不同碳源的生物质炭-磷化铁/零价铁的制备及对水中3,4,5,6-四氯吡啶-2-羧酸的去除

靳惠文; 张小乐; 牛红云; 蔡亚岐

doi:10.7524/j.issn.0254-6108.2023030601

华北理工大学生命科学学院，唐山，063210

环境化学与生态毒理学国家重点实验室，中国科学院生态环境研究中心，北京，100085

通讯作者: Tel：(086) 0315- 8805611，E-mail：smilxin@126.com;

基金项目:

国家自然科学基金（22036007，22276207）和河北省自然科学基金（B2020209005）资助.

中图分类号: X-1；O6

Preparation of biochar-iron phosphide/zero-valent iron with different carbon sources and removal of 3, 4, 5, 6-Tetrachloropyridine-2-carboxylic acid from water solution

School of Life Science, North China University of Science and Technology, Tangshan, 063210, China

State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China

Corresponding author: ZHANG Xiaole, smilxin@126.com ;

Fund Project: the National Natural Science Foundation of China (22036007, 22276207) and the Natural Science Foundation of Hebei Province of China (B2020209005).

摘要: 改性生物炭材料在环境污染物去除中的应用越来越广泛. 本文以鸡粪(CM)、咖啡渣(CG)、活性污泥(SL)等3种废弃生物质为碳源，制备了3种生物质炭-磷化铁/零价铁复合材料(BC-Fe_xP/Fe). 这些材料主要由生物质炭、磷酸铁、磷化铁、零价铁或碳化铁及氧化铁组成. 用于降解水中的3,4,5,6-四氯吡啶-2-羧酸(TCPA)时，以活性污泥为碳源的SL-Fe_xP/Fe材料对TCPA的去除效果明显优于以鸡粪为碳源的CM-Fe_xP/Fe和以咖啡为碳源的CG-Fe_xP/Fe材料，而且SL-Fe_xP/Fe对TCPA的降解受pH影响较小. 在中性pH反应6 h后，CM-Fe_xP/Fe、CG-Fe_xP/Fe和SL-Fe_xP/Fe对10 mg·L⁻¹的TCPA的降解率分别为90.1%、71.1%和100%，矿化率分别为33.25%、22.61%和64.27%. 掩蔽实验和电子自旋共振(ESR)结果表明，SL-Fe_xP/Fe体系存在多种活性氧物质. 使用前后材料的X射线晶体衍射和X射线光电子能谱分析，材料中的Fe_xP、Fe₃C、Fe和氮掺杂生物质炭均在有机污染物的降解过程中发挥了作用.

Abstract: Modified biochar materials are more and more widely used in the removal of environmental pollutants. In this study, several biochar-iron phosphide/zero-valent iron composites (BC-Fe_xP/Fe) were prepared with chicken manure (CM), coffee grounds (CG) or activated sludge (SL) as carbon source. These materials were mainly composed of biochar, iron phosphate, zero-valent iron or iron carbide and iron oxide. When used for the degradation of 3,4,5,6-tetrachloropyridine-2-carboxylic acid (TCPA) from water, the removal efficiency of TCPA by SL-Fe_xP/Fe with activated sludge as carbon source was better than that by CM-Fe_xP/Fe with chicken manure as carbon source and CG-Fe_xP/Fe with coffee ground as carbon source. Furthermore, the degradation of TCPA by SL-Fe_xP/Fe was less affected by pH than those by CM-Fe_xP/Fe and CG-Fe_xP/Fe. At neutral pH, the degradation percentage of TCPA (10 mg·L⁻¹) by CM-Fe_xP/Fe, CG-Fe_xP/Fe and SL-Fe_xP/Fe were 90.1%, 71.1% and 100%, and the mineralization efficiency was 33.25%, 22.61% and 64.27%, respectively within 6h. The masking experiments and electron spin resonance (ESR) results showed the coexistence of various active oxygen species in SL-Fe_xP/Fe system. X-ray diffraction and X-ray photoelectron spectroscopy analysis of the fresh and used materials suggested that Fe_xP, Fe₃C, Fe and nitrogen-doped biochar in the materials all played roles during the degradation of organic pollutants.

Key words:

waste biomass /
modified biochar /
composites /
3,4,5,6-tetrachloropyridine-2-carboxylic acid

不同碳源的生物质炭-磷化铁/零价铁的制备及对水中3,4,5,6-四氯吡啶-2-羧酸的去除

通讯作者: Tel：(086) 0315- 8805611，E-mail：smilxin@126.com;

1. 华北理工大学生命科学学院，唐山，063210

2. 环境化学与生态毒理学国家重点实验室，中国科学院生态环境研究中心，北京，100085

收稿日期: 2023-03-06

录用日期: 2023-11-09

网络出版日期: 2024-09-27

基金项目:

国家自然科学基金（22036007，22276207）和河北省自然科学基金（B2020209005）资助.

关键词:

Preparation of biochar-iron phosphide/zero-valent iron with different carbon sources and removal of 3, 4, 5, 6-Tetrachloropyridine-2-carboxylic acid from water solution

Corresponding author: ZHANG Xiaole, smilxin@126.com ;

1. School of Life Science, North China University of Science and Technology, Tangshan, 063210, China

2. State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China

Received Date: 2023-03-06

Accepted Date: 2023-11-09

Available Online: 2024-09-27

Fund Project: the National Natural Science Foundation of China (22036007, 22276207) and the Natural Science Foundation of Hebei Province of China (B2020209005).

Keywords:

waste biomass /
modified biochar /
composites /
3,4,5,6-tetrachloropyridine-2-carboxylic acid

全文HTML

氯代吡啶是医药、农药等精细化工产品的常见结构或中间体，具有广泛的应用. 比如3, 6-二氯吡啶-2-羧酸（CLP）是一种用于控制一年或多年生阔叶杂草的常见氯代吡啶除草剂. CLP能够穿透土壤导致地下和地表水污染，在水中的溶解度高达1000 mg·L^{−1 [1]}. 据报道，北美地区由融雪和降雨径流补给的水库中CLP浓度高达1050 ng·L^{−1 [2]}. CLP生产过程产生的废水含有多种具有高毒性和致癌作用的氨基和氯取代的吡啶类物质^{[3 − 4]}. 其中，3,4,5,6-四氯吡啶-2-羧酸（TCPA）是采用电化学还原法制备CLP的重要原材料和中间体^{[5 − 6]}. TCPA含有吡啶环和4个氯代基团，具有更强稳定性和高毒性，属于典型的难降解有机污染物，可以长期存在于水体中，并导致人体多项功能紊乱^{[7- 8]}. 由于较高的生物毒性和稳定性，氯代吡啶废水进入生物处理系统前必须进行预处理.

高级氧化技术（AOPs），如Fenton氧化^[9]、光催化^[3]、电化学氧化^{[10 − 11]}和过硫酸盐氧化^[12]是氯代吡啶类废水预处理的常用方法. 但是，这些技术具有能耗高、氧化剂投入多以及污泥产生量高等缺点^[11]. 研究一种低成本且能够高效去除水环境中氯吡啶类污染物的催化剂至关重要.

零价铁（ZVI）的比表面积大、还原性强，已有研究将其用于吡啶类废水的预处理^{[11, 13]}. 但是单独ZVI处理效果较差且产生污泥量高. 研究表明，磷化铁（Fe_xP）和碳化铁比ZVI具有更高的活性和稳定性，可以高效活化溶解氧，产生羟基自由基、单线态氧和超氧阴离子自由基等多种活性氧物质，从而促进污染物的氧化降解^{[14 − 18]}. 近年来，生物炭（BC）是污染修复领域的热点材料之一，它具有原材料廉价易得、表面积大、官能团丰富等优点^{[19 − 21]}. 生物质炭可吸附去除污染物，还可以作为铁基纳米材料的载体^[22]，将ZVI等铁基材料负载到生物炭中能提高ZVI的反应活性和稳定性，增强污染物去除效果^{[23, 24]}.

生物质炭的原材料种类丰富，不同种类也影响生物质炭的结构及性能. 我国每年产生牲畜粪便高达几十亿t，所含的有害物质可造成地表水和地下水的污染，将禽畜粪便热解制备成生物炭对解决能源危机和环境污染具有重要意义^{[25 − 27]}. 近年来我国咖啡市场逐年增长，预计每年可产生80多万t的咖啡渣，利用咖啡渣合成生物炭用于污染物处理备受关注^{[28 − 29]}. 随着我国城市化进程快速推进，每年产生大量的活性污泥，污泥中通常含有人类致病菌、重金属等有害物质，如果不处理将对环境造成二次污染并威胁人类健康^[30]。污泥中含有大量有机质，制备成生物质炭是污泥资源化的重要处理技术^{[31 − 32]}.

本研究以咖啡渣、鸡粪和活性污泥等3种不同类型的生物质为原材料，合成了生物质炭负载的磷化铁/零价铁/碳化铁复合材料. 以制备材料为催化剂，对水中TCPA的预处理，确定不同种类生物质对生物炭复合材料的影响，获得了一种对水环境中难降解污染物具有强去除能力的水质净化材料.

1. 材料与方法（Materials and methods）

1.1. 试剂和仪器

试剂：3,4,5,6-四氯吡啶-2-羧酸（TCPA）购于北京J&K化学有限公司，甲醇、乙腈、冰醋酸购于上海麦克林生化科技有限公司，磷酸、硫酸、氢氧化钠购于国药集团化学试剂有限公司，以上试剂均为分析纯. 超纯水由Milli-Q Advantage A10超纯水系统（美国Millipore）制备. 铁矿石（Fe₂O₃）粉末、干鸡粪（CM）和咖啡（CG）渣从淘宝店铺购得，其中干鸡粪来自于河北石家庄市某畜禽养殖场，咖啡渣来自于北京某咖啡店. 污泥选用北京市某污水处理厂活性污泥（SL）.

仪器：场发射扫描电子显微镜（日立S-5500，日本日立公司），X射线晶体衍射分析仪（XRD，D8 ADVANCE，德国BRUKER公司），X射线光电子能谱仪（XPS，ESCA-Lab-250Xi，Thermo Fisher Scientific），电子自旋共振波谱仪（ESR，EMX，德国BRUKER公司），高效液相色谱仪（HPLC, UltiMate 3000，Thermo Fisher Scientific），管式炉（OTF-1200X-60，合肥科晶材料技术公司），电热鼓风干燥箱（YLD-2000，黄石市恒丰医疗器械公司），电热板（EH20A Plus，北京莱伯泰科），球磨仪（BM4，北京格瑞德曼），总有机碳分析仪（TOC-L CPH，日本岛津），超高压液相色谱-四极杆串联飞行时间质谱联用仪（UPLC-Q-TOF-HRMS，Agilent-6540，美国安捷伦）.

1.2. 改性BC-Fe_xP/Fe材料的制备

将CM先在300 ℃氮气保护下炭化2 h，然后将炭化产物在1 mol·L⁻¹ H₃PO₄中浸泡12 h，用去离子水洗涤至中性后，在60 ℃干燥箱中烘干备用. 干燥的咖啡渣和活性污泥分别浸泡在1 mol·L⁻¹ H₃PO₄溶液中，于200 ℃加热2 h，冷却后用去离子水洗涤至中性，60 ℃烘干备用.

将上述准备好的磷酸处理后的生物质炭分别与铁矿石按照质量比1:1的比例放入氧化锆研磨罐中，加入适量研磨小球，300 r·min⁻¹研磨1 h. 随后，将混合均匀的前体物在N₂保护下管式炉中800 ℃碳化1 h，冷却至室温即可获得BC-Fe_xP/Fe材料（CM-Fe_xP/Fe、CG-Fe_xP/Fe、SL-Fe_xP/Fe）.

1.3. TCPA的降解及检测

将5 g·L⁻¹的BC-Fe_xP/Fe催化剂分散到50 mL含有（10—200） mg·L⁻¹ TCPA的水溶液中，在25 ℃恒温摇床上以300 r·min⁻¹的转速振荡反应. 在一定的时间间隔内，取1.0 mL悬浊液，经0.22 μm尼龙滤膜过滤后，进行高效液相色谱分析. 液相色谱所使用的色谱柱为Dikma C18色谱柱（5 μm，4.6 mm×150 mm），流动相由70%乙腈+30%水与0.2%乙酸组成. 检测波长为295 nm，流速为1.0 mL·min⁻¹，柱温为30 ℃. 利用TOC分析仪测定样品的总有机碳（TOC）去除率.

3. 结论（Conclusion）

本研究以鸡粪、咖啡渣、活性污泥三种废弃生物质为碳源，以铁矿石为铁源，制备了生物质炭负载的磷化铁和零价铁复合材料. 其中，以活性污泥为生物质炭原材料所得复合材料（SL-Fe_xP/Fe）具有明显的多孔结构. 将三种材料用于水中难降解污染物四氯吡啶酸的去除. 结果表明，SL-Fe_xP/Fe对TCPA的降解和矿化能力均优于CM-Fe_xP/Fe和CG-Fe_xP/Fe，该材料对TCPA的降解几乎不受溶液pH的影响. 而且SL-Fe_xP/Fe具有良好的重复利用性，循环3次后TCPA去除率仍可达到100%. 掩蔽实验和ESR结果表明，在SL-Fe_xP/Fe体系中可以原位生成∙OH、∙O₂⁻和¹O₂等多种活性物质，促进了TCPA的快速、高效降解和矿化. SL-Fe_xP/Fe材料中的Fe_xP、Fe及N掺杂生物质炭均参与溶液中溶解氧的活化，因此SL-Fe_xP/Fe体系具有超高的反应活性.

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