Totally found 4408 items.

  • [期刊] Simultaneous coupling of photocatalytic and biological processes: A promising synergistic alternative for enhancing decontamination of recalcitrant compounds in water
    Decontamination of water polluted with recalcitrant chemicals, such as phenolic and aromatic substances, for which conventional wastewater treatment processes are largely not effective, remains a major challenge all over the world. The simultaneous combination of photocatalytic and biological processes in a single system, either with or without the support of porous carriers, exhibits superior synergistic performance for removing refractory contaminants with the advantages of both photocatalysis and biotransformation. This promising emerging alternative, defined as simultaneous coupling here, has attracted increased attention and has been substantially developed over the last five years. To our best knowledge, this is the first critical review systematically focusing on the simultaneous coupling of photocatalytic and biological processes in enhancing decontamination of recalcitrants from water. The current review includes not only the synergy for pollutant oxidation/reduction removal and corresponding key factors affecting coupled systems, but also the underlying mechanisms of two different couplings in the interaction view of photocatalytic and biological responses. Last but not least, the challenges and opportunities faced by the coupling are pointed out. This review can provide useful information on the design and application of the synergistic coupling of chemical and biological processes for efficient and complete decontamination of recalcitrant compounds in water.
  • [期刊] Mixed oxidation of aqueous nonylphenol and triclosan by thermally activated persulfate: Reaction kinetics and formation of co-oligomerization products
    As two representative endocrine disrupting chemicals (EDCs), nonylphenol (NP) and triclosan (TCS) often coexist in water and wastewater. In this study, the mixed elimination of aqueous NP and TCS in thermally activated persulfate system was investigated in detail. The effects of the initial oxidant dosage, initial pH, and reaction temperature, as well as the presence of humic acid and coexisting anions and the water matrix on NP and TCS removal were evaluated. The results showed that the pseudo-first-order reaction rate constant of NP was higher than that of TCS in every case. In addition, the presence of TCS enhanced NP conversion, whereas the latter hindered the degradation of the former. A total of 23 intermediates were identified, and four pathways including hydroxylation, sulfate addition, cleavage of an ether bond and the single-electron coupling reaction were elucidated. Furthermore, numerous polymerization products formed by the self- and cross-coupling reactions of NP and TCS were discovered, and their abundance could be further improved under acidic conditions. Based on the density functional theory calculation, the energy barrier (Delta G) values of hydrogen atom extraction by (OH)-O-center dot from NP and TCS molecules to generate phenoxy radicals were just 4.37 and 12.70 kJ mol(-1), respectively, which was significantly lower than those of the other reaction pathways. Combined with the results of quenching tests, we proposed a single-electron coupling reaction induced by (OH)-O-center dot as the dominant route in the mixed system. These findings can provide useful information for the elimination of mixed EDCs in water and wastewater.
  • [期刊] Optimizing high voltage Na3V2(PO4)(2)F-3 cathode for achieving high rate sodium-ion batteries with long cycle life
    Sodium-ion batteries have gained an intense attention as a promising alternate for Li-ion batteries due to their low cost, and abundant availability. To meet high energy density requirements, developing a high voltage cathode with ultra-long cycle life is of great importance. Na3V2(PO4)(2)F-3 (NVPF) features a high working voltage, fast sodium-ion diffusion channels, and small volume change during the cycling process. However, the practical performance of NVPF cathode is currently hindered by poor Na+ ion diffusion at high voltage, low cycle life, and limited rate behavior. Herein, we evaluate the effect of synthesis conditions in sol-gel technique, binders (PVDF, PAI and CMC), and electrolytes (ether, and ester based solvents) to overcome the diffusion limitation in high voltage NVPF cathode. Benefiting from the synergistic effect of CMC binder, and DEGME electrolyte, and reduced graphene oxide composite, NVPF effectively overcome the potential barrier during Na+ ion insertion/extraction at high voltage. NVPF with CMC binder and DEGDME electrolyte displayed a high Na+ ion diffusion kinetics, low cell resistance, and delivered an excellent electrochemical performance. NVPF delivered a high coulombic efficiency (92%), long cycle life (10,000 cycles), and an excellent rate performance (50 C), outperforming the conventional PVDF binder, and carbonate based electrolytes. Furthermore, the full-cell constructed by NVPF cathode, and Na3V2(PO4)(3) anode delivered an capacity retention. The current study provides new insights for overcoming the kinetic barrier during sodium ion storage in high voltage cathode that could direct the research development towards high energy sodium-ion batteries.
  • [期刊] Biodegradable microspheres made of conductive polyorganophosphazene showing antioxidant capacity for improved bone regeneration
    Reactive oxygen species (ROS) are likely to accumulate around severe bone defects, which jeopardizes activities of surrounding cells and hampers new bone formation. An effective strategy to address this issue is to develop scaffolding biomaterials with both antioxidant and osteoinductive capacities. An aniline tetramer (AT) and glycine ethyl ester co-substituted polyorganophosphazene (PATGP) was synthesized, and expected to meet the demands, since the AT moieties were antioxidant and the phosphorus-rich phosphazene moieties were osteocompatible. Moreover, the AT endowed the PATGP with conductivity to match the electrophysiology of bone tissues. By applying in vitro cell culture and in vivo evaluations, microsphere-type scaffolds made of PATGP were systematically characterized on their capacities including ROS-scavenging effect, cytotoxicity and osteoinductivity, using non-conductive poly[(ethylalanato)(ethylglycinato)]phosphazene (PAGP) and poly(lactide-co-glycolide) (PLGA) microspheres as control groups. Among them, PATGP microspheres demonstrated the strongest promotion effects on up-regulating cellular activities and on speeding up neobone formation in rat calvarial defects. Compared to polyester-type biomaterials, in summary, polyorganophosphazenes demonstrated strong flexibility in functionalization by introducing supplementary features such as antioxidant activity and electroactivity, which made them to be quite efficient in enhancing osteogenesis.
  • [期刊] Fabrication of a novel type visible-light-driven heterojunction photocatalyst: Metal-porphyrinic metal organic framework coupled with PW12/TiO2
    Metalloporphyrinic metal-organic framework (PCN-222) is a promising photocatalytic material due to its large surface area and 1D channel, exceptional stability, high visible-light capture capability, and semiconductor properties. Herein, we constructed a highly efficient visible-light-driven type II heterojunction photocatalyst PCN-222-PW12/TiO2 by one step solvothermal method. The 5 wt% PCN-222-PW12/TiO2 showed the superior photocatalytic properties for degrading rhodamine B (RhB) and Ofloxacin, which are 10.69 and 10.48 times higher than pure TiO2 under same conditions. The excellent photocatalytic performance of PCN-222-PW12/TiO2 ternary composite material was attributed to the improved adsorption capacity of organic pollutants, optical absorption in the entire visible light region, and highly-efficient separation of photoinduced carriers. Besides, we found that h(+), center dot O-2(-), and center dot OH are the main active elements in the photocatalytic degradation process. This will back up the higher photocatalytic activity of PCN-222-PW12/TiO2 compared with pure TiO2. The photocatalytic efficiency of composite maintained a similar level of photoactivity after four times recovery, which showed excellent stability and recyclability of PCN-222-PW12/TiO2. This work provides new insights into the fabrication porphyrin-MOF composite materials with high photocatalytic efficiency for environmental remediation.
  • [期刊] Composite pesticide nanocarriers involving functionalized boron nitride nanoplatelets for pH-responsive release and enhanced UV stability
    With increasing global food demand, the production and protection of agricultural crops in safe and secure fashion has become a critical issue. Herein, we report a novel type of nanopesticide based on avermectin (AVM) and composite nanocarriers made from the functionalization boron nitride nanoplatelets (BNNP) with 3-mercaptopropyl trimethoxysilane (MPTMS) and poly(ethylene glycol) diacrylate (PEG). Such nanocarriers exhibit a high pesticide loading capacity (181.9 +/- 5.2 mg/g) due to their layered nanostructure and their favorable interactions with AVM molecules achieved through hydrophobic effect, p-p stacking, and electrostatic interactions. By changing pH from 7 to 11, the release kinetics could be transformed to a zero-order process from a first-order process, with about a two-to-three-fold increase in the release rate. The pH-responsive behavior was ascribed to hydrolysis of ester groups of PEG under alkaline conditions. These pesticide nanocarriers reduced the degradation rate of AVM against UV irradiation about 30%. In summary, novel nanopesticides based on BN composite nanocarriers opens new avenues for the delivery of hydrophobic pesticides in the field of agriculture and crop protection.
  • [期刊] Multifunctional injectable protein -based hydrogel for bone regeneration
    Protein plays an important role in the maintenance of osmotic pressure and binding and transportation of nutrients to cells, which is essential for the rapid regeneration of bone tissues. Bovine serum albumin (BSA) is the most abundant plasma protein in the body. Here, theBSA-based hydrogel was first developed through the thiolated bovine serum albumin (sBSA) employing the robust and reversible -SAg coordination, which owns injectable, self-healing and antibacterial properties for the treatment of bone defect regeneration. First, the BSA was treated with Traut's reagent to replace the primary amine groups of the lysine residue in its primary structure with thiol groups. Then, the thiolated BSA (sBSA) was added with silver nitrate to be crosslinked. -SAg coordination took place immediately when sBSA and silver were mixed and a shear-thinning hydrogel was thus produced. By adjusting the proportion of BSA, the mechanical properties of the hydrogels can be adjusted. Moreover, this novel protein-based hydrogel is bio-degradable and can slowly release silver ions to generate an antibacterial effect for P. gingivalis and F. nucleatum bacterial. Moreover, the protein-based injectable hydrogel has very good biocompatibility and bioactivity on promoting bone regeneration. As shown in this study, the in vitro experiments showed that the hydrogel effectively enhanced the osteogenesis differentiation of osteogenic precursor cells. And the in vivo study showed faster and better bone repair outcomes in large cranial defect rabbit model, in comparison to the commercially used spongious bone substitutes (Bio-OSS). Therefore, protein-based hydrogel is a very good promising material for bone regeneration.
  • [期刊] Optimization of three-phase fluidized bed cell disruptor for the release of alcohol dehydrogenase from baker's yeast
    A three-phase fluidized bed cell disruptor equipped with a multi-disk impeller was applied in the disruption of baker's yeast cells for the release of alcohol dehydrogenase (ADH). The performance of cell disruption was assessed by the kinetics of disruption contributed by different operation parameters. The operating conditions of cell disruption, including rotational and linear speed of impeller, cell mass concentration, percentage volume of glass bead, duration of operation, and rate of gas bubbling, were optimized by design of experiment method. Based on the first-order model derived using path of steepest ascent, it was found that the rotational and linear speed of impeller, cell mass concentration, and percentage volume of glass bead were the significant process parameters. The optimal values of these parameters were then predicted using central composite design of experiments. As predicted with a second-order polynomial model, the maximum release of ADH was achieved under the operating conditions: agitator speed of 5000 rpm, 25% (ww/v) of cell mass concentration, 1500 mL of glass bead, 10 L/min of gas bubbling and operating duration of 5 min. The maximum release of ADH obtained from the experiment under the optimal conditions was 329.8 U/min/dw-cell, which was close to the value of 331.2 U/min/dw-cell predicted by the response surface model.
  • [期刊] Hydrothermal carbonization of sewage sludge: Effect of aqueous phase recycling
    In this study, the aqueous phase produced from the hydrothermal carbonization (HTC) of sewage sludge (SS) with pure water was reused for the HTC of fresh SS, aiming to maximize energy recovery from the aqueous phase. The aqueous phase was recycled four times. The effects of aqueous phase recycling on the properties of the aqueous phase and hydrochar produced at temperatures of 200, 230, and 260 degrees C were studied. The hydrochar yield always decreased with increasing temperature regardless of whether the aqueous phase was recycled. The C and N contents and higher heating values of the hydrochars produced with aqueous phase recycling were all higher than that of the hydrochar produced with pure water and slightly increased as the number of recycling times increased. The O/C and H/C atomic ratios of the hydrochars revealed that dehydration was the main reaction pathway during HTC of SS. The pH value of the aqueous phase increased as the number of recycling times increased, indicating that the concentration of NH4+-N in the aqueous phase increased. The process of aqueous phase recycling affected the carbonization of the hydrochar. These results suggest that aqueous phase recycling was favorable for energy recovery from the aqueous phase produced from the HTC of SS and for improving the combustion properties of the hydrochar. Thus, we believe that aqueous phase recycling was a promising strategy for energy recovery, aqueous phase disposal, and the production of high-quality hydrochar with respect to the HTC of SS.
  • [期刊] Defect-rich carbon based bimetallic oxides with abundant oxygen vacancies as highly active catalysts for enhanced 4-aminobenzoic acid ethyl ester (ABEE) degradation toward peroxymonosulfate activation
    Meeting with severe environmental problems, highly efficient, environmental friendly and multiple reusable catalysts are demanding to develop. In this work, carbon based bimetallic oxides with oxygen vacancies were prepared toward peroxymonosulfate (PMS) activation for 4-aminobenzoic acid ethyl ester (ABEE) degradation. Among different molar ratios of ferrous ions and manganese ion, Fe1Mn1-Fe NC appeared optimum catalytic performance. The degradation of ABEE should contain free radical pathway and non-free radical pathway. All of sulfate radical, hydroxyl radical, superoxide radical and singlet oxygen were responsible for efficient degradation and mineralization of ABEE. Lattice oxygen was the main reactive site for ABEE degradation. Electron transport provided good synergistic redox reaction between Fe and Mn and promoted lattice oxygen released. New proposed pathway for ABEE degradation included electrophilic and radical addition, hydrogen abstraction reaction and diazotization. This work is expected to provide rational design of bimetallic materials with oxygen vacancy for in-situ environmental remediation.