염화동 에칭 공정에서 발생한 철염 폐수를 전구체로 활용하여 마그네타이트(Fe3O4)를 합성하고, 이를 인산염 흡착 및 회수에 적용하였다. 합성 조건 최적화를 위하여 Box–Behnken Design를 적용한 반응표면분석법(Response Surface Methodology, RSM)을 활용하여 회귀모델을 구축하였다. 모델을 통해서 도출한 최적 합성 조건은 Fe3+/Fe2+ 비율 1.7, NaOH 농도 0.7 N, 숙성 시간 86.3분으로 확인되었다. 해당 조건에서 합성된 마그네타이트는 10.9 mg-P g-1 마그네타이트의 인산염 흡착 용량을 나타내었다. 기기 분석 결과, 최적화된 마그네타이트는 고순도 결정 구조와 초상자성 특성을 나타냈으며, 비표면적과 반응성이 향상된 것이 확인되었다. 또한 연속 회분식 반응조(Sequencing Batch Reactor, SBR)에 적용한 결과, 5회 반복 흡착–탈착 동안 평균 인산염 회수율은 46.6%로 나타났다. 유입 인산염 농도가 200 mg-P L-1의 고농도 조건에서도 회수율이 안정적으로 유지되어, 마그네타이트가 인산염 흡착제로서의 활용 가능성과 안정성을 입증하였다.

This research aimed to find an eco-friendly way to neutralize water recovered from ready-mixed concrete by dissolving carbon dioxide in it, and to verify the potential use of such water for mixing concrete. Carbon dioxide was injected using nanobubble technology into recovered water, and the optimized conditions for dissolution were established by analyzing the carbon dioxide concentration in the water and measuring pH over time. Mortar was manufactured using this recovered water following carbon dioxide nanobubbles treatment, and measurements of compressive strength and thermogravimetric analysis (TGA) were conducted to verify the formation of calcium carbonate. 2,464 mg/L of carbon dioxide was dissolved in the recovered water, and the pH was measured to be 6.34. The compressive strength of the manufactured mortar was found to be 32.02 % stronger than mortar manufactured with normal tap water. According to the thermogravimetric analysis results, the amount of calcium hydroxide produced in the mortar manufactured with recovered water from ready-mixed concrete was 8.10 %, and the production amount of calcium carbonate was 6.49 %. This means that the amount of calcium carbonate produced was greater than that in mortar manufactured with normal tap water, as well as tap water containing nanobubble carbon dioxide. The carbon dioxide was stably dissolved in water recovered from ready-mixed concrete using nanobubbles, enabling environmentally friendly neutralization without the use of chemicals. Also, when the recovered water from ready-mixed concrete containing dissolved carbon dioxide was used for mixing concrete, it was determined that the carbonation reaction influenced the formation of calcium carbonate, which contributed to the improvement in concrete strength.

This study sought various ways to prevent the occurrence of waste fishing gear and promote the recovery. It is expected that the problem of waste fishing gear can be effectively solved through measures such as strengthening education and publicity, technical measures, establishment of recovery infrastructure, and provision of incentives. In particular, introduction of the waste fishing gear recovery promotion point system gives fishermen practical motivation. It can be an important means of inducing leisure and sustainable fishing activities. In addition, by inducing the participation of private companies, it is expected to promote the recovery and recycling of waste fishing ports and contribute to the protection of the marine environment and fisheries resources. The government or local government should actively review the measures suggested in this study and prepare related laws and policies. In addition, it is necessary to establish a system to induce the participation of various stakeholders and support sustainable fishing activities through public-private cooperation. Through this, we will be able to achieve carbon neutrality goals in the fishing sector in response to climate change. This study suggests an early stage plan, and in future research, it is necessary to evaluate and find and improve practical effects through pilot projects. Moreover, it is necessary to study the management of closed fishing gear and carbon neutrality practice measures at the global level by seeking international cooperation measures. Consequently, more effective and sustainable marine environment and fishery resource protection measures can be prepared.

에너지 저장 장치의 필수 요소인 리튬에 대한 필요성이 증가함에 따라 전 세계 리튬 침전물의 주요 공급원인 염 수로부터 효율적인 리튬 회수 방법의 개발이 요구됩니다. 염수로부터 리튬을 회수하는 과정은 유사한 특성을 가진 공존하는 이온의 존재로 인해 복잡합니다. 크라운 에테르 기능화된 막은 선택적 리튬 회수를 위한 유망한 솔루션을 제시합니다. 이온- 쌍극자 상호 작용을 통한 금속 이온에 대한 강한 친화력으로 유명한 크라운 에테르는 공동-이온 크기 호환성에 기반한 리튬 이온의 선택적 추출을 촉진하는 “호스트-게스트” 복합체를 형성합니다. 다양한 연구에서 크라운 에테르 이식된 막이 리튬 선 택성을 향상시키는 데 효과가 있음이 입증되었습니다. 이 리뷰는 크라운 에테르 기능화된 막의 발전을 탐구하여 염수로부터 의 리튬 회수 문제를 해결할 수 있는 잠재력을 보여줍니다.