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In view of the characteristics of heavy metal and antibiotic compound pollution in the Pearl River Basin in Guangzhou. More scientifically modified cellulose, named HVUC, is characterized by multiple hydrophilic groups, long chains and large space and displays highly efficient adsorption of both Cd and sulfamethoxazole (SMZ) and good adaptability in a wide pH range and at high ion strength. Furthermore, the coadsorption mechanism was elaborated from multiple angles. Multiple adsorption experiments explained the competition and synergy effect in the adsorption process. The electrostatic potential maps indicated that HVUC had advantageous adsorption sites for both Cd and SMZ and that electrostatic interactions had the greatest impact on the adsorption of Cd and SMZ. The electron density and differential charge density images proved that Cd more easily overlapped electron clouds and transferred electrons with HVUC and that SMZ - and could act as a bridge for SMZ - . The equilibrium configuration indicated that the formation of Cd-SMZ - complexes led to the bending and folding of SMZ - , which was not conducive to overall adsorption when SMZ - was close to HVUC and could lead to the release of SMZ - when Cd was close to HVUC, which confirmed the proposed mechanism of complexation-decomplexation-complexation., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Phosphonic chelating fiber (PCCSF) as a novel adsorbent was produced through alkalization, etherification, amination and phosphonation, and then it was applied to adsorb sulfonamides (SAs), such as sulfadiazine (SD), sulfamonomethoxine (SMM) and sulfamethoxazole (SMZ). Specially, their adsorption behavior at different pH values was studied. As a result, PCCSF was provided with amino (NH 2 or NH) and PO(OH) 2 (PO) groups, and its equilibrium data were generally represented by both Langmuir and Freundlich models. Combining adsorbent-to-solution distribution coefficients (K d ) values and the effect of pH, the primary mechanism suggested that adsorption capacity of PCCSF was lower in strong acid and alkali solution, due to the electrostatic repulsion and hydrophobic interactions. By contrast, its adsorption affinity became more excellent at 3 < pH < 9 owing to the π-π electron-donor-acceptor (EDA) charge-assisted H-bond, Lewis acid-base interaction and charge-assisted H-bond (CAHB)., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

One kind of PVA/PAA-based alkaline solid polyelectrolyte (ASPE) membrane with high conductivity and good mechanical property was prepared via the introduction of the micro-crystalline cellulose (MCC) as functional fillers. An ion conductivity of 95 mS cm−1 with high alkali resistance was achieved when the MCC content reached up to 5wt%, which is 4.5-fold higher than the control. SEM image showed a denser pore structure that is beneficial for the OH− conduction after MCC addition. X-ray diffraction further indicated a gradually decreased crystallinity of KOH with the addition of MCC. This means more content of KOH would exist in the ionic form in the remained water caused by the added MCC in the system. This leads to the increased content of OH− and the resulting ion conductivity. The window equals to 0.9 V and improved mechanical properties were observed after a 5wt% content of MCC was added in the ASPE membrane system. [ABSTRACT FROM AUTHOR]

In this study, a type of alkaline solid polyelectrolyte (ASPE) membrane was developed via the introduction of microcrystalline cellulose (MCC) and its modified product (QMCC) into the polyvinyl alcohol (PVA) matrix. In this process, green NaOH/urea-based solvent was used to achieve a good dispersion of MCC in the PVA matrix; meanwhile, the OH− groups in the NaOH/urea-based solvent provided an alkaline environment for good ion conductivity. Compared to the MCC-incorporated ASPE, further improved conductivity was achieved when the MCC was modified with quantitative quaternary ammonium salt. TGA showed that the addition of QMCC improved the water retention of the matrix, which was beneficial to the OH− conduction in the system. Compared to the control (50 mS cm−1), a maximum conductivity of 238 mS cm−1 was obtained after the incorporation of QMCC in the PVA matrix. Moreover, the tensile strength of the polymer electrolyte were also significantly increased with the addition of QMCC. Finally, this developed ASPE membrane was used in assembling a flexible Zn–air battery and showed a promising potential in the development of flexible electronic devices. [ABSTRACT FROM AUTHOR]

For the treatment of heavy metal (HM)-polluted wastewater, an increasing number of novel and practical adsorbents have been developed and applied, especially cellulose-based materials, which have received increasing attention from researchers in recent years. This research has mainly focused on the influencing factors, thermodynamics, and kinetics of HM ion removal, and the associated mechanisms have been investigated theoretically. Density functional theory (DFT) is typically combined with experimental research to develop new materials and investigate their applications, and considerable progress has been achieved. Parameters calculated by DFT, such as the adsorption or interaction energy (E ads), frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP), natural bond orbitals (NBOs), electrostatic potential (ESP), and Mulliken population, play a crucial role in the study of adsorption behaviour. In this paper, the developments in DFT calculations of the properties of cellulose-based materials, as well as the applications and technical factors related to the removal of HM ions and HM composite pollutants, are reviewed. Furthermore, our team has focused on DFT approaches such as the sequential investigation of adsorption structure → functional groups → key elements. This sequential approach was used to assess the removal of HM ions and complexation–decomplexation–recomplexation processes related to the adsorption of HM composite pollutants to provide insights and methods supporting the development and substantive application of cellulose-based materials. [Display omitted] • Cellulose-based materials showed excellent performance in HMs-contained wastewater. • DFT calculations played a key role in quantitative analysis of adsorption mechanism. • DFT calculations can predict and provide key non-experimental information. • Our research explored a set of DFT calculations routes suitable for HMs removal. • DFT can reveal the mechanism such as complexation-discomplexation-recomplexation. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • C S, NH and NH 2 groups were introduced into the cellulose successfully. • TMCS exhibited excellent adsorption capacity of 54.71 mg g−1. • The complex formation played a significant role during adsorption process. • Non-linear and linear isotherm models were analyzed using 8 error functions. • The Fritz-Schlünder as 4-parameter isotherm model fit the experimental data best. Abstract Sulfur-chelating based cellulose was produced successfully through alkali-pretreatment, etherification-substitution, amination-crosslinking and sulfurate-reaction. Further, its physico-chemical properties were characterized thoroughly, and several impact factors, i.e. adsorbent dosage, pH, co-existing ions, temperature and contact time were discussed in details. Particularly, the linear and non-linear isotherm models were used to determine the best-fitting one with the verification of 8 error functions. As a result, the adsorbent had more excellent adsorption capacity of 54.71 mg g−1 at the optimal conditions, i.e. dosage of 4 g L−1; 5.1 of pH value (50 mL of solution), 298 K of temperature, at least 180 min of contact time, and 5 cyclical regeneration of the adsorbent with 0.1 g L−1 ethylenediaminetetraacetic. The Fritz-Schlünder as 4-parameter isotherm model gave the best correlation of the experimental data. Moreover, a complex formation between Cd (II) and the C S, NH 2 and NH groups was confirmed as the dominant chemical adsorption interactions. [ABSTRACT FROM AUTHOR]

Diethylenetriamine pentaacetic acid (DTPA) functionalized modified corn stalk cellulose (DCS) was successfully prepared and applied to the adsorption of sulfamethoxazole (SMZ) wastewater in the presence of copper (Cu). Compared with the raw corn stalk cellulose (RCS), DCS has the characteristics of more hydrophilic groups, larger contact space and lower steric hindrance. The adsorption amount for Cu and SMZ in binary system were 4.41 mg/g and 29.7 mg/g, respectively. Additionally, DCS has good pH buffering capability, resistance to potentially interfering ions (NaCl and HA) and great regeneration performance after 5 cycles. More importantly, the experimental results demonstrated competitive adsorption and complexation synergy occurred between Cu, SMZ and DCS. Cu inhibited the adsorption of SMZ while SMZ promoted the adsorption of Cu, which was attributed to the fact that SMZ provided additional adsorption sites or complexation reduced the surface charge of Cu. Based on this situation, density functional theory (DFT) calculations were carried out for the further explanation of adsorption mechanism. The molecular electrostatic potential maps showed that DCS possessed more SMZ adsorption sites than Cu, and the adsorbed Cu or SMZ on DCS would provide additional adsorption sites. The equilibrium configurations and binding energy indicated that the competitive adsorption, bridge effect adsorption and co-adsorption would occur simultaneously. The total electron density and differential charge confirmed that SMZ was more likely to overlap electron clouds and transfer electrons with DCS, while the adsorption process of Cu was conformed the complexation adsorption dynamic equilibrium. This paper provided a new perspective on the co-adsorption and competitive adsorption processes by multisystem experiments and abundant DFT calculations and indicated the good adsorption performance of DCS on SMZ in the presence of Cu. [Display omitted] • DTPA provided carboxyl and quaternary ammonium groups for DCS. • Co-adsorption and competitive adsorption occurred simultaneously. • Electrostatic interaction had the greatest effect on Cu and SMZ adsorption. • The formation of Cu-SMZ- complexes promoted the adsorption of Cu. [ABSTRACT FROM AUTHOR]

A new self-assembled cellulose (SACS) containing multi-functional amine, carboxyl and hydroxyl groups was successfully obtained through etherification, cross-linking and grafting processes. Then, the adsorption of sulfamethoxazole (SMZ) and Cd(II) onto SACS at pH values of 3, 5.7 and 7.5 was systematically investigated by batch experiments of single, sequential and binary systems, characterization and density functional theory (DFT) calculations. The presence of Cd(II) decreased the adsorption of SMZ because of hydrophilic site competition, while SMZ inversely increased the adsorption of Cd(II), which was attributed to bridging and especially to electrostatic shielding effects; moreover, both the inhibitory and synergistic effects were more obvious in the binary system and at a pH of 7.5. There was a dynamic balance between the inhibitory and synergistic effects that depended on the system, pH value and concentration ratio. DFT results further indicated that SMZ– more easily coordinated with Cd(II) at sulfonyl oxygen and nitrogen sites, and the cationic bridge of Cd(II) with SMZ– mainly occurred in the sequential system. Moreover, a complexation–decomplexation–complexation balance of SMZ– and Cd(II) probably occurred in the binary system. ga1 • Cellulose was assembled with amine, carboxyl and hydroxyl groups. • The cationic bridge of Cd(II) for SMZ– mainly occurred in the sequential system. • Both competition and the inhibitory effect were most obvious at a pH of 7.5. • SMZ– more easily coordinated with Cd(II) at sulfonyl oxygen and nitrogen sites. • A complexation–decomplexation–complexation balance occurred in the binary system. [ABSTRACT FROM AUTHOR]