Application of common industrial solid waste in water treatment: a review.

Industrial solid waste has a wide range of impacts, and it is directly or indirectly related to land, atmosphere, water, and other resources. Industrial solid waste has a large amount of production, complex and diverse components and contains a variety of harmful substances. However, as industrial by-products, it also has a lot of available value. Industrial solid waste has been continuously studied in water treatment due to its special composition and porous and loose structure. It is known that there are few reviews of various industrial solid wastes in the field of wastewater treatment, and most of them only discuss single industrial solid waste. This paper aims to sort out the different studies on various solid wastes such as fly ash, red mud, wastewater sludge, blast furnace slag and steel slag in dyeing, heavy metal, and phosphorus-containing wastewater. Based on the modification of industrial solid waste and the preparation of composite materials, adsorbents, coagulants, catalysts, filtration membranes, geological polymers, and other materials with high adsorption properties for pollutants in wastewater were formed; the prospect and development of these materials in the field of wastewater were discussed, which provides some ideas for the mutual balance of environment and society. Meanwhile, some limitations of solid waste applications for wastewater treatment have been put forward, such as a lack of further researches about environment-friendly modification methods, application costs, the heavy metal leaching, and toxicity assessment of industrial solid waste.

Enhanced Electrochemical Performance of the LiNi0.5Mn1.5O4 Cathode Material by the Construction of Uniform Lithium Silicate Nanoshells.

In order to alleviate the rapid capacity decay caused by the instability of the crystal structure and electrode/electrolyte interface, a series of Li2SiO3-coated LiNi0.5Mn1.5O4 materials have been prepared via the lithium acetate-assisted sol-gel method followed by a short-term calcination process. During the sol-gel process, TEOS is hydrolyzed, condensed, and polymerized with the assistance of lithium acetate to form a Li+-embedded [Si-O-Si]n network structure to ensure the uniformity of the coating. By changing the amount of TEOS and lithium acetate, the coating thickness can be precisely controlled, whose effects on the structural and electrochemical properties of LiNi0.5Mn1.5O4 materials are intensively investigated. The results show that the material with an appropriate thickness of Li2SiO3 coating exhibits a larger primary particle size and reduced secondary particle agglomeration. The uniform Li2SiO3 coating with appropriate thickness can not only improve Li+ ion diffusion kinetics but also suppress side reactions and CEI growth at the electrode/electrolyte interface. Besides, the interaction of Li2SiO3 with HF can alleviate electrode corrosion and the dissolution of transition metal ions. All the abovementioned factors together promote the significant improvement of the electrochemical performance of Li2SiO3-coated LiNi0.5Mn1.5O4 materials.

Experimental study on pressure pulses in long-distance gas pipeline during the pigging process.

Long-distance gas pipelines generally have complex, undulating sections. Trapped air pockets are often present at the high points or ends of pipelines. This article carries out an experimental research to figure out the transient changes. First of all, under the condition of using the pig with 231 g and the injection pressure of 0.3 MPa, the hydraulic pulse increases from 0.31 to 0.54 MPa as the liquid level rises from 1 to 8 m. And at the liquid level of 8 m, the injection pressure grows from 0.3 to 0.75 MPa and the hydraulic pulse from 0.54 to 0.95 MPa. When the interception air mass is located at the blind side of the pipeline's end, the injection pressure is 0.75 MPa, and the hydraulic pulse decreases from 4.9 to 3.21 MPa with the increase in the void fraction. The maximum hydraulic pressure generates when the air pocket is located at the rear end of the drainage system (4.9 MPa) is far higher than that when the air pocket is located in front of the pig (1.0 MPa). Therefore, it is necessary to minimize the generation of trapped air pockets at the rear end of the pipeline system to ensure safety.

Effect of Conductive Material Morphology on Spherical Lithium Iron Phosphate.

As an integral part of a lithium-ion battery, carbonaceous conductive agents have an important impact on the performance of the battery. Carbon sources (e.g., granular Super-P and KS-15, linear carbon nanotube, layered graphene) with different morphologies were added into the battery as conductive agents, and the effects of their morphologies on the electrochemical performance and processability of spherical lithium iron phosphate were investigated. The results show that the linear carbon nanotube and layered graphene enable conductive agents to efficiently connect to the cathode materials, which contribute to improving the stability of the electrode-slurry and reducing the internal resistance of cells. The batteries using nanotubes and graphene as conductive agents showed weaker battery internal resistance, excellent electrochemical performance and low-temperature dischargeability. The battery using carbon nanotube as the conductive agent had the best overall performance with an internal resistance of 30 mΩ. The battery using a carbon nanotube as the conductive agent exhibited better low-temperature performance, whose discharge capacity at -20 °C can reach 343 mAh, corresponding to 65.0% of that at 25 °C.

A porous hierarchical micro/nano LiNi0.5Mn1.5O4 cathode material for Li-ion batteries synthesized by a urea-assisted hydrothermal method.

A spinel LiNi0.5Mn1.5O4 cathode material was synthesized by a urea-assisted hydrothermal method followed by high-temperature calcination with a lithium source. The effects of the molar ratio of urea to transition metal ions (U/TM ratio) on the structure, morphology and electrochemical properties of the carbonate precursor and LiNi0.5Mn1.5O4 product were systematically investigated. The as-synthesized samples were characterized by XRD, FT-IR, SEM, TEM, a constant-current charge/discharge test, CV and EIS. XRD and FT-IR results show that the LiNi0.5Mn1.5O4 samples synthesized at U/TM ratios of 1.0 : 1 to 4.0 : 1 have mainly a disordered structure with the Fd3m space group, and the sample synthesized at a U/TM ratio of 2.0 : 1 has the lowest cation disordering degree (Mn3+ content). SEM observations show that the U/TM ratio has a significant influence on the phase composition, particle morphology and size of the carbonate precursor, thus leading to different electrochemical properties of the LiNi0.5Mn1.5O4 material. Among them, the carbonate precursor synthesized at the U/TM ratio of 2.0 : 1 shows the smallest particle size with the most homogeneous distribution, thus leading to an optimal electrochemical performance of the derived LiNi0.5Mn1.5O4 material in spite of its lowest Mn3+ content, whose discharge capacity at 10C rate can reach 120.2 mA h g-1, accounting for 98.6% of that at 0.2C rate, and capacity retention rate after 100 cycles at 1C rate can reach 95.3%.

Urea-assisted hydrothermal synthesis of a hollow hierarchical LiNi0.5Mn1.5O4 cathode material with tunable morphology characteristics.

A hollow hierarchical LiNi0.5Mn1.5O4 cathode material has been synthesized via a urea-assisted hydrothermal method followed by a high-temperature calcination process. The effect of reactant concentration on the structure, morphology and electrochemical properties of the carbonate precursor and corresponding LiNi0.5Mn1.5O4 product has been intensively investigated. The as-prepared samples were characterized by XRD, FT-IR, SEM, CV, EIS, GITT and constant-current charge/discharge tests. The results show that all samples belong to a cubic spinel structure with mainly Fd3m space group, and the Mn3+ content and impurity content initially decrease and then increase slightly with the reactant concentration increasing. SEM observation shows that the particle morphology and size of carbonate precursor can be tailored by changing reactant concentration. The LiNi0.5Mn1.5O4 sample obtained from the carbonate precursor hydrothermally synthesized at a reactant concentration of 0.3 mol L-1 exhibits the optimal overall electrochemical properties, with capacity retention rate of 96.8% after 100 cycles at 1C rate and 10C discharge capacity of 124.9 mA h g-1, accounting for 99.9% of that at 0.2C rate. The excellent electrochemical performance can be mainly attributed to morphological characteristics, that is, smaller particle size with homogeneous distribution, in spite of lower Mn3+ content.

Synthesis and electrochemical performance of nano-metastructured LiFePO4/C cathode material.

The nano-metastructured LiFePO4/C composites were synthesized by carbothermal reduction method using starch gel as carbon source and dispersing media to obtain high tap density LiFePO4 with excellent electrochemical performance. The raw materials were coated by starch gel as compact precursors, which was sintered at 750 degrees C for 8 h to obtain high-density LiFePO4/C composite aggregated with nano-sized particles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations showed that the primary particles had an average size of about 50-80 nm and the aggregates had a homogeneous particle size distribution of about 400 nm. The asprepared samples had a shortened lithium-ion diffusion length but with higher tap density, thus leading to the excellent electrochemical performance of the cathode materials. Electrochemical results showed that the samples delivered high discharge capacities of 155.6 and 120.7 mAh/g at 0.2C and 5C rates, respectively, with excellent cycling performance.

Performance and application of far infrared rays emitted from rare earth mineral composite materials.

Rare earth mineral composite materials were prepared using tourmaline and cerous nitrate as raw materials. Through characterization by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, dynamic contact angle meter and tensiometer, and Fourier transform infrared spectroscopy, it was found that the composite materials had a better far infrared emitting performance than tourmaline, which depended on many factors such as material composition, microstructure, and surface free energy. Based on the results of the flue gas analyzer and the water boiling test, it was found that the rare earth mineral composite materials could accelerate the combustion of liquefied petroleum gas and diesel oil. The results showed that the addition of Ce led to the improvement of far infrared emitting performance of tourmaline due to the decrease of cell volume caused by the oxidation of more Fe2+ ions and the increase of surface free energy. The application of rare earth mineral composite materials to diesel oil led to a decrease in surface tension and flash point, and the fuel saving ratio could reach 4.5%. When applied to liquefied petroleum gas, the composite materials led to the enhanced combustion, improved fuel consumption by 6.8%, and decreased concentration of CO and O2 in exhaust gases by 59.7% and 16.2%, respectively; but the temperature inside the flue increased by 10.3%.

Effects of mineral tourmaline particles on the photocatalytic activity of TiO2 thin films.

Titania composite thin films (T/TiO2) containing tourmaline particles were prepared by a sol-gel method, using alkoxide solutions as precursor. The tourmaline particles and thin films were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and so on. The effects of tourmaline on the photocatalytic activity of TiO2 were measured with methyl orange as an objective photodegradation substance. The results showed that the photocatalytic degradation of methyl orange conformed to the first-order kinetic equation and the composite thin films had better photocatalytic activity due to the cooperation of polarity and the far infrared emission of tourmaline. The T/TiO2 thin films including 0.5 wt% tourmaline exhibited better photocatalytic activity when heat-treated at 250 degrees C for 3 h, than pure TiO2 thin films under the ultraviolet irradiation.