The ubiquitous presence of contaminants in water poses a major threat to the safety of ecosystems and human health, and so more materials or technologies are urgently needed to eliminate pollutants. Polymer materials have shown significant advantages over most other adsorption materials in the decontamination of wastewater by virtue of their relatively high adsorption capacity and fast adsorption rate. In recent years, “green development” has become the focus of global attention, and the environmental friendliness of materials themselves has been concerned. Therefore, natural polymers-derived materials are favored in the purification of wastewater due to their unique advantages of being renewable, low cost and environmentally friendly. Among them, natural plant gums show great potential in the synthesis of environmentally friendly polymer adsorption materials due to their rich sources, diverse structures and properties, as well as their renewable, non-toxic and biocompatible advantages. Natural plant gums can be easily modified by facile derivatization or a graft polymerization reaction to enhance the inherent properties or introduce new functions, thus obtaining new adsorption materials for the efficient purification of wastewater. This paper summarized the research progress on the fabrication of various gums-based adsorbents and their application in the decontamination of different types of pollutants. The general synthesis mechanism of gums-based adsorbents, and the adsorption mechanism of the adsorbent for different types of pollutants were also discussed. This paper was aimed at providing a reference for the design and development of more cost-effective and environmentally friendly water purification materials.

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Green and Superior Adsorbents Derived from Natural Plant Gums for Removal of Contaminants: A Review

We investigated the Cu/Ni-O$_2$ bilayer multi-orbital Hubbard model with Cu/Ni impurity approximation embedded in the O lattice by incorporating the 3d$^{8}$ multiplet structure coupled to a full O-2p band. For this simplified model of describing the local electronic structure of hole doped homo-bilayer Cu(Ni)O$_2$-Cu(Ni)O$_2$ and hetero-bilayer CuO$_2$-NiO$_2$, we demonstrate that the homo-bilayer system hosts rich phase diagram with inversion symmetry breaking between two layers at strong enough interlayer hybridization, especially the coexistence of two-hole singlet and triplet states in opposite layers. Besides, we show that the interlayer hybridization in hetero-bilayer systems destabilizes the Zhang-Rice singlets or 3d$^{8}$ triplets within each layer via charge transfer between layers. The relevance of these electronic redistribution to the bilayer or interface systems of cuprates and/or nickelates are discussed.

Inversion symmetry breaking in bilayer multi-orbital Hubbard model with impurity approximation

Solvent-Free Synthesis of Self-Healable and Recyclable Crosslinked Polyurethane Based on Dynamic Oxime-Urethane Bonds

Introducing covalently crosslinked network to telechelic polymers can enable the formation of advanced polymeric materials with enhanced material properties. In this contribution, well-defined telechelic polymers bearing acetoacetate groups were synthesized via Ru-catalyzed ring-opening metathesis polymerization of cyclooctene in the presence of chain transfer agents. Given the unique feature of muti-site reactive acetoacetate end groups, several crosslinked networks were constructed using different crosslinkers under mild conditions. In the Michael addition reaction system, the introduction of di/trifunctional aliphatic acrylate as crosslinkers significantly enhanced the mechanical properties of the generated crosslinked network (tensile strength up to 27 MPa, elongation at break up to 500%). On the other hand, vitrimers with dynamic covalent crosslinked networks were accessed via transamination of vinylogous urethane reaction using telechelic polymers and tris(2-aminoethyl)amine. These vitrimers presented great mechanical properties and reprocessing properties. These strategies can be potentially applied to construct other types of high-performance polymeric materials. This article is protected by copyright. All rights reserved. Supporting Information Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. 

Covalently Crosslinked Networks from Telechelic Polycyclooctene with Reinforced Properties

Ru-Catalyzed Enantioselective Hydrogenation of Diaryl 1,4-Diketones: Synthesis of Chiral 1,4-Diarylbutane-1,4-Diols.

Transient Polymer Hydrogels Based on Dynamic Covalent Borate Ester Bonds

Low-concentration organic dye wastewater severely threatens the growth and reproduction of animals and plants, as well as the survival and development of human beings and the environment. Although versatile hydrogel composites have been prepared owing to their excellent adsorption performance, the high-removal efficiency and fast adsorption rate are still two crucial problems related to practical applications. Herein, xanthan gum-g-poly (acrylic acid-co-acrylamide)/biochar composite hydrogels with high-removal efficiency and fast adsorption rate of methylene blue (MB) are synthesized using sodium dodecyl sulfate as a pore-foaming agent. The composite hydrogels exhibit rough and porous three-dimensional structures, which can make the internal active adsorption sites to be fully exposed and facilitate the MB diffusion process. MB's removal efficiency can reach 96.64% within 30 minutes, which is almost the first time that a biochar-contained hydrogel could show superior removal efficiency of more than 95% in such a short adsorption time. The factors affecting the adsorption performance are studied comprehensively. Langmuir and pseudo-second-order models fit the adsorption process well. Moreover, the MB removal rate still exceeds 80% after eight cycles, which is also a vital indicator for practical treatment. Adsorption mechanism analysis shows that the synergistic effect among biochar, xanthan gum, and polymer chains and the porous structure improve the adsorption performance of the composite hydrogels. The proposed hydrogel-biochar composites with high-removal efficiency and adsorption rate are highly promising as an alternative adsorbent for advanced printing and dyeing wastewater treatment. 

Hydrogel‐biochar composites for removal of methylene blue: Adsorption performance, characterization, and adsorption isotherm, kinetics, thermodynamics analysis


 The discovery superconductivity in Sr/Ca-doped infinite-layer nickelates Nd(La)NiO2 thin films inspired extensively experimental and theoretical research. However, the research on the possibilities of enhanced critical temperature by interface heterostructuring is still lacking. Due to the similarities of the crystal structure and band structure of infinite-layer nickelate LaNiO2 and cuprate CaCuO2, we investigate the crystal, electronic and magnetic properties of LaNiO2:CaCuO2 heterostructure using density functional theory and dynamical mean-field theory. Our theoretical results demonstrate that, even a very weak inter-layer z-direction bond is formed, an intrinsic charge transfer between Cu-3d
 
 x
 2-y
 2
 and Ni-3d
 
 x
 2-y
 2
 orbital is obtained. The weak interlayer hopping between Cu and Ni leaves a parallel band contributed by Ni/Cu-3d
 
 x
 2-y
 2
 orbitals near the Fermi energy. Such an infinite-layer heterostructure with negligible interlayer interaction and robust charge transfer opens a new way for interface engineering and nickelate superconductors.

Chunxiao Zhang

Papers

Transient Polymer Hydrogels Based on Dynamic Covalent Borate Ester Bonds

Hydrogel‐biochar composites for removal of methylene blue: Adsorption performance, characterization, and adsorption isotherm, kinetics, thermodynamics analysis

Electronic structure of cuprate-nickelate infinite-layer heterostructure

Erasable Polymer Hydrogel Wells

Porous biochar composite hydrogel for effective removal of low-concentration methylene blue from wastewater