Graphene oxide and adsorption of chloroform: A density functional study

Abstract

Chlorinated hydrocarbon compounds are of environmental concerns, since they are toxic to humans and other mammals, are widespread, and exposure is hard to avoid. Understanding and improving methods to reduce the amount of the substances is important. We present an atomic-scale calculational study of the adsorption of chlorine-based substance chloroform (CHCl 3 ) on graphene oxide, as a step in estimating the capacity of graphene oxide for filtering out such substances, e.g., from drinking water. The calculations are based on density functional theory (DFT), and the recently developed consistent-exchange functional for the van der Waals density-functional method (vdW-DF-cx) is employed. We obtain values of the chloroform adsorption energy varying from roughly 0.2 to 0.4 eV per molecule. This is comparable to previously found results for chloroform adsorbed directly on clean graphene, using similar calculations. In a wet environment, like filters for drinking water, the graphene will not stay clean and will likely oxidize, and thus adsorption onto graphene oxide, rather than clean graphene, is a more relevant process to study.

Finite-temperature properties of nonmagnetic transition metals: Comparison of the performance of constraint-based semilocal and nonlocal functionals

“…Importantly, it also captures the more general problem when nonlocal correlation forces compete with other types of forces [9], for example, giving rise to binding across important regions of low electron densities [10,14]. The method was expected to be relevant in first-principles DFT for both pure vdW problems including regular physisorption [49,[78][79][80], porous-materials gas absorption [81][82][83][84][85][86][87][88][89][90], and DNA base-pair interactions [91][92][93][94][95]. It was also quickly realized that truly nonlocal correlations affect materials descriptions much more broadly than what was perhaps originally anticipated [10,14,57,77,[96][97][98][99][100].…”

Electronic Properties of Graphene Oxide in the Presence of Cellulose Chains: A Density Functional Theory Approach

“…In this model, each O atom forms an epoxy functional group with two C atoms, alternating above and below the graphene sheet, thereby minimizing the Coulomb repulsion. 19,20 As shown in Figure 1, the GO model I exhibits a buckling structure. The effects of this buckling are balanced by the alternating O atoms coverage and so this structure is considerably more stable than that with O atoms coverage only on one side of the graphene sheet.…”

“…The effects of this buckling are balanced by the alternating O atoms coverage and so this structure is considerably more stable than that with O atoms coverage only on one side of the graphene sheet. 19,20 We have considered that a supercell contains 32 C and 16 O atoms in the present work. Here, the C:O ratio is 2:1.…”

Friends or strangers? Attempts at reactivating buyer–supplier relationships

“…It also works for studies of the role of polycyclic aromatic hydrocarbons in interstellar H 2 formation [130], of electric-field driven reactions [131], and of mechanochemical cocrystal formation [132]. Use of vdW-DF-cx is also helping the understanding of the crossover from physisorption to weak chemisorption in molecular adhesion [11,[133][134][135][136][137][138][139][140][141][142][143][144][145], of catalysis [146][147][148], of hydrogen tunneling [149], of magnetic coupling between adsorbates [150], and of charge transfer and electron transport in and through molecular adsorbates [151][152][153]. It is therefore worth exploring why (spin) vdW-DF-cx works well.…”