warjito@eng.ui.ac.id
1988 – Mechanical Engineering, Universitas Indonesia
1999 – Mechanical Science, Hokkaido University, Japan
2002 – Mechanical Science, Hokkaido University, Japan
Compared to detergents, a water spray containing bubbles plays a more effective role in removing impurities of a particular medium.
Bubble is a gas phase immersed within the liquid phase, formed due to a surface tension that, together with the bubble’s internal pressure and environmental pressure, forms a balance. In terms of size, bubbles are classified as macrobubbles (more than 100 micrometers), microbubbles (below 100 micrometers), and nanobubbles (below 10 micrometers). The smaller the bubble size, the closer the geometric shape to the ball will be. The size of a bubble also determines its characteristics. People are actively doing basic research about bubbles, such as bubble making, bubble dynamics in both single and group bubbles, bubbles and their sounds, etc. In addition to those fundamental researches, some research in the bubble application industries attracts a lot of attention, one of which is in the field of separation: separating a desired from an unwanted material by utilizing the nature of hydrophobic and hydrophilic materials. Flotation, a kind of separation method in the mining world, is a method using this technique property. Flotation can be used to clean a river during the preparation of the 2018 Asian Games. When we inject bubbles into a river, they will remove the dirt polluting the river. Another similar example was what was done in the River Thames, London, which also experienced pollution problems in the past. Bubble injection of that river also improved BOD.
It’s a challenge to produce bubbles of a specific size consistently, so it is essential to research how to develop a microbubble generator. We have successfully developed a microbubble generator with various working principles in our laboratory with quite good results. Microbubbles that are developed can produce bubbles following the micro criteria. Microbubbles work very effectively as a suspension of suspended solids. A microbubble generator has been used to try and clean up batik waste by separating the dyed material to improve the quality of batik wastewater. This technology will focus on portable macro bubbles as a cleaning method for household use as a future consideration. The smaller the microbubbles are, the more effective they will be in removing dirt. More effective than detergents, more bubbles provide more effective results. Splashing water to a water surface will invite surrounding air to form bubbles. In Japan, a water spray containing bubbles has been tested for cleaning. The results showed that the spray proved to be able to remove dirt more efficiently; thus, detergents would no longer be used. In the future, microbubbles can be used as alternative desalinating agents due to their simpler technological work system.
Bubble technology is widely applied, including in the material production field. Microbubbles are generated in concrete manufacturing to produce a hunk of lightweight concrete. Microbubbles technology is also involved in molding injection to produce lighter plastic goods and save raw materials. In fact, in the medical field, specifically cancer treatment, the doctor delivers the drugs by inserting them through tiny bubbles flowing to the area of a sick body. The bubbles will then be broken and stuck specifically only in the affected area; they will not be spread to other areas.