Carbon Nanotubes Hybrid Hydrogels for Environmental Remediation: Evaluation of Adsorption Efficiency under Electric Field.

Giuseppe Cirillo,Manuela Curcio,Fiore Pasquale Nicoletta,Lorenzo Francesco Madeo,Giovanni De Filpo,Francesca Iemma,Silke Hampel

doi:10.3390/molecules26227001

Abstract

The performance of Carbon Nanotubes hybrid hydrogels for environmental remediation was investigated using Methylene Blue (MB), Rhodamine B (RD), and Bengal Rose (BR) as model contaminating dyes. An acrylate hydrogel network with incorporated CNT was synthesized by photo-polymerization without any preliminary derivatization of CNT surface. Thermodynamics, isothermal and kinetic studies showed favorable sorption processes with the application of an external 12 V electric field found to be able to influence the amount of adsorbed dyes: stronger interactions with cationic MB molecules ( and of 19.72 and 33.45 mg g−1, respectively) and reduced affinity for anionic RD ( and of 28.93 and 13.06 mg g−1, respectively) and neutral BR ( and of 36.75 and 15.85 mg g−1, respectively) molecules were recorded. The influence of pH variation on dyes adsorption was finally highlighted by reusability studies, with the negligible variation of adsorption capacity after five repeated sorption cycles claiming for the suitability of the proposed systems as effective sorbent for wastewater treatment.

Highlights

The environmental contamination is becoming the major concern of government regulatory agencies, due to the harmful effects on ecosystems [1,2], with organic dyes used in textile, plastic, wood, paper, and food industries representing the most challenging contaminants for an effective environmental remediation [3,4]
multi-walled CNT (MWCNT) underwent non-covalent functionalization with Gel to improve their stability in water
Within the present study, experimental evidence that the high adsorption ability of MWCNT and the water affinity of acrylate polymer networks can be effectively combined for the fabrication of hybrid hydrogels suitable for wastewater treatment

Summary

Introduction

The environmental contamination is becoming the major concern of government regulatory agencies, due to the harmful effects on ecosystems [1,2], with organic dyes used in textile, plastic, wood, paper, and food industries representing the most challenging contaminants for an effective environmental remediation [3,4] Their chemical structure, often consisting in water soluble aromatic amines, together with the negligible biodegradation profiles, is responsible for severe adverse effects on human health, with kidney, liver, central nervous system, and cancer diseases being the most dangerous disorders [5,6,7]. The applicability of unmodified CNT in adsorption processes is significantly restricted by the absence of polar functional groups resulting in a poor interaction with hydrophilic compounds [27] It is evident the importance of both CNT and polymer counterparts for an effective wastewater remediation, with the modification of CNT surface allowing the enhancement of the eco- and biocompatibility of the composite sorbents [28,29]

Objectives

Methods

Results

Conclusion