Facile synthesis of nanostrip-structured pseudo-boehmite "nest" for nano-TiO2/γ-Al2O3construction to remove tetracycline hydrochloride in water.

A particular bird's nest-like pseudo-boehmite (PB) composed of cohesive nanostrips was prepared by a novel and facile approach based on the reaction of Al-Ga-In-Sn alloy and water, together with ammonium carbonate. The PB possesses a large specific surface area (465.2 m2g-1), pore volume (1.0 cm3g-1), and pore diameter (8.7 nm). Subsequently, it was utilized as a precursor to form the TiO2/γ-Al2O3nanocomposite for tetracycline hydrochloride removal. The removal efficiency can reach above 90% at TiO2:PB = 1:1.5 under the Sunlight irradiation simulated by a LED lamp. Our results indicate that the nest-like PB is a promising carrier precursor for efficient nanocomposite catalysts.

Fabrication of Pd/Mg2 P2 O7 via a Struvite-Template Way from Wastewater and Application as Chemoselective Catalyst in Hydrogenation of Nitroarenes.

A highly efficient heterogeneous catalyst Pd/Mg2 P2 O7 was fabricated by combining palladium nanoparticles (PdNPs) and mesoporous Mg2 P2 O7 fibers/rods. Mg2 P2 O7 fibers with ultra-high specific surface area were prepared from struvite as templates, which were synthesized from waste water containing N- and P-containing pollutants. This strategy provided a novel pathway for developing advanced catalysts from eutrophication-polluted water. The composite Pd/Mg2 P2 O7 showed brilliant performance in selective hydrogenation of nitro aromatics to give anilines. As an example of nitrobenzene hydrogenation, the conversion to aniline and selectivity were found to reach almost 100 % at a temperature of T=90 °C and under a pressure of P H 2 =2.0 MPa. The superior performance was found to originate from PdNPs, which were boosted by electron transfer afforded by the nanofiber Mg2 P2 O7 supports. The favorable adsorption of withdrawing groups (-NO2 ) was realized by synergistic effects between Pd and oxygen vacancies provided by pyrolysis of struvite. The catalyst remained stable after cycles of reuse with little degradation in catalytic performance.

Prolonged-Photoresponse-Lifetime Ni2P Nanocrystalline with Highly Exposed (001) for Efficient Photoelectrocatalytic Hydrogen Evolution.

Seeking highly efficient non-preference electrocatalytic materials that serve photoelectrochemical (PEC) water splitting in acidic systems is expectant in the context of environmentally friendly production. We designed Ni2P electrocatalysts synthesized in oil phases via the hot-bubbling method with superb stability in air and sulfuric acid solution for PEC, which were found with excellent hydrogen evolution performance. A tunable particle size and highly exposed (001) planes of Ni2P nanocrystals were achieved. The designed catalysts achieved a notable promotion in the hydrogen evolution reaction activity compared to that of Ni2P synthesized in the water phase. More specifically, the electrode prepared by self-assembled Ni2P nanoparticles was found to have decent over-potential of η10 = 164 mV in darkness and was further decreased to 129 mV with irradiation of visible light. The cyclic stability tests manifested brilliant durability in 0.5 M H2SO4. Measurement of the transient photocurrent response and PEC water splitting catalytic performance indicated that the Ni2P had high carrier concentration upon irradiation, lower carrier recombination probability, and prolonged photo-response lifetime (3.03-3.14 s).

Universality of mesoporous coal gasification slag for reinforcement and deodorization in four common polymers.

Mesoporous adsorbents and polymer deodorants are difficult to implement on a large scale because of their complicated preparation methods. Herein, a mesoporous adsorbent (CGSA) with a specific surface area of 564 m2g-1and a pore volume of 0.807 cm3g-1was prepared from solid waste coal gasification slag using a simple acid leaching process. The adsorption thermodynamics and adsorption kinetics results verified that the adsorption mechanism of propane on CGSA was mainly physisorption. Then the universality of CGSA in different polymers was investigated by introducing CGSA and its commercialized counterparts (CaCO3, and zeolite) into four common polymers. When the filler content was 30 wt%, the average reinforcement effect of CGSA on the tensile, flexural, and impact strengths of the four polymers was 46.68%, 83.62%, and 211.90% higher than that of CaCO3, respectively. Gas chromatography results also showed that CGSA significantly decreased total volatile organic compound emissions from the composites, and its optimal deodorization performance reached 69.58%, 81.33%, and 91.09% for different polymers, respectively, far exceeding that of zeolite. Therefore, this study showed that low-cost, high-performance, and multifunctional mesoporous polymer fillers with excellent universality can be manufactured from solid contaminants.

Study of the synthesis, adsorption property, and photocatalytic activity of TiO2/coal gasification fine slag mesoporous silica glass microsphere composite.

In this study, TiO2/MSGM composite material with adsorption-photocatalytic properties was prepared by extracting mesoporous silica glass microsphere (MSGM) from coal gasification fine slag (CGFS) as a novel TiO2 carrier. The results of characterization and properties of the composite showed that MSGM could improve the adsorption capacity and photocatalytic activity of the composite by improving the pore structure of the composite, hindering the growth of TiO2 particles, increasing the phase transition temperature of TiO2, enhancing the dispersion of TiO2 particles. The sample 1:3-TiO2/MSGM-2-500 prepared under the optimized conditions possesses satisfactory morphology characteristics, high adsorption capacity, and photocatalytic activity to rhodamine B (RhB). The synergistic effects of adsorption and photocatalytic significantly increase the total removal rate of RhB. This study not only provides a new direction for high-value-added resource utilization of CGFS but also gives a new kind of low-cost carrier material with adsorption property for TiO2 loading to remove organic dye pollutants.

A Facile Temperature-Controlled "Green" Method to Prepare Multi-kinds of High-Quality Alumina Hydrates via a Ga-In-Sn-Alloyed Aluminum-Water Interface Reaction.

The Al sheets alloyed by Ga-In-Sn are generally utilized to react with water for H2 production, while the valuable byproducts, i.e., alumina hydrates, have not been fully studied. In this work, through controlling the reaction temperature, three types of alumina hydrates, bayerite (40 °C), pseudo-boehmite (PB) (70-120 °C), and boehmite (130-160 °C), were successfully prepared based on a series of interface reactions and structural transformations. These alumina hydrates and their calcined products (alumina) possess high purity with a total impurity element content of <450 ppm, especially an extremely low sodium content (<21 ppm) and iron content (<52 ppm). Significantly, the obtained pseudo-boehmite displays excellent surface properties (specific surface area: 332.7 m2 g-1, pore volume: 0.3 cm3 g-1, and pore diameter: 3.6 nm), competitive to the current commercial SB powder by Sasol. This work not only deepens the understanding of the byproducts in a Ga-In-Sn-alloyed Al-water reaction but also establishes a facile "green" method oriented to industrial applications, which is promising for the linkage benefits of the hydrogen production industry.

Mesoporous Spherical Silica Filler Prepared from Coal Gasification Fine Slag for Styrene Butadiene Rubber Reinforcement and Promoting Vulcanization.

Coal gasification fine slag (CFS) is a solid contaminant produced by an entrained flow gasifier, which pollutes fields and the air in the long term. CFS is a potential polymer reinforcement filler and has been used in polypropylene and acrylonitrile butadiene styrene resins. Coal gasification fine slag mesoporous silica (FS-SiO2) was prepared by acid leaching, calcination, and pH adjustment, with a larger specific surface area and less surface hydroxyl compared to the commercial precipitated silica (P-silica). The cure characteristics, crosslink density, mechanical properties, the morphology of the tensile fractures, dynamic mechanics, and rubber processing of the prepared styrene butadiene rubber (SBR) composites filled with P-silica and FS-SiO2 were analyzed, respectively. The results indicated that FS-SiO2 was dispersed more uniformly in the SBR matrix than P-silica owing to its smaller amount of surface hydroxyl and spherical structure, resulting in a better mechanical performance and wet skid resistance. In particular, the SBR composites with a filler pH of 6.3 exhibited the highest crosslink density and tensile strength, being superior to commercial P-silica. Significantly, the curing time decreased with the increase in the pH of FS-SiO2, which caused the rubber processing to be more efficient. This strategy can reduce the cost of rubber composites and the environmental pollution caused by CFS.

Highly Stable and Recyclable Sequestration of CO2 Using Supported Melamine on Layered-Chain Clay Mineral.

A type of highly stable and recyclable clay-based composite was developed for sequestration of CO2, which was synthesized by loading melamine (MEL) onto attapulgite (ATT) via a wet impregnation method. The synthesized materials were characterized by N2 adsorption-desorption, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and transmission electron microscopy (TEM). By means of thermal and acidic treatments more active sites of ATT were exposed, and large surface areas were obtained. The MEL molecules were well combined with those exposed sites, which enhanced stability and cyclability for CO2 sequestration. On the basis of CO2 adsorption-desorption measurements, the composite of ATT-MEL was found to have a higher CO2 adsorption capacity (4.91 cm3/g) which was much higher than that of CO2 absorption on bare MEL (1.30 cm3/g) at 30 °C. After ten cycles of reusing, the composite exhibited even higher capacity for CO2 adsorption by an increased percentage of 5.91% (30 °C) and 5.77% (70 °C) compared to the capacity in the first cycle. The reason lies in the strong interaction between melamine and attapulgite matrix which was further confirmed by DFT calculations. The MEL was validated to have advantages over aliphatic amines (TEPA) in modifying ATT to get high stability of CO2-adsorbents.

Carbon-silica mesoporous composite in situ prepared from coal gasification fine slag by acid leaching method and its application in nitrate removing.

Coal gasification fine slag (CGFS) was produced in the coal gasification process which was classified as an industrial solid waste. It was featured with naturally formed amorphous structures and an abundance of silicon, carbon and metal oxides. In this study, on the basis of the composition and structure characteristics of CGFS, a simple hydrochloric acid (HCl) leaching technology was applied to in situ prepare carbon-silica mesoporous composites (CSMCs) from CGFS by fully considering the value of the residual carbon. Special focus was put on the novel mechanism of pore formation in amorphous silica glass microspheres (SGM) during acid leaching. Experimental evidences showed that the metal oxides were uniformly distributed in SGM thus the dissolution of the metal oxides were starting from the surface of SGM, then gradually extending to the interior, and finally leading to form "tree branch" mesoporous channels. In addition, a response surface method was used to predict the optimal reaction conditions and the optimal sample (named as CGFS-O) was successfully prepared. CGFS-O possessed a prominent specific surface area (SSA) (337.51 m2/g) as well as an excellent pore volume (0.341 cm3/g). CGFS-O also exhibited a desirable capacity for NO3- removing and the adsorption process was studied detailed by changing different adsorption conditions. Adsorption results proved that CSMCs have the potential to purify wastewater in an economically and environmentally way. Therefore, combined with a proof-of-concept adsorption performance experiment, our study has not only provided a cost-effective strategy to industrially prepare CSMCs, reutilizing CGFS in an environmentally friendly way, but also contributed to the future applications of CSMCs with valuable insights into the pore formation mechanism in SGM during acid leaching process.

Preparation of a new high-efficiency resin deodorant from coal gasification fine slag and its application in the removal of volatile organic compounds in polypropylene composites.

Deodorizing materials are often restricted from large-scale industrial production due to the high preparation cost. By utilizing the simple acid leaching technology, this study made use of the coal gasification fine slag (FS) as raw material to prepare a cost effective FS-based deodorant (FSD) with a specific surface area of 393 m2 g-1 and a pore volume of 0.405 cm3 g-1. The propane adsorption test on FSD showed the maximum adsorption capacity to be as high as 121.61 mg g-1 at 273 K. The partition coefficient values at 10% and 100% breakthrough (BT) for FSD to adsorb propane were 1.5 × 10-3 and 3.2 × 10-4 mol kg-1 Pa-1, respectively. Furthermore, the FSD was applied in the removal of volatile organic compounds (VOCs) pollutants from polypropylene resin (PP). It showed that the deodorizing effect of the FSD was nearly three times as good as the commonly used zeolite deodorants, which was able to decrease 50 percent of the VOCs volatilization amount in PP resin. Moreover, the FSD can better strengthen the mechanical properties of PP resin. This work provides a new method for the industrial production of deodorants as well as a new direction for the recycle of coal gasification wastes.

Using chemical experiments and plant uptake to prove the feasibility and stability of coal gasification fine slag as silicon fertilizer.

Coal gasification fine slag (CGFS) is a kind of industrial waste that is generated from entrained-flow coal gasification with a high content of 0.5 M hydrochloric acid (HCl)-extractable silicon (Si). Si fertilizer has been widely used in agriculture to enhance the mechanical properties and yield of crops. An evaluation was actualized by analyzing HCl-extractable Si fractions and X-Ray diffraction (XRD) of different treatments (acid, alkali, salt, grind, calcination, temperature, and time) for CGFS samples and other Si source materials. The results showed that CGFS had stable HCl-extractable Si concentrations of 60 ± 2 g/kg except in the calcination treatment, which decreased the content of extractable Si by 28.2%. Furthermore, under the same processing conditions, CGFS showed a higher content of extractable Si than other Si source samples. Moreover, a rice growth experiment was carried out for 120 days in a different mass incorporation of CGFS in the greenhouse. The strength index and total Si content of the stem proved that using CGFS at 5 wt.% markedly promoted the growth of rice. The study indicated that an appropriate application of CGFS as a Si resource to an agricultural field could be considered as a viable option for safe disposal of this industrial waste.

Porous Ga-In Bimetallic Oxide Nanofibers with Controllable Structures for Ultrasensitive and Selective Detection of Formaldehyde.

The design of appropriate composite materials with unique surface structures is an important strategy to achieve ideal chemical gas sensing. In this paper, efficient and selective detection of formaldehyde vapor has been realized by a gas sensor based on porous GaxIn2-xO3 nanofibers assembled by small building blocks. By tuning the Ga/In atomic ratios in the materials, crystallite phase, nanostructure, and band gap of as-obtained GaxIn2-xO3 nanofibers can be rationally altered. This further offers a good opportunity to optimize the gas sensing performances. In particular, the sensor based on porous Ga0.6In1.4O3 nanofibers assembled by small nanoparticles (∼4.6 nm) exhibits best sensing performances. Toward 100 ppm formaldehyde, its highest response (Ra/Rg = 52.4, at 150 °C) is ∼4 times higher than that of the pure In2O3 (Ra/Rg = 13.0, at 200 °C). Meanwhile, it has superior ability to selectively detect formaldehyde against other interfering volatile organic compound gases. The significantly improved sensing performance makes the Ga0.6In1.4O3 sensor very promising for selective detection of formaldehyde.

Synthesis and photocatalytic activity of N-doped NaTaO3 compounds calcined at low temperature.

N-doped NaTaO(3) compounds (NaTaO(3-x)N(x)) were successfully synthesized using NaTaO(3) prepared at low calcination temperature as starting material and melamine (C(3)H(6)N(6)) as nitrogen source. The as-prepared NaTaO(3-x)N(x) samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV-vis diffuse reflectance spectra. The XRD results indicate that the crystallization temperature of NaTaO(3) is up to 700 degrees C and the doping of N does not lead to significant structural changes. Moreover, as observed by SEM images, the particle sizes of resultant NaTaO(3-x)N(x) are in the range of 100-150 nm, which are much smaller than NaTaO(3) particles synthesized by traditional solid state reaction method. The photocatalytic activities of NaTaO(3-x)N(x) were examined by methylene blue (MB) aqueous solution under UV light. It is found that the photocatalytic activity of NaTaO(3-x)N(x) depend strongly on the doping content of N, and sample NaTaO(2.961)N(0.039) shows the highest photocatalytic activity for the degradation of MB. Furthermore, it is also found that NaTaO(3-x)N(x) catalysts display super structural stabilities during photocatalytic degradation, and could recover their photocatalytic activity after calcination at 500 degrees C, suggesting a promising utilization of such photocatalyst.