Adsorption of Nonylphenol to Multi-Walled Carbon Nanotubes: Kinetics and Isotherm Study

Yung-Dun Dai,Hyunook Kim,Kinjal J Shah,Pen-Chi Chiang,Ching P Huang

doi:10.3390/app8112295

Yung-Dun Dai, Hyunook Kim + Show 3 more

Open Access

https://doi.org/10.3390/app8112295

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Journal: Applied Sciences	Publication Date: Nov 19, 2018
Citations: 15	License type: CC BY 4.0

Affiliation: University of Seoul, National Taiwan University

Abstract

We explored the occurrence and distribution of nonylphenol (NP) in 13 Taiwanese source waters. From all the surveyed waters, NP was detected at a high concentration, which could be attributed to contamination by wastewater discharges. In this study, we applied modified multi-walled carbon nanotubes (MWCNTs) for removing NP from aqueous solution. The impact of a few experimental factors, i.e., pH, contact time, MWCNTs dose, and temperature on the NP removal efficiency of modified MWCNTs was studied. The maximum adsorption capacity of the MWCNTs was observed to be 1040 mg NP/g when the initial NP concentration was 2.5 mg/L, and the solution pH was 4. The adsorption process followed the Elovich kinetics and the Elovich isotherm, indicating it is multilayer adsorption. The thermodynamic analysis demonstrated the NP adsorption by MWCNTs was thermodynamically satisfactory and, for the most part, endothermic as in the case of phenol adsorption. The result of the current study demonstrated the significance of free binding sites and the pore size of MWCNTs in the NP adsorption. This paper will help to better comprehend the adsorption behavior and mechanism of alkyl phenolic compounds onto MWCNTs.

Highlights

Nonylphenol (NP), a hydrophobic contaminant, has frequently been found in surface water, groundwater, sediment, and soil [1,2]
The result of the current study demonstrated the significance of free binding sites and the pore size of multi-walled carbon nanotubes (MWCNTs) in the NP adsorption
The concentration of NP was habitually distinguished at a critical level in Taiwan surface water, especially in 12 of 13 investigated source waters, indicating the traditional water treatment processes are not effective

Summary

Introduction

Nonylphenol (NP), a hydrophobic contaminant, has frequently been found in surface water, groundwater, sediment, and soil [1,2]. It is a significant byproduct of a non-ionic surfactant, nonylphenol polyethoxylate, which is used as an ingredient of pesticides and personal care products, lubricating additive, the catalyst in curing agent of epoxy resin, defoamer in industrial laundries and dispersant in paper industries [2,3,4]. Inadequate NP removal by wastewater treatment plants (WWTPs) results in a high NP concentration in the aquatic environment [6]

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