•Chitosan/cellulose-based sorbents designed for heavy metals removal from drink water.•The sorbents combined with renewability, biocompatibility and magnetic property.•The sobents had micro/nano pore ...structure and operational convenience.•Magnetic microspheres displayed superior adsorption and desorption capabilities.
Development of highly cost-effective, highly operation-convenient and highly efficient natural polymer-based adsorbents for their biodegradability and biocompatibility, and supply of safe drinking water are the most threatening problems in water treatment field. To tackle the challenges, a new kind of efficient recyclable magnetic chitosan/cellulose hybrid microspheres was prepared by sol–gel method. By embedding magnetic γ-Fe2O3 nanoparticles in chitosan/cellulose matrix drops in NaOH/urea aqueous solution, it combined renewability and biocompatibility of chitosan and cellulose as well as magnetic properties of γ-Fe2O3 to create a hybrid system in heavy metal ions removal.
Ag nanoparticles were deposited on the surface of g-C3N4 by a chemical reduction method to increase visible-light absorption via the localized surface plasmon resonance effect, resulting in the ...reduced recombination of photo-generated electron-holes and enhanced photocatalytic activity. The Ag/g-C3N4 composite with a Ag loading of 3 wt% has the optimum photoactivity that is almost 3.6 and 3.4 times higher than pure g-C3N4 and the same photocatalysis system which has been reported, respectively. Fluorescein was introduced as a photosensitizer and H2 evolution soared to 2014.20 μmol g(-1) h(-1) and the rate is even about 4.8 times higher than that of the 3 wt% Ag/g-C3N4 composite. The chemical structure, composites, morphologies and optical properties of the obtained products are well-characterized by XRD, FTIR, TEM, EDS, XPS and UV-Vis DRS. Meanwhile, the photocatalyst exhibits high stability and reusability.
Restricted by the poor ability of polymers to dissociate lithium salts and transport ions, solid‐state polymer electrolytes (SPEs) show extremely low ionic conductivities (≈10−7–10−5 S cm−1) and ...transference number of lithium ions (tLi+ ≈0.2–0.4) at 25 °C. Here, a novel polymer matrix of SPEs that simultaneously promotes lithium salt dissociation and ion transportation based on a high dielectric poly(vinylidene fluoride‐trifluoroethylene‐chlorotrifluoroethylene) (TerP) and an all‐trans conformational poly(vinylidene fluoride‐trifluoroethylene) (CoP), is developed. The high dielectric constant increases the polarity of CH2CF2 polar groups; then, brings a strong electronegative end that dissociates Li+ from lithium salts. The all‐trans conformation assures all fluorine atoms locate on one side of the chain, constructing ion hopping highways. As a result, the TerP/CoP (TC) SPE exhibits a high ionic conductivity (2.37 × 10−4 S cm−1) and a quite large tLi+ of 0.61 at 25 °C. The Li/TC SPE/Li symmetric cells cycle stably for more than half a year (>4500 h) and the LiNi0.8Co0.1Mn0.1O2/TC SPE/Li cell cycles steadily for 1000 and 600 cycles at 1 C and 2 C at 25 °C, respectively. This work paves a new way to prepare high‐performance SPEs by simultaneously modulating dielectric constants and conformation of polymers.
Through conformational regulation of the high dielectric P(VDF‐TrFE‐CTFE), an all‐trans conformation with all F atoms located on one side of the chain is achieved, which constructs ion hopping highways and results in a high lithium‐ion transference number of 0.61. Both the Li//Li symmetric cells and the high‐voltage NCM811//Li cells show long‐term cycling stability at 25 °C.
The climatology, trends and leading modes of land surface latent heat flux (LHF) and sensible heat flux (SHF) as well as their responses to monsoon and precipitation in global land monsoon domains ...are presented. During the past three decades, LHF and SHF have generally undergone a rising and decreasing trend (that is, (LHF+, SHF-)), respectively, in Asian, North African, Austrian, and South American monsoon domains. Moreover, the increasing rate of LHF was higher than the decreasing rate of SHF, which causes a decreased trend in Bowen ratio. Two other dominant trend patterns, (LHF-, SHF-) and (LHF+, SHF+), are observed in South African and South American monsoon domains, respectively. The trends in LHF and SHF are closely linked to increasing global monsoon intensity and precipitation, especially for the monsoon domain that has annual precipitation lower than 1300 mm yr
. Singular value decomposition (SVD) analyses show that monsoon strength explains 25.2% and 22.2% total covariance of LHF and SHF respectively in the first modes, and that precipitation slightly raises the percentages up to 27.8% and 24% respectively. The increasing monsoon and precipitation on one hand favor more land surface available energy being converted into LHF; on the other hand they enhance the LHF by increasing the land surface net radiation. Moreover, remarkable phase shifts in LHF and SHF are observed for monsoon domains during late-1990s, which are in phase with those of precipitation and monsoon strength. The intensifying LHF and precipitation indicate the acceleration of hydrological cycle in global terrestrial monsoon domains.
Poly(lactic acid) (PLA) is regarded as one of the most promising biobased and biodegradable polymers due its various advantages including high mechanical strength, easy processability, high melting ...temperature, renewability, biodegradability, and biocompatibility. However, the inherent brittleness significantly restricts its wide application. Therefore, toughening PLA has attracted more and more attention and various materials have been used to blend with PLA for toughening. Considering the fact that the use of petroleum-based species to toughen PLA would partially sacrifice the sustainability, various renewable polymers have recently been employed to toughen PLA. A series of important achievements have been obtained but not reviewed. This article aims to review progress in toughening PLA with renewable polymers. The toughening theories and compatibilization strategies are also briefly introduced.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
•Underwater superoleophobic cotton fabric was prepared by a mussel-inspired method.•The underwater superoleophobic cotton fabric is efficient in oil/water separation.•The underwater superoleophobic ...cotton fabric exhibited outstanding mechanical resistance.•The underwater superoleophobic cotton fabric showed excellent chemical resistance.
Superhydrophilic and underwater superoleophobic textiles exhibit excellent oil/water separation performance but are limited by the poor stability and environmental incompatibility. Inspired by strong adhesion of marine mussels, we designed and fabricated a stable and eco-friendly superhydrophilic and underwater superoleophobic cotton fabric (CF) from all renewable resources through in-situ surface deposition of polydopamine (PDA) particles followed by adsorption of hydrophilic chitosan via dip coating at room temperature. The as-prepared superhydrophilic and underwater superoleophobic CF exhibited outstanding oil/water separation performance with separation efficiency and water flux higher than 99 % and 15,000 L m−2 h-1, respectively. Moreover, it not only showed excellent resistance to mechanical abrasion and ultrasound treatment but also had outstanding superwetting stability against acid/alkali/salt erosion. We believed that the eco-friendly superhydrophilic and underwater superoleophobic CF would exhibit great potential in oil/water separation especially under harsh conditions.
Thermosets have many advantages such as excellent mechanical properties, dimensional stability, and chemical and environmental resistance, but suffer from unsustainability because they cannot be ...reprocessed, are difficult to recycle, and are overdependent on petroleum chemicals. Biobased covalent adaptable networks (CANs) represent a new type of crosslinking polymer derived from biomass-derived feedstocks and crosslinked by dynamic covalent bonds (DCBs). Biobased CANs provide an alternative solution to the sustainable development of traditional thermosetting polymers because they are not only not dependent on petroleum chemicals, but are also reprocessable and recyclable through the exchange reaction of DCBs under suitable conditions. Moreover, biobased CANs exhibit some other attractive functionalities such as self-healing, weldability, configurability, shape memory, and intelligent response. In such contexts, much effort has been devoted to designing and synthesizing biobased CANs from various biomass-derived chemicals such as vegetable oils, lignin and its derivatives, natural rubber, and sugars by incorporating various existing or designed DCBs, and notable progress has been achieved in this field. In this review, we summarize the recent progress on the design and synthesis of biobased CANs and suggest opportunities and challenges for their future development.
Thermosets have many advantages such as excellent mechanical properties, dimensional stability and environmental resistance, but suffer from unsustainability because they are difficult to recycle and overdependent on petroleum chemicals.
Despite the importance of stem cells in plant and animal development, the common mechanisms of stem cell maintenance in both systems have remained elusive. Recently, the importance of hydrogen ...peroxide (H2O2) signaling in priming stem cell differentiation has been extensively studied in animals. Here, we show that different forms of reactive oxygen species (ROS) have antagonistic roles in plant stem cell regulation, which were established by distinct spatiotemporal patterns of ROS‐metabolizing enzymes. The superoxide anion (O2·−) is markedly enriched in stem cells to activate WUSCHEL and maintain stemness, whereas H2O2 is more abundant in the differentiating peripheral zone to promote stem cell differentiation. Moreover, H2O2 negatively regulates O2·− biosynthesis in stem cells, and increasing H2O2 levels or scavenging O2·− leads to the termination of stem cells. Our results provide a mechanistic framework for ROS‐mediated control of plant stem cell fate and demonstrate that the balance between O2·− and H2O2 is key to stem cell maintenance and differentiation.
Synopsis
Superoxide regulates plant stem cell fate, and the balance between superoxide and H2O2 serves as a key switch for stem cell maintenance versus differentiation by antagonistically regulating expression of stem cell fate transcription factor WUSCHEL.
Superoxide specifically accumulates in plant stem cells to determine the stem‐cell fate.
H2O2 is enriched in the differentiating peripheral zone to promote plant stem cell differentiation.
Repression of superoxide dismutases and activation of peroxidases establishes the high superoxide and low H2O2 distribution patterns in plant stem cells.
H2O2 negatively regulates superoxide accumulation in stem cells by inhibiting key enzymes in superoxide anabolism.
The superoxide/H2O2 balance controls plant stem cell fate by antagonistically regulating WUSCHEL expression.
Superoxide regulates plant stem cell fate, and the balance between superoxide and H2O2 serves as a key switch for stem cell maintenance versus differentiation by antagonistically regulating expression of stem cell fate transcription factor WUSCHEL.
Vitamin D deficiency is a candidate risk factor for a range of adverse health outcomes. In a genome-wide association study of 25 hydroxyvitamin D (25OHD) concentration in 417,580 Europeans we ...identify 143 independent loci in 112 1-Mb regions, providing insights into the physiology of vitamin D and implicating genes involved in lipid and lipoprotein metabolism, dermal tissue properties, and the sulphonation and glucuronidation of 25OHD. Mendelian randomization models find no robust evidence that 25OHD concentration has causal effects on candidate phenotypes (e.g. BMI, psychiatric disorders), but many phenotypes have (direct or indirect) causal effects on 25OHD concentration, clarifying the epidemiological relationship between 25OHD status and the health outcomes examined in this study.
The substitution of petroleum-based self-healing elastomers with biobased counterparts is crucial to the global sustainable development of the rubber industry, which highly depends on the ease of the ...synthesis procedure. Herein, we show that highly stretchable, recyclable, and self-healable biobased elastomers were synthesized via condensation polymerization of succinic acid, adipic acid, sebacic acid, and 1,4-butanediol in the presence of a small amount of glycerol as a curing agent and 3,3′-dithiodipropionic acid as a dynamic covalent monomer. The macroscopic properties of our elastomers, including thermal, mechanical, stress relaxation, and self-healing performance, were finely regulated via microscopic chemical and topological structure. As such, a highly stretchable (up to ∼1700%), recyclable (almost without degradation of the mechanical performance over several repeats), rapid room temperature self-healable (in 20 min) biobased vitrimeric elastomer was achieved, which is the first aliphatic disulfide metathesis assisted self-healing polymer achieved at such low temperatures. The ease of the polycondensation with which the elastomers can be readily scaled up points to exciting opportunities for sustainable polymers with minimal environmental impact.
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