Flowing water energies minerals
The electric charge of mineral surfaces changes in flowing water - a finding that is also important for understanding geological processes
When water flows over glass or rock, the chemical changes that occur are more profound than had been previously assumed. Using a sophisticated spectroscopic method, a team from the Mainz-based Max Planck Institute for Polymer Research and the University of Namur in Belgium has discovered that the electric charge of mineral surfaces changes radically under a flow of water, as many ions are preferentially dissolved from the material. The type of mineral involved and the acidity or alkalinity of the flowing water determine whether and how strongly the surface is positively or negatively charged. However, the change in the charge can be so radical that it corresponds to a 100-fold change in the acid concentration. The change in the surface charge is directly linked to electrical activity and consequently changes the energy of the surface and its reactivity. This recent discovery could therefore have consequences for understanding numerous chemical processes in nature and in industry.
In chemistry, surface often play key roles - certainly when reactions on solid materials are involved. Changes to the charge of mineral surfaces in flowing water were previously an unknown phenomenon, which affects the properties of surfaces and thus their chemical behaviour - almost across the board in nature and science: when raindrops run down a window pane, when streams and rivers leach away their beds, when cliffs are eroded or when dissolved reactants converge at a solid catalyst. [MAX-PLANCK-GESELLSCHAFT]
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