【作者】 张虹；

【导师】 郭喜明；

【作者基本信息】 哈尔滨工业大学 ， 生物学， 2023， 硕士

【摘要】 随着纺织、皮革、电镀等行业的迅速发展,由有机污染物和重金属离子引起的水污染问题,在诸多环境污染中尤为突出。传统的吸附法、化学沉淀法、生物法等废水处理方法都存在着去除不彻底、二次污染、成本高等不足,在实际应用中受限。为了探索一种绿色高效的节能环保的去除废水中多种污染物的方法,光催化技术应运而生。该技术具有反应条件温和、无二次污染、能耗低的独特优势,受到国内外研究者的广泛关注。在众多光催化材料中,MOFs作为一种新兴的高结晶性多孔材料,展现出了大比表面积、结构可调、活性位点多等突出优势。其中Zr-MOF(UiO-66系列)具有热、化学稳定性及优异的水稳定性,在废水处理中显示出了巨大的应用潜力。但目前UiO-66存在着禁带较宽、吸收紫外光能力弱的缺陷。因此,探究如何提升UiO-66的光催化性能成为了当前的研究热点。目前,对UiO-66进行配体修饰是拓宽其光吸收范围、改善光响应的有效方法之一。本文采用溶剂热法成功制备了 UiO-66-(SH)2光催化材料,实现了对UiO-66材料的能带调控和光吸收性能的提升。通过扫描电镜、X射线衍射及电化学方法对所制备材料的形貌、结构及性能进行了分析。研究了紫外光下UiO-66-(SH)2对罗丹明B的光催化降解活性和对Cr(Ⅵ)的光催化还原活性,并考察了不同条件下的光催化效果,摸索出了光催化的最佳条件。结果表明,最佳反应条件下,UiO-66-(SH)2在85 min内降解了 98%的罗丹明B;UiO-66-(SH)2在95 min内还原了 98.6%的Cr(Ⅵ),并且催化剂对Cl-、SO42-、PO43-、CO32-有良好的抗干扰性,适量甲醇的加入能提升催化还原Cr(VI)的效果。在此基础上,进一步研究了 UiO-66-(SH)2同时光催化RhB和Cr(VI)的效果。结果表明,混合溶液中RhB和Cr(VI)的光催化效率均高于相同实验条件下单一组分溶液的光催化效率,存在协同催化效果。进一步通过循环实验、催化前后材料的SEM对比分析,表明UiO-66-(SH)2有较好的可重复利用性和稳定性。并根据自由基捕获实验,提出了关于上述光催化实验的机理。与UiO-66相比,该材料通过引入巯基展现了更高效的光响应性能,可以协同光催化降解罗丹明B和光催化还原Cr(Ⅵ)。更多还原

【Abstract】 With the rapid development of industries such as textiles,leather,and electroplating,water pollution caused by organic pollutants and heavy metal ions is particularly prominent among many environmental pollution issues.Traditional wastewater treatment methods such as adsorption,chemical precipitation,and biological methods all have shortcomings such as incomplete removal,secondary pollution,and high cost,which are limited in practical applications.In order to explore a green,efficient,energy-saving,and environmentally friendly method for removing multiple pollutants from wastewater,photocatalytic technology has emerged.This technology has the unique advantages of mild reaction conditions,no secondary pollution,and low energy consumption,and has received widespread attention from domestic and foreign researchers.Among many photocatalytic materials,MOFs,as a new kind of highly crystalline porous materials,show outstanding advantages such as large specific surface area,adjustable structure,and many active site.Among them,Zr MOF(UiO-66 series)has thermal,chemical stability and excellent water stability,showing great application potential in wastewater treatment.But currently,UiO-66 has defects such as a wide bandgap and weak ability to absorb ultraviolet light.Therefore,exploring how to improve the photocatalytic performance of UiO-66 has become a current research hotspot.Currently,ligand modification of UiO-66 is one of the effective methods to broaden its light absorption range and improve its light response.This article successfully prepared UiO-66-(SH)2 photocatalytic material using solvothermal method,achieving band regulation and improved light absorption performance of UiO-66 material.The morphology,structure,and properties of the prepared materials were analyzed by scanning electron microscopy,X-ray diffraction,and electrochemical methods.The photocatalytic degradation of rhodamine B and the photocatalytic reduction of Cr(VI)by UiO-66-(SH)2 under UV light were studied.The results showed that under the optimal reaction conditions,UiO-66-(SH)2 degraded 98%of RhB within 85 min;UiO-66-(SH)2 reduced 98.6%of Cr(VI)within 95 minutes,and the catalyst showed good interference resistance to Cl-,SO42-,PO43-,and CO32-.The addition of an appropriate amount of methanol can enhance the catalytic reduction effect of Cr(VI).On this basis,further research was conducted on the catalytic effects of UiO-66(SH)2 on RhB and Cr(Ⅵ)at the same time.The results showed that the photocatalytic efficiency of RhB and Cr(Ⅵ)in the mixed solution was higher than that of a single component solution under the same experimental conditions,indicating a synergistic catalytic effect.Furthermore,through cyclic experiments and SEM comparative analysis of the materials before and after catalysis,it was found that UiO-66-(SH)2 has good reusability and stability.And based on the free radical capture experiment,the mechanism of the aforementioned photocatalytic experiment was proposed.Compared with UiO-66,this material exhibits more efficient photoresponse performance by introducing sulfhydryl group,which can synergistically degrade RhB and photocatalytic reduce Cr(Ⅵ).更多还原