吸着

• Reading: きゅうちゃく
• Romaji: kyuchaku
• Kanji breakdown: 吸 (kyu) — to inhale, to absorb; 着 (chaku) — to adhere, to attach to a surface
• Pronunciation: /kjɯː.tɕa.kɯ/

Meaning

Adsorption; the adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface, forming a thin film.

Distinguished from 吸収 (absorption — kyushu), where the substance penetrates throughout the bulk material; 吸着 (adsorption) refers specifically to surface accumulation. Key in heterogeneous catalysis (不均一触媒), water purification (活性炭による吸着 — activated carbon adsorption), chromatography, and nanotechnology. 物理吸着 (physisorption — weak van der Waals forces) is contrasted with 化学吸着 (chemisorption — stronger chemical bonds). The verb form is 吸着する.

Examples

1. 活性炭は表面積が非常に大きいため、不純物を効率よく吸着して水を浄化できる。 Because activated carbon has a very large surface area, it can efficiently adsorb impurities and purify water.
2. 触媒反応では、反応物が触媒表面に吸着することで反応が促進される。 In catalytic reactions, the reactants adsorb onto the catalyst surface, thereby promoting the reaction.
3. 空気清浄機に使われるフィルターは、吸着材によって有害物質を捕捉する仕組みになっている。 The filters used in air purifiers work by capturing harmful substances using adsorbent materials.

Usage Guide

Context: chemistry, materials science, environmental engineering, nanotechnology

Tone: technical, academic

Origin & History

Sino-Japanese compound: 吸 (kyu) — to inhale, to absorb + 着 (chaku) — to adhere, to attach. 着 conveys adherence to a surface, distinguishing adsorption from 吸収 (absorption, where 収 means to collect internally).

Cultural Context

Era: Meiji-Modern

Generation: Adult

Social background: Educated