Application Of Illite Micro Flakes In Ultraviolet Shielding And Photocatalyst Carriers

Illite is widely distributed and abundant in the nature.However,due to the difficulty in purification,poor expansibility and plasticity,its development and utilization are limited.At present,the research of illite mainly follows the idea of other layered aluminosilicate minerals and the application combined with its own characteristics is very few.In this paper,high purity illite was obtained by conventional washing purification method and its application in ultraviolet?UV?shielding and catalytic carrier was explored.Considering the superior film-forming properties and excellent light-reflecting performances on?001?crystal plans of illite,such natural clay mineral could be a potential candidate for novel inorganic UV shielding materials by high-quality purification and particle refinement.Firstly,two physical methods,ball milling and ultrasonic treatment were used to strip illite particles and the effects of ball milling and ultrasonic time on the structure,morphology,surface charge,especially UV shielding properties of illite were investigated.The results of X-ray diffraction?XRD?,special surface area?SSA?,scanning electron microscopy?SEM?and transmission electron microscopy?TEM?show that both ball milling and ultrasonic treatments lead to reduction of particle size,increase of surface area and changes of morphology.However,the effect of ball milling on illite is much greater than that of ultrasonic treatment.With the increase of milling time,the point of zero charge?PZC?of illite decreases and the p H of illite slurry increases.In addition,UV shielding experiments show that the ball-milled illite has better UV shielding performance than purified illite.When the milling time is 2 h,the UV shielding ability is best.After 8 h irradiation,the retention rate of rupture strength of fabrics coated by BM-2 h illite is 69.94%,and about 34% increase over uncoated fabrics.Then,the TiO₂/illite composites were synthesized by a simple hydrothermal method,taking Ti?SO4?2 as Ti precursor and the illite milled for 3 h as substrate.Under the precondition of optimal conditions,the effects of hydrothermal p H value on the structure,morphology and photocatalytic performance of the composite photocatalyst were discussed emphatically.The results of XRD and FT-IR show that TiO₂ particles do not enter the interlayer of the illite during the hydrothermal process and illite and TiO₂ are connected by Si-O-Ti and Al-O-Ti bond.The results of SEM,TEM and SSA show that the dispersion of titanium dioxide in the composite is obviously improved.Moreover,the hydrothermal p H controlled the hydrolysis rate of Ti?SO4?2.Moreover,when the p H value is 1.5,the loading of titanium dioxide is uniform and there is almost no agglomeration.At this time,the photocatalytic performance of the composites is the best.The degradation rate of methylene orange?MO?solution can reach 73.4% after 8 h visible light irradiation and 93.6% after 40 min ultraviolet light irradiation,which is better than commercial TiO₂.