铁氧体基钙钛矿羊毛纤维复合材料光催化降解印染废水的机理研究

A clean technology for the innocuous treatment of notorious printing and dyeing wastewaters is desirable for a sustainable textile industry. In order to degrade printing and dyeing wastewaters containing reactive dyes and heavy ions, based on our latest findings about the photocatalytic effect of TiO2 doped by both nitrogen and sulfur elements from wool fibres, a novel nanoporous wool-TiO2-ferrite based perovskite composite photocatalyst is proposed for the photodegradation of reactive dyes and removal of heavy ions in wastewaters simultaneously. The photocatalytic mechanism of titanium dioxide/ferrite-based perovskite nanoparticles doped by wool fibers will be explored. TiO2 nanoparticles diffused into the cortex of wool fibers and immobilized on the surface of wool fibers are doped by nitrogen and sulfur elements from the wool fibers. The ferrite-based perovskite nanoparticles deposited on top of the titanium dioxide will be expected to be doped by nitrogen and sulfur elements as well. The photocatalytic mechanism of the wool-TiO2-ferrite perovskite composite photocatalysts will be investigated and the photocatalytic degradation of reactive dyes and heavy ions by the titanium dioxide and ferrite-based perovskite compound co-doped with the chemical elements of wool keratin will be revealed. A prototype of the photocatalyst composite materials for the photodegradation of the printing and dyeing wastewaters containing reactive dyes and heavy metals ions will be established..The following problem will be investigated: (1) The bonding principle of the ferrite-based perovskite nanoparticles deposited on top of the titanium dioxide immobilized on wool fibers will be discussed under hydrothermal conditions. (2) The photocatalytic mechanism of the wool-TiO2-ferrite perovskite composite materials will be discussed and the photocatalytic degradation of bi-functional reactive dyes having vinyl sulphone and monochlorotriazine groups by the titanium dioxide and ferrite-based perovskite compound co-doped with the chemical elements of wool keratin under visible light irradiation will be studied. (3) The removal mechanism of heavy metal ions by the wool-TiO2-ferrite perovskite composite materials will be investigated. (4) A prototype model of the photocatalyst composite materials for the photodegradation of the printing and dyeing wastewaters containing reactive dyes and heavy metal ions will be established.

印染废水无害化处理对于纺织工业可持续发展非常重要。本研究针对纺织印染废水中的活性染料和重金属离子的处理难题，提出了合成二氧化钛—铁氧体基钙钛矿型氧化物纳米颗粒集合物—羊毛纤维复合材料光催化降解活性染料和去除重金属离子的新概念，阐明羊毛纤维内部渗入和表面负载二氧化钛—铁氧体基钙钛矿纳米颗粒的生长机制，揭示掺杂的二氧化钛—铁氧体基钙钛矿纳米孔隙结构的光催化降解活性染料和去除重金属离子的作用机理，建立铁氧体基钙钛矿纳米颗粒—纤维复合材料光催化降解印染废水的实体模型。课题研究内容：（1）水热法生长铁氧体基钙钛矿纳米颗粒与羊毛纤维表面的键合原理；（2）负载铁氧体基钙钛矿纳米颗粒的羊毛纤维复合材料光催化降解乙烯砜和均三嗪型活性染料的作用机理；（3）负载铁氧体基钙钛矿纳米颗粒的羊毛纤维去除重金属离子的作用机理；（4）高效光催化降解活性染料和去除重金属离子的铁氧体基钙钛矿纳米颗粒—纤维复合光催化材料模型。

印染废水无害化处理对于纺织工业可持续发展非常重要。同时，纺织废固物的回收再利用不仅有利于保护环境，而且可以减少对纺织原料用量的需求，另外还能够制备出具有特殊功能的新材料。本研究针对印染废水和纺织固废物的两个处理难题，提出了利用废弃纺织纤维—羊毛或棉制备催化材料用于光催化降解废水中的有机染料和去除重金属离子的新方法。本课题主要研究了四个方面的内容：一是纺织纤维水热合成光催化纳米复合材料的负载机理；二是负载光催化复合材料的纤维光催化降解有机染料的作用机理；三是负载光催化复合材料的纤维去除重金属离子的作用机理；四是高效光催化降解有机染料和去除重金属离子的羊毛基光催化复合材料模型。实验和理论研究表明，其一，二氧化钛改性羊毛正皮质细胞的光催化活性较二氧化钛改性副皮质细胞为高，是因为纳米二氧化钛进入到亲水性的正皮质细胞内部；揭示了碳、氮、氧和硫元素共掺杂二氧化钛提升羊毛-二氧化钛光催化活性的作用机制；解释了煅烧导致羊毛角蛋白-二氧化钛复合膜光催化活性增强的原因，是由于表面变得粗糙、形成了多孔结构、接触角增大和吸附能增加；明确了羊毛基光催化复合材料中光催化降解染料的吸附增强作用；分析了羊毛基光催化复合材料中光生电荷载流子的迁移和氧空位对光催化性能的影响。其二，纤维素晶型会影响负载在棉纤维表面的二氧化钛的能带结构；棉纤维基体会影响负载在棉纤维表面的铁酸铋-二氧化钛或氮化碳-二氧化钛异质结的能带结构；棉生物炭的吸附作用会增强生物炭-氮化碳-二氧化钛复合材料光催化降解污染物的能力。建立了羊毛-铁酸铋-二氧化钛、棉-氮化碳-二氧化钛异质结的实体模型。