Pb掺杂尾煤基纳米TiO2的制备及光催化降解PAM废水的研究  

Preparation of Pb-doped tailings-based nano-TiO_(2)and study on photocatalytic degradation of PAM wastewater

作　　者：邢慧娟 樊玉萍[1] 马晓敏 董宪姝[1] 侯金瑛[1] 郭嘉奇 裴伟伟 XING Huijuan;FAN Yuping;MA Xiaomin;DONG Xianshu;HOU Jinying;GUO Jiaqi;PEI Weiwei(School of Mining Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024

出　　处：《煤炭科学技术》2023年第6期257-264,共8页Coal Science and Technology

基　　金：国家自然科学基金资助项目(51820105006,52074189);山西省留学回国人员择优资助项目(2019)。

摘　　要：聚丙烯酰胺(PAM)作为一种高效絮凝剂被广泛应用于水处理过程,残留PAM解聚生成的丙烯酰胺单体(AM)已被列为ⅡA类致癌物,对其处理迫在眉睫。选用浮选尾煤(TC)为原料,通过碱激发制备出改性尾煤基体,采用水热法将纳米TiO_(2)负载到改性尾煤基体,制备了尾煤基纳米TiO_(2)复合材料(TiO_(2)/TC)和Pb掺杂尾煤基纳米TiO_(2)复合材料(Pb-TiO_(2)/TC)。以PAM为目标污染物分析了TC、改性尾煤基体、TiO_(2)/TC和Pb-TiO_(2)/TC的光催化降解性能,通过XRD、SEM、UV-vis和BET对样品进行表征,结合高效液相色谱−质谱联用技术对降解产物的分析与研究,探究了PAM的降解机理。研究结果表明:TC呈不规则状态,表面较为粗糙;TiO_(2)/TC的表面疏松,孔隙结构明显,细管状TiO_(2)均匀包覆在改性尾煤基体表面;Pb-TiO_(2)/TC的结构更加蓬松,改性尾煤基体负载着更多的细管状TiO_(2)。TiO_(2)/TC的禁带宽度为3.16 eV,Pb^(2+)掺杂使Pb-TiO_(2)/TC的禁带宽度减小到3.08 eV。TiO_(2)的比表面积为286.66 m^(2)/g,TiO_(2)/TC和Pb-TiO_(2)/TC的比表面积分别为360.33 m^(2)/g和358.54 m^(2)/g,较高的比表面积为反应提供更多活性位点,产生的吸附−催化协同效应显著提升光催化效率。TC和改性尾煤基体对PAM的降解效率分别为3.39%和4.68%,TiO_(2)负载后的TiO_(2)/TC和Pb-TiO_(2)/TC对聚丙烯酰胺的降解率提升至38.92%和63.87%,经过5次循环使用后TiO_(2)/TC和Pb-TiO_(2)/TC的光催化性能基本保持不变。PAM的降解过程中大分子PAM断链变成小分子量PAM分子,进一步氧化分解为NO3−、丙烯酸、乙酰胺和乙酸等。As an efficient flocculant,polyacrylamide(PAM)is widely used in water treatment process.The acrylamide monomer(AM)produced by depolymerization of residual PAM has been listed as a class IIA carcinogen,and its treatment is imminent.Flotation tailing(TC)was used as raw material to prepare a modified tailing matrix by alkali excitation.Nano-TiO_(2)was loaded onto the modified tailing matrix by hydrothermal method to prepare tailing-based nano-TiO_(2)composite(TiO_(2)/TC)and Pb-doped tailing-based nano-TiO_(2)composite(Pb-TiO_(2)/TC).The photocatalytic degradation properties of TC,modified coal matrix,TiO_(2)/TC and Pb-TiO_(2)/TC were analyzed with PAM as the target pollutant.The samples were characterized by XRD,SEM,UV-vis and BET,and the degradation products were analyzed and studied by high performance liquid chromatography-mass spectrometry.The degradation mechanism of PAM was explored.The results show that TC is irregular and the surface is rough;the surface of TiO_(2)/TC is loose,the pore structure is obvious,and the fine tubular TiO_(2)is uniformly coated on the surface of modified tailings.The structure of Pb-TiO_(2)/TC is more fluffy,and the modified coal matrix is loaded with more tubular TiO_(2).The band gap of TiO_(2)/TC was 3.16 eV,and Pb2+doping reduced the band gap of Pb-TiO_(2)/TC to 3.08 eV.The spe-cific surface area of TiO_(2)is 286.66 m^(2)/g,the specific surface area of TiO_(2)/TC and Pb-TiO_(2)/TC are 360.33 m^(2)/g and 358.54 m^(2)/g.The high-er specific surface area provides more active sites for the reaction,and the adsorption-catalytic synergistic effect significantly improves the photocatalytic efficiency.The degradation rates of PAM by TC and modified tailing matrix were 3.39%and 4.68%.The degradation rates of polyacrylamide by TiO_(2)/TC and Pb-TiO_(2)/TC loaded with TiO_(2)increased to 38.92%and 63.87%.After five cycles,the photocatalytic properties of TiO_(2)/TC and Pb-TiO_(2)/TC remained basically unchanged.In the degradation process of PAM,the macromolecular PAM breaks into small molec

关 键 词：尾煤 二氧化钛 高比表面积 聚丙烯酰胺 絮凝剂 

分 类 号：X703[环境科学与工程—环境工程]