插层法制备g-C3N4/高岭石复合材料及其对罗丹明B的光催化机理研究

伴随着印染行业的快速发展,部分含有罗丹明B(RhB)的染料废水未经处理便被排出.因RhB较难自然降解,对环境造成了恶劣的影响.本文通过置换插层-煅烧法制备出g-C3 N4/高岭石复合材料,在恒温模拟太阳光催化系统下,研究了复合材料对RhB的光催化性能,并探讨其催化机理.结果表明,随g-C3 N4含量递增的复合光催化材料1g-C3 N4/K、2g-C3 N4/K、3g-C3 N4/K、4g-C3 N4/K和5g-C3 N4/K的催化性能呈先升后降的趋势,4g-C3 N4/K催化效果最好,光照6 h对RhB的降解率可达73％.进一步研究提出g-C3 N4/高岭石复合光催化材料的催化机理为光照激发复合光催化剂,产生具有较强氧化还原能力光生载流子空穴对,其可与RhB发生反应,使之氧化成小分子碳氢化合物或被矿化成二氧化碳和水.所制备的高岭石负载石墨相氮化碳光催化材料具有较好的亲水性,使得复合材料在染料溶液中有较好的分散性,有利于光催化过程的进行,有效实现了对RhB的光催化降解.

Intercalation Preparation of g-C3N4/Kaolinite Compsite and Its Photocatalytic Mechanism on Rhodamine B

With the rapid development of printing and dyeing industry , a lot of untreated wastewater containing rhodamine B were emitted directly , which does bad to environment because it is hardly to degrade naturally .g-C3 N4/kaolinite complexes were prepared by using the replacement intercalation-calcination method .The photocatalytic properties of the composites were investigated in the constant temperature simulation photocatalytic system .The catalytic mechanism was also being proposed in the paper.It is indicated that the contents of g-C3 N4 in samples 1g-C3 N4/K, 2g-C3 N4/K, 3g-C3 N4/K, 4g-C3 N4/K and 5g-C3 N4/K are increased, however, their degradation effect gets better at first and goes worse then.The highest activity of the photocatalyst is 4g-C3 N4/K whose catalytic rate is as high as 73％with 6 h light .The further study showed that light stimulates the semiconductor catalysts to generate electrons and holes which react with rhodamine B to form small molecule hydrocarbons or carbon dioxide and water.The hydrophilicity of the prepared g-C3 N4/kaolinite complexes was so excellent that they can dissolve in dye solution which promote the photocatalytic process and degrade rhodamine B more efficiently .