聚合物基有机/无机功能化MFe2O4复合微球的制备及其构筑非均相催化反应降解TBBPA的研究

Tetrabromobisphenol A (TBBPA), one of the most widely used brominated flame retardants(BFRs), is regarded as a potential endocrine disruptor and a new persistent organic pollutants(POPs), causing negative impacts on the ecological environment and public health due to its toxicity, persistance and lipophilicity. Therefore, developing more effective methods for the removal of TBBPA from the contaminated environment with high debromination and TOC removal is of necessity and importance. Spinel ferrites (MFe2O4) have attracted much attention due to their advantages of adsorption, catalysis and rapid magnetic separation. In addition, small size and the use of suspension are the key issues which hinder the application of MFe2O4 as an effective technology for the wastewater treatment. This study will combine the components of adsorption and catalytic degradation to synthesize a series of polymer-based (polyvinyl alcohol) organic/inorganic functionalized MFe2O4 composite microspheres via the formation of polyelectrolyte complexes (chitosan and carrageenan) changes surface charge, dicyandiamide (DCDA) is grafted onto chitosan to introduce active functional groups and MFe2O4 is intercalated into organo-attapulgite to create the hydrophobic organic phase. These active components would promote the rapid adsorptive enrichment of TBBPA. Meanwhile, the as-prepared composite microspheres are used as heterogeneous catalyst of peroxymonosulfate(PMS) for the degradation of TBBPA. MFe2O4 can effectively catalyze PMS to generate the reactive oxygen species (ROSs) (•OH和SO4•-) on its surface. Thus, a “two-stage” process combining adsorption and catalytic degradation is used to remove TBBPA by the novel composite beads. TBBPA in the bulk solutions will be enriched rapidly by the active components and diffuse into the interior of the composite beads through the pores. And then hydroxyl radicals and sulfate radicals (•OH和SO4•-) on MFe2O4 surface with high oxidation activity would induce the oxidative degradation of TBBPA through debromination, decomposition and transformation in order to achieve the purpose that rapid adsorptive enrichment promotes the efficient degradation of TBBPA. The removal of TBBPA by the composite beads will be performed on the static batch operations and dynamic continuous flow systems in combination with FTIR, XPS, GC-MS to analyze the adsorption behaviors and degradation efficiency of TBBPA, and the degradation mechanism and pathway of TBBPA will be explored so that a new method and thought for the effective removal of persistent organic pollutants from the contaminated water will be provided.

四溴双酚A(TBBPA)是应用最广泛的溴代阻燃剂之一，是潜在内分泌干扰素，因其引起的生态环境安全问题而备受关注。研究表明，尖晶石型铁氧体(MFe2O4)具有吸附、催化和磁分离的优点。但是极小粒径和悬浮使用是阻碍其应用的关键问题。本研究将吸附组元与催化降解组元相结合，拟构建系列聚合物基(聚乙烯醇)有机/无机功能化MFe2O4复合微球来构筑非均相催化反应降解TBBPA。以形成聚电解质复合物(壳聚糖与卡拉胶)改变表面电荷负载、双腈胺接枝壳聚糖引入活性基团和MFe2O4插层有机凹凸棒创造疏水有机相作为活性吸附组元。同时MFe2O4催化过一硫酸盐产生活性自由基•OH和SO4•-进行TBBPA脱溴，实现以吸附促进TBBPA的高效降解。本研究通过静态批处理和动态流动方式结合FTIR、XPS、GC-MS等分析TBBPA的吸附行为，初步探讨其催化降解机理和路径，为水环境中难降解有机污染物有效去除提供新思路。

四溴双酚A（Tetrabromobisphenol A，TBBPA）是应用最广泛的溴代阻燃剂之一，也被认为是一种新的持久性有机污染物 (POPs)。TBBPA稳定性良好，自然条件下很难分解，又由于具有亲油性，很容易在环境及生物体内累积。TBBPA也是一种内分泌干扰素，长期接触将会妨碍大脑和骨骼的发育以及对甲状腺激素系统产生严重危害。因此，开展和研究水环境中TBBPA等难降解有机物的有效去除方法和技术，探索有机物污染治理的理论基础研究与实践应用研究具有重要意义。本项目的研究内容主要包括：1. 制备N掺杂CNTs稳定Cu2O纳米粒子作为新型吸附剂用于高效去除水体中的TBBPA，采用SEM、TEM、XRD、FTIR、XPS进行物理化学性质表征。批处理试验结果表明该吸附剂对TBBPA具有高的吸附容量（116.72 mg/g），这主要归因于无机种类和聚合物的引入所形成的协同效应。2. 制备聚合电解质固载纳米双金属磁性复合材料用于吸附和快速降解有机污染物。该材料同时具有吸附富集、还原降解与磁分离三重功能，呈现出优异的重复使用性及稳定性。该材料可在5 min内去除92.5%的MB (100 mg/L)。还可有效去除92.4%、85.1%及34.7%的土霉素、TBBPA和诺氟沙星 (50 mg/L)。 3. 制备聚吡咯功能化CoFe2O4-CNTs新型环境修复材料用于选择性吸附和快速降解有机污染物。试验结果表明该纳米材料可选择性去除阴离子型有机染料。CoFe2O4不仅作为磁响应介质，还可催化PMS产生•OH和SO4- •自由基氧化降解阳离子型染料。4. 合成聚多巴胺功能化磁性海藻酸盐复合球高效富集水体中的有机污染物，该复合球制备简单，具有多孔结构，并可快速磁分离，对有机合成染料具有高的吸附量和去除效率以及宽泛的pH适用性。FTIR 和XPS 分析显示，羧酸盐基团、酚羟基、羟基和氨基参与到吸附过程当中。5. 制备PVA-PDA复合球固载Au NPs新型催化剂用于快速降解有机污染物。当RhB浓度低于600 mg/L，该复合球在NaBH4存在下，60 min内即可去除96.6%的RhB，即使在高浓度下（1000 mg/L），也可去除84.2%的RhB。此外，对低浓度的TBBPA还具有高的去除效率，PVA/PDA-Au NPs可以在90 min内去除近100%的TBBPA（25 mg/L）