Copper alloy metal fiber was incorporated into the conventional water-soluble metal working fluids to increase the antimicrobial activity. Fluid treated by copper alloy metal fiber is shown that bacteria is disappeared whereas that untreated metal fiber is increased bacteria as increasing the life time. When the electrochemical potential of Cu/Zn ion is -268mV, radicals with molecular oxygen are easily made. Especially, hydroperoxide radical shows strong toxicity to the strains, leading to the conformational change of plasma membrane. As a result antimicrobial activity of copper alloy metal fiber in metal working fluid is superior to that of copper fiber.

This study is focused on the possibility of copper alloy metal fiber for an antimicrobial activity in the water soluble metal working fluids. Electrochemical potential of Cu/Zn ion is -268mV, and easily makes radicals with molecular oxygen. Especially, hydroperoxide radical shows strong toxicity to the strains. Plasma membrane causes conformational change when hydroperoxide radical binds to plasma membrane. Elution of copper ion from copper alloy metal fiber is detected in metal working fluid. As a result antimicrobial activity of copper alloy metal fiber in metal working fluid is superior to that of copper fiber.

As industry continues to develop, the contents of various recalcitrant substances that are not removed by conventional wastewater treatment have increased in modern society. The metal working fluids (MWFs) used in the metal working process contain chemical substances, such as mineral oils, anticorrosive agents, extreme-pressure additives, and stabilizers, as well as high concentrations of organics and ammonia-nitrogen. Accordingly, MWFs are required to develop advanced treatments to conserve hydro-ecological resources. This study investigated the removal efficiency of ammonia nitrogen from MWFs according to operating time, applied voltage, and NaCl concentration using a Ti/IrO2 electrode in a batch-type reactor. The experimental results showed that ammonia-nitrogen removal efficiencies without NaCl were 89% and 92% when voltage was adjusted to 15 and 20 V for 60 min and removal efficiency was 90% at 25 V for 40 min. Removal efficiencies of 10 mM NaCl were 4% and 2% greater than those of not adding NaCl at 15 V for 50 min and 20 V for 30 min.

1900년대 초부터 금속 가공 장비의 수명 연장 및 가공물의 품질 향상을 위해 금속 가공 공정에 절삭유가 이용되어 왔다. 금속 가공 특성에 따라 절삭효율 향상을 위해 각종 첨가제를 포함시켜 여러 종류의 절삭유가 제조되고 있으며, 일반적으로 수용성과 비수용성으로 분류된다. 비수용성 절삭유의 경우, 폐유처리과정에서 유독성 물질 발생, 발연･발화 등의 문제로 수용성 절삭유의 사용이 점차 증가해 왔으며, 국내에서 이용되는 절삭유의 60% 이상이 수용성 절삭유이다. 사용된 수용성 절삭유는 비수용성 절삭유와 같이 소각처리 하기에는 비용이 크며, 수계로 유출시 COD 약 30,000~100,000ppm의 고농도 유기성분에 의해 인근 수계를 오염시킬 수 있으므로 각별한 처리가 필요하다. 따라서 본 연구에서는 Ti-IrO2전극을 이용하여 NaCl 첨가, 인가전압 변화를 통해 수용성 절삭유 내 오염물질의 전기화학적 처리에 미치는 영향을 검토하고, 수용성 절삭유의 전기화학적 처리에 대한 기초자료를 제공하고자 한다. 시료는 U사의 W1-1종 수용성 절삭유를 이용하였으며 증류수와 혼합하여 5% 농도의 인공 시료를 제조하였다. 시료의 특성은 Table 1, 실험 조건은 Table 2에 나타내었다.

Generally, metal working fluids (MWFs) are used to reduce friction in metalworking processes. In addition to mineral oils, MWFs contain many chemical substances, such as anticorrosive agents, extreme-pressure additives, and stabilizers, as well as high concentrations of organics and ammonia nitrogen. Accordingly, MWFs must be managed to advanced treatment for hydro-ecological conservation. This study investigated the removal efficiency of ammonia nitrogen from MWFs according to operating time, applied voltage, distance between electrodes, and NaCl concentration using aluminum in a batch-type reactor. The experimental results were as follows: First, without NaCl, removal efficiencies of ammonia nitrogen were 69.6%, 37.9%, and 22.7%, when the distance between electrodes was adjusted to 1, 4, and 7 cm, respectively, at 15 V for 60 min. Secondly, without NaCl, removal efficiencies of ammonia nitrogen were 49.5 and 90.9% when the voltage was adjusted to 5 V and 10 V, respectively, for 60 min and 94.6% at 15 V for 40 min. Lastly, with the addition of NaCl 10 mM, the removal efficiency of ammonia nitrogen was 40.3% and 11.5% greater than that of no addition of NaCl at 5 V for 60 min and at 10 V for 30 min.