An evaluation of mercury emissions from the chlor-alkali industry in China

The present status and the history of chlor alkali industry using mercury as cathode in China has been studied. Quantitative mercury emission has been estimated. At present, 17.5%—20% of the consumed mercury is released into water, 49.1%—53.3% of the Hg is discharged to the brine system outside the plants. 10%—14% of the Hg is emitted directly to the atmosphere, 5 3%—6 7% enters waste materials. The chlor alkali industry in China discharged about 17 tons every year. The total amount of mercury released by the chlor alkali industry in China is estimated to be 1400—2700 tons since 50's. With the result of improved technology and more strict environmental regulations started in late 1970's, chlorine plants reduced their mercury loss factor from 0 5? ? 4 kg/t NaOH before 1977 to 0.16—0.18 kg/t NaOH in 1997. The number of mercury cells in alkali plants was also reduced. In 1998, China is planning to finish the history of producing chlorine and caustic soda using the mercury cell process in the near future. How to deal with the emitted mercury will remain a main problem.

Comparative Study on Application of Bimetallic Pt-Based Alloy Electrocatalysts in Advanced Chlor-Alkali Electrolysis

Application of an oxygen-depolarized cathode will contribute to energy saving in chlor-alkali electrolysis. For this purpose, the development of high-performance cathode with the best electrocatalyst is essential. Using bimetallic Pt-based alloy electrocatalysts including PtPd and PtAg carbon-supported in oxygen-depolarized cathode chlor-alkali cell has been shown to have the high cell performance. This study presents application of PtRu carbon supported electrocatalyst oxygen-depolarized cathode and performance comparison of cells with carbon-supported PtRu, PtPd and PtAg electrocatalysts cathodes using the same DSA-Cl2 anode. Results show that there are quite similarity between the effects of various factors on the caustic current efficiency (CCE) in a zero-gap oxygen-depolarized chlor-alkali cells employing carbon-supported PtPd, PtRu and PtAg electrocatalysts. Besides, it seems that the PtPd/C electrocatalyst cathode has relatively higher performance than the other cathodes with PtAg/C and PtRu/C electrocatalysts in zero-gap chlor-alkali cells.

Elevated Mercury in Ambient Air and Soils Impacts of Historical Air Emissions (1897-1991) from a Chlor-Alkali Plant (CAP)

Mercury contamination was found to be widespread in soils at a property in Upstate New York. Historical site use suggested that the mercury did not result from prior industrial use of the property. Soil contamination may have resulted from atmospheric deposition of mercury released from properties in close proximity to the contaminated property. The purpose of this forensics investigation was to examine to what extent atmospheric deposition of elemental mercury may have influenced mercury levels found in surficial soils on the contaminated property and further to identify the source(s) of the mercury. Work efforts included an examination of historical records available for a chlor-alkali plant (CAP) upwind of the contaminated property to establish historical use and disposal practices for elemental mercury. Mercury emissions test data from the Upstate New York chlor-alkali facility were modeled (USEPA ISC3) as a means of estimating impacts on ambient air and soils vicinal to the facility. Mercury emissions from the facility were modeled as both a point source and volume source. For example, at a location 305 meters to the east and 30 meters to the north of the modeled source centerline elemental mercury concentrations in ambient air were estimated at 270 ng/m3 (average results based upon 5 years of meteorological data). This value is contrasted to a background concentration of 1.6 ng/m3 (USEPA Report to Congress 1997). As a result of the modeling data in combination with findings related to mercury use and disposal practices at the NY CAP documented from the records review, it was concluded that emissions from the CAP facility during the period of operation (1897-1991) most likely accounted for the concentrations of elemental mercury found in surficial soils at properties situated downwind of the CAP. These findings were further corroborated by information available in the open literature for CAPs world-wide.

Response of Rice Growth and Nutrient Absorption in a SalineAlkali Paddy to Different Nitrogen Fertilizer Applications

Nitrogen(N),phosphorus(P)and carbon(C)are essential nutrients for rice growth and development,but the response of nutrient absorption by rice plants to different types of nitrogen fertilizer(N-fertilizer)under saline-alkali conditions is unclear.This study conducted a 147-day field-scale experiment to evaluate rice biomass and nutrient absorption capacity with five N-fertilizer applications.The results showed that the biomass.

The Decarbonization of Construction—How Can Alkali-Activated Materials Contribute?

1.Introduction and context Enormous emphasis is currently being paid to the decarbonization of the global built environment as a leading priority for the engineering community and related industrial sectors[1].One of the main contributors to the overall emissions footprint of the built environment-and thus a cornerstone of efforts to achieve decarbonization-is the emissions profile of construction materials during their production and utilization.The cement and concrete sector is the largest-volume contributor to the emissions incurred in meeting the world’s construction material needs and is therefore targeted in the discussion of the deep,rapid decarbonization that must be achieved in order to minimize irreversible damage to the Earth and its ecosystems.

Calcium carbonate-associated milk-alkali syndrome as a cause of altered mental status in the emergency department:a case report

Hypercalcemic crises as a result of milk-alkali syndrome(MAS)are an uncommon cause of altered mental status and acute renal failure in the emergency department.Although it is uncommonly reported in the emergency medicine literature,emergency physicians should be aware of this syndrome due to significant morbidity and mortality if left undiagnosed.

Steric hindrance shielding viologen against alkali attack in realizing ultrastable aqueous flow batteries

Viologens known as a kind of promising negolyte materials for aqueous organic redox flow batteries,face a critical stability challenge due to the S_N2 nucleophilic attack by hydroxide ions(OH-)during the battery cycling.In this work,a N-cyclic quaternary ammonium-grafted viologen molecule,viz.1,1'-bis(4,4'-dime thylpiperidiniumyl)-4,4'-bipyridinium tetrachloride((DBPPy)Cl_(4)),is developed by the molecular engineering strategy.The obtained(DBPPy)Cl_(4) molecule shows a decent solubility of 1.84 M and a redox potential of-0.52 V vs.Ag/AgCl,Experimental and theoretical results reveal that the grafted N-cyclic quaternary ammonium groups act as the steric hindrance to prevent nucleophilic attack by OH~-,increasing the alkali resistance of the electroactive molecule.The symmetrical battery with 0.50 M(DBPPy)Cl4shows negligible decay during the 13-day cycling test.As demonstration,the flow battery utilizing 1.0 M(DBPPy)Cl_(4) as the negolyte and 1-(1-oxyl-2,2',6,6'-tetramethylpiperidin-4-yl)-1'-(3-(trimethylammonio)propyl)-4,4'-bipyridinium trichloride as the posolyte exhibits a high capacity retention rate of 99.99%per cycle at 60 mA cm^(-2).

Insight into the Alkali Resistance Mechanism of CoMnHPMo Catalyst for NH_(3) Selective Catalytic Reduction of NO

The existence of alkali metals in fl ue gases originating from stationary sources can result in catalyst deactivation in the low-temperature selective catalytic reduction(SCR)of nitrogen oxides(NO_(x)).It is widely accepted that alkali metal poisoning causes damage to the acidic sites of catalysts.Therefore,in this study,a series of CoMn catalysts doped with heteropolyacids(HPAs)were prepared using the coprecipitation method.Among these,CoMnHPMo exhibited superior catalytic performance for SCR and over 95%NO_(x) conversion at 150-300.Moreover,it exhibited excellent catalytic activity and stability after alkali poisoning,demonstrating outstanding alkali metal resistance.The characterization indicated that HPMo increased the specifi c surface area of the catalyst,which provided abundant adsorption sites for NO_(x) and NH_(3).Comparing catalysts before and after poisoning,CoMnHPMo enhanced its alkali metal resistance by sacrifi cing Brønsted acid sites to protect its Lewis acid sites.In situ DRIFTS was used to study the reaction pathways of the catalysts.The results showed that CoMnHPMo maintained high NH_(3) adsorption capacity after K poisoning and then reacted rapidly with NO intermediates to ensure that the active sites were not covered.Consequently,SCR performance was ensured even after alkali metal poisoning.In sum-mary,this research proposed a simple method for the design of an alkali-resistant NH_(3)-SCR catalyst with high activity at low temperatures.

Alkali Tolerance of Concrete Internal Curing Agent Based on Sodium Carboxymethyl Starch

Internal curing agents (ICA) based on super absorbent polymer have poor alkali tolerance and reduce the early strength of concrete.An alkali tolerate internal curing agent (CAA-ICA) was designed and prepared by using sodium carboxymethyl starch (CMS) with high hydrophilicity,acrylic acid (AA) containing anionic carboxylic group and acrylamide (AM) containing non-ionic amide group as the main raw materials.The results show that the ratio of CAA-ICA alkali absorption solution is higher than that existing ICA,which solves the low water absorption ratio of the ICA in alkali environment.The water absorption ratio of CAA-ICA in saturated Ca(OH)_(2) solution is 95.8 g·g^(-1),and the alkali tolerance coefficient is 3.4.The application of CAA-ICA in cement-based materials can increase the internal relative humidity and miniaturize the pore structure.The compressive strength of mortar increases up to 12.95%at 28 d,which provids a solution to overcome the reduction of the early strength.

Alkali burn injury model of meibomian gland dysfunction in mice

AIM:To establish a stable,short-time,low-cost and reliable murine model of meibomian gland dysfunction(MGD).METHODS:A filter paper sheet soaked in 1.0 mol/L sodium hydroxide(NaOH)solution was used to touch the eyelid margin of C57BL/6J mice for 10s to establish the model.The other eye was left untreated as a control group.Eyelid margin morphological changes and the meibomian glands(MGs)were observed by slit lamp microscopy on days 5 and 10 post-burn.Hematoxylin-eosin(HE)staining and Oil red O staining were adopted in detecting the changes in MGs morphology and lipid deposition.Real-time polymerase chain reaction,Western blot,immunofluorescence staining and immunohistochemical staining were used to detect interleukin(IL)-6,IL-1β,IL-18,tumor necroses factor(TNF)-α,interferon(IFN)-γ,nicotinamide adenine dinucleotide phosphate(NADPH)oxidase 4(NOX4),3-nitroturosine(3-NT),4-hydroxynonenal(4-HNE)and cytokeratin 10(K10)expression changes in MGs.RESULTS:MGs showed plugging of orifice,glandular deficiency,abnormal acinar morphology,ductal dilatation,and lipid deposition after alkali burn.The expressions of IL-6,IL-18,IL-1β,IFN-γ,and TNF-αindicators of inflammation and oxidative stress in MGs tissues were significantly increased.Abnormal keratinization increased in the MG duct.CONCLUSION:A murine model of MGD is established by alkali burn of the eyelid margin that matches the clinical presentation of MGD providing a stable,short-time,lowcost,and reliable MGD model.The new method suggests efficient avenues for future research.

Residual alkali-evoked cross-linked polymer layer for anti-air-sensitivity LiNi_(0.89)Co_(0.06)Mn_(0.05)O_(2)cathode

High-energy density lithium-ion batteries(LIBs)with layered high-nickel oxide cathodes(LiNi_(x)Co_(y)Mn_(1-x-y)O_(2),x≥0.8)show great promise in consumer electronics and vehicular applications.However,LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)faces challenges related to capacity decay caused by residual alkalis owing to high sensitivity to air.To address this issue,we propose a hazardous substances upcycling method that fundamentally mitigates alkali content and concurrently induces the emergence of an anti-air-sensitive layer on the cathode surface.Through the neutralization of polyacrylic acid(PAA)with residual alkalis and then coupling it with 3-aminopropyl triethoxysilane(KH550),a stable and ion-conductive cross-linked polymer layer is in situ integrated into the LiNi_(0.89)Co_(0.06)Mn_(0.05)O_(2)(NCM)cathode.Our characterization and measurements demonstrate its effectiveness.The NCM material exhibits impressive cycling performance,retaining 88.4%of its capacity after 200 cycles at 5 C and achieving an extraordinary specific capacity of 170.0 mA h g^(-1) at 10 C.Importantly,this layer on the NCM efficiently suppresses unfavorable phase transitions,severe electrolyte degradation,and CO_(2)gas evolution,while maintaining commendable resistance to air exposure.This surface modification strategy shows widespread potential for creating air-stable LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)cathodes,thereby advancing high-performance LIBs.

Alkali and Plasma-Treated Guadua angustifolia Bamboo Fibers:A Study on Reinforcement Potential for Polymeric Matrices

This study focuses on treating Guadua angustifolia bamboo fibers to enhance their properties for reinforcement applications in composite materials.Chemical(alkali)and physical(dry etching plasma)treatments were used separately to augment compatibility of Guadua angustifolia fibers with various composite matrices.The influence of these treatments on the fibers’performance,chemical composition,and surface morphology were analyzed.Statistical analysis indicated that alkali treatments reduced the tensile modulus of elasticity and strength of fibers by up to 40%and 20%,respectively,whereas plasma treatments maintain the fibers’mechanical performance.FTIR spectroscopy revealed significant alterations in chemical composition due to alkali treatments,while plasma-treated fibers showed minimal changes.Surface examination through Scanning Electron Microscopy(SEM)revealed post-treatment modifications in both cases;alkali treatments served as a cleanser,eliminating lignin and hemicellulose from the fiber surface,whereas plasma treatments also produce rough surfaces.These results validate the impact of the treatments on the fiber mechanical performance,which opens up possibilities for using Guadua angustifolia fibers as an alternative reinforcement in composite manufacturing.

Defect Engineering in Earth-Abundant Cu_(2)ZnSnSe_(4) Absorber Using Efficient Alkali Doping for Flexible and Tandem Solar Cell Applications

To demonstrate flexible and tandem device applications,a low-temperature Cu_(2)ZnSnSe_(4)(CZTSe)deposition process,combined with efficient alkali doping,was developed.First,high-quality CZTSe films were grown at 480℃by a single co-evaporation,which is applicable to polyimide(PI)substrate.Because of the alkali-free substrate,Na and K alkali doping were systematically studied and optimized to precisely control the alkali distribution in CZTSe.The bulk defect density was significantly reduced by suppression of deep acceptor states after the(NaF+KF)PDTs.Through the low-temperature deposition with(NaF+KF)PDTs,the CZTSe device on glass yields the best efficiency of 8.1%with an improved Voc deficit of 646 mV.The developed deposition technologies have been applied to PI.For the first time,we report the highest efficiency of 6.92%for flexible CZTSe solar cells on PI.Additionally,CZTSe devices were utilized as bottom cells to fabricate four-terminal CZTSe/perovskite tandem cells because of a low bandgap of CZTSe(~1.0 eV)so that the tandem cell yielded an efficiency of 20%.The obtained results show that CZTSe solar cells prepared by a low-temperature process with in-situ alkali doping can be utilized for flexible thin-film solar cells as well as tandem device applications.

Recovery of Solid Oxide Fuel CellWaste Heat by Thermoelectric Generators and AlkaliMetal Thermoelectric Converters

A Solid Oxide Fuel Cell(SOFC)is an electrochemical device that converts the chemical energy of a substance into electrical energy through an oxidation-reduction mechanism.The electrochemical reaction of a solid oxide fuel cell(SOFC)generates heat,and this heat can be recovered and put to use in a waste heat recovery system.In addition to preheating the fuel and oxidant,producing steam for industrial use,and heating and cooling enclosed rooms,this waste heat can be used for many more productive uses.The large waste heat produced by SOFCs is a worry that must be managed if they are to be adopted as a viable option in the power generation business.In light of these findings,a novel approach to SOFC waste heat recovery is proposed.The SOFC is combined with a“Thermoelectric Generator and an Alkali Metal Thermoelectric Converter(TG-AMTC)”to transform the excess heat generated by both the SOFC and the TG-AMTC.The proposed TG-AMTC is evaluated using a number of performance indicators including power density,operating temperature,heat recovery rate,exergetic efficiency,energy efficiency,and recovery time.The experimental results state that TG-AMTC has provided an exergetic efficiency,energetic efficiency,and recovery time of 97%,98%,and 23%,respectively.The study proves that the proposed TG-AMTC for SOFC is an efficient method of recovering waste heat.

Coordination and Supramolecular Assemblies from Alkali+-Cucurbit[5]uril-[CdCl_(4)]^(2-)Systems

Thispaper has investigated the coordination and supramolecular assemblies of alkali metal ions,cucurbit[5]uril(Q[5]),and[CdCl_(4)]^(2-)to confirm whether[CdCl_(4)]^(2-)can produce the“honeycomb effect”,induce coordination of alkali metal ions to Q[5],and form linear coordination polymers.In this work,the effect of alkali metal ions on the construction of Q[5]-Cd^(2+)ion system under acidic conditions was investigated.Five complexes were successfully obtained by solvent evaporation method.Among the five crystal structures obtained,it can be observed that the presence of[CdCl_(4)]^(2-)did not result in the complexation of alkali metal ions by the Q[5]molecule.Instead,a bowl-like Cd^(2+)@Q[5]complex was formed.Indeed,[CdCl_(4)]^(2-)did not produce the honeycomb effect but led to the formation of Q[5]-based honeycomb frameworks with hexagonal cellsoccupied by[CdCl_(4)]^(2-).The experimental results show that cadmium ion showed stronger ability to coordinate to Q[5]in HCl solution.

Fundamental Study on Alkali-Activated Slag System with Sodium Carbonate or Calcium Hydroxide

Cement as a building material, has high fluidity, compressive strength, and durability, but carbon dioxide emissions during cement production are a major problem. As one of the countermeasures, alkali-activated cement using blast furnace slag powder with alkaline stimulants is considered to be a very promising solution for reducing carbon dioxide emissions, but there is a lack of information about the fundamental properties of alkali-activated materials. This study presents an experimental investigation of the fundamental properties of an alkali-activated slag system with sodium carbonate (NC) and calcium hydroxide (CH). The effects of calcium sulfo-aluminate (CSA) and shrinkage reducing agent (SRA) on the properties of blast furnace slag (BFS) based alkali-activated mixture were also investigated. In the experiments, fundamental characteristics including compressive strength, drying shrinkage, and water penetration tests of mortar were evaluated. Porosity, pH, and ignition loss were measured to verify the effectiveness of the materials. The experimental investigation revealed that the compressive strength was increased with the increasing replacement rates of NC in the BFS mortar, and in the case of water to BFS ratio of 0.45 with sodium carbonation addition contents 10 wt.%, the compressive strength for 28 days of curing reaches more than 50 MPa. Low water to BFS ratio and higher addition ratio of NC had a positive effect on the compressive strength development of mortar. Incorporating NC into BFS would affect the decrease in porosity and increase in ignition loss, leading to higher compressive strength. There was a negligible change to the compressive strength, porosity, pH, and ignition loss of BFS samples made with CH, thus, the addition rates of CH to BFS have no or little significant effect on the fundamental properties of alkali-activated cement. From the results of drying shrinkage and water penetration tests, the addition of NC and CH only to BFS exhibited poor drying shrinkage and water penetration characteristics. However, these problems may be overcome due to the use of CSA or SRA in the alkali-activated system made with NC or CH.

Performance characterization, of rigid polyurethane foam with refined alkali lignin and modified alkali lignin

The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.

Reaction behaviour of Al_2O_3 and SiO_2 in high alumina coal fly ash during alkali hydrothermal process

The reaction behaviours of A1203 and SiO2 in high alumina coal fly ash under various alkali hydrothermal conditions were studied. The means of XRD, XRF, FTIR and SEM were used to measure the mineral phase and morphology of the solid samples obtained by different alkali hydrothermal treatments as well as the leaching ratio of SiO2 to A1203 in alkali solution. The results showed that with the increase of the hydrothermal treating temperature from 75 to 160 ~C, phillipsite-Na, zeolite A, zeolite P, and hydroxysodalite were produced sequentially while the mullite and corundum phase still remained. Zeolite P was massively formed at low-alkali concentration and the hydroxysodalite was predominantly obtained at high-alkali concentration. By the dissolution of aluminosilicate glass and the formation of zeolites together, the leaching efficiency of SiO2 can reach 42.13% with the mass ratio of A1203/SIO2 up to 2.19：1.

Reaction pathway led by silicate structure transformation on decomposition of CaSiO_3 in alkali fusion process using NaOH

The mechanism of decomposition of calcium inosilicate(CaSiO_3) synthesized through chemical deposition method using analytical reagent NaSiO_3·9H_2O and CaCl_2 during the alkali fusion process using NaOH was investigated by Raman spectroscopy in situ,X-ray diffraction and Fourier transform infrared spectrometer(FTIR).The results show that the tetrahedral silica chains within CaSiO_3 are gradually disrupted and transformed into nesosilicate with the isolated SiO_4 tetrahedra at the beginning of the alkali fusion process.The three intermediates including Ca_2SiO_4,Na_2CaSiO_4 and Na_2SiO_3 appear simultaneously in the decomposition of CaSiO_3,while the final products are Ca(OH)_2 and Na_4SiO_4.It can be concluded that there exist two reaction pathways in the alkali fusion process of CaSiO_3:one is ion exchange,the other is in the main form of the framework structure change of silicate.The reaction pathway is led by silicate structure transformation in the alkali fusion process.

Effect of alkali treatments on apatite formation of microarc-oxidized coating on titanium alloy surface

Alkali treatments with three concentrations were used to modify a microarc-oxidized(MAO) coating on titanium alloy surface in order to further improve its surface bioactivity. Morphology, chemical compositions and phase constitues, roughness, contact angle and apatite induction of the alkali-treated coatings were studied and compared. Scanning electron microscope(SEM) was applied to observe the morphologies, X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) were used to detect the phase constitutes and chemical compositions, a surface topography profilometer was used to analyze the surface roughness, and contact angle was measured by liquid drop method. Alkali treatements result in the formation of Na2Ti6O13 and Na2Ti3O7 phase on the MAO coating, which leads to the increase of surface roughness and the decrease of contact angle. Experimental results showed that the apatite induction of the alkali-treated coatings was dependent on the applied alkali concentrations during treatments, and Na+concentration can promote the formation of apatite phase.