CMC修饰的镍铁双金属对水中2,4-二氯苯酚的降解

Degradation of 2,4-dichlorophenol in water using nickel-iron bimetal modified by carboxymethyl cellulose

以镍为催化剂、羧甲基纤维素(CMC)为改性剂,利用液相还原法制备了修饰型纳米镍铁双金属(CMC Ni/Fe),并用SEM、XRD和EDS对其进行了表征,然后将其用于水中2,4二氯苯酚(2,4 DCP)的降解。SEM表征结果表明,制备的CMC Ni/Fe颗粒均匀、粒径小、呈球形,CMC改善了纳米颗粒的分散性,降低了其团聚现象;XRD表征结果表明在衍射角2θ约为44.8°左右出现了衍射峰,说明制备的样品中存在零价铁;EDS元素分析图表明制备的CMC Ni/Fe纳米颗粒中存在镍、铁元素。通过批平衡试验法研究了CMC Ni/Fe对2,4 DCP的降解效果,重点考察了CMC Ni/Fe投加量、溶液pH值、2,4 DCP初始浓度、CMC修饰量及Ni添加量对2,4 DCP降解的影响。结果表明,在1 g/L CMC Ni/Fe、10 mg/L 2,4 DCP、CMC在Fe0上修饰质量比为1∶1、Ni添加质量分数5%的条件下,2,4 DCP的降解率可达95%;降解率及反应速率随着CMC Ni/Fe投加量、CMC修饰量、Ni添加量的增加呈现出上升和加快趋势。2,4 DCP的降解率在酸性条件下比碱性条件下好,但pH<3及Ni的添加质量分数超过5%时,反而不利于2,4 DCP的降解。试验结果表明CMC改性后的纳米CMC Ni/Fe双金属材料提高了2,4 DCP的降解率,为CMC Ni/Fe去除地下水中2,4 DCP的应用研究提供理论依据和技术支持。

The modified nickel-iron bimetallic nanoparticles(CMC Ni/Fe)were prepared by liquid-phase reduction method using nickel as catalyst and carboxymethylcellulose(CMC)as a modifier.The nanoparticles were characterized by SEM,XRD,and EDS.Then,the materials were used for the removal of 2,4-dichlorophenol(2,4 DCP)from water.The SEM characterization results show that the prepared CMC Ni/Fe particles are homogeneous,small,and spherical.The addition of CMC improves the dispersion property of the nanoparticles and decreases the agglomeration of the particles.The XRD characterization results show that a diffraction peak appears at a diffraction angle of about 44.8°at 2θ,indicating the presence of zero-valent iron in the prepared sample.The EDS elemental analysis graphs indicates the presence of nickel and iron in the prepared CMC Ni/Fe nanoparticles.The efficiency of 2,4 DCP degradation was studied through the batch equilibrium experimental method.The degradation experiments focus on the effects of CMC Ni/Fe dosage,solution pH,initial concentration of 2,4 DCP,CMC modification,and Ni addition on the degradation of 2,4 DCP.The results reveal that under the conditions of CMC Ni/Fe concentration 1 g/L,2,4 DCP concentration 10 mg/L,CMC modification 1:1 and Ni addition 5%,the degradation efficiency of 2,4 DCP is up to 95%;the degradation efficiency and reaction rate tend to increase with increasing CMC Ni/Fe dosage,CMC modification,and Ni addition.The degradation efficiency of 2,4 DCP under acidic conditions is higher than that of alkaline conditions,but the condition of pH<3 and the addition of Ni>5%do not facilitate the degradation of 2,4 DCP.The experimental results show that the CMC modified nano CMC Ni/Fe bimetallic material improves the degradation rate of 2,4 DCP.It provides a theoretical basis and technical reference for the application study of CMC Ni/Fe for the removal of 2,4 DCP in groundwater.