Search

A porous self-supporting titanium sheet electrode embedded with Cu sites was constructed by anodic oxidation combined with hydrothermal/pyrolysis strategy, and high ammonia yield rate and near 100 % Faradaic efficiency were achieved in the electrocatalytic conversion of nitrate. [Display omitted] • Anodic oxidation tandem hydrothermal/pyrolysis embed Cu sites in porous titanium sheets. • Ammonia yield rate and FE as high as 7292.43 μg h−1 cm−2 and 97.34 %, respectively. • Cu/PTS can efficiently catalyze eNitRR in complex water environments. • Operando ATR-FTIRAS measurements reveal the evolution of NO 3 − to NH 3. • Nitrate hazard concentration can be reduced below the limit value of WHO and US EPA. Electrochemical nitrate reduction synthesis of ammonia can use clean energy to convert low-value nitrate pollutants into high value-added ammonia yield. The development of eNitRR catalyst with high activity, high selectivity and stability is the key to achieve distributed small-scale production of nitrate. In this study, a self-supported catalyst (Cu/PTS) with high catalytic activity (for eNitRR) was constructed by anodic oxidation combined with hydrothermal/pyrolysis strategy to realize the embedding of Cu species on the substrate of porous titanium sheet. The ammonia production rate of Cu/PTS catalyzed eNitRR is as high as 7292.43 μg h−1 cm−2 (−1.0 V vs. RHE), the Faradaic efficiency is close to 100 %, reaching 97.34 %, and isotope labeling and Operando ATR-FTIRAS verified and revealed the fact that NO 3 − to NH 3 , respectively. Density functional theory calculations well reveal the roles of various components in Cu/PTS and reveal the factors for the enhancement of eNitRR performance. Thanks to the self-supporting characteristics of porous titanium sheet and the surface embedding of copper species, Cu/PTS not only have good electrochemical stability when catalyzing eNitRR, but also can drive eNitRR to operate efficiently in complex water environment. While realizing the purification of nitrate wastewater and the synthesis of ammonia, Cu/PTS can be used as a positive electrode to construct a nitrate–zinc battery to realize the dual functions of self-driven ammonia production and external power supply. [ABSTRACT FROM AUTHOR]

• A microfluidic platform is provided for observing Zn-anode under different operational situations. • The impacts of shear stress and discharging current density on Zn-anode are studied. • The microfluidic zinc-air battery delivers a substantially high power density. With the evolving demands towards the ever-growing portable and wearable electronics, Zn-air battery (ZAB) has attracted considerable attention as their higher energy density and abundant material reservations compared with other electrochemical energy-conversion systems. Herein, we provide an effective and powerful microfluidic platform for ex-site observing the zinc electrode variation in the electrolytes under different operational situations. The power generation properties of microfluidic ZAB (μZAB) are facilely controlled via the microfluidic flow control. The device delivers the maximum power density of 194 mW/cm2 at the current density of 242 mA/cm2, outperforming previously reported power supplies with similar working volume. More importantly, the combination of ZAB with microfluidic control provides a platform to study the impacts of laminar shear stress and discharging situation on the zinc-electrode behaviors. It indicates on the condition of limited laminar shear stress at zinc anode surface, as the laminar shear stress increases, the passivation of zinc anode is reduced. The amount of zinc oxide deposition on the electrode surface decreases with the increasing of laminar shear stress, and the power-generation property is obviously improved. The zinc anode can expose a large amount of active area during the discharge process. When the laminar shear stress is greater than 120 dyn/cm2, the increase of laminar shear stress has no obvious effect on the reduced passivation anymore. It demonstrates the potential of utilizing microfluidic tool to screen and optimize the operational environments of zinc-electrode in flow battery and fuel cell. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pulsed electric field treatment significantly enhanced pepsin activity (65 %). • Novel proteolytic membrane was prepared with PEF-treated pepsin. • PAPM showed a better hydrolysis performance (25%) compared to PM. • The α-helix and β-sheet contents in PAPM were increased by 3.13 and 9.63%. • Heterogeneous charge interactions contribute to promoting the protein hydrolysis of PAPM. Although the immobilization of enzymes on the membrane is an effective method to improve enzyme stability and reusability, the immobilized enzyme also causes low activity and reduces substrate accessibility. In order to overcome these shortcomings and provide a viable proteolytic membrane with increasing enzyme activity and substrate accessibility, a pulsed electric field (PEF)-assisted proteolytic membrane (PAPM) was constructed by immobilizing PEF-treated pepsin on PDA and PEI co-deposited ultrafiltration membrane. The PEF-treated pepsin endowed high activity (165.33 ± 2.31 %) and charge amount (−3.95 mV), with stable and uniform particle size (39 nm). These phenomena were attributed to the multiple effects driven by PEF, including the diffusion effect, electrolysis reactions, and microstructural regulation. Specifically, PAPM retained 80 % of original pepsin activity and enhanced 25 % pepsin activity compared to the conventional proteolytic membrane (PM). Such improvement can be ascribed to two factors: Firstly, PEF regulated pepsin microstructure to an optimal structure (4.6 % increase of the α-helix and 4.0 % reduction of the random coil) for pepsin immobilization. Secondly, PEF changed pepsin charge properties from positive (+1.62 mV) to negative (−3.95 mV), while substrate charges were positive. Heterogeneous charge interactions between pepsin and substrates increased the accessibility of the substrate to immobilized pepsin, effectively promoting enzymatic reactions. This study offers a feasible method to prepare the proteolytic membrane in protein hydrolysis. [ABSTRACT FROM AUTHOR]

• Structural, thermodynamic and electronic properties of three Ca x Al y O z were analyzed. • Ca x Al y O z were thermodynamically stable and O–Al bonds dominated crystal stiffness. • Ca 4 Al 6 O 13 had the most negative cohesive energy and formation enthalpy. • O and Ca atoms of Ca x Al y O z contributed mostly to the reactivity for CaO adsorption. • Adsorption energies of CaO on Ca x Al y O z were at least 2 times higher than that on CaO. Calcium looping has been recognized as a key technology for both CO 2 capture and concentrated solar energy storage. The inert support is significant in improving the sintering-resistance of CaO-based materials. This paper provided a comprehensive study of structural, thermodynamic and electronic insights into calcium aluminates as supports for CaO by density functional theory (DFT) calculations. Thermodynamic stabilities of three phases including Ca 3 Al 2 O 6 , Ca 12 Al l4 O 33 and Ca 4 Al 6 O 13 were investigated and the adsorption parameters (energies and electronic properties) of CaO binding with calcium aluminates were determined. The results show that Al-O bonds play dominant roles in determining the crystal strength of Ca x Al y O z. The phonon dispersions show that three Ca x Al y O z are dynamically stable. Ca 4 Al 6 O 13 has the more negative cohesive energy and formation enthalpy than Ca 3 Al 2 O 6 and Ca 12 Al l4 O 33. O and Ca atoms of Ca x Al y O z contribute mostly to the reactivity for CaO adsorption, which is related to the degree of freedom of O atoms in Ca x Al y O z. The adsorption energies of CaO on Ca 3 Al 2 O 6 , Ca 12 Al l4 O 33 and Ca 4 Al 6 O 13 are −5.12 eV, −4.27 eV and −3.83 eV, which are more than 2 times higher than that of pure CaO. The corresponding charge transfers (0.34 e, 0.34 e and 0.15 e) from CaO to Ca x Al y O z surfaces are larger than that in pure CaO. The interaction of CaO and Ca x Al y O z results in electron redistribution around O sites, which may slightly affect further CO 2 adsorption reactivity. The higher average bond populations of AlO 4 skeleton with adsorbed CaO indicate that Ca x Al y O z with superior refractory properties are good supports for CaO. The study furnishes information for calcium aluminates-supported CaO and provides evidence for further research on composite CaO-based materials with high reactivity and novel properties. [ABSTRACT FROM AUTHOR]

• A NIR phosphor GLGA:Cr3+ was successfully prepared. • The NIR phosphor exhibits high IQE/EQE and low thermal quenching behavior. • The emission spectrum of GLGA:Cr3+ fits well with the absorption band of P FR. • The NIR pc-LED shows superior photoelectric conversion efficiency and output power. • The NIR pc-LED device has an obvious positive effect on biomass of pea seedlings. Far-red/phytochrome (P FR) plays a key role in photomorphogenesis of plants. However, how to obtain a near-infrared (NIR) emitting phosphor with high external quantum efficiency (EQE), suitable spectral profile, and low thermal quenching remains a huge challenge. Herein, a NIR phosphor, Gd 2.4 Lu 0.6 Ga 4 AlO 12 :Cr3+,H 3 BO 3 (GLGA:Cr3+) was developed via regulating the crystal field environment and adding fluxes, which exhibits a peak maximum at 728 nm with a relatively narrow full-width at half maximum (FWHM) of 107 nm, matching well with the absorption band of P FR. Upon 450 nm excitation, the internal quantum efficiency (IQE) and EQE of the optimal phosphor are 90.3% and 32.0%, respectively. At 423 K, the integrated emission intensity of the investigated phosphor is about 75% of that at room temperature. Benefiting from the excellent optical performance, a NIR phosphor-converted light-emitting diode (pc-LED) was fabricated, which shows a NIR output power of 505.99 mW and photoelectric conversion efficiency of 11.24% at 300 mA. Moreover, plant growth experiments demonstrate that the biomass of pea seedlings is increased by 67.72% under supplementary NIR light irradiation. The findings of this research will motivate further research on new Cr3+-doped NIR phosphors for regulating photomorphogenesis of plants. [ABSTRACT FROM AUTHOR]

The complexation confinement and in-situ crystallization strategies realized the effective anchoring of single atom Co in nitrogen-doped hollow carbon nanotubes, close to 100% elimination of tetracycline pollutants while achieving a record mineralization rate of 89.07%. [Display omitted] • Complexation confinement and in-situ crystallization confinement to fabricate single-atom Co. • The removal rate of tetracycline is close to 100% and the mineralization rate reached a record of 89.07% • Multiple perspective reveals the mechanism of ROS production and tetracycline degradation. • Graphite nitrogen regulates cobalt microenvironment to promote activation of PMS. Advanced-oxidation-process (AOPs) based on peroxymonosulfate (PMS) can provide strong reactive oxygen species (ROS) for the elimination of persistent-organic-pollutants (POPs), but the input of highly active environmentally friendly catalysts is the key. Here, confined cobalt was in-situ deposited on natural mineral halloysite nanotubes by Coulomb interaction, which further realizes the introduction of atomically-dispersed cobalt sites in nitrogen-doped hollow-carbon-nanotubes with large specific surface area. The constructed CoNC/NHCNTs-900 material can effectively activate PMS, resulting in the removal rate of tetracycline probe pollutants close to 100%, and the mineralization rate reached a record of 89.07%. Combined with density functional theory calculations, it was proved that the enrichment of graphite nitrogen is beneficial to regulate the microenvironment of Co and promote the adsorption and activation of PMS. In-depth tracking of the formation of ROS and the mechanism of tetracycline mineralization proved that CoNC/NHCNTs-900-driven AOPs degradation of POPs into a low-toxic species has reliability and practical significance. [ABSTRACT FROM AUTHOR]

In a TiO 2 /Chlorophyll and microalgae hybrid semi-artificial photosynthetic system, Q 0 is proved as electron relay that helps electron transmission from abiotic component to microalgae for amplifying N 2 fixation ability. Furthermore, TiO 2 /Chlorophyll is applied as anode material and microalgae is dispersed in catholyte, as for building a microbial photo-electrolysis cells that can produce 122.62 μg/h of ammonia. [Display omitted] • TiO 2 /Chlorophyll annealed at 400 °C shows visible light response catalysis. • The photogenerated electrons of the TiO 2 -400 °C are captured by Chl-400 °C. • Q 0 effectively relays photogenerated electron from Chl-400 °C to microalgae. • In the material-cell system, the activity of nitrogenase increased by 5.90 times. • The top ammonia content was up to 122.62 μg/h, determined by an ammonia assay kit. Significant process has been made on the development of semi-artificial photosynthesis catering to the production of H 2 – and CO 2 – derived value-added products. But there are little reports on the application of semi-artificial photosynthetic system to nitrogen fixation areas. In this study we report the successful and highly efficient N 2 fixation in one step at room temperature and ambient pressure by constructing new semi-artificial photosynthetic systems based on material-cell hybrids and microbial photo-electrolysis cells (MPECs). Improved TiO 2 /Chlorophyll composite that annealed at 400 °C was selected as electron donator to replenish additional electrons to Nostoc commune Vauch microalgae cell for N 2 fixation. Ubiquinone-0 (2,3-dimethoxy-5-methyl-1,4-benzoquinone, Q 0) was selected as electron relay that guarantees efficient transmission of electrons from abiotic material to microalgae cells. Determined by an ammonia assay kit, at constant concentration of microalgae, the constructed material-cell hybrid system photosynthetically synthesized 40.67 μM/h ammonia, while H-shape MPECs synthesized 132.70 μM/h, 19.23 times higher than that produced by pure microalgae. Using 15N 2 as the reduction gas, the constructed H-shape MPECs photosynthetically synthesized 28.37 μM/h 15NH 4 +, 2.80 time higher than that of the MPECs without Q 0 as electron relay. [ABSTRACT FROM AUTHOR]

Through the chelation effect of 1,10-phenanthroline and the spatial confinement effect of polydopamine-derived nitrogen-doped hollow carbon spheres, sub-nanometer-scale copper active species were constructed, which realized the electrochemical reduction of nitrate to ammonia in a complex water environment and purified nitrate wastewater. [Display omitted] • Double confinement mechanism realizes sub-nanometer-scale copper preparation. • Ammonia yield rate and FE as high as 21413.5 μg h−1 mg cat. −1 and 92.07%, respectively. • CuCN/NHCSs can efficiently catalyze eNitRR in complex water environments. • Nitrate hazard concentration can be reduced below the limit value of WHO and US EPA. Electrochemical-nitrate-reduction-reaction (eNitRR) ammonia synthesis shows the vision of green ammonia synthesis and is also an effective way to purify nitrate wastewater. In this study, the complex of 1,10-phenanthroline and Cu2+ was adsorbed on the surface of polydopamine-derived nitrogen-doped-hollow-carbon-spheres, and sub-nanometer-scale copper species (CuCN/NHCSs) were obtained after heat treatment. Using CuCN/NHCSs as catalyst, the ammonia yield rate and Faradaic efficiency of eNitRR reached 21413.5 μg h−1 mg cat. −1 (−1.1 V vs RHE) and 91.08% (−0.9 V vs RHE), respectively. CuCN/NHCSs still have high catalytic activity for eNitRR even in complex water environments (such as acidity, alkalinity, coexisting ions). In the face of low concentration of nitrate in natural sewage, CuCN/NHCSs as a catalyst can reduce the concentration of NO 3 − to below the limits set by WHO and US EPA within 10 h, and achieve effective purification of nitrate sewage. DFT calculations show that both single-atom Cu sites and Cu atom cluster sites on NHCSs can promote the electrochemical conversion of NO 3 − to ammonia, so minimizing copper sites can maximize the unit activity. Furthermore, the simultaneous anchoring of Cu atom clusters and single-atom Cu in the carbon matrix is beneficial to lower the energy barrier of the potential-determining step of eNitRR. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-type ZnO/TiO 2 and p-type pTTh/CuO x photoelectrodes are prepared for promoting the kinetics of OER and ORR. • A novel PRZAB is fabricated by ZnO/TiO 2 and pTTh/CuO x to sandwich a Zn electrode. • The PRZAB achieves an ultra-low charge voltage of 0.63 V and a remarkably high discharge voltage of 1.64 V. • The overall solar-to-output energy conversion efficiency (SOEE) of the PRZAB turns out to be 1.38%. Traditional Zn-air batteries (ZABs) require a large charge voltage but deliver a small discharge voltage due to their slow kinetics of oxygen evolution and reduction reaction (OER and ORR) on air electrodes. Herein, a novel photorechargeable Zn-air battery (PRZAB) is fabricated by two photoelectrodes to sandwich a Zn electrode, significantly promoting the kinetics of OER and ORR. As a result, the PRZAB achieves an ultra-low charge voltage of 0.63 V and a remarkably high discharge voltage of 1.64 V at a current density of 0.1 mA cm−2, leading to a considerable voltage gap of 1.01 V that the process of discharge exceeds charge to be realized in ZABs. Compared with the ZAB with a state-of-the-art Pt/C catalyst, the charge energy of the PRZAB is saved 184% and its output is enhanced by 18%. Finally, the overall solar-to-output energy conversion efficiency (SOEE) is estimated to be 1.38%. The work provides an innovative way to boost rechargeable battery performance and offers an efficient strategy to store and utilize solar energy. [ABSTRACT FROM AUTHOR]

[Display omitted] • PCMC can start up, maintain and recover PN under adverse condition for up to 157 d. • PCMC changed EPS content and structure, and it inhibited NXR more than AMO. • The increased number and succession oligotypes of Nitrosomonas ensured stable PN. • The reduction of Nitrospira and Nitrobacter were vital for stable PN. • PCMC was a safe PN inhibitor due to the ability to reduce numerous ARGs. The p-chloro-m-cresol (PCMC) is a versatile preservative with extensive appliance in various pharmaceutical personal care products. In this study, PCMC in-situ anaerobic soaking of activated sludge was implemented to initiate, maintain and restore partial nitrification (PN). The optimal treatment condition was 80 mg/L PCMC and 30 h exposure time, which stably sustained PN for up to 157 days. Results showed that PCMC had a great influence on the content and secondary structures of extracellular polymeric substances, thus enhanced the aggregation and tolerance of bacteria to PCMC. The molecular docking simulation illustrated that PCMC achieved long-term PN by inhibiting nitrite oxidoreductase. The microbial community results showed that PCMC had a stronger inhibitory effect on nitrite oxidizing bacteria, and ammonia oxidizing bacteria was enriched in both quantity and oligotypes which could adapt to PCMC. Meanwhile, PCMC can obviously block the enrichment of some resistance genes without increasing resistance gene transmission burden of system. PCMC is a novel and promising PN inhibitor. [ABSTRACT FROM AUTHOR]

[Display omitted] • Peroxymonosulfate could remove antibiotic resistant bacteria and genes efficiently. • Peroxymonosulfate could work in a wide pH and ambient temperature range. • Peroxymonosulfate could destroy the structural and functional integrity of cells. • Peroxymonosulfate changed the expression of mRNA including conjugative genes. • Peroxymonosulfate is low-cost, easy operation and engineering applicability. As the emerging contaminants, antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have caught considerable research attention, horizontal gene transfer is one of the most primary contributors to antibiotic resistance dissemination. The application of the oxidant peroxymonosulfate (PMS) as a disinfection alternative has been systemically explored. Also, the effects of various process parameters on ARB inactivation and plasmid-mediated horizontal transfer inhibition, initial bacterial concentration, pH value and temperature, were systemically investigated. The changes in cell substances (cell membrane integrity and intracellular reactive oxygen species) were determined by flow cytometry. The results suggested that the inactivation efficiency of Escherichia coli DH5α (donor) and Pseudomonas sp. HLS-6 (recipient) by 0.8 mM PMS treatment reached 4.45 log and 4.15 log in 30 min, respectively. The conjugative transfer didn't arise after treatment for only 1 min when the dosage of PMS exceeded 0.4 mM. PMS could work in a wide pH and ambient temperature range. It also showed significant removal efficiency on intracellular ARGs and extracellular ARGs. To identify the underlying mechanisms of restraining conjugative transfer, the mRNA expression of conjugative genes, oxidative stress genes, save our souls (SOS) response-related gene, cell outer membrane proteins genes and global regulatory genes were evaluated. The results demonstrated that the expressions of these genes were altered by 0.8 mM PMS treatment. PMS has the advantages of low cost, easy operation and technical applicability. This study illustrated that PMS treatment showed great potential for controlling the antibiotic resistance for wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • PN/A-SAD coupling system was successfully achieved within only four days at 25 °C. • TNRE increased from 66% in PN/A phase to more than 90% in PN/A-SAD coupling phase. • AOB, AnAOB and SOB were enriched with the inhibition of NOB during SAD coupling. • SAD eliminated heterotrophic denitrifiers that might be potential hosts of ARGs. • PN/A-SAD coupling system reduced the risks of the ARGs and MGEs dissemination. Partial nitrification/anaerobic ammonium oxidation (anammox) (PN/A) was considered as an economically beneficial and environmentally friendly biological nitrogen removal process. The elimination of nitrate produced by PN/A system was the key to improving the total nitrogen removal efficiency (TNRE) of the system under mainstream conditions. In this study, the feasibility of the coupling S(0)-driven autotrophic denitrification (SAD) with PN/A in a single sequencing moving bed biofilm reactor (SMBBR) at room temperature was explored. Additionally, biological treatment process is ideal environments for the emerge and spread of emerging pollutants antibiotic resistance genes (ARGs), therefore, the shifts of ARGs in the system were investigated. After the coupling of PN/A and SAD, SMBBR was steadily operated with high TNRE. Nitrite-oxidizing bacteria (Nitrospira and Candidatus Nitrotoga) and nitrite oxidoreductase enzyme were inhibited by SAD process. And anammox bacteria were enriched, especially oligotype GAGTTTAAT of Ca. Brocadia. Sulfurimonas became the predominant autotrophic denitrifier. Heterotrophic denitrifiers Thauera and Dechloromonas were elutriated out from the system during the coupling of PN/A and SAD process, and they might be potential hosts for ARGs, leading to the decrease of ARGs. Overall, this study proposed a new strategy that SAD could promote the TNRE of PN/A and cut the risks of ARGs propagation, and PN/A-SAD coupling system was a biological nitrogen removal technology with promising applications under mainstream conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The inhibitory effect of QACs on denitrification ranked: BAC > ATMAC > DADMAC. • Inhibition of QACs on denitrification might relate to the reduction of Thauera. • QACs caused a significant decrease in ROS and CCK and inhibited EPS secretion. • QRGs abundance in both sludge and water all increased under shock loads of QACs. • High concentration BAC boosted greatly in wi-MGEs, wi-ARGs, we-ARGs and we-QRGs. The wastewater containing high quaternary ammonium compounds (QACs) concentrations from hospitals and other sources may cause the transient shock loads on the wastewater treatment plants (WWTPs). Denitrification is the key part of nitrogen removal from wastewater, however, the effects of QACs on the denitrification and the spread patterns of intracellular and extracellular resistance genes were still unknown. The short-term stress of three frequently detected QACs on denitrification were systematically investigated in this study. The inhibitory effect on nitrate removal had the following rules: BAC C12 > ATMAC C12 > DADMAC C12. The inhibition of QACs on denitrification performance was correlated with the reduction of Thauera abundance, and a higher QACs concentration made stronger inhibitory effect. Moreover, high concentrations of QACs could cause a significant decrease in reactive oxygen species, inhibit cell activity and extracellular polymeric substances secretion. Furthermore, QACs stimulated an overall increase of intracellular and extracellular QACs resistance genes in denitrification systems, both in sludge and in water. And co-selection among resistance genes occurred under shock loads of QACs, especially a high BAC C12 concentration caused a substantial raise in abundances of resistance genes in water. It was worth noting that resistance genes in sludge and water were mainly contributed by different bacteria. Rhizobium and Pseudomonas may be the potential hosts contributed to resistance genes in sludge while Thauera mainly contributed to that in water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Elastic brushite/polyethyleneimine/nanofibrillated cellulose aerogel was developed. • The coupling of brushite and polyethyleneimine enhanced adsorption property. • PNFCA/BRU-0.2 exhibited high selectivity for Cu(II) with 332.66 mg/g. • The continuous flow purification of copper-containing wastewater was realized. • PNFCA/BRU-0.2 could block the toxicity of heavy metals to crops. To achieve efficient removal of copper(II) from heavy metal wastewater, designing an eco-friendly and low-cost adsorbent is highly desirable. Here, a novel air- and underwater shape-memory cellulose aerogel was reported via coupling brushite and polyethyleneimine (PEI)-modified nanofibrillated cellulose (NFC) for selectively adsorbing Cu(II) ions. The adsorption kinetic and isotherm studies were consistent with pseudo-second-order model and Langmuir model, indicating the removal of Cu(II) was a monolayer chemisorption process. Benefiting from the open three-dimensional (3D) framework structure and abundant exposed active sites, such compressible aerogel exhibited excellent adsorption capacity of 332.66 mg/g for Cu(II). In addition, the developed aerogel could be conveniently used as a continuous flow filter for successive purification of industrial wastewater, where the up-to-standard treatment volume was about 5.6 L. The Cu(II)-loaded aerogel could be regenerated after being eluted by 0.1 M EDTA-2Na, and its structure, shapeability and selective adsorption properties were hardly affected even after 8 consecutive cycles. Mechanistic analysis confirmed that the surface complexation, ion exchange and chemical deposition were the main driving forces for the superior adsorption performance. Finally, PNFCA/BRU could inhibit the contamination of crops by heavy metals, which was a great safeguard for wheat growth. [ABSTRACT FROM AUTHOR]

[Display omitted] • SA/PEI-0.25 aerogel showed high elastic, stability and adsorption performance. • The maximum adsorption capacities of Cr(VI) and Cd(II) were 678.67 and 464.23 mg/g. • The fixed-bed continuous filtration of Cr(VI) and Cd(II) wastewater was realized. • SA/PEI-0.25 aerogel reduced the toxicity of heavy metal ions to rice. • The adsorption mechanisms of Cr(VI) and Cd(II) were investigated. Herein, an elastic polyethyleneimine/sodium alginate aerogel was designed by a one-step freeze-drying method. The 3D honeycomb-like structure endowed it excellent compressibility and plentiful exposed adsorption sites to accelerate Cr(VI) and Cd(II) adsorption. The adsorption processes matched the pseudo-second-order and Langmuir models, and the saturated adsorption capacity for Cr(VI) and Cd(II) was 678.67 and 464.23 mg/g, respectively. The obtained aerogel still expressed superior removal performance for Cr(VI) and Cd(II) even in the coexistent of multiple interfering factors and maintained stable adsorption capacity at least after 5 cycles. Importantly, the elastic cylindrical aerogel (∼0.59 g) could achieve dynamic filtration of industrial wastewater containing Cr(VI) and Cd(II) in fix-bed column system with corresponding effective treatment volume of 4.47 and 3.25 L, respectively. The reasonable mechanisms for the adsorption behaviors of heavy metals on the as-prepared aerogel was investigated via FTIR, XPS and Density functional theory (DFT), which could be attributed to the surface electrostatic adsorption, chelation and reduction effects. Eventually, the ecological assessment verified that eco-friendly SA/PEI aerogel had a powerful auxiliary effect on the anti-fouling growth of rice. Overall, such novel biomass aerogel adsorbent possessed great application potential and theoretical guiding significance for the purification of heavy metal wastewater. [ABSTRACT FROM AUTHOR]

Through high temperature dehalogenation/polymerization process, a new class of green-emitting silanized carbon dots (Si-CDs) featuring ultrahigh photoluminescence quantum yield (PLQY) is developed. The mechanism of improving the PLQY of Si-CDs mainly includes two steps. Firstly, the dehalogenation process can alleviate the spin–orbit coupling (SOC) effect of heavy-atom-rich organic fluorophores with severe intersystem crossing through high temperature hydrothermal reaction, meanwhile the possibility of transition from excited state (S 1) to triplet state (T 1) in the Si-CDs is significantly reduced, thus enhancing the fluorescence intensity and prolong fluorescence lifetime of Si-CDs. Besides, multiple fluorescent emitters can be integrated into one nano dot to effectively enhance the emission intensity in a single nano dot level by cross-linking polymerization. Moreover, Si-CDs can be used as fluorescent nanoprobes, which can rapidly and universally label dead cells, thus fast discriminate live/dead cells. [Display omitted] • Ultrabright green Si-CDs with small size and robust photostability was obtained. • Enhanced the fluorescence intensity by alleviates the spin–orbit coupling effect. • Enhanced the emission intensity by integrating multiple emitters into one nanodot. • Si-CDs can be applied in fast discriminating live/dead cells. Developing high-performance carbon dots (CDs) with high photoluminescence quantum yield, excellent stability, and good biocompatibility as well as explore the related luminescence mechanism is still an urgent problem to be solved at present. Herein, we develop a new class of green-emitting silanized carbon dots (Si-CDs) featuring average size of ~ 2.8 nm, ultrahigh photoluminescence quantum yield of ~ 93%, robust photostability, and low cytotoxicity by high-temperature dehalogenation/polymerization process. Our experiments verify the dehalogenation process can alleviate the spin–orbit coupling (SOC) effect of heavy-atom-rich organic fluorophores with severe intersystem crossing through high-temperature hydrothermal reaction, meanwhile, the possibility of transition from the excited state (S 1) to triplet state (T 1) in the Si-CDs is significantly reduced, thus enhancing the fluorescence intensity and prolong fluorescent lifetime of Si-CDs. Besides, multiple fluorescent emitters can be integrated into one nanodot to effectively enhance the emission intensity by cross-linking polymerization. Owing to good optical properties of the obtained Si-CDs, when used as fluorescent nanoprobes, Si-CDs can rapidly and universally label dead bacteria, fungi, and mammalian cells, which can meet the needs of green fluorescent nanoprobes for specific imaging of dead cells, so as to fast discriminate live/dead cells. We believe that Si-CDs with excellent optical performance, ultrasmall particle size, and low cytotoxicity can be applied to the fields of biological imaging, optical devices, and anti-counterfeiting. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrabright Red carbon dots are dominated by surface state emission mechanism. • Oxidation-induced quenching mechanism of ultrabright red carbon dots. • Constructing antioxidant RCDs/PVA film to convert yellowish green light to red light. • The film for practical agricultural planting can improve the biomass of plants. Red emissive carbon dots (RCDs) dominated by surface state emission mechanism were prepared by one-step hydrothermal method, the photoluminescence quantum yield (QY) of RCDs reaches to 78.3% in N,N-Dimethylformamide (DMF). RCDs mainly absorb UV and yellowish green light and emit red light in the region from 550 to 800 nm, which perfectly matches the light needed by plant for photosynthesis. Besides, the fluorescence quenching of RCDs is ascribed to oxidation on the surface of RCDs by oxygen. Further evidences about that are obtained from the changes in fluorescence, singlet oxygen (1O 2) signal of RCDs and the amount of O elements between the RCDs and quenched RCDs (QCDs). Antioxidant RCDs/PVA film, served as an agricultural sunlight conversion film, consisting of RCDs, polyvinyl alcohol-1799 (PVA-1799) and ascorbic acid, not only converts yellowish green light (500–610 nm) to red light (610–800 nm) from RCDs with tough, environment-friendly, waterproof properties from PVA-1799, but also gain antioxidant ability on account of ascorbic acid preventing the antioxidant RCDs/PVA film from fluorescence quenching. When antioxidant RCDs/PVA film was applied to the practical agricultural planting, the fresh weight, dry weight and the chlorophyll a content of the mung bean sprouts increased by 10.4% and 13.9%, and 7.1%, respectively. The application of the antioxidant RCDs/PVA film improve the utilization rate of solar energy in agricultural field. [ABSTRACT FROM AUTHOR]