Effects Of Humic Acids On The Sorption And Photodegradation Of Nano-TiO₂

Nanometer materials are becoming a kind of ideal and potential industry applicationsof material because they are used in all aspects of economic life. Along with the continuingdemand of the material and the increase of products containing the material, nanometerparticles are inevitable to release into the environment. Because of their specialcharacteristics, environmental behavior and ecological effect of nanoparticles have beenconcerned by researchers. Humic acids are a kind of natural organic macromolecularcompound which widely exists in environment. Humic acids are easy to interact withnano-TiO2, which would affect the surface properties of nano-TiO2and further affect theenvironmental behavior of nano-TiO2. This paper investigated the frontier field ofenvironmental behavior of nanomaterials. humic acids were extracted from different sourcesand then prepared the nano-TiO2and humic acids complexes. This study has investigated therelation between the structure and properties of humic acids and the adsorption characteristicsand photodegradation behavior of complexes to provide scientific basis for understandingenvironmental behavior of nanomaterials. Our main research results are as follows:1. This study investigated the phenanthrene sorption characteristics of complexes. Our resultsshowed that different sources of humic acids showed different structure and properties. Peathumic acids contained more aromatic fraction, while sediment humic acids and straw humicacids contained more aliphatic fraction. Humic acids can significantly enhance thephenanthrene adsorption on nano-TiO2and the structure and properties of humic acids wererelated to the adsorption ability of complexes.2. Humic acids can accelerated the sorption of phenanthrene on nano-TiO2. The adsorptionprocess mainly included membrane diffusion, interparticle diffusion and sorption on thesurface. The pH value, ionic strength and ionic type can affect the sorption of phenanthreneon complexes. Therefore, When evaluating the environmental risk of nano-TiO2, theenvironmental factors should be considered.3. Humic acids could promote the phenanthrene photodegradation by nano-TiO2underUV-vis light. The photodegradation rate of complexes were related to the structure andproperties of humic acids.