Continuous synthesis of magnesium-hydroxide, zinc-oxide, and silver nanoparticles by microwave plasma in water

Nanoparticles are continuously synthesized from submerged magnesium, zinc, and silver rods 1-2 mm in diameter by microwave plasma in pure water at 20 kPa. Magnesium-hydroxide nanoplates shaped as triangles, truncated triangles or hexagons with 25-125 nm in size are synthesized with a production rate of 60 g h−1. Zinc-oxide nanoparticles formed as sharp sticks with diameters of 50 nm and lengths of 150-200 nm are synthesized with a production rate of 14 g h−1. Silver nanoparticles with a diameter of approximately 6 nm are synthesized with a production rate of 0.8 g h−1. The excitation temperature is estimated by applying the Boltzmann plot method in assumption of local thermodynamic equilibrium. The excitation temperatures obtained from hydrogen, magnesium, and zinc lines are 3300 ± 100 K, 4000 ± 500 K, and 3200 ± 500 K, respectively.