Reduction of heavy metals in municipal solid waste incineration fly ash followed by making transparent glass.

Municipal solid waste incineration (MSWI) fly ash is a hazardous waste containing heavy metals. Secondary aluminum dross (SAD) is a hazardous waste discharged from aluminum smelting, containing active aluminum nitride (AlN). In this work, heavy metals from MSWI fly ash were reduced into alloy by AlN from SAD, and the slag was manufactured into transparent glass for building. Reduction of iron and zinc was 67 and 100 %, respectively. Reduction mechanism was explored after applying XRD, XRF and thermodynamics analysis. It was found that the reduction reaction was an ion reaction. The AlN and heavy metal oxide transformed into anionic group containing nitrogen and heavy metal cation, after entering slag. The heavy metals were reduced into alloy after electron was transferred from anionic group to cation. In addition, the reduced iron and zinc could merge into alloy, which inhibited evaporation of zinc. Yellow transparent glass was obtained after the reduction process. Yellow was come from titanium oxide, which could not be reduced by AlN. Microhardness, density and water absorption of the transparent glass were 741 HV, 2.86 g·cm-3 and 0.04 %, respectively. Leaching content of Ni, Cu, Zn and Pb of the glass were 0.1, <0.1, 0.6 and < 0.1 mg/L, respectively, all below the TCLP limit. About 115 âˆ¼ 213 dollars were earned after manufacturing 500 kg of MSWI fly ash into transparent glass. This work provided a novel idea of recycling solid waste into alloy and transparent glass for building.

Self-Assembly of Glutamic Acid and Serine on Au(111).

Amino acids provide novel and superior performance for two-dimensional materials and bio-based devices. The interaction and adsorption of amino acid molecules on substrates have thus attracted extensive research for exploring the driving forces involved in the formation of nanostructures. Nevertheless, the interactions within amino acid molecules on inert surfaces have not been fully understood. Herein, from the interplay of high-resolution scanning tunneling microscopy imaging and density functional theory calculations, we show the self-assembled structures of Glu and Ser molecules on Au(111), which are dominated by intermolecular hydrogen bonds, and further investigate their most stable structural models at the atomic scale. This study would be of fundamental importance in understanding the formation processes of biologically relevant nanostructures and provide possibilities for chemical modification.

Co-vitrification of municipal solid waste incinerator fly ash and bottom slag: Glass detoxifying characteristics and porous reformation.

Safety and efficient dispose of municipal solid waste incineration (MSWI) fly ash with high toxicity has emerged as a worldwide challenge. Vitrification provides the advantages of capacity reduction, detoxification, and solidification of heavy metals, which has the potential to dispose of hazardous waste on a large scale. Herein, co-vitrification of MSWI fly ash and bottom slag has been accomplished based on the characteristics of calcium and silicon composition. A novel approach for producing glass ceramic foams by alkaline activation-crystallization was developed to realize the disposal of the obtained glass. The effect of MSWI fly ash/bottom slag ratios on the glass network, crystallization ability of the basic glass, pore structure, and physical properties of the porous green body was investigated. The results revealed that with increasing MSWI fly ash proportion, the Si-O of [SiO4] in the basic glass changed significantly and the crystallization ability steadily reduced. Si-O and Al-O in basic glass are easy to corrode under alkaline conditions, releasing Ca2+ and forming a low solubility product, calcium silicate hydrate. When the crystallization temperature increases from 950 â„ƒ to 1150 â„ƒ, it is more conducive to the precipitation of the gehlenite phase. Extending the crystallization time promotes three-dimensional growth of crystals that are coupled with each other to form a network structure and a multi-stage pore structure. The pore structure was developed with the help of NH3 and H2 generated by the secondary aluminum ash (SAA). Through the preparation of glass ceramic foams, the raw materials were detoxified. The toxic heavy metals showed extremely low leaching concentrations, which were smaller than the limit of TCLP. The prepared samples had 70.22-80.61% of porosity, 0.78-1.19 g/cm3 of low bulk density, and 0.54-7.86 MPa of compressive strength.

Interconversion between guanine quartets and triads on the Au(111) surface.

Based on STM imaging and DFT calculations, we show the real-space experimental evidence of the interconversion between G-quartets and G-triads on the Au(111) surface, and further reveal the relative stabilities of these two elementary motifs, which helps to increase the fundamental understanding of the relationship between G-triplex and G-quadruplex DNA structures.

Reduction for heavy metals in pickling sludge with aluminum nitride in secondary aluminum dross by pyrometallurgy, followed by glass ceramics manufacture.

Secondary aluminum dross (SAD) from aluminum industry is classified as a hazardous solid waste due to containing aluminum nitride (AlN). In this work, AlN was first used to reduce heavy metals by pyrometallurgy. The reduction rates for iron, chromium and nickel were up to 90%, 80% and 100%, respectively. However, the reduction from AlN and oxygen oxidization of AlN occurred simultaneously. AlN which formed solid solution with alumina could reduce heavy metals, while the rest was oxidized by oxygen. In addition, the reduction rates for iron and chromium could be increased with increasing CaF2 from 6.7 to 9.0 wt%. CaF2 could decreased viscosity of molten slag, which favored the ion migration, and then increased the reduction rates. After the reduction, glass ceramics were manufactured from the molten slags. The bending strength, microhardness and alkali resistance of the glass ceramics were up to 77 MPa, 1011 HV and 98.7%, respectively. According to XRD and SEM results, glass ceramics with CaAl2SiO6 crystal phase, crosslinked network structure grains and smaller pores exhibited better bending resistance. In addition, glass ceramics with CaAl2SiO6 crystal phase possessed the highest microhardness and alkali resistance. After this process, hazardous pickling sludge and SAD were totally recycled.

Harmless disposal and resource utilization for secondary aluminum dross: A review.

Secondary aluminum dross (SAD) is solid waste of primary aluminum dross extracted aluminum, which contains approximately 40-60 wt% alumina, 10-30 wt% aluminum nitride (AlN), 5-15 wt% salts and other components. The salts include sodium chloride, potassium chloride and fluorine salts. SAD has dual attributes as resource and pollutant. SAD landfill disposal has the disadvantages of occupying land, wasting resources, a high cost and great environmental impact. SAD utilization methods are currently pyrometallurgy and hydrometallurgy. In pyrometallurgy, AlN is oxidized and the salts are evaporated at high temperature. After mixing, molding and calcination, firebricks and ceramics can be manufactured from SAD. In hydrometallurgy, AlN is hydrolyzed and salts are dissolved in water. After dissolving, filtrating, precipitating, washing and calcination, γ-Al2O3 can be prepared from SAD. Resource consumption and emission from both utilization methods were assessed. A ton of magnesium aluminum titanate based ceramics by pyrometallurgy consumes 1043 kg raw materials and releases 69 kg of waste gas, 4.17 t of waste water and no solid waste. A ton of γ-Al2O3 by hydrometallurgy consumes 3389 kg raw materials and releases 111 kg of waste gas, 12.98 t of waste water and 267 kg of solid waste. Therefore, the resource consumption and emission of SAD utilization by pyrometallurgy is lower than that by hydrometallurgy. We should focus on reducing the emission of the three wastes from pyrometallurgy. We are sure that SAD can be utilized for glass ceramics by pyrometallurgy. AlN and salts can be transformed into alumina and glass phases at high temperature with no emission. We should clarify mechanisms for SAD composition adjustment to lower the glass ceramics' melting point, AlN and salts transformed into alumina and glass phases respectively, and nucleation and crystal growth of glass ceramics at high temperature.

High N2 selectivity in selective catalytic reduction of NO with NH3 over Mn/Ti-Zr catalysts.

A series of Mn-based catalysts were prepared by a wet impregnation method for the selective catalytic reduction (SCR) of NO with NH3. The Mn/Ti-Zr catalyst had more surface area, Lewis acid sites, and Mn4+ on its surface, and showed excellent activity and high N2 selectivity in a wide temperature range. NH3 and NO oxidation was investigated to gain insight into NO reduction and N2O formation. The formation of N2O was primarily dominated by the reaction of NO with NH3 in the presence of O2 via the Eley-Rideal mechanism. An intimate synergistic effect existed between the Mn-based and the Ti-Zr support. It was demonstrated that the Ti-Zr support greatly promoted the catalytic performance of Mn-based catalysts.

Characterization of the APP/PS1 mouse model of Alzheimer's disease in senescence accelerated background.

The APP/PS1 mouse model of Alzheimer's disease (AD) exhibits remarkable elevation of ß-amyloid production associated with certain behavioral abnormalities, while the senescence accelerated mouse prone 8 (SAMP8) is characterized by early and age-related deterioration of learning and memory. In order to obtain an AD model that develops earlier pathological changes and cognitive impairment, we generated SAMP8-APP/PS1, a novel senescence accelerated APP/PS1 transgenic mouse model of AD. Standard histological staining and immunohistochemistry using an amyloid beta (Aß) antibody showed an age, genotype and strain-dependent progression of amyloid deposition and neuron loss in the cerebral cortex and hippocampus of SAMP8-APP/PS1 mice. Results from the cognitive behavioral tests revealed early deficits in learning and memory in SAMP8-APP/PS1 mice in the two way active avoidance and Morris water maze tests compared with C57-APP/PS1, SAMP8 wild-type and control mice. These results suggest that accelerated senescence exacerbates amyloid deposition and cognitive dysfunction in APP/PS1 mice and the senescence accelerated-APP/PS1 (SAMP8-APP/PS1) mouse model might be a valuable tool to study AD progression and to evaluate the effect of drugs on AD.

Effects of accelerated senescence on learning and memory, locomotion and anxiety-like behavior in APP/PS1 mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is characterized by a deficit in motor and spatial learning-memory and alteration of non-cognitive behavior. The generation of transgenic mice with presence of AD pathologies that cause learning and memory deficits has led to improved understanding of the behavioral and pathophysiological processes underlying AD. A novel APP/PS1 mouse model in the senescence accelerated mouse prone 8 (SAMP8) background--SAMP8 APP/PS1 was generated. To assess the behavioral and other AD-related changes in this SAMP8 APP/PS1 model, the present report covers a phenotypical analysis of this model for working memory, spatial memory, motor performance and anxiety-like behavior. SAMP8 APP/PS1 mice showed motor and spatial memory impairments, together with an increase of locomotor activity and lower anxiety-like behavior at 9months old. In contrast, C57 APP/PS1 and SAMP8 wild type mice were inconspicuous in all of these tasks and properties except C57 APP/PS1 mice which showed motor memory impairment in the shuttle box task at 9 months old. Standard senescence-associated beta-galactosidase (SA-beta-GAL) staining and amyloid beta (Aß) immunohistochemistry showed more severe pathological changes in the SAMP8 APP/PS1 mice. SAMP8 APP/PS1 mice exhibited earlier deficits in their non-cognitive and cognitive behaviors which are coincident in the AD patient and the results suggest that this new type of mice might be a better model for studying the age-related dementia of the Alzheimer type and for assessing the potential therapeutic agents for AD.

ZY-1, a novel nicotinic analog, promotes proliferation and migration of adult hippocampal neural stem/progenitor cells.

Neural stem/progenitor cells (NSPCs) of the subgranular zone have been implicated in cognitive processes, which represent a potentially important source of regenerative medicine for the treatment of neurodegenerative diseases such as Alzheimer's disease (AD). In our previous studies, ZY-1, a novel nicotinic analog, improved cognitive function in transgenic mice model of AD. However, the effect of ZY-1 on the NSPCs remains unclear. Here, we show that ZY-1 significantly increased proliferation and migration of NSPCs, but failed to affect NSPCs differentiation in vitro. Furthermore, during the proliferative period, ZY-1 enhanced intracellular reactive oxygen species (ROS) levels. Meanwhile, ZY-1 also inhibited the levels of Aß42-induced ROS. Our data indicate that ZY-1 regulates adult hippocampal neurogenesis in vitro, at least partly due to modulating intracellular ROS levels. These results, taken together with those of our previous studies, suggest that ZY-1 might have a potential therapeutic effect for the treatment of AD.

New nicotinic analogue ZY-1 enhances cognitive functions in a transgenic mice model of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder marked by progressive loss of memory and cognitive function. One of the new approaches for treating AD is direct stimulation of nicotinic acetylcholine receptors (nAChRs) in the brain. α4ß2-nAChR agonists have shown promising potential in preclinical cognition models of AD. The present report describes the pharmacological properties of ZY-1, a new nicotinic analogue that activates α4ß2-nAChR. We describe in detail the binding profile and pharmacological effects of ZY-1 on transgenic AD mice. ZY-1 has high affinity to α4ß2-nAChR. In a Morris water maze test, ZY-1 significantly decreases the escape latency and increases both the times in the platform quadrant and the times of platform crossing of transgenic mice. ZY-1 enhances cognitive functions in transgenic mice models of AD. As a novel nicotinic analogue, ZY-1 deserves further study as a potential candidate against AD.

Structural characterization and radioprotection of bone marrow hematopoiesis of two novel polysaccharides from the root of Angelica sinensis (Oliv.) Diels.

Two novel homogeneous polysaccharides, APS-1a and APS-3a were successfully isolated from the root of Angelica sinensis. APS-1a was composed of galactose, arabinose and glucose in a relatively molar percentage of 57.34%, 27.67% and 14.98%, and had a molecular weight of 49.0kDa, whereas APS-3a was composed of galactose, arabinose and glucose in a relatively molar percentage of 84.54%, 6.50%, and 8.96%, and had a molecular weight of 65.4kDa. APS-1a and APS-3a mainly consisted of 1,4-linked galactose, 1,3,6-linked galactose, T-galactose and T-arabinose, and the molar ratio of each linkage was different between APS-1a and APS-3a. The bioactivity analysis showed that APS-1a and APS-3a increased the thymus and spleen index, the number of red blood cell (RBC) and white blood cell (WBC) in peripheral blood and the cellularity of bone marrow cell numbers in irradiated mice, protected mice against radiation-induced micronucleus formation in bone marrow, suggesting that polysaccharides could be used as radioprotective agents, especially for promoting bone marrow hematopoiesis.