Carboxymethylcellulose and cellulose xanthate matrices as potential adsorbent material for potentially toxic Cr 3+ , Cu
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Carboxymethylcellulose and cellulose xanthate matrices as potential adsorbent material for potentially toxic Cr3+, Cu2+ and Cd2+metal ions: a theoretical study Davi Texeira Reis1 · Sílvio Quintino de Aguiar Filho1 · Carlos Guilherme Lopes Grotto1 · Murielly Fernanda Ribeiro Bihain1 · Douglas Henrique Pereira1 Received: 30 January 2020 / Accepted: 11 May 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Cellulose derivatives have been synthesized and used in various applications with emphasis on possible application in environmental remediation. In this context, the present work theoretically studied the adsorption of C r3+, Cu2+ and C d2+ metal ions in the carboxymethylcellulose (CMC) and cellulose xanthate (CX) matrices, both derived from cellulose. From the calculations, it was possible to obtain map of electrostatic potential, frontier molecular orbitals, reactivity indices, and with these, analyses infer that the cations would interact with the CMC and CX oxygen and also with the CX sulfo group. After complexation, the results showed that the CX and CMC matrices studied have potential to be used to remove toxic metals and presented chemical adsorption and the processes occur spontaneously (ΔG Cd2+ > Cu2+. Unlike CMC, the CX presented a more effective interaction for the C u2+ ion than 2+ for the C d ion and the order of interaction found was Cr3+ > Cu2+ > Cd2+. Eint values for CX also show that the two interactions studied at work are possible and practically similar in terms of energy. This fact indicates that CX is an excellent adsorption matrix, as it has more than one effective interaction site. Comparing the results with those previously reported by our research group for cellulose and cellulose acetate, it is possible to observe that CMC follows the same trend as CE and CA [13]. In general it can be confirmed that both cellulose and CA, CMC and CX derivatives interact with the metallic ions studied from the theoretical point of view, thus allowing experimental studies of these systems with environmental applications. 3.2.3 QTAIM analysis The topological parameters were evaluated using QTAIM theory, and the complex results for the interactions are shown in Table 4. The properties analyzed were electron density (ρ(r)), electron density Laplacian (∇2ρ(r)) and total (H(r)) energies. The higher the electron density value (ρ(r)) in the bond critical point (BCP), the greater the intensity of the interaction. When the values of ∇2ρ(r) and total energy H(r) are positive, the nature of the interaction is electrostatic,
Theoretical Chemistry Accounts
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Carboxymethylcellulose
Cellulose Xanthate
Color of atoms:
Fig. 2 Optimized structures of CMC and CX interacting with metallic ions Cu2+, Cd2+ and Cr3+
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Theoretical Chemistry Accounts
Table 2 Calculated interaction distances (in Å) and vibrational frequencies (in c m−1) of carboxymethylcellulose, cellulose xanthate and complexes formed Molecul
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