In response to worldwide concern over the adverse effects of chemical substances on human health and the environment, most developed countries have legally restricted the use of dyes containing heavy metals or carcinogenic organic compounds; thus, replacing such color materials with safer substances is an urgent issue. Motivated by this, a Nagoya University research group has found that pigments of various colors can be obtained by combining fine silica particles (white powder) and a complex of iron and tannic acid (black compound), both of which are inexpensive and harmless substances used for foods and cosmetics. The pigments are expected to be an alternative to conventional harmful color materials. This study was reported in ACS Sustainable Chemistry & Engineering on August 8, 2019.
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Source: Phys.org