}^{3-}$ which generated from the partial dissolution of oyster shell

Synthesis of aragonite-precipitated calcium carbonate from oyster shell waste via a carbonation process and its applications

  • Ramakrishna, Chilakala;Thenepalli, Thriveni;Han, Choon;Ahn, Ji-Whan
    • Korean Journal of Chemical Engineering
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    • v.34 no.1
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    • pp.225-230
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    • 2017
  • Oyster shells are abundantly available in nature without eminent use and are dumped into landfills in vast quantities. Their improper disposal causes environmental problems, resulting in a waste of natural resources. Recycling shell waste could potentially eliminate the environmental problems and, moreover, convert the waste into high-valueadded products, such as synthetic precipitated calcium carbonate (PCC), which can be obtained from oyster waste and which is used to enhance the mechanical properties of various materials. It can also be used as a filler material in the plastic and paper industries. This study presents a simple method for the extraction of aragonite needles from oyster shell waste via a carbonation process. The obtained aragonite-precipitated calcium carbonate (PCC) is characterized by XRD and SEM, which is used to assess the morphology and particle size. Using the proposed process, oyster shell waste powder was calcined at $1,000^{\circ}C$ for 2 h, after which the calcined shell powder was dissolved in water for hydration. The hydrated solution was mixed with an aqueous solution of magnesium chloride at $80^{\circ}C$ and $CO_2$ was then bubbled into the suspension for 3 h to produce needle-shaped aragonite PCC. Finally, aragonite-type precipitated calcium carbonate was synthesized from the oyster shell powder via a simple carbonation process, yielding a product with an average particle size of $30-40{\mu}m$.

Transformation Characteristics of Calcined Oyster Shell to Liquid Lime (소성된 굴패각의 액상소석회로의 전환 특성)

  • Ha, Su Hyeon;Kim, Yeongkyoo
    • Korean Journal of Mineralogy and Petrology
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    • v.33 no.3
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    • pp.185-193
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    • 2020
  • There have been many studies on the calcination of oyster shells in the perspective of recycling of resources. The quicklime made by the calcination of oyster shells is used either as it is or after reacting with water to transform to liquid lime before being used. However, the liquid lime made from calcined oyster shells show slightly different properties from that of limestone. In this study, to compare these properties of oyster shell with those of limestone, the samples were calcined and reacted with water at various temperatures to transform to a liquid lime and filtered using 150 ㎛ sieves to calculate the transform rate to liquid lime. The calcined limestone was transformed to liquid lime at all temperatures, but calcined oyster shell did not show any transformation at 30℃ and 50℃ under the experimental conditions of this study, and rather increased the weight for the remaining after filtration due to the presence of Ca(OH)2 produced by the reaction with water, Even at 90℃, the transformation rate of calcined oyster shell to liquid lime was lower than that of limestone. This difference in oyster shell can be explained partly by the preventing calcined one from reacting with water by conchiolin which is protein found in the prismatic and pearl layers of oyster shell. Conchiolin is also known to be stable and does not decompose even at high temperature. However, even the calcined chalk layer without conchiolin shows lower transformation rate than that of calcined limestone, probably due to the small amount of Na in oyster shell, which may cause additional reaction including eutectic melt during calcination process.

Prismatic shell repairs by hemoctyes in the extrapallial fluid of the Pacific Oyster, Crassostrea gigas

  • Cho, Sang-Man;Jeong, Woo-Geon
    • The Korean Journal of Malacology
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    • v.27 no.3
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    • pp.223-228
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    • 2011
  • To understand the role of hemocytes in the shell repair process, a hole was drilled in the right valves of the Pacific oyster, Crassostrea gigas, and the repair process was observed. Histological observations suggested that the exterior surface of the shell was repaired by aggregated hemocytes. The nuclei of the hemocytes were cleary stained in the regenerated shell while appearing fragmented after calcification at the $7^{th}$ day. Globular calcium granules were genegenerated from the hemocytic monolyer after 6 days of incubation which were morphologically and chemically identical with those from prismatic shell. Our finding suggested that the repaired prismatic shell was composed by aggregated hemocytes and that their endogenous calcium component might support the nucleation of calcium biomineralization during shell repair.

Assessment for Effect of Water Environment by Addition of Improvement Agents on Sediments (저질 개선제의 주입에 의한 수 환경에 미치는 영향 평가)

  • Kim Woo-Hang;Kim Do-Hee
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.10 no.1
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    • pp.69-73
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    • 2004
  • Control if Sediment is very important in prawn farm due to the eruption of toxic materials such as unionized $H_{2}S,\;NH_{3}\;and\;NO_3$. In this study, column test was conducted with filter media such as activated carbon, zeolite, oyster shell and iron chloride to evaluate the reduction of toxicity from sediment. ammonia-N($NH_3$) was effectively removed by Zeolite and oyster shell. It was indicated that ammonium ion($NH_4^+$) was removed by ion exchange of zeolite. And the ammonia in the column of oyster shell was existed as the form of $NH_4^+$, which is not toxic for prawn because oyster shell was stably kept at $8{\sim}9g$ of pH. Therefore, some of ammonia($NH_4^+$) was removed by oyster shell. Hydrogen sulfide and COD were effectively removed by adsorption of activated carbon and a partial removal of hydrogen sulfide was accomplished by Oyster shell. Phosphorous was removed by activated carbon, oyster shell and iron chloride. In prawn farm, the concentration of ammonia was increased with increase of pH by algae photosynthesis in the column of activated carbon, zeolite and iron chloride, but it was revealed that pH was stably kept in the column of oyster shell.

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Relationship between the Incidence of Bitter pit and the Application Level of Crushed Oyster Shell in Apple Orchard (굴껍질 시비수준이 사과 고두병 발생에 미치는 영향)

  • Heo, Jae-Young;Lee, Seong-Tae;Kim, Min-Geun;Hong, Kang-Pyo;Song, Won-Doo;Rho, Chi-Woong;Cho, Ju-Sik;Lee, Young-Han
    • Korean Journal of Soil Science and Fertilizer
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    • v.43 no.5
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    • pp.637-643
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    • 2010
  • For enhancement of apple productivity, the calcium fertilizers to increase the calcium content of fruit, and reduce the incidence of bitter pit in apples are applied. Crushed oyster shell contains a plenty of calcium carbonate, and a very small amount of boron, ferrous, and manganese. A field study was conducted to determine the optimum level of crushed oyster shell for soil nutrient management, and its effect on the induction of bitter pit in cultivar 'Gamhong' apple. The application of crushed oyster shell increased organic matter, available phosphate, and exchangeable cation concentration in soil. We found a significant positive correlation between soil pH, and application level of crushed oyster shell in both top, and subsoils. The incidence of bitter pit in apple fruit at the harvest stage was significantly higher in non treatment and calciummagnesium carbonate treatment than on over applications 4 Mg $ha^{-1}$ for crushed oyster shell. However, the optimum level of crushed oyster shell was 2 Mg $ha^{-1}$, especially considering the soil Ca content, soil pH, fruits weight, and yield. Our results show that the crushed oyster shell can be effective in restoring the soil nutrient balance, and inducing the bitter pit in apple fruit.

Physical Properties of Pyrolized Oyster Shell Consisting of Porous CaO/CaCO3 and Phosphorus Removal Efficiency (CaO/CaCO3 다공체로 이루어진 활성 굴 패각의 물성 및 인 제거 효능에 관한 연구)

  • Lee, Chan-Won;Jeon, Hong-Pyo;Kwon, Hyok-Bo
    • Journal of the Korean Ceramic Society
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    • v.47 no.6
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    • pp.524-528
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    • 2010
  • In this study, the structure and properties of waste oyster shell and its phosphorus removal efficiency were investigated. Waste oyster shells are troublesome environmental waste in the coastal region where the oysters are produced. Waste oyster shells were pyrolyzed by bench-scale rotary kiln for its activation. It shows maximum 76% of phosphorus removal efficiency for the municipal wastewater and livestock wastewater. We found that the activated oyster shells can be used as a phosphorus removal agent with the consideration of high efficiency, easy processing, and cost effectiveness.

Study on the Wastewater treatment as a Coagulant Using the Waste Oyster Shells and Loess (폐굴껍질과 황토로 제조한 응집제를 利用한 폐수처리에 관한 연구)

  • 고현웅;장성호;성낙창
    • Resources Recycling
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    • v.11 no.2
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    • pp.45-51
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    • 2002
  • This study was performed to investigate removal efficiency of wastewater by the prepared coagulant using waste oyster shell and loess. Waste oyster shell and loess contain respectively high CaO(55.43% by weight), $SiO_2$(45.30% by weight). Waste oyster shell was calcined to improve the purity of CaO at the calcination condition of $900^{\circ}C$ for 2hours, and then crushed 0.074 mm(200mesh) size by ball mill. Also, coagulant was prepared with calcined waste oyster shell and loess powder by hydration reaction. Calcined waste oyster shell and loess powder were combined with mixing ratio of 6 : 4, 7:3, 8:2 and 9:1. Though comparison experiment between prepared coagulant and chemical )$Ca(OH_2$, prepared coagulant was proved as having replaceable possibility of chemical )$Ca(OH_2$in wastewater treatment plant.

Effect of Oyster Shell Meal on Improving Soil Microbiological Activity (굴패화석 비료 시용이 토양의 생물학적 활성에 미치는 영향)

  • Lee, Ju-Young;Lee, Chang-Hoon;Ha, Byung-Hyun;Kim, Seok-Cheol;Lee, Do-Kyoung;Kim, Pil-Joo
    • Korean Journal of Soil Science and Fertilizer
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    • v.38 no.5
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    • pp.281-286
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    • 2005
  • The effect of oyster shell meal, which is made of a simple crushing and alkaline calcium materials, on soil microbial properties, microbial biomass C, N and P contents, and enzyme activities were evaluated in silt loam soil. The oyster shell meal fertilizer was added at the rates of 0, 4, 8, 12 and $16Mg\;ha^{-1}$. Microbial biomass C, N and P contents were significantly increased with increasing application of oyster shell meal. Soil enzyme activities, such as urease, ${\beta}$-glucosidase and alkaline phosphomonesterase were increased significantly by shell meal application, due to increased soil pH towards neutral range and increased nutrient availability in soil. In particular, the increased microbial biomass P content and phosphomonoesterase activities were strongly correlated with available P content in soil. Conclusively, oyster shell meal fertilizer could be a good supplement to improve soil microbial activities.

Shear Strength Characteristics of Dredged Soil with Oyster Shell Binder (굴패각 고화재를 혼합한 준설토의 전단특성)

  • Lee, Sangjin;Yoon, Gillim;Lee, Yoongyu;Lee, Kidong;Kang, Ingyu;Kim, Hongtaek;Baek, Seungcheol
    • Journal of the Korean GEO-environmental Society
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    • v.8 no.1
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    • pp.27-32
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    • 2007
  • Trafficability for construction equipments in soft ground should be secured by improving the surface course. For this situation, the ground improvement technique has been used with stiffening agent, but the improvement cement has been mostly used so far. However, oyster shell has been developed and used as the stiffening agent to expand the chance of recycling oyster shell, which is regarded as solid waste. In this research, it was confirmed mechanical characteristics of oyster shell as stiffening agent by analyzing the strength characteristic such as mixing rates, water contents, and curing days of that to the dredging soil.

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