Hydrogels Based on Polyacrylamide and Functionalized Carbon Nanomaterials for Adsorption of a Cationic Dye

Abstract

Malachite green (MG) is used for the dyeing of cotton, paper, and jute, among other materials, and presents acute toxicity to a wide range of aquatic and terrestrial animals. A polyacrylamide (PA) hydrogel modi ed with a low content of oxygenated and aminated carbon nanomaterials may be a suitable candidate to adsorb MG from wastewater. Herein, modi ed graphene and carbon nanotubes (CNTs) were incorporated during the in situ polymerization of PAM. The swelling and adsorption capacity were investigated to explore the in uences of different carbon dimensionalities (1D and 2D), zeta potentials and nano ller concentrations on the adsorption behavior of the hydrogel. There was an increase of approximately 1,500% in the adsorption capacity after 24 h of exposure of a hydrogel with graphene oxide (GO) at 0.25 wt% with respect to the neat PA. Aminated graphene produced similar gains in the adsorption capacity of the GO-hydrogel, although it presents a positive zeta potential that is the opposite of that of GO. The modi ed CNTs showed smaller gains in the adsorption capacity, reaching a maximum 400% increase with respect to the PA hydrogel. The main factors that seem to affect the adsorption capacity were the dimensionality and degree of functionalization. The graphene-based nano llers were 3 to 4 times more functionalized than the nanotubes. The adsorption results were adjusted with a pseudosecond order kinetic model that allowed a complementary discussion about the nature of the physicochemical effects on the process of MG adsorption in the hydrogel nanocomposites.

Additive manufacturing of 3D networks based on poly(lactic acid) and amine functionalized graphene oxide as a platform for scaffolds

“…Freeze-dried GO obtained by modified Hummers method, 38 and amine functionalized GO were provided by Center for Technology in Nanomaterials and Graphene (CTNANO-UFMG). 38,39 Dichloromethane (CH 2 Cl 2 ; CAS 75-09-2) was purchased from CRQ Produtos Químicos and acetone (C 3 H 6 O; CAS 67-64-1) from Êxodo Científica Brazil.…”

“…PLA (grade: 3D850, NatureWorks) in the form of pellets with a density of 1.24 g/cm 3 (ASTM D792) and melt flow index of 7–9 g/10 min (ASTM D1238) were kindly donated by 3DLab Indústria LTDA. Freeze‐dried GO obtained by modified Hummers method, 38 and amine functionalized GO were provided by Center for Technology in Nanomaterials and Graphene (CTNANO‐UFMG) 38,39 . Dichloromethane (CH 2 Cl 2 ; CAS 75‐09‐2) was purchased from CRQ Produtos Químicos and acetone (C 3 H 6 O; CAS 67‐64‐1) from Êxodo Científica Brazil.…”

An oriented MXene/silk fibroin nanofiber hydrogel with high strength and strain response ability

“…Nowadays, hydrogels have attracted much attention due to their unique swelling ability, flexibility, biocompatibility, porosity and other properties. [8][9][10] They are widely used in many fields such as bioengineering, smart sensing, and environmental pollution treatment, and can achieve excellent electrical conductivity and strain response by doping with ions, [11][12][13] doped carbon nanomaterials, [14][15][16] or doped metal nanomaterials. 17,18 However, the relatively poor mechanical properties and fragility characteristics limit the application of hydrogels in flexible sensor components.…”