Dechlorination of 2,4-dichlorophenoxyacetic acid by sodium carboxymethyl cellulose-stabilized Pd/Fe nanoparticles.
This paper describes the synthesis of sodium carboxymethyl cellulose (CMC)-stabilized Pd/Fe nanoparticles and their applications to the dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) under controlled laboratorial conditions. For this purpose batch mode experiments were conducted to understand the effects of CMC on the surface characteristics of Pd/Fe nanoparticles, optimum removal of 2,4-D and other surface interactions mechanism. Our experimental results demonstrated considerable enhancements in particle stability and chemical reactivity with the addition of CMC to Pd/Fe nanoparticles. Transmission electron microscopy (TEM) analysis indicated that CMC-stabilized Pd/Fe nanoparticles were well dispersed, and nanoparticles remained in suspension for days compared to non-stabilized Pd/Fe nanoparticles precipitated within minutes. The isoelectric point (IEP) of the nanoparticles shifted from pH 6.5 to 2.5, suggesting that CMC-stabilized Pd/Fe nanoparticles were negatively charged over a wider pH range. Our batch experiments demonstrated that CMC-stabilized Pd/Fe nanoparticles (0.6 g Fe L(-1)) were able to remove much higher levels of 2,4-D with only one intermediate 2-chlorophenoxyacetic acid (2-CPA) and the final organic product phenoxyacetic acid (PA), than non-stabilized Pd/Fe nanoparticles or microsized Pd/Fe particles. The removal percentage of 2,4-D increased from 10% to nearly 100% as the reaction pH decreased from 11.5 to 2.5. The optimal CMC/Fe mass ratio for the dechlorination of 2,4-D was determined to be 5/1, and the removal of 2,4-D was evidently hindered by an overdose of CMC.
College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, People's Republic of China. zhouhy@zjut.edu.cn
Hongyi
H
Zhou
Jian
J
Han
Shams Ali
SA
Baig
Xinhua
X
Xu
D015084:2,4-Dichlorophenoxyacetic Acid / Q000737:chemistry*; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007526:Isoelectric Point; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D010165:Palladium / Q000737:chemistry*
D015084:2,4-Dichlorophenoxyacetic Acid; D002713:Chlorine; D010165:Palladium; D002482:Cellulose; D007501:Iron; D002266:Carboxymethylcellulose Sodium