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TiO2 nanotubes co-doped with iron and nitrogen were successfully synthesized with commercial TiO2 powders (CTPs) using a one-step hydrothermal method. The morphology, structure and composition of the as-prepared nanotubes were characterized using transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis), photoluminescence (PL) spectroscopy and Raman spectroscopy. The photocatalytic activities of the samples are evaluated for the degradation of tannic acid (TA, 25 mg L−1) in aqueous solutions under visible light (λ > 420 nm). The results of TEM suggest that all the samples present a diameter of approximately 9 nm and a length of approximately 200–600 nm. The results of XRD suggest that the predominant phase of all the as-prepared samples was the anatase crystal. The XPS results indicate that Fe and N were successfully introduced into the TiO2 nanotubes (TNTs). Compared with the CTPs and pure TNTs, the Fe and N co-doped TiO2 nanotubes (Fe/N-TNTs) exhibit a stronger visible-light absorption capability, and an enhanced photocatalytic activity toward the photodegradation of TA aqueous solution under visible-light irradiation. Notably, the xFe/N-TNT catalysts can be easily recycled due to their one-dimensional nanostructural properties.

A novel Pt/ACF (Pt supported on activated carbon fibers) electrode was successfully prepared with impregnation and electrodeposition method. Characterization of the electrodes indicated that the Pt/ACF electrode had a larger effective area and more active sites. Electrochemical degradation of ethylenediaminetetra-acetic acid (EDTA) in aqueous solution with Pt/ACF electrodes was investigated. The results showed that the 3% Pt/ACF electrode had a better effect on EDTA removal. The operational parameters influencing the electrochemical degradation of EDTA with 3% Pt/ACF electrode were optimized and the optimal removal of EDTA and chemical oxygen demand (COD) were 94% and 60% after 100 min on condition of the electrolyte concentration, initial concentration of EDTA, current density and initial value of pH were 0.1 mol/L, 300 mg/L, 40 mA/cm2 and 5.0, respectively. The degradation intermediates of EDTA in electrochemical oxidation with 3% Pt/ACF electrode were identified by gas chromatography-mass spectrum (GC-MS).

This study was inspired by the unique multi-scale and multi-level ‘brick-and-mortar’ (B&M) structure of nacre layers. We prepared the B&M, environmentally-friendly graphene oxide-carrageenan (GO-Car) nanocomposite films using the following steps. A natural polyhydroxy polymer, carrageenan, was absorbed on the surface of monolayer GO nanosheets through hydrogen-bond interactions. Following this, a GO-Car hybridized film was produced through a natural drying process. We conducted structural characterization in addition to analyzing mechanical properties and cytotoxicity of the films. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses showed that the nanocomposite films had a similar morphology and structure to nacre. Furthermore, the results from Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Thermogravimetric (TG/DTG) were used to explain the GO-Car interaction. Analysis from static mechanical testers showed that GO-Car had enhanced Young’s modulus, maximum tensile strength and breaking elongation compared to pure GO. The GO-Car nanocomposite films, containing 5% wt. of Car, was able to reach a tensile strength of 117 MPa. The biocompatibility was demonstrated using a RAW264.7 cell test, with no significant alteration found in cellular morphology and cytotoxicity. The preparation process for GO-Car films is simple and requires little time, with GO-Car films also having favorable biocompatibility and mechanical properties. These advantages make GO-Car nanocomposite films promising materials in replacing traditional petroleum-based plastics and tissue engineering-oriented support materials.

Robust, high-strength and environmentally friendly antibacterial composite films were prepared by simply blending konjac glucomannan (KGM) and silver nanowires (Ag NWs) in an aqueous system. The samples were then characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravimetric analysis, mechanical property tests, Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS) and antimicrobial tests. The results showed that there was a high ratio of Ag NWs uniformly distributed in the composite films, which was vital for mechanical reinforcement and stable antibacterial properties. The enhanced thermal stability and mechanical intensity increased, while the elongation at break was reduced with an increase in the amount of Ag NWs found in the composite films. When the percentage of Ag NWs in the composite films reached 5%, the tensile strength was 148.21 MPa, Young's modulus was 13.79 GPa and the ultimate strain was 25.28%. Antibacterial tests showed that the KGM films had no antibacterial effect. After the addition of Ag NWs, the composite films had an obvious inhibitory effect on bacteria, with the uniform dispersion of Ag NWs promoting the antibacterial effect to a certain degree. These results indicated that these composite films would have a potential application in the fields of environmentally friendly packaging or medicine.

The coatings of microorganism-induced calcium carbonate onto the stone surface carried out by using both of the immersion method and coating method were investigated. Various analysis and testing techniques such as scanning electron micrograph (SEM) and X-ray diffraction (XRD) were used to characterize the deposited mineral layer. The adhesive property, acid resistance, frost resistance, light and aging resistance, water adsorption and permeability were investigated in detail. The results showed that both immersion method and coating method could produce calcium carbonate granules with sizes ranging from 1 to 10 μm and form a layer of dense mineralization membrane which is about 50 to 100 μm thick. Immersion method was more efficient than coating method. The large cohesive force between calcium carbonate layer and stone materials could improve the acid rain resistance as well as excellent heat tolerance, frost resistance and light aging resistance. The coating process could not only help the stone materials maintain its original permeability with the aid of calcium carbonate layers but also improve the penetration resistance significantly. Therefore, this type of technology shows a great potential in the protection of stone relics.

In this paper, the microprism reflective structure is optimized by theoretical research and simulation calculations, and based on the current technology of V-shaped diamond blade manufacturing mode, an improved microprism retroreflective material is designed. By adjusting the intensity distribution and angle of the light cone, we can control the style of light cone which is formed by the reflected light for optimal reflective effect. The microprism reflective structure contains the positive unit and negative unit. The negative unit relative to the positive unit is rotated 60° for producing phase superposition to reduce the non-uniform of the material orientation. Cutting along a straight line by V-shaped diamond blade, the technology creates a plurality of higher-precision and smaller reflective elements and enhances the retroreflective performance. Meanwhile, the overall processing technology which reduces labor force greatly is beneficial to the cost control and highly practical during the fabrication process. Keywords: microprism retroreflective material, improvement and optimization

Compared to pyrochar (PC), little is known about the capability of torrefaction char (TC) in water pollution control. In this study, the physicochemical properties of TC and PC, and their adsorption performances for uranium (U(VI)) and methylene blue (MB) were investigated. Results showed that TC was higher in oxygen content, and richer in oxygen-containing functional groups. The maximum U(VI) and MB adsorption capacities were increased from 56.21 and 192.67 mg/g for PC, respectively, to >100 and >350 mg/g for TC, respectively, indicating that TC was much more efficient than PC. Furthermore, torrefaction atmosphere affected the adsorption performance of resulting TC. For example, TC from N2 was more efficient in MB adsorption, while TC from air was more efficient in U(VI) adsorption. Thus, attributed to the lower processing temperature, simpler preparation route, and higher adsorption capacity, TC could be a competent candidate for water pollution control.

With the consumption of nonrenewable energy, environmental and energy issues require prompt solutions. With cellulose acetate being the main component, cigarette butts have become one of the most common items of household garbage due to nondegradability, which poses an important challenge in dealing with a series of problems caused by the discarded cigarette butts. Based on this problem, this work prepares nitrogen-doped cigarette butt-derived carbon (N-CBDC) through continuous carbonization, activation and a subsequent hydrothermal method and applies it to supercapacitor electrode materials. N-CBDC has high specific surface area (1633.37 m2 g−1), a hierarchical porous structure, oxygen-rich functional groups, and high contents of nitrogen doping. The results demonstrate that such nitrogen-doped cigarette butt-derived carbon applied has excellent specific capacitance (330.1 F g−1 at 0.5 A g−1), good rate performance (45.75% from 0.5 to 10 A g−1) and high cycling stability (93.48% after 10,000 cycles). This strategy, along with thoroughly disposing of cigarette butt wastes and avoiding cigarette butt pollution to the environment, is also expected to be used to develop various carbon-derived materials for supercapacitors to tackle the problem of nonrenewable energy consumption.

The interfacial structures and bonding mechanism of the adsorption of chitosan monomers (GlcN and GlcNAc) on calcite (104) surface are investigated using first principles molecular dynamics simulations. It is revealed that the strong coordination Ca-O bonds are formed between five-fold coordinated Ca atoms on calcite surface and O atoms of hydroxyl groups (-OH) and acetyl groups of chitosan in the chitosan-calcite nanocomposites, improving the chemical compatibility between organic and inorganic phases at the interface in the natural occurring nacre. Although, the presence of interfacial hydrogen bonds is also confirmed by analyzing the valence electron density difference in terms of induced dipole, the evolution of the equilibrium adsorption geometry is found to be mainly governed interfacial Ca-O coordination bonds. The amide group (-NH 2 ) of chitosan binds with calcite at the interface mainly through the formation of weak hydrogen bond. The predicted interfacial electronic structure can be either conductive (GlcNAc) or insulating (GlcN). The frequencies of the characteristic peaks in the calculated total and partial vibrational densities of states of GlcN/calcite systems are found to be in agreement with the FT-IR spectrum of the experimentally prepared chitosan-calcite nanocomposites, crucially validating the modelling structures and computational methodology employed in current work. Theoretical results strongly indicate that the peculiar adsorption in FT-IR spectrum at 2500 cm -1 is related to the presence of free GlcN molecule due to the hydrolysis of chitosan in aqueous solution.

Direct fixation of N2 at room temperature by photocatalysis is the most intriguing process toward sustainable production of ammonia, where chemisorption of inert N2 and delivery of photogenerated electrons to N N bond are recognized bottlenecks. Here, we develop a catalyst of amorphous SmOCl nanosheets (A-SmOCl) with remarkable activity for photocatalytic reduction of N2. Impressively, the ammonia production rate of A-SmOCl reached 426 μmol·gcat.−1·h−1 under light irradiation in water without any sacrificial agents. Moreover, A-SmOCl exhibited an apparent quantum efficiency of 0.32% at 420 nm. Further mechanistic studies revealed that the existence of abundant oxygen vacancies in A-SmOCl significantly improved the adsorption and activation of N2. Meanwhile, the enhanced Sm–O covalency promoted the delivery of photogenerated electrons to chemisorbed N2, contributing to the superior catalytic activity of A-SmOCl.

Doping of heteroatoms is an effective way to improve the specific capacitance of carbon-based supercapacitors. In this paper, we prepared an active biomass carbon electrode with a considerable nitrogen content of 10.82%. In the N-doped biomass carbon materials, pyridine nitrogen and pyrrole nitrogen were the main forms of nitrogen, and the presence of sp3 hybrid nitrogen greatly enhanced the specific capacitance. Among the precursors of biomass in this study, fungal hypha (FH) enabled the best electrochemical performance of carbon electrode with specific capacitances of up to 279 F/g and 190 F/g at a high current density of 1 A/g and 20 A/g, respectively. In addition, the sample possessed an excellent anti-radiation capability, with the specific capacity of 227 F/g at 1 A/g after irradiated by γ-ray (50 kGy). This universal and cost-friendly method will expand the specific surface area of biomass materials and augment the amount of nitrogen in biomass carbon materials.

In this paper, nano-montmorillonite (nano-MMT) was introduced into the microbial mineralization system of strontium carbonate (SrCO3). By changing the nano-MMT concentration and the mineralization time, the mechanism of mineralization was studied. SrCO3 superstructures with complex forms were acquired in the presence of nano-MMT as a crystal growth regulator. At low concentrations of nano-MMT, a cross-shaped SrCO3 superstructure was obtained. As the concentration increased, flower-like SrCO3 crystals formed via the dissolution and recrystallization processes. An emerging self-assembly process and crystal polymerization mechanism have been proposed by forming complex flower-like SrCO3 superstructures in high concentrations of nano-MMT. The above research indicated that unique bionic synthesis strategies in microbial systems could not only provide a useful route for the production of inorganic or inorganic/organic composites with a novel morphology and unique structure but also provide new ideas for the treatment of radionuclides.

Carbonate mineralization microbe is a microorganism capable of decomposing the substrate in the metabolic process to produce the carbonate, which then forms calcium carbonate with calcium ions. By taking advantage of this process, contaminative uranium tailings can transform to solid cement, where calcium carbonate plays the role of a binder. In this paper, we have studied the morphology of mineralized crystals by controlling the mineralization time and adding different concentrations of montmorillonite (MMT). At the same time, we also studied the effect of carbonate mineralized cementation uranium tailings by controlling the amount of MMT. The results showed that MMT can regulate the crystal morphology of calcium carbonate. What is more, MMT can balance the acidity and ions in the uranium tailings; it also can reduce the toxicity of uranium ions on microorganisms. In addition, MMT filling in the gap between the uranium tailings made the cement body more stable. When the amount of MMT is 6%, the maximum strength of the cement body reached 2.18 MPa, which increased by 47.66% compared with that the sample without MMT. Therefore, it is reasonable and feasible to use the MMT to regulate the biocalcium carbonate cemented uranium tailings.

Macroscale assembly of nanoscale building blocks is an intriguing way to translate the unique characteristics of individual nanoparticles into macroscopic materials. However, the lack of the efficient universal assembly strategy seriously hinders the possibility of macroscale architectures in practical applications. Herein, we develop a general, environment-friendly, and scalable microbial growth method for the construction of macroscopic composite assemblies with excellent mechanical strength by in situ integrating various types of nanoparticles into fungal hyphae (FH) macrospheres. Notably, the size of the FH-based composite spheres and the loading amount of the nanoparticles with different dimensions can be well tuned by controlling the cultivation time and the dosage of nanoparticles, respectively. Interestingly, bifunctional FH-based core-shell macrospheres can also be achieved by programmed assembling two different kinds of nanoparticles in the cultivation process. The produced multifunctional FH-based composite spheres exhibit wide potential applications in magnetic actuation, photothermal therapy, and contaminant adsorption, etc.

The effects of temperature, pH, precipitation time, reactant concentration, the crystal formation additive on the yield of calcium carbonate precipitation induced by bacillus pasteurii were investigated through orthogonal test. The morphology and structure of the calcium carbonate were characterized by scanning electron microscopic (SEM), Fourier transform infrared spectroscopy (IR) and powder X-ray diffraction (XRD). The results showed that the optimum conditions of calcium carbonate precipitation induced by bacillus pasteurii were temperature of 40oC, pH of 8, precipitation time of 3 d, Ca2+ of 1.5 mol/L, and Mg2+ of 0.05 mol/L. The crystal of calcium carbonate was calcites or mixture of calcites and vaterite. Its morphology and packing density were changed by different external conditions.

The calcium carbonate crystallization was controlled by Ca2+concentrations, under the system of lignin solution with concentration of 10 g / L. Its morphology, structure and thermal decomposition were characterized by FT-IR, SEM, XRD and TG. Results showed that in lignin solution system, concentration of Ca2+had significant effects on the crystallized morphology, orientation and crystallinity of calcium carbonate. Calcium carbonate crystal under low Ca2+concentration had more uniform size while under high Ca2+concentration which tended to form various sizes with more complete crystallization. The calcium carbonate crystals were all calcite calcium carbonate, which formed under different Ca2+concentrations.

Various crystal forms of calcium carbonate were successfully synthesized with CaCl2 and Na2CO3 in 10%(V/V) egg white protein solution system at 20 °C, 40 °C and 60 °C, respectively. The obtained calcium carbonate were characterized by SEM, XRD, FTIR and TG. In addition, the possible mechanism of crystal formation were analyzed. The results indicated that egg white protein could regulate the crystal forms of calcium carbonate and the calcium carbonate, which contained a small amount of egg white protein and consisted of mixed calcite and aragonite, was mainly spherical. With the temperature rosing, the vaterite content gradually increased while the calcite decreased.

The calcium carbonate crystallization were controlled by Ca2+ concentration in the 10% (V/V) egg white protein solution and the morphology, structure and thermal decomposition of which were characterized by FT-IR, SEM, XRD and TG. The results showed in egg white protein solution system, concentration of Ca2+ had significant effects on the crystallized morphology, orientation and crystallinity of calcium carbonate. Calcium carbonate particles have more uniformed calcite and vaterite mixed crystallization in low Ca2+ concentration while calcium carbonate tends to form mixed particle sizes and more complete calcite crystallization in high Ca2+ concentration.

Environmental and energy issues have always been a hot topic of global research. Oil leakage has caused great damage to the environment, affecting a wide area and it is difficult to clean up. In most cases, carbon-based adsorbents are typically utilized to remove oil spills because of their economic benefits and high adsorbent efficiency. At the same time, its excellent material properties can also be used for the preparation of supercapacitors. In this paper, the carbon aerogels were prepared by the one-step method. The prepared materials endowed a 3D network structure with a huge number of micropores and mesoporous, and the material is light-weight, stable, hydrophobic and has affinity for oil (17.02[Formula: see text]g/g) to the KGM carbon aerogel. Through the physic-chemical characterization, the KGM carbon aerogel shows specific surface area is 689[Formula: see text]m2/g, high water contact angle (136.64[Formula: see text]) and excellent reusability (more than 15 cycle times). In addition, we also discussed the electrochemical properties of the material and obtained the specific electrical capacity of 139[Formula: see text]F/g under the condition of 1[Formula: see text]A/g.

Sugar is one of the key nutrients required to microorganism growth. In this paper , the effects of various sugars on the mineralization of calcium carbonate induced by Bacillus pasteurii . The precipitation amount, forms and structures of calcium carbonate were characterized. The results indicated that the induced calcium carbonate precipitation are mainly calcite as irregular aggregated bodies and rhombus blocks and aragonite appeared when the culture medium was added with dextran. The calcium carbonate precipitation reached a maximum of 2.32 g when glucose was added into the culture.

Calcium carbonate with various structures and morphologies were prepared under double injection of the CaCl2 and Na2CO3 solutions with molar ratio of 1:1 at 30 °C, taking lignin as the induction agents. They were characterized by scanning electron microscopy, infrared spectroscopy thermal analysis and X-ray diffraction. The synthesis mechanism was also discussed. The results showed that calcium carbonate of different shape were obtained with the concentration of lignin at 10g/L, 20g/L and 30g/L, respectively, under 30°C while CaCl2 and Na2CO3 were kept at the same concentration of 0.5mol/L. The size of the particles was in a range between 3 and 5μm and the particles were calcites. Compared with the normal calcium carbonate, the compound has advanced thermal decomposition behavior. Fourier transform infrared spectroscopy (FT-IR) analysis revealed the presence of lignin and calcite. The electrostatic interaction of Ca2+ with lignin and the complementary of stereo-structure play important roles in the formation of Dumbbell Shaped Calcium Carbonate.

A three-dimensional (3D) MoS2 coated CoS2-nitrogen doped graphene (NG) (CoS2@MoS2-NG) hybrid has been synthesized by a one step hydrothermal method as supercapacitor (SC) electrode material for the first time. Such a composite consists of NG embedded with stacked CoS2@MoS2 sheets. With a 3D skeleton, it prevents the agglomeration of CoS2@MoS2 nanoparticles, resulting in sound conductivity, rich porous structures and a large surface area. The results indicate that CoS2@MoS2-NG has higher specific capacitance (198 F g−1 at 1 A g−1), better rate performance (with about 56.57% from 1 to 16 A g−1) and an improved cycle stability (with about 96.97% after 1000 cycles). It is an ideal candidate for SC electrode materials.

Mesoporous gold sponges were prepared using 4-dimethylaminopyridine (DMAP)-stabilized Au seeds. This is a general process, which involves a simple template-free method, room temperature reduction of HAuCl4·4H2O with hydroxylamine. The formation process of mesoporous gold sponges could be accounted for the electrostatic interaction (the small Au nanoparticles (~3 nm) and the positively charged DMAP-stabilized Au seeds) and Ostwald ripening process. The mesoporous gold sponges had appeared to undergo electrostatic adsorption initially, sequentially linear aggregation, welding and Ostwald ripening, then, they randomly cross link into self-supporting, three-dimensional networks with time. The mesoporous gold sponges exhibit higher surface area than the literature. In addition, application of the spongelike networks as an active material for surface-enhanced Raman scattering has been investigated by employing 4-aminothiophenol (4-ATP) molecules as a probe.

Tough and biocompatible nanocomposite films: A new type of bioinspired ultrastrong, highly biocompatible, and bioactive konjac glucomannan (KGM)/graphene oxide (GO) nanocomposite film is fabricated on a large scale by a simple solution-casting method. Such KGM-GO composite films exhibit much enhanced mechanical properties under the strong hydrogen-bonding interactions, showing great potential in the fields of tissue engineering and food package.

Bayberry tannin (BT)–reduced graphene oxide (rGO) sponges have been prepared by self–assembly, with bayberry tannin serving as both reductant and surface functionalization agent. The synthetic method is based on the self-assembly of graphene oxide (GO) sheets into porous hydrogel structures. By varying the weight ratio of GO to BT, a series of sorbents with different densities of organic molecules have been obtained and applied to remove Sr2+ from aqueous solutions. Adsorption isotherms (Langmuir and Freundlich) and kinetics (pseudo-first order and pseudo-second order) have been investigated to discuss the sorption performance of rGO/BT sponges. The rGO/BT (w/w 1:1) sponge shows excellent adsorption properties for Sr2+, with maximum capacities of 67.98 mg g−1. The adsorption capacity is much higher than those in classic Sr2+ adsorbents, such as hydrous manganese dioxide, Egyptian soils, Hydroxyapatite nanoparticles, sodium hexa-titanate nanofibers, Graphene oxide, artificially altered phlogopite(Ca–Phl), and PB/Fe3O4/GO. Adsorption mechanisms have been examined using the x-ray photoelectron spectra of sorbents before and after Sr2+ adsorption, and the results indicate that the sorption of Sr2+ on GO and GO/BT 1.0 is largely depended on oxygen functional groups. The results show that the GO/BT sponge is a promising candidate for adsorbing Sr2+ ion.

In this paper, The strontium carbonate precipitate was induced with the role of the enzymes according to the bacillus pasteurii reproduction in different concentrations of Sr2+. The morphology and structure of strontium carbonate were characterized by X-ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDS) and Scanning Electronic Microscope (SEM). The results showed that the induced strontium carbonate precipitation was mainly orthorhombic, it's morphology was irregular aggregated bodies and rhombus blocks. Bacterial played an important role in the strontium carbonat crystal nucleation, growth and accumulation process.

Pyrofomes demidoffii is a new recorded species of the new recorded genus in the China. To study the high yield and economical medium productive conditions, this experiment selected and used single factors such as carbon source, nitrogen source, C/N rations, rational speed, temperature, pH value, bottled volume and inoculated bulk and multifactor experiment design with submerged fermentation mycelia to explore the effects of these various factors on the mycelia yield. The results of the experiment indicated that mycelia of P. demidoffii could be produced by submerged fermentation process. Meanwhile starch and bran were the optimum carbon and nitrogen source; P, K, Mg had facilitation to the growth of mycelia. The optimal rotational speed for the growth of mycelia is 150 rpm, temperature 25~30, pH value 5~7, bottled volume 100 ml, and inoculated bulk 8%, C/N ratios 20:1~25:1. The optimal nutritional conditions when the mycelia of this sort of fungi were cultivated by means of submerged culture are follow: glucose 25 g•l-1, bran 350 g•l-1, K2HPO4 0.25 g•l-1, pH 6.5.The growth curve of the logistic equation was deduced: y = 0.22/(1+1.019e-0.013x), the weight of the dry mycelia was 0.22 g100 ml-1.