Wu Hongdan, Wang Junwen, Liu Hong, Fan Xianyuan
College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan 430081, China.
Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan 430081, China.
Materials (Basel). 2022 Jun 2;15(11):3957. doi: 10.3390/ma15113957.
Attapulgite (ATP) disaggregated by a ball milling-freezing process was used to support Fe/Ni bimetallic nanoparticles (nFe/Ni) to obtain a composite material of D-ATP-nFe/Ni for the dechlorination degradation of 2,4-dichlorophenol (2,4-DCP), thus improving the problem of agglomeration and oxidation passivation of nanoscale zero-valent iron (nFe) in the dechlorination degradation of chlorinated organic compounds. The results show that Fe/Ni nanoparticle clusters were dispersed into single spherical particles by the ball milling-freezing-disaggregated attapulgite, in which the average particle size decreased from 423.94 nm to 54.51 nm, and the specific surface area of D-ATP-nFe /Ni (97.10 m/g) was 6.9 times greater than that of nFe/Ni (14.15 m/g). Therefore, the degradation rate of 2,4-DCP increased from 81.9% during ATP-nFe/Ni application to 96.8% during D-ATP-nFe/Ni application within 120 min, and the yield of phenol increased from 57.2% to 86.1%. Meanwhile, the reaction rate of the degradation of 2,4-DCP by D-ATP-nFe/Ni was 0.0277 min, which was higher than that of ATP-nFe/Ni (0.0135 min). In the dechlorination process of 2,4-DCP by D-ATP-nFe/Ni, the reaction rate for the direct dechlorination of 2,4-DCP of phenol ( = 0.0156 min) was much higher than that of 4-chlorophenol (4-CP, = 0.0052 min) and 2-chlorophenol (2-CP, = 0.0070 min), which suggests that the main dechlorination degradation pathway for the removal of 2,4-DCP by D-ATP-nFe/Ni was directly reduced to phenol by the removal of two chlorine atoms. In the secondary pathway, the removal of one chlorine atom from 2,4-DCP to generate 2-CP or 4-CP as intermediate was the rate controlling step. The final dechlorination product (phenol) was obtained when the dechlorination rate accelerated with the progress of the reaction. This study contributes to the broad topic of organic pollutant treatment by the application of clay minerals.
采用球磨-冷冻法解聚的凹凸棒石（ATP）负载铁/镍双金属纳米颗粒（nFe/Ni），制备了用于2,4-二氯苯酚（2,4-DCP）脱氯降解的复合材料D-ATP-nFe/Ni，从而改善了纳米零价铁（nFe）在氯代有机化合物脱氯降解过程中的团聚和氧化钝化问题。结果表明，通过球磨-冷冻-解聚的凹凸棒石将Fe/Ni纳米颗粒团簇分散为单个球形颗粒，平均粒径从423.94 nm降至54.51 nm，D-ATP-nFe/Ni的比表面积（97.10 m²/g）是nFe/Ni（14.15 m²/g）的6.9倍。因此，在120 min内，2,4-DCP的降解率从使用ATP-nFe/Ni时的81.9%提高到使用D-ATP-nFe/Ni时的96.8%，苯酚产率从57.2%提高到86.1%。同时，D-ATP-nFe/Ni降解2,4-DCP的反应速率为0.0277 min⁻¹，高于ATP-nFe/Ni（0.0135 min⁻¹）。在D-ATP-nFe/Ni对2,4-DCP的脱氯过程中，2,4-DCP直接脱氯生成苯酚的反应速率（k = 0.0156 min⁻¹）远高于4-氯苯酚（4-CP，k = 0.0052 min⁻¹）和2-氯苯酚（2-CP，k = 0.0070 min⁻¹），这表明D-ATP-nFe/Ni去除2,4-DCP的主要脱氯降解途径是通过去除两个氯原子直接还原为苯酚。在次要途径中，从2,4-DCP中去除一个氯原子生成2-CP或4-CP作为中间产物是速率控制步骤。随着反应进行，脱氯速率加快，最终得到脱氯产物（苯酚）。本研究为应用粘土矿物处理有机污染物这一广泛课题做出了贡献。
