Chemical oxygen demand removal from electroplating wastewater by purified and polymer functionalized carbon nanotubes adsorbents

被引：47

作者：

Bankole, M.T. ^{[1
,5
]}

Abdulkareem, A.S. ^{[2
,5
]}

Tijani, J.O. ^{[1
,5
]}

Ochigbo, S.S. ^{[1
]}

Afolabi, A.S. ^{[3
]}

Roos, W.D. ^{[4
]}

机构：

[1] Department of Chemistry, Federal University of Technology, PMB.65, Minna, Niger State, Nigeria

[2] Department of Chemical Engineering, Federal University of Technology, PMB.65, Minna, Niger State, Nigeria

[3] Department of Chemical, Materials and Metallurgical Engineering, Botswana International University of Science and Technology (BIUST), Plot 10071, Boseja ward, Palapye, Botswana

[4] Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein,ZA-9300, South Africa

[5] Nanotechnology Research Group, Centre for Genetic Engineering and Biotechnology (CGEB), Federal University of Technology, P.M.B 65, Bosso, Minna, Niger State, Nigeria

来源：

Water Resources and Industry | 2017年 / 18卷

关键词：

Electroplating - Adsorption - Chemical oxygen demand - Oxygen - Calcite - Chemicals removal (water treatment) - Polyethylenes - Purification - Adsorbents - Binary alloys - Chemical vapor deposition - Isotherms - Polyethylene glycols - Water supply - Calcium carbonate - Wastewater treatment - Yarn - Rate constants;

D O I：

10.1016/j.wri.2017.07.001

中图分类号：

学科分类号：

摘要：

This study investigated the removal of chemical oxygen demand (COD) from electroplating industry wastewater via batch adsorption by purified and polymers functionalized carbon nanotubes (CNTs) as nano-adsorbents. Bimetallic Fe-Co supported on CaCO3 was utilized to produce multi-walled carbon nanotubes (MWCNT) via the catalytic chemical vapor deposition (CCVD) technique. This was subsequently followed by the purification of the as-prepared MWCNTs by a mixture of HNO3 and H2SO4 in order to remove the support and metal particles. The purified MWCNTs was further functionalized using known mass of the following polymers: Amino polyethylene glycol (PEG), polyhydroxylbutyrate (PHB) and amino polyethylene glycol with polyhydroxylbutyrate (PEG-PHB). The purified (P-CNTs) and functionalized CNTs coded PEG-CNTs; PHB-CNTs, and PEG-PHB-CNTs were characterized by HRSEM, HRTEM-EDS, BET, XRD and XPS. The electroplating wastewater was subjected to physicochemical characterization before and after treatment with various prepared nano-adsorbents using standard methods. The adsorption process under the influence of contact time, adsorbent dosage and temperature was measured using the chemical oxygen demand (COD) as indicator parameter. The HRSEM/XRD/BET confirmed that the purified and polymer functionalized CNTs were homogeneously dispersed; highly graphitic in nature with fewer impurities and of high surface area (>145 m2/g). The order of maximum COD removal by the nano-adsorbents at equilibrium time of 70 min are as follows: PEG-CNTs (99.68%) > PHB-CNTs (97.89%) > P-CNTs (96.34%) > PEG/PHB-CNTs (95.42%). Equilibrium sorption data were better described by Freudlich isotherm with the correlation coefficient (R2>0.92) than Langmuir isotherm. The adsorption kinetics for COD removal from electroplating wastewater fitted well to the pseudo-second-order model with rate constant in the range of 4 × 10-5-1 × 10-4 (g mg-1 min-1). Thermodynamics analysis of the adsorption process revealed that the enthalpy (ΔH°) of the reaction was positive and endothermic in nature. The Gibbs free energy (ΔG°) was negative which showed the feasibility and spontaneity of adsorption process. The findings from this study support the potential use of PEG-functionalised CNTs as a nanoadsorbent to purify electroplating wastewater than others prepared sorbents. © 2017 Published by Elsevier B.V.

引用

页码：33 / 50