Hydrothermal Synthesis of Xonotlite-type Calcium Silicate Insulation Material Using Industrial Zirconium Waste Residue

Xonotlite-type insulation material was prepared by hydrothermal synthesis technology using industrial zirconium waste residue in this paper,and the phase analysis together with the observation of micro–morphology were also carried out by XRD,SEM and TEM.The density and thermal conductivity were measured finally.The results indicate,chlorine ion impurity contained in zirconium waste residue can be removed effectively via water washed process,and the reactive activity of silicon dioxide is almost not affected,which make it be a good substitution of silicon material for the preparation of calcium silicate insulation material by hydrothermal synthesis technique.The density and thermal conductivity of xonotlite-type calcium silicate insulation material obtained by hydrothermal synthesis technique can reach 159 kg/m3,0.049 W/（m·° C）,respectively,meeting with National Standard well,when synthesis conditions are selected as follows：Ca/Si molar ratio equal to 1,synthesis temperature at 210°C and kept for 8 hrs.It provides a new approach to realize lightweight and low thermal conductivity of calcium silicate insulation material.

Comprehensive Recycling Technology of Waste Residues in Zinc Hydrometallurgy

In order to improve the refining effect of zinc ore and promote the development of this industry,taking the hydrometallurgical zinc smelting process as an example,this paper first establishes a model for the recycling of waste residues in the hydrometallurgical process,proposes optimization measures based on proven comprehensive recycling technology for purifying residues to obtain higher valuable metal recovery rate,and provides reference for those in relevant fields.

Selective recovery of Th(Ⅳ) from radioactive rare earth waste residue by utilizing MoS_(2)-modified ion-absorbed type rare earth tailings

In the process of extracting ion-absorbed rare earth ore(IREO),the production of radioactive waste is a major environmental concern.To address this issue,MoS_(2) was used to modify ion-absorbed rare earth tailings(RET) to synthesize a novel MoS_(2)@RET composite material for the effective handling of radioactive waste generated in IREO separation industry.The composite material was thoroughly characterized using various analytical techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),thermogravimetry(TG),Fourier-transform infrared(FTIR),scanning electron microscopy(SEM),Brunaue r-Emmett-Teller(BET) and energy dispersive spectroscopy(EDS).By optimizing the operating parameters,the optimal experimental conditions were determined to be pH=3,contact time=60 min,liquid-solid ratio=6 g/L,and initial concentration=150 mg/L.The adsorption data fitted well with the pseudo second-order rate model.The thermodynamic parameters concerning the adsorption of Th(Ⅳ) were analyzed and computed.Langmuir isotherm model is a more fitting choice for the adsorption process compared to the Freundlich isotherm model.MoS_(2)@RET was used in the acid leachate of IREO waste residue,achieving the separation of Th and rare earth successfully.The mechanism of Th(Ⅳ) adsorption by MoS_(2)@RET was investigated,revealing that the adsorption process involves electrostatic interactions,chemical bonding,and redox reactions.The above research results indicate that MoS_(2)@RET composite materials have application potential in the sustainable treatment of IREO radioactive waste.

Shearing-force-driven delamination of waste residue into oxidatively stable MXene composites for high-performance Si anode

The low yield of MXene is normally related to the delaminating step,contributing to the key technical challenges in moving toward industrial applications.Here,a shearing-force-driven strategy is proposed for re-exfoliating waste MXene residue to prepare oxidatively stable MXene composites in a low-cost manner,where the strong shear stress in the assisted solvent,such as carbon nanotubes(CNTs),chitosan(CS),and polyacrylamide(PAM)aqueous solutions,acts on the surface of MXene(Ti_(3)C_(2)T_(x))through coordination between hydroxyl and Ti atoms,resulting in a rapid and efficient exfoliation of waste Ti_(3)C_(2)T_(x)residue under stirring.Furthermore,this formed coordinate bond helps to stabilize the low-valent Ti atoms on the surface of MXene,thereby enhancing the oxidative stability of Ti_(3)C_(2)T_(x).Besides,the CNT@MXene composite is selected to construct a free-standing membrane to encapsulate Si nanoparticles,achieving a high and reversible capacity after 50 cycles.This work supports the concept of valorizing waste and adopts a fluid shear forceassisted method to re-exfoliate waste residues,which greatly reduces the cost of processing and improves the chemical stability of MXene.More importantly,this work has uncovered a new direction for the commercialization of MXene composites and has significantly improved the realworld applications of MXene-based materials.

Analysis of a Composite Admixture Based on Ready-Mixed Concrete Waste Residuals

Reasonable treatment and utilization of waste residuals discharged during the production of ready-mixed concrete is an important problem in the cement industry.In this study,a composite admixture was prepared by using ready-mixed concrete waste residuals,furnace slag,and water granulated slag.The grinding characteristics of such material were investigated.Moreover,the effect of such admixture on cement hydration and pore structure was analyzed by X-ray diffraction,thermogravimetric-differential scanning calorimetry,scanning electron microcopy and mercury intrusion porosimetry.As shown by the results:The grinding characteristics of the waste residuals can be improved significantly by mixing them with furnace slag and water granulated slag.Furthermore,the composite admixture does not change the composition of hydration products;rather it contributes to refine the pore structure of the matrix,thus improving the mechanical properties of these cement-based materials.

Recycling of waste carbon residue from spent lithium-ion batteries via constant-pressure acid leaching

Waste carbon residue(WCR)was efficiently detoxicated and regenerated to high-purity graphite(PGC)used in lithium-ion batteries through the constant-pressure acid leaching technique.The leaching conditions were optimized by the combination of orthogonal and single-factor experiments.Results show that PGC with 99.5%purity is regenerated at temperature of 60℃,initial acid concentration of 12%,leaching time of 180 min,and liquid-to-solid ratio of 25:1,satisfying the requirements of commercial graphite.Meanwhile,the sodium hydroxide precipitation process was designed to recover valuable components from leachate efficiently.Ni,Co,Mn,and Al recoveries reach 96.92%,87.5%,97.83%,and 92.17%,respectively,at pH=11.Moreover,the co-product NaF can be recovered with purity over 99%via evaporative crystallization.The loss rate of fluorine is less than 0.5%,thereby eliminating the pollution risk of fluorine to the environment.The proposed process shows considerable environmental and economic benefits.

New Insights into Microplastic Contamination in Different Types of Leachates: Abundances, Characteristics, and Potential Sources

Municipal solid waste(MSW)is an important destination for abandoned plastics.During the waste disposal process,large plastic debris is broken down into microplastics(MPs)and released into the leachate.However,current research only focuses on landfill leachates,and the occurrence of MPs in other leachates has not been studied.Therefore,herein,the abundance and characteristics of MPs in three types of leachates,namely,landfill leachate,residual waste leachate,and household food waste leachate,were studied,all leachates were collected from the largest waste disposal center in China.The results showed that the average MP abundances in the different types of leachates ranged from(129±54)to(1288±184)MP particles per liter(particlesL1)and the household food waste leachate exhibited the highest MP abundance(p<0.05).Polyethylene(PE)and fragments were the dominant polymer type and shape in MPs,respectively.The characteristic polymer types of MPs in individual leachates were different.Furthermore,the conditional fragmentation model indicated that the landfilling process considerably affected the size distribution of MPs in leachates,leading to a higher percentage(>80%)of small MPs(20–100 lm)in landfill leachates compared to other leachates.To the best of our knowledge,this is the first study discussing the sources of MPs in different leachates,which is important for MP pollution control during MSW disposal.

Biodegradation of Medicinal Plants Waste in an Anaerobic Digestion Reactor for Biogas Production

Glycyrrhiza glabra,Mint,Cuminum cyminum,Lavender and Arctium medicinal are considered as edible plants with therapeutic properties and as medicinal plants in Iran.After extraction process of medicinal plants,residual wastes are not suitable for animal feed and are considered as waste and as an environmental threat.At present there is no proper management of waste of these plants and they are burned or buried.The present study discusses the possibility of biogas production from Glycyrrhiza Glabra Waste(GGW),Mentha Waste(MW),Cuminum Cyminum Waste(CCW),Lavender Waste(LW)and Arctium Waste(AW).250 g of these plants with TS of 10%were digested in the batch type reactors at the temperature of 35℃.The highest biogas production rate were observed to be 13611 mL and 13471 mL for CCW and GGW(10%TS),respectively.While the maximum methane was related to GGW with a value of 9041 mL(10%TS).The highest specific biogas and methane production were related to CCW with value of 247.4 mL.(g.VS)-1 and 65.1 mL.(g.VS)-1,respectively.As an important result,it was obvious that in lignocellulose materials,it cannot be concluded that the materials with similar ratio of C/N has the similar digestion and biogas production ability.

High Water Content Material Based on Ba-Bearing Sulphoaluminate Cement

A new type of high water content material which is made up of two pastes is prepared, one is refute from lime and gypsum, and another is based on Ba-bearing sulphoaluminate cement. It has excellent properties such as slow single paste solidifing ,fust double pustes solidifing ,fast coagulating and hardening, high early strength, good suspeasion property at high W/C ratio and low cost. Meanwhile, the properties and hydration mechanism of the material were analyzed by using XRD, DTA- TG and SEM. The hydrated products of new type of high water content material are Ba-bearing ettringite, BaSO4 , aluminum gel and C-S-H gel.

Arsenic biotransformation in industrial wastewater treatment residue: Effect of co-existing Shewanella sp.ANA-3 and MR-1

Shewanella sp. ANA-3 with the respiratory arsenate reductase(ArrAB) and MR-1 with ferric reduction ability always coexist in the presence of high arsenic(As)-containing waste residue. However, their synergistic impacts on As transformation and mobility remain unclear. To identify which bacterium, ANA-3 or MR-1, dominates As mobility in the coexisting environment, we explored the As biotransformation in the industrial waste residue in the presence of Shewanella sp. ANA-3 and MR-1. The incubation results show that As(Ⅲ)was the main soluble species, and strain ANA-3 dominated As mobilization. The impact of ANA-3 was weakened by MR-1, probably due to the survival competition between these two bacteria. The results of micro X-ray fluorescence and X-ray photoelectron spectroscopy analyses further reveal the pathway for ANA-3 to enhance As mobility. Strain ANA-3 almost reduced 100% surface-bound Fe(Ⅲ), and consequently led to As(V) release. The dissolved As(V) was then reduced to As(Ⅲ) by ANA-3. The results of this study help to understand the fate of arsenic in the subsurface and highlight the importance of the safe disposal of high As-containing industrial waste.

Extraction of High Purity Bischofite(MgCl_2·6H_2O) from Left Over-Resiudal Bittren,Lake Quroun,Egypt

1 Introduction The left-over(residual)brines often in industrial facilities is disposed back to the sea or in dump areas e.g.abundant salt mines in other cases.Dumping into the sea

Distribution and leaching characteristics of trace elements in ashes as a function of different waste fuels and incineration technologies

Impact of waste fuels（virgin/waste wood, mixed biofuel（peat, bark, wood chips） industrial,household, mixed waste fuel） and incineration technologies on partitioning and leaching behavior of trace elements has been investigated. Study included 4 grate fired and 9 fluidized boilers. Results showed that mixed waste incineration mostly caused increased transfer of trace elements to fly ash; particularly Pb/Zn. Waste wood incineration showed higher transfer of Cr,As and Zn to fly ash as compared to virgin wood. The possible reasons could be high input of trace element in waste fuel/change in volatilization behavior due to addition of certain waste fractions. The concentration of Cd and Zn increased in fly ash with incineration temperature.Total concentration in ashes decreased in order of Zn 〉 Cu 〉 Pb 〉 Cr 〉 Sb 〉 As 〉 Mo. The concentration levels of trace elements were mostly higher in fluidized boilers fly ashes as compared to grate boilers（especially for biofuel incineration）. It might be attributed to high combustion efficiency due to pre-treatment of waste in fluidized boilers. Leaching results indicated that water soluble forms of elements in ashes were low with few exceptions.Concentration levels in ash and ash matrix properties（association of elements on ash particles）are crucial parameters affecting leaching. Leached amounts of Pb, Zn and Cr in 〉50% of fly ashes exceeded regulatory limit for disposal. 87% of chlorine in fly ashes washed out with water at the liquid to solid ratio 10 indicating excessive presence of alkali metal chlorides/alkaline earths.