Graphene Oxide/Carbon Nanotube Membranes for Highly Efficient Removal of Metal Ions from Water

Abstract

Graphene oxide (GO) has an excellent adsorption capacity toward metal ions. Therefore, it is widely recognized as an auspicious material for fabrication of membranes applied in metal ion separation. However, GO membranes are not stable in aqueous solution because of electrostatic repulsion between GO nanosheets which are negatively charged. This paper shows that stable GO membranes can be easily obtained by the noncovalent interaction of GO with oxidized carbon nanotubes (CNTs). The experiment also shows that the GO/CNTs membranes can be used for the effective adsorption of metal ions. The kinetic data, adsorption isotherms, competitive adsorption experiment, and X-ray photoelectron spectroscopy indicate that the adsorption of metal ions is based on chemisorption. The membranes are remarkably durable in acidic, neutral, and basic solutions. Although the significant stabilization of the membranes by CNTs is observed, they strongly influence the adsorption process. Our study reveals that even a small amount of CNTs (GO/CNTs in the ratio 8:1) significantly reduces adsorption capacities of the membranes which were as follows: 37, 40, 50, 42, 48, and 98 mg g–1 for Co­(II), Ni­(II), Cu­(II), Zn­(II), Cd­(II), and Pb­(II), respectively. The reduction of the membrane adsorption capacities results from the creation of micro- and nanochannels formed by entangled CNTs. Durability and adsorptive properties of studied membranes indicate their potential use for the removal of metals from water.

Photocatalytic and Adsorptional Removal of Heavy Metals from Contaminated Water using Nanohybrids

“…Further, hierarchical nanoporous material synthesized using trimercaptos--triazine-trisodium salt and trimercaptos-triazine-monosodium salt display efficient adsorption capacity of 735.3 and 3775.9 mgg -1 for Hg 2+ and Pb 2+ ions, respectively [103]. The outstanding adsorption capacity and mechanical properties of graphene and graphene oxide imparts broader application in water purification [104,105]. About 98.46% and 99.99% is elimination efficiency acquired by graphene and graphene oxide towards Pb 2+ ion.…”

The stability of a graphene oxide (GO) nanofiltration (NF) membrane in an aqueous environment: progress and challenges

“…82 Incorporation of other nanomaterials can increase the d-spacing, thus improving the water flux while maintaining enough stability in water. So far, many kinds of nanomaterials such as CNTs, [83][84][85] Fe 3 O 4 , 86 TiO 2 , 86 UiO-66, 86 attapulgite, 87 niobate nanosheets, 88 MoS 2 , 89 boron nitride nanosheets, 90 and MXenes 91 have been utilized to improve the stability and permeation of GO membranes.…”

High‐flux PVDF/PVP nanocomposite ultrafiltration membrane incorporated with graphene oxide nanoribbones with improved antifouling properties

“…Among the various advanced methods used to improve the PVDF properties, introduction of various nanofillers such as carbon nanomaterials has received much attention 36,38,46–55 . Carbon nanomaterials, such as GO and CNTs with outstanding properties, have attracted considerable attention 8,44,56–58 . Carbon nanomaterials can be used as nanofillers to produce nanocomposite membranes.…”

“…36,38,[46][47][48][49][50][51][52][53][54][55] Carbon nanomaterials, such as GO and CNTs with outstanding properties, have attracted considerable attention. 8,44,[56][57][58] Carbon nanomaterials can be used as nanofillers to produce nanocomposite membranes. As reported in the literature, [59][60][61][62][63] by adding small amounts of carbon nanomaterials to the polymer matrix, less than 2 wt%, the performance of the prepared nanocomposite membranes could be effectively enhanced.…”