Removal of phosphorus from aqueous solution using multi-wall carbon nanotube (MWCNT) as adsorbent: Kinetics and isotherms

Abstract

The discharge of phosphorus from urban and industrial wastewater into water bodies causes eutrophication and algae blooms. What it seems essential is that treatment of such wastewater before its discharge into the environment. The main purpose of this study is to investigate phosphorus adsorption from aqueous solutions by using multi-walled carbon nanotubes (MWCNT) as the adsorbent. In experiments, Scanning Electron Microscope (SEM) is applied for characterizing the adsorbent. The impact of variables effecting the adsorption of phosphorus such as amount of adsorbent, the initial concentration of phosphorus and pH are studied at room temperatures. Furthermore, for assessing data, isotherm and kinetic models are considered. The results indicate that the elevation of pH and the amount of adsorbent enhance the efficiency of phosphorus adsorption, while an increase in phosphorus concentration decrease adsorption. The results also show that phosphorus adsorption follows the Freundlich isotherm model. To determine the adsorption kinetics, in traparticle diffusion, pseudo-first-order and pseudo-second-order kinetics are widely used. Finding results indicate that a good compliance with a pseudo-second-orderkinetic model. Finally, results demonstrate that thatmulti-walled carbon nanotubes (MWCNT) is good adsorbent for the elimination of phosphorus from aqueous solutions in a relatively short time, owing to their highcapacity of adsorption.

Keywords:

• Adsorption
• Multi-Walled Carbon Nanotubes (MWCNT)
• Phosphorus
• Kinetics
• Isotherm

Acknowledgements

The authors would like to express their gratitude to Department of Environmental Health Engineering, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran, for their financial supports. This work was also supported by Xinjiang Technical Institute of Physics and Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences (CAS), Urumqi, 830011, China, CAS Special Research Assistant Project, Project No: E15R6301.