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• Waste production from schools changes depending on the level of institutions. • High rate of positive answers but unsuccessful sorting indicate lack of practice. • Recycling capture rates do not differ significantly between school types. • There is a strong positive correlation between capture rates of some recyclables. • The success of recycling is higher if it is is supported with specific programmes. In this study, the waste generation at the educational institutes chosen from four different levels (kindergartens, primary, secondary and high schools) in Istanbul was measured on-site and the contents of the waste thrown into the recycling bins were determined to specify capture rates. Separation and weighing processes were performed at 16 spots in high schools, 12 spots in secondary schools, 7 spots in primary schools and 7 spots in kindergartens. A survey was conducted to determine the students' awareness of recycling in these schools. It was revealed that the wastes produced from educational institutes are organics (36.4 %), paper (24 %), plastics (14.4 %), glass (8.1 %), metals (4.8 %) and miscellaneous (12.3 %). The survey results indicate that 93 % of the participants think recycling is important, 71 % of them throw their waste into suitable waste bins and 59 % of them know the location of the recycling bins. At the primary school level, a very high rate of paper waste (92.3 %) was reported in plastic bins while plastic waste collected in these bins remained only 5.7 %. It was also seen that glass waste captured in glass bins and metal waste in metal bins remain very low rates (20.9 % and 29.2 %, respectively) at the secondary school level. At the high school level, it was determined that the most commonly captured wastes in glass, plastics and paper bins are glass (47.5 %), plastic (43.2 %) and paper (32.5 %), respectively. Correlation analyses indicated a high positive correlation (p < 0.05) between particular types of waste. [ABSTRACT FROM AUTHOR]

Rapidly increasing heavy metal waste has adversely affected the environment and the Earth's health. The lack of appropriate remediation technologies has worsened the issue globally, especially in developing countries. Heavy-metals contaminants have severely impacted the environment and led to devastating conditions owing to their abundance and reactivity. As they are nondegradable, the potential risk increases even at a low concentration. However, heavy-metal remediation has increased with the up-gradation of technologies and integration of new approaches. Also, of all the treatment methodologies, microbial-assisted multifaceted approach for ameliorating heavy metals is a promising strategy for propagating the idea of a green and sustainable environment with minimal waste aggregation. Microbial remediation combined with different biotechniques could aid in unraveling new methods for eradicating heavy metals. Thus, the present review focuses on various microbial remediation approaches and their affecting factors, enabling recapitulation of the interplay between heavy-metals ions and microorganisms. Additionally, heavy-metals remediation mechanisms adapted by microorganisms, the role of genetically modified (GM) microorganisms, life cycle assessment (LCA), techno-economic assessment (TEA) limitations, and prospects of microbial-assisted amelioration of heavy-metals have been elaborated in the current review with focus toward "sustainable and greener future." [ABSTRACT FROM AUTHOR]

[Display omitted] • Heavy metals can controlled well in solid waste/sludge pyrolysis by vermiculite. • Interlayer spacing of vermiculite is positively correlated with heavy metal retention. • Heavy metals except Cd are at low potential ecological risk and 3IV reduces this risk. • Heavy metal oxides react more readily with vermiculite flakes than their chlorides. • The reactivity of Cr/Zn with vermiculite flakes is stronger than those of Cd/Pb/Cu. Pyrolysis is effective in reducing the volume of solid waste and sludge, and produces less pollutants than incineration and landfill, but the process still suffers from heavy metal pollution. Four types of intercalated-exfoliated modified vermiculite (UIV, DIV, TIV and 3IV) were prepared using urea, dimethylsulfoxide, tributyl phosphate and 3-aminopropyltriethoxysilane as intercalators for the control of Cd, Cr, Cu, Pb and Zn in municipal sewage sludge (MSL), paper mill sludge (PML), municipal domestic waste (MWA) and aged refuse (AFE). The larger the interlayer spacing of the vermiculite, the more favorable the retention of heavy metals. 3IV was the most effective additive, with an average retention of more than 75 % of all heavy metals at 450 ℃ for the four raw materials. Cr, Cu, Pb and Zn were all at low potential ecological risk (Pr), while Cd was moderate or considerable Pr, and the addition of 3IV reduced the Pr. Distribution of intercalators between vermiculite interlayers was haphazard, and interlayer spacing results were close to those of the experiment (except for tributyl phosphate). The reactive electrons mainly flowed from the Highest Occupied Molecular Orbital (HOMO) of vermiculite flakes to the Lower Unoccupied Molecular Orbital (LUMO) of heavy metal chlorides. In contrast, the reactive electrons mostly flowed from the HOMO of heavy metal oxides to the LUMO of vermiculite flakes. Heavy metal oxides were more readily adsorbed on vermiculite flakes than heavy metal chlorides, and the adsorption capacity of Cr and Zn was stronger than that of Cd, Pb and Cu. [ABSTRACT FROM AUTHOR]

Using metallurgical solid waste Titanium-extracted Residual Slag (TRS) as mine-filling cementitious material is crucial to reduce the filling cost and promote the utilization of solid waste resources. In this paper, taking the strength of the backfill at different curing ages as the response target, the Design-expert mixing design was used to optimize the proportioning experiment of titanium-extracted residual slag, titanium gypsum, silicate cement, and total tailings, to analyze the interactions and influences of the materials on the strength of the backfill, and to analyze the hydration mechanism of the titanium-extracted residual slag-based filling cementitious materials under the optimal proportioning. The results show that: (1) the order of the sensitivity of each component to the strength of backfill is: composite activator > cement > titanium gypsum > titanium-extracted residual slag, and there are different degrees of interaction between them; (2) the optimal ratio of titanium-extracted residual slag-based filling cementitious materials is TRS:titanium gypsum:cement:composite activator = 55:25:17:3; (3) early strength formation of backfill is mainly related to its hydration products ettringite and C-S-H, the rapid nucleation and cross-growth of ettringite in the early stage forms an effective physical filling effect, which is the main reason for the formation of high early strength, and the later strength of backfill benefited from the continuous accumulation of C-S-H encapsulation and bonding, which further densified its internal structure; (4) the use of titanium-extracted residual slag-based filling cementitious materials contributes to safe, green, and economic mining. [ABSTRACT FROM AUTHOR]

The possibility of selective Cu and Zn leaching from the sample of old pyrite tailings, which is one of the most widespread types of solid waste forming during non-ferrous metal production, using sulfuric acid solutions and water was studied. It was shown that water leaching provided selective extraction of Cu and Zn and comparatively low iron ion extraction. At the same time, acid leaching provided the obtainment of pregnant solutions with high ferric ion concentration, which can be used for oxidative leaching of substandard copper concentrates. Water and acid leaching also provided increased Au recovery by cyanidation. The results suggest that acid leaching can be an effective approach for processing old flotation tailings, which allows the extraction of base metals from these wastes and treating flotation tailings for subsequent cyanidation. Effective flotation treatment methods should also provide environmental load reduction, which is caused by the long-term storage of metal-bearing wastes. [ABSTRACT FROM AUTHOR]

The impact of induction heating on the self-healing of asphalt mixture test specimens prepared with scrap metal and styrene–butadiene–styrene (SBS) modified bitumen was investigated in this study. In addition, the effects of waste metals used instead of aggregates in asphalt mixtures on the asphalt mixtures' mechanical properties were determined. To this end, asphalt mixtures were prepared to use two different percentages (inst aggregates of 50% and 100% aggregates) of waste metal in two different mill scale (cold mill scale and hot mill scale) and SBS in two different percentages (2% and 3%) to create prismatic and Marshall asphalt test specimens. Induction heating systems were used to determine self-healing properties. The samples were heated in five different heating times as 120 s, 100 s, 80 s, 60 s, and 40 s. To measure the performance of the recovery processing, five recovery cycles were performed for every asphalt sample. According to the results, the hardness of the mixtures, the mixes' fatigue life and load repetitions both shorten as the waste metal usage ratio in the asphalt mixtures increases. As both the amount of sludge and the amount of SBS in the asphalt mixtures increase, the maximum temperatures of the asphalt mixtures also increase. When the SBS ratio in the asphalt mixtures increases, the recovery rates increase. In addition, as the waste metal content in the asphalt mixture increases, an increase in HL values is observed. Finally, the general binding and rheological properties of SBS modified binders were evaluated. [ABSTRACT FROM AUTHOR]

Incineration is a common method in municipal solid waste management, which has several advantages such as reducing the volume of waste, but with concerns about exhaust gas and ash management. In this study, heavy metals in bottom ash, secondary furnace ash and fly ash of two waste incinerators in Tehran and Nowshahr were analyzed and its control in cement production was investigated. For this purpose, twelve monthly samples of three types of incinerator ash were analyzed. By combining the studied ashes in the raw materials, the quantity of metals in the cement was analyzed. Finally, by investigating four scenarios based on quantitative variations in the routes of municipal solid waste, ash quantity and the related risk caused by its heavy metals were studied. The results showed that the concentration of heavy metals in the three ash samples of the studied incinerators was 19,513–23,972 µg/g and the composition of the metals included Hg (less than 0.01%), Pb (2.93%), Cd (0.59%), Cu (21.51%), Zn (58.7%), As (less than 0.01%), Cr (15.88%), and Ni (0.91%). The best quality of produced cement included 20% ash and 10% zeolite, which was the basis of the next calculations. It was estimated that the reduction of the release of metals into the environment includes 37 gr/day in best scenario equal to 10.6 tons/year. Ash solidification can be considered as a complementary solution in waste incinerator management. [ABSTRACT FROM AUTHOR]

Non-Ferrous Metallurgical Wastes, including copper slag, red mud, jarosite residue, zinc-bearing dust, pyrite cinder, and nickel slag, are hazardous waste products released during the metal extraction process. Metallurgical solid wastes pose significant risks to the environment due to their content of hazardous elements, which may impact the quality of surface water and groundwater. However, the iron content in non-ferrous metallurgical solid wastes such as copper slag, red mud and zinc-containing dust can often reach 30–50%, which is higher than the average iron grade (27%) of the iron ores found in China and has a high utility value. In this manuscript, we summarize the primary optimization process of the coal-based direct reduction-magnetic separation method for metallurgical recovery and further purification of metallurgical solid waste. We discuss technological advancements, including rotary kiln, rotary bottom furnace, and tunnel kiln methods, and address environmental and economic aspects, especially in coal-rich regions with limited natural gas resources. Additionally, we have highlighted the technical challenges and developmental bottlenecks of the direct reduction-magnetic separation process; our findings reveal that the improved processes, characterized by high recycling efficiency and low energy consumption and secondary environmental pollution, continue to be the focus of research and development for the sustainable utilization of metallurgical solid waste. [Display omitted] [ABSTRACT FROM AUTHOR]

Metallurgical solid waste blast furnace water quenched slag (WBFS) was employed as carrier materials to prepare Fe–TiO 2 /WBFS composite photocatalyst using a sol-gel method for improving both the photocatalytic activity and the high-value utilization of metallurgical solid waste. The Fe3+ doping technology was adopted to increase the utilization of solar energy. The influencing factors and photocatalytic activity were systematically evaluated by thermogravimetry/differential thermal analyser (TG-DSC), X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) method, scanning electron microscopy-energy spectrometer (SEM-EDS), X-ray photoelectric spectroscopy (XPS), UV–Vis absorption spectrum and photoluminescence spectra technology through the degradation rate of methylene blue (MB) solution. The results showed that the Fe3+ ions were successfully incorporated into the TiO 2 lattice, which had no effect on the crystalline phase of TiO 2 and expanded the spectral response range of TiO 2 from the ultraviolet region to the visible light region. When the calcination temperature was at 450 °C and the number of Fe–TiO 2 sol loading cycles was two times, the photocatalytic activity of Fe–TiO 2 /WBFS presented the strongest, and the degradation ratio of MB reach the maximum value of 98.9 %. A uniform and dense anatase TiO 2 thin film was wrapped on the surface of WBFS. The photocatalytic activity first improved and then weakened with an increase of calcination temperature, Fe3+ doping amounts and the loading cycles of sol. The TiO 2 film changed from thin to thick and uneven to uniform, until cracking and spalling phenomenon finally occurred with an increase of Fe–TiO 2 sol loading cycle from 1 to 3 times. When the Fe–TiO 2 /WBFS was reused for four times, the degradation rate of MB could still show 67.4 %, being far higher than that of TiO 2 /WBFS of 25.4 %. [ABSTRACT FROM AUTHOR]

The production process of the metallurgical industry generates a significant quantity of hazardous waste. At present, the common disposal method for metallurgical hazardous waste is landfilling, which synchronously leads to the leaching of toxic elements and the loss of valuable metals. This paper presents a comprehensive review of the research progress in the harmless treatment and resource utilization of stainless steel dust/sludge (including stainless steel dust and stainless steel pickling sludge) and aluminum ash (including primary aluminum ash and secondary aluminum dross), which serve as representative hazardous wastes in ferrous metallurgy and nonferrous metallurgy, respectively. Additionally, the general steps involved in the comprehensive utilization of metallurgical hazardous waste are summarized. Finally, this paper provides a prospective analysis on the future development and research trends of comprehensive utilization for metallurgical hazardous waste, aiming to offer a basis for the future harmless, high-value, resource-based treatment of metallurgical hazardous waste and the realization of industrial applications in China. [ABSTRACT FROM AUTHOR]

Electronic waste generation and accumulation keeps on increasing and possess a serious threat to the environment. To find a legitimate or suitable eco-friendly method for metal recovery from e-waste this includes the noble metals, rare earth metals and also the heavy metals. Methods like magnetic separation, Eddy current separation and Electrostatic separation results in separation of metallic parts from the crushed e-waste and its PCBs (Printed Circuit Boards). For synthesising nanoparticles out of the recovered metallic parts, pyrometallurgy using Tubular furnace, hydrometallurgical methods, cryo-milling techniques and bio-approaches using plant leaf are utilised. Heavy metal in Electronic waste plays a vital role in polluting the ecology/environment. Researchers are trying to enhance the metal recovery from e-waste process by improving the environmentally friendly approaches. In this review, harmless to the ecosystem draws near and the techniques that depicts about the Nanoparticle synthesis from electronic waste printed circuit boards are critically reviewed. [ABSTRACT FROM AUTHOR]

Thermochemical water splitting is one of the methods to produce green hydrogen. In this study, metal scrap is used to split water by thermochemical process in a packed-bed reactor. Hydrogen production conditions are optimized by varying the particle size of the metal wastes in the range of 250 μm to greater than 1000 μm and the temperatures from 900 °C to 1200 °C. The maximum yield of hydrogen obtained is ∼500 mL of H 2 per gram of the scrap sample. This study demonstrates that the discarded metal wastes can be utilized as feed-materials for thermochemical production of green hydrogen. The process has good conversion efficiency and is a promising solution for both metal waste management and the production of green hydrogen. Medium size metal particles show higher hydrogen production capacity compared to both smaller (<250 μm) and larger (600–1180 μm) size particles. [Display omitted] • Hydrogen production using ferrous metal scrap materials. • Optimum size of ferrous scrap metal particles is in the range of 355–600 μm. • ∼500 mL of green hydrogen produced per gram of ferrous scrap materials at 1100 °C. [ABSTRACT FROM AUTHOR]

Theaim of this cross-sectional study was to compare workplace conditions and metal exposures in 431 waste pickers who worked nearby at the Estrutural Dump in Brasilia utilizing hair (n = 310) and nail (n = 355) as matrices of exposure. Waste pickers were grouped according to their workplace (open waste dump: G1 and sorting plants: G2). Hair and nail samples were collected and analyzed using ICP-MS. The work duration in the facilities was significantly different between the groups with averages of 16.46 (8.48) yrs and 9.26 (6.28) yrs for hair donors in G1 and G2, and 15.92 (7.72) yrs and 8.55 (5.77) yrs for toenail donors in G1 and G2, respectively. The arithmetic means (µg/g) of cadmium, copper, lead, and manganese in hair were significantly higher in G2 (0.076 ± 0.133; 19.61 ± 18.16; 2.27 ± .56 and 3.87 ± 5.59, respectively) compared to G1 (0.069 ± 0.235; 15.72 ± 15.18; 1.72 ± 4.04 and 3.65 ± 5.5, respectively). Concentrations of arsenic, barium, cadmium, copper, cobalt, lead, manganese, and molybdenum in nail were significantly higher in G2 (0.57 ± 0.39; 22.74 ± 42.06; 0.1 ± 0.08; 22.7 ± 51.60; 0.48 ± 0.45; 4.69 ± 9.43; 19.07 ± 20.75; 1.80 ± 1.76, respectively) compared to G1 (0.40 ± 0.28; 15.32 ± 22.31; 0.08 ± 0.11; 11.91 ± 16.25; 0.37 ± 0.37; 3.94 ± 15.04; 13.01 ± 19.08; 1.16 ± 1.80, respective. Our findings suggest that the studied population was exposed to toxic metals and indicates the need for chemical exposure prevention policies to monitor chemical risk exposures in waste pickers. [ABSTRACT FROM AUTHOR]

The extensive use of lithium-ion batteries (LIBs) has generated a huge amount of their wastes. As waste, LIBs can be used as a source for valuable metals such as lithium, cobalt, manganese, and nickel. Like the ores of these metals, their values are recognized as raw material. This can ultimately help bring down the cost of LIB production while reducing their harmful environmental impacts. As a result, recycling has become a major opportunity for industrialists and a challenge to environmentalists all across the globe. Researchers have explored various methods to recover cobalt and lithium precious metals from worn out batteries. This review provides an overview of the recent technological solutions on the recovery from waste LIBs using organic acids-based hydrometallurgical processes concerning chemical reactions, structures, and leaching efficiency with different organic acids. Subsequently, the advantages of organic acids over inorganic acid have also been discussed with an emphasis on possible complex formations during the recovery process. At last, the potent role of process variables: reductant concentration, reaction time, temperature, solid:liquid ratio, and concentration of complexing agent during the Co and Li leaching has been discussed along with prospects in this research area. [ABSTRACT FROM AUTHOR]

Sludge, due to its form and significant moisture and zinc content, is the most problematic metallurgical waste. Near the site of a disused steelworks plant in Krakow (Poland) there is an estimated 5 million tonnes of landfill sludge that consists of more than 90% iron and other metal oxides. There is a global tendency to switch steel production towards carbonless technologies, which is why the presented work investigates the possibility of simultaneous waste liquidation and recovery of valuable metals with the use of hydrogenous reduction. Direct reduced iron (DRI) production was selected as the targeted technology, so the sludge was lumped and bound with cement or CaO addition. The obtained lumps were reduced in a hydrogenous atmosphere with gradual heating to 950 °C, after which their phase structure was analyzed and elemental analysis was performed. It was found that zinc evaporated during the experiment, but mostly thanks to the carbon contained in the sludge. The increased addition of binder to the sludge resulted in the enhancement of the lumps, but also limited the reduction range. The products obtained were mostly wustite and less pure iron. Taking into account the degree of reduction and the lumps' compression strength, the best binding was achieved by adding cement at a quantity of 5% mass. [ABSTRACT FROM AUTHOR]

Researchers in related fields are concentrating on the use of metallurgical slag waste heat to deliver stable heat for the pyrolysis or gasification of carbon–based materials. The key technology to achieve the clean utilization of coal is coal gasification. An important challenge for the technology is how to increase the amount of H 2 in the mixture while decreasing the energy consumption of the gasification process. The typical temperature of copper slag, a typical iron–rich metallurgical slag, is 1300 °C. Relevant studies have demonstrated that copper slag can increase H 2 production and support the water gas shift (WGS) reaction in addition to providing stable heat for coal gasification. The largest contribution of copper slag to the catalytic effect of the WGS reaction is demonstrated by the density functional theory (DFT) calculations, which reveal that the presence of copper slag lowers the energy barrier of H 2 O molecules dissociation from 6.57 eV to 4.61 eV. Additionally, the reduction in the CO 2 formation process on the copper slag surface from 4.92 eV to 3.94 eV encouraged CO 2 formation. This explains how the WGS reaction, which is catalyzed by copper slag acting as a heat carrier during the pulverized coal–vapor gasification process, works. • The most likely pathway of WGSR on copper slag surface is the redox pathway. • The copper slag reduces the energy barrier of H 2 O molecules dissociation. • The CO 2 formation process on the copper slag surface decreased. [ABSTRACT FROM AUTHOR]

The possibility of decontaminating radioactively contaminated metal surfaces using laser treatment was examined. The results obtained show that the use of laser treatment allows the metal waste to be transferred from the low-level waste (LLW) category to the very low-level waste (VLLW) category. It is appropriate to use the local gas treatment system for preventing the contamination of the working zone and equipment with radioactive aerosols. [ABSTRACT FROM AUTHOR]

"Ashkelon 8: The Islamic and Crusader Periods" is a book review of Tracy Hoffman's publication on the excavations at Ashkelon. The volume focuses on the Islamic and Crusader periods of the site, providing insight into the city itself and the nature of the excavations. Divided into six parts, the book covers topics such as historical setting, architecture, pottery, small finds, organic remains, and conclusions. The review highlights the detailed and well-illustrated nature of the chapters, while also acknowledging some limitations in the research. Overall, the volume is a valuable resource for scholars studying maritime trade, warfare, and urbanism in the Levant during the seventh to thirteenth centuries. [Extracted from the article]

In this work, a novel carbon-free smelting reduction process is proposed to recover valuable metals from molten copper slag, in which secondary aluminum dross is used as the reductant via co-modification with CaO and Na 2 O additions. The influence of Na 2 O addition on the metal recovery and slag properties under different CaO/SiO 2 ratios was investigated at 1550 °C. The results show that the modifier Na 2 O not only reduces the melting temperature of the slag, but also inhibits the precipitation of spinel and prevents the polymerization of aluminosilicate units to a certain extent by providing more O2-, which results in a relatively lower slag viscosity. These effects are more significant at the CaO/SiO 2 of 0.9. The multiple strengthening mechanisms improve the kinetic conditions for smelting reduction, resulting in optimal results when the Na 2 O addition reaches 4 wt% at the CaO/SiO 2 of 0.9, at which 99.1% of iron and 98.5% of copper in the slag can be recovered as the high-purity alloy. The leaching toxicity of the tailings is 2–3 orders of magnitude lower than the original slag, suggesting that they are clean sources for ceramic production. Furthermore, the assessment of the proposed process indicates that it is technically feasible even without an external energy supply, which indicates that the process is green, efficient, and cost-effective. [Display omitted] [ABSTRACT FROM AUTHOR]

Using high temperature CO 2 sorbent for carbon capture is an effective approach to reduce carbon footprint. Copper slag, as an abundant metallurgical waste containing substantial amount of Si and Fe resources, was being explored as cheap raw material for the preparation of lithium-based sorbent. The results shows that the lithiation is initiated at 450–600 °C, where fayalite and magnetite in slag are firstly oxidized by released water vapor from the decomposition of LiOH, then further react with Li 2 O to form Li 4 SiO 4 and LiFeO 2. As the temperature rises, the conversion of LiFeO 2 to Li 5 FeO 4 and incorporation of Fe3+, Al3+ into Li 4 SiO 4 lattice occur in parallel. The resulting sorbent exhibited excellent CO 2 chemisorption ability with a capture capacity of 420 mg/g material at 725 °C. Particularly, even in the gas stream containing 5 vol% CO 2 , it showed a CO 2 uptake capacity of 383 mg/g material. In the CO 2 cycling tests, the sorbent suffered a decay in sorption capacity, which was ascribed to the poor regeneration ability of Li 5 FeO 4. Comparatively, it possesses a relatively high capacity of 241 mg/g material in 20 vol% CO 2 after 20 cycles, which is higher than those of previously reported Li-silicate sorbents derived from wastes. [ABSTRACT FROM AUTHOR]

A novel synergistic extractant consisting of a deep eutectic solvent (DES) and tri‐n‐butyl phosphate (TBP) is proposed for selective extraction of valuable metals from waste lithium‐ion batteries (LIBs). The extraction efficiencies of Ni2+, Co2+, and Mn2+ were 99.8%, 99.1%, and 95.9%, respectively, and high‐purity Li+ was enriched in the raffinate after the single‐stage extraction. Valuable metal salts, lithium carbonate (92.3 wt%) and cobalt oxalate (94.9 wt%), were obtained. The DES + TBP extractant retained its high extraction performance even after multiple regeneration cycles. The extraction process followed the so‐called "cation exchange mechanism" with thermodynamic properties of ΔH < 0, ΔG < 0, and ΔS < 0. The molecular‐level extraction mechanism demonstrated that the extraction process was dominated by both electrostatic and coordination interactions between the metal ions and DES/TBP, based on quantum chemical calculations. This study aims to provide a new strategy for recycling valuable metals from waste LIBs. [ABSTRACT FROM AUTHOR]

Heterostructure engineering by coupling different nanocrystals has received extensive attention because it can enhance the reaction kinetics of the anode of sodium-ion batteries (SIBs). However, constructing high-quality heterostructure anode materials through green and environmentally friendly methods remains a challenge. Herein, we have proposed a simple one-step method by recycling the electronic waste metal materials to synthesize the Cu1.94S/ZnS heterostructure materials. Combined with the experimental analysis and first principle calculations, we find that the synergistic effect of different components in heterostructure structures can significantly enhance the reversible capacity and rate performance of anode materials. Based on the constructed Cu1.94S/ZnS anode, we obtain a superior reversible capacity of 440 mAh·g−1 at 100 mA·g−1 and 335 mAh·g−1 after 3000 cycles at 2000 mA·g−1. Our work sheds new light on designing high-rate and capacity anodes for SIBs through the greenness synthesis method. [ABSTRACT FROM AUTHOR]

Given the high impact of traditional mining, the recovery of rare earth elements (REEs) from hazardous waste materials could become an option for the future in accordance with the principles of the circular economy. In this work, the technical feasibility of REEs recovery from metal mine tailings has been explored using electrokinetic-assisted phytoremediation with ryegrass (Lolium perenne L.). Phytoextraction combined with both AC current and DC current with reversal polarity was applied (1 V cm−1, 8 h day−1) to real mine tailings containing a total concentration of REEs (Sc, Y, La, Ce, Pr, and Nd) of around 146 mg kg−1. Changes in REEs geochemical fractionation and their concentrations in the soil pore water showed the mobilization of REEs caused by plants and electric current; REE availability was increased to a higher extent for combined electrokinetic-assisted phytoextraction treatments showing the relevant role of plants in the process. Our results demonstrated the initial hypothesis that it is feasible to recover REEs from real metal mining waste by phytoextraction and that the performance of this technology can be significantly improved by applying electric current, especially of the AC type, which increased REE accumulation in ryegrass in the range 57–68% as compared to that of the treatment without electric field application. [ABSTRACT FROM AUTHOR]

The development of civilization is causing an increase in the amount of industrial wastes, especially hazardous wastes. Among the methods of utilisation of this type of waste, the methods of stabilisation and solidification deserve attention, which enable the transformation of hazardous waste and the heavy metals it contains into an environmentally safe form, that is, immobilised. This paper proposes a method to stabilize and solidify galvanic sludge using geopolymerization reactions. The surface morphology was studied, and the chemical composition was analyzed using the SEM-EDS method. The presence of characteristic functional groups on the surface of the galvanic sludge and the geopolymer obtained on its basis was determined by FTIR spectroscopic analysis. Moreover, we evaluated of the recovery of selected heavy metals were performed on the basis of leaching tests. It was found that, as a consequence of geopolymerization of galvanic sludge, this hazardous waste is transformed in such a way that the heavy metals it contains, which occur in the form of soluble compounds are immobilised. In relation to the metals analyzed, reduction in solubility were obtained at a practical level of 100% for Zn and Mn, for the remaining metals, respectively, 94% for Cu and in the range of 40 to 90% for Pb. Analysis of the FTIR spectra showed that the ions of the metals studied were permanently immobilised in the aluminosilicate structure of the geopolymers obtained. This shows, that galvanic sewage sludge, as hazardous waste, is chemically transformed into inert waste that may be deposited in landfills. [ABSTRACT FROM AUTHOR]

Polysaccharides are functional foods or drugs that can be used to alleviate heavy metal poisoning by cadmium, lead, mercury, and arsenic. Industries generate substantial quantities of toxic heavy metal wastes, such as wastewater discharges, paints, electronic waste, batteries, pigments, and plastics, into the environment that pose a risk to human health. Therefore, it is imperative to eliminate accumulated heavy metal ions from the body and the environment. Heavy metal toxicity can lead to decreased energy levels and impair the functioning of vital organs, such as the brain, lungs, kidneys, liver, and blood. Prolonged exposure can result in progressive physical, muscular, and neurological degeneration that resembles conditions such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, and muscular dystrophy. Polysaccharides operate through mechanisms such as chelation, antioxidant defense, immunomodulation, and tissue repair. Polysaccharides involved in heavy metal removal include methionine and cysteine, together with N-acetylcysteine, an acetylated form of cysteine, S-adenosylmethionine, a metabolite of methionine, α-lipoic acid, and the tripeptide glutathione (GSH). These compounds effectively bind with harmful heavy metals to create a stable complex and defend biological targets from metal ions, thus decreasing their harmful effects and causing them to be excreted from the body. This review also highlights the importance of polysaccharides' ability to mitigate oxidative stress, enhance immune responses, and support tissue repair processes. Polysaccharides are ubiquitous in nature and take part in diverse processes, making them potential natural therapies for heavy metal-related diseases. This review discusses the effectiveness of natural polysaccharides and the mechanisms that allow them to bind with heavy metals to alleviate their effects from the body and the environment. Polysaccharides have inherent features that enable them to function as pharmacological agents and regulate the immune response. [ABSTRACT FROM AUTHOR]

For many years, especially in emerging nations like India, the environment has been threatened by the increased output of industrial wastes and heavy metal toxicity. The usage of inexpensive adsorbents has recently attracted a lot of attention in studies on the removal of heavy metals like nickel from industrial wastewater. The use of agro-based adsorbent is an alternative to conventionally used activated charcoal. In this research, adsorption experiments were carried out using agro-based adsorbent prepared from rice husk, wheat husk, and soybean husk to reduce nickel from industrial wastewater. The adsorption process is simple, economical, and effective is the most preferred method used for the removal of toxic metals like nickel from industrial wastewater. Adsorbents prepared from these husks can be effectively used for adsorption due to low cost & high availability. Characterization of agricultural material by various tests like XRF, proximate analysis, bulk density, and iodine number was conducted on agro-based adsorbents to know the co-relation between removal efficiency and adsorption capacity. The effect of turbidity and pH parameters on Ni removal efficiency is also studied. Results indicated that wheat husk adsorbent appeared to be the most effective for the adsorption of Ni from wastewater as compared to soybean husk and rice husk adsorbent. Wheat husk, soybean husk, and rice husk have removal efficiency in the range of 62.50 to 73.33. Composite absorbents CA-2 with the proportion of 50% wheat husk, 33% soybean husk, and 17% rice husk have 82.50% efficiency, and CA-3 has 80.83% efficiency in removing Nickel. Wheat husk adsorbent, CA-2, and CA-3 are more effectively and sustainably used for the treatment of industrial wastewater to remove heavy metals. [ABSTRACT FROM AUTHOR]

Hundreds of thousands of tons of waste are generated from decommissioned nuclear- power facilities, and it has become a critical global issue to secure technology for reducing and recycling this waste. Concrete waste (CW) is estimated to comprise 60–80% of the total waste, and concrete-waste powder (CWP) includes enough inorganic substances used as effective materials for waste treatment. Accordingly, it can be used to produce recycled cement (RC). This study aimed to evaluate the performance of a solidification agent manufactured using recycled cement (SRC) for the safe packing of radioactive wastes, such as coarse aggregates of CW, waste soil, and metal wastes originating from decommissioned nuclear facilities. The experimental results indicated that the most relevant incineration temperature of CWP for RC was 700 °C. The optimum water-to-binder ratio was determined to be 0.4, and the most relevant substitution ratio of ground granulated blast furnace slag for CWP was determined to be 15%. In addition, calcium silicate hydrate is the most effective hydration product for improving the compressive strength of SRC. The maximum packing capacities of the SRC for coarse aggregates, waste soil, and metal waste, which were simulated as radioactive wastes, were determined to be 30, 5, and 7 wt%, respectively. The results of leaching tests using SRC containing radioactive wastes contaminated with Co, Cs, and Sr indicated that their leachability indices met the acceptance level for disposal. Consequently, the RC composed of CWP can be used as a solidifying agent to safely dispose of radioactive wastes, such as coarse aggregates, waste soil, and metal waste. [ABSTRACT FROM AUTHOR]

This work evaluates the efficiency of three biochar samples toward the adsorption of manganese, iron, and selenium present in a sample of urban wastewater. The biochar was produced from the pyrolysis of rice husks at 350 °C for 6 h (RHB) and subsequently modified using HCl (RHBHCl) or NaOH (RHBNaOH) to increase its surface area. The RHBNaOH sample exhibited the highest removal efficiency for the three metals. The metals' adsorption removal efficiency for RHBNaOH was in the order Mn (76%), Se (66%), and Fe (66%), while for RHBHCl, it was Fe (59%), Mn (30%), and Se (26%). The results show that the as-prepared RHB can remove the metals, even if in low amounts (Fe (48%), Mn (3%), and Se (39%)). The adsorption removal for the three types of adsorbents follows the Langmuir isotherm model. Pseudo-first-order and pseudo-second-order models were used to determine the adsorption mechanism for each of the three adsorbents. Both models showed a good fit with R2 (>0.9) for the RHBNaOH and RHB sorption of Fe, Mn, and Se. Overall, this work demonstrates the potential of biochar for the removal of metals from real wastewater. [ABSTRACT FROM AUTHOR]

To solve the problems of deep nitrogen removal in wastewater treatment plants and the high value utilization of steel slag in the metallurgical industry, this work aims to prepare a sulfur/steel slag-based filter using the melting method. The melt granulation method and the utilization of metallurgical waste were the main innovations of this work. On this basis, the nitrogen removal performance of the filter media in simulated wastewater and actual wastewater were systematically investigated. Furthermore, the factors affecting the nitrogen removal performance of the filter media were studied, and pilot experiments were carried out. The microbial community in the reactor was also analyzed. The results showed that when the mass ratio of sulfur and steel slag was 9:1, the filter media could remove up to 90% of TN in simulated wastewater at room temperature, with a hydraulic retention time (HRT) of 5–20 h and an influent TN of 21 mg/L. In the simulated wastewater, the effluent NO3−-N was less than 2 mg/L, the SO42− was less than 200 mg/L, and the pH was between 6 and 8. The removal of TN from actual wastewater was also greater than 90% at room temperature under a hydraulic retention time (HRT) of 8–20 h and an influent TN of 8 mg/L. Influence factor experiments were conducted at room temperature, with a C/N of 2:1, a DO of 0.9–1 mg/L, and an HRT of 4 h. The results of the pilot experiment confirmed that the effluent TN was stable below 10 mg/L. The filter media was compounded for practical engineering applications. Microbial community analysis showed that the sulfur autotrophic denitrifying bacterial species Thiobacillus accounted for 3.69% and 5.55% of the simulated and actual wastewater systems, respectively. This work provides a novel strategy for the application of solid metallurgical waste in the field of nitrate-containing wastewater treatment. [ABSTRACT FROM AUTHOR]

The recycling of metals from waste printed circuit boards (WPCBs) has been presented as a solid–liquid extraction process using two deep eutectic solvents (DESs) and four ionic liquids (ILs). The extraction and separation of Cu(II), Ag(I), and other metals, such as Al(III), Fe(II), and Zn(II), from the solid WPCBs (after the physical, mechanical, and thermal pre-treatments) with different solvents are demonstrated. Two popular DESs were used to recover valuable metal ions: (1) choline chloride + malonic acid, 1:1, and (2) choline chloride + ethylene glycol, 1:2. The extraction efficiencies of DES 1 after two extraction and two stripping stages were only 15.7 wt% for Cu(II) and 17.6 wt% for Ag(I). The obtained results were compared with those obtained with four newly synthetized ILs as follows: didecyldimethylammonium propionate ([N10,10,1,1][C2H5COO]), didecylmethylammonium hydrogen sulphate ([N10,10,1,H][HSO4]), didecyldimethylammonium dihydrogen phosphate ([N10,10,1,1][H2PO4]), and tetrabutylphosphonium dihydrogen phosphate ([P4,4,4,4][H2PO4]). Various additives, such as didecyldimethyl ammonium chloride surfactant, DDACl; hydrogen peroxide, H2O2; trichloroisocyanuric acid, TCCA; and glycine or pentapotassium bis(peroxymonosulphate) bis(sulphate), PHM, were used with ILs during the extraction process. The solvent concentration, quantity of additivities, extraction temperature, pH, and solid/liquid, as well as organic/water ratios, and the selectivity and distribution ratios were described for all of the systems. The utilization of DESs and the new ILs with different additives presented in this work can serve as potential alternative extractants. This will help to compare these extractants, additives, extraction efficiency, temperature, and time of extraction with those of others with different formulas and procedures. The metal ion content in aqueous and stripped organic solutions was determined by the ICP-MS or ICP-OES methods. The obtained results all show that solvent extraction can successfully replace traditional hydrometallurgical and pyrometallurgical methods in new technologies for the extraction of metal ions from a secondary electronic waste, WPCBs. [ABSTRACT FROM AUTHOR]

Gallium and indium are crucial metals in various industries, such as the medical and telecommunication industries. They can find applications as pure metals, alloys and alloy admixtures, oxides, organometallic compounds, and compounds with elements such as nitrogen or arsenic. Recovery of these two metals from waste is an important issue for two main reasons. First, gallium and indium are scattered in the Earth's crust and their minerals are too rare to serve as a primary source. Second, e-waste contributes to the rapidly growing problem of Earth littering, as its amount increased significantly in recent years. Therefore, it is essential to develop and implement procedures that will enable the recovery of valuable elements from waste and limit the emission of harmful substances into the environment. This paper discusses technological operations and methods that are currently used or may be used to produce pure gallium and indium or their oxides from waste. The first step was described—waste pretreatment, including disassembly and sorting in several stages. Then, mechanical treatment as well as physical, chemical, and physicochemical separations were discussed. The greatest emphasis was placed on the hydrometallurgical methods of gallium and indium recovery, to be more precise on the extraction and various sorption methods following the leaching stage. Methods of obtaining pure metals or metal oxides and their refining processes were also mentioned. [ABSTRACT FROM AUTHOR]

This study addresses the pressing environmental problem of the emissions of ecotoxic heavy metals from high-temperature waste combustion processes, including incineration and pyrolysis. Such emissions pose a serious threat to ecosystems and human health. This study investigated the behaviour of the heavy metals Cu, Ni, and Pb during the combustion of various waste materials such as plastic waste, pharmaceutical waste, and pesticide waste. To limit the release of heavy metals into the exhaust gas stream, various additives were used: divanadium pentoxide (V2O5), borax (Na2B4O7), and their mixtures with calcium oxide (CaO). Additionally, this study examined the impact of the content of chlorine heteroatoms (Cl) in burned waste materials on the emission levels of Cu, Ni, and Pb. The findings shed light on the mobility of ecotoxic heavy metals in high-temperature waste incineration processes (1273, 1373 K) and offer insight into strategies to improve their immobilisation in grate residues. At a temperature of 1273 K, V2O5 with CaO reduced Pb emissions by ~65% for plastic waste and by ~40% for pesticide. [ABSTRACT FROM AUTHOR]

The current study presents an overview of heavy metals bioremediation from halo–alkaline conditions by using extremophilic microorganisms. Heavy metal remediation from the extreme environment with high pH and elevated salt concentration is a challenge as mesophilic microorganisms are unable to thrive under these polyextremophilic conditions. Thus, for effective bioremediation of extreme systems, specialized microbes (extremophiles) are projected as potential bioremediating agents, that not only thrive under such extreme conditions but are also capable of remediating heavy metals from these environments. The physiological versatility of extremophiles especially halophiles and alkaliphiles and their enzymes (extremozymes) could conveniently be harnessed to remediate and detoxify heavy metals from the high alkaline saline environment. Bibliometric analysis has shown that research in this direction has found pace in recent years and thus this review is a timely attempt to highlight the importance of halo-alkaliphiles for effective contaminant removal in extreme conditions. Also, this review systematically presents insights on adaptive measures utilized by extremophiles to cope with harsh environments and outlines the role of extremophilic microbes in industrial wastewater treatment and recovery of metals from waste with relevant examples. Further, the major challenges and way forward for the effective applicability of halo-alkaliphilic microbes in heavy metals bioremediation from extremophilic conditions are also highlighted. [ABSTRACT FROM AUTHOR]

Deep Eutectic Solvents (DESs) have been lauded as novel solvents, but is there really a difference between them and concentrated aqueous brines? They provide a method of adjusting the activity of water and chloride ions which can affect mass transport, speciation and reactivity. This study proposes a continuum of properties across concentrated ionic fluids and uses metal processing as an example. Charge transport is shown to be governed by fluidity and there is no discontinuity between molar conductivity and fluidity irrespective of cation, charge density or ionic radius. Diffusion coefficients of iron(III) and copper(II) chloride in numerous concentrated ionic fluids show the same linear correlation between diffusion coefficient and fluidity. These oxidising agents were used to etch copper, silver and nickel and while the etching rate increased with fluidity for copper, etching of silver and nickel only occurred at high chloride and low water activity as passivation occurred when water activity increased. Overall, brines provide a high chloride content at a lower viscosity than DESs, but unlike DESs, brines are unable to prevent passivation due to their high water content. The results show how selective etching of mixed metal waste streams can be achieved by tuning chloride and water activity. [ABSTRACT FROM AUTHOR]

The construction of a 1,158 km long dam on the Romanian course of the Danube led to the disappearance of more than 400,000 hectares of lakes, ponds, marshes. The Danube was not dammed between the kms 817 and 665, and is characterized by structural and functional diversity of lacustrine ecosystems. This sector, covering 56,425 ha, is a sample of the former floodplain, which preserves biocoenotic structures specific to wetlands. Eutrophication is one of the fundamental factors affecting the structure and functionality of lacustrine ecosystems. The benthos facies consists of a thick layer of organic silt and vegetal detritus, explaining the clogging tendency of the lakes. The main groups of benthic invertebrates are Oligochaeta, Chironomidae, Plecoptera, Bivalves. Gastropods represent the dominant group of the benthic production with 37 species. Thus, the development of technological processes based on the activity of indigenous microorganisms demonstrated their involvement in the biogeochemical cycles, byː chemical-bacterial solubilisation of industrial wastes and precipitation of metal ions from industrial effluents; concentration and removal of heavy metals from industrial waste waters. Acidophilic microorganisms present in soil and water, through the mineralization of organic substances, ensure the circulation of organic matter, releasing mineral elements used by plants for their nutrition. The role of acidophilic microorganisms in reduction of soluble iron sulfide and other metal sulfides to insoluble ions is well established. The presence of other species in the microbial culture has proven useful in increasing the oxidation and reduction rate of heavy metals from extreme environments. The study of the way in which acidophilic microorganisms interact in extreme environmental conditions has a strong influence over the technologies used for the remediation of environments polluted with heavy metallic ions. The knowledge of the degree of spread use of acidophilic microorganisms is a benchmark in establishing the influence of extreme environmental conditions on the processes of bioaccumulation and solubilization of heavy metal ions by their action on metabolic processes in the microbial cell. [ABSTRACT FROM AUTHOR]

[Display omitted] • Investigation of EPS impact on bioleaching process was done. • Most bacterial EPS contains polysaccharides, which facilitate biomass adhesion. • PVP effectively removed EPS from the STPCBs surfaces. • Au and Ag recovery rates were reached 26 % and 43.2 %, respectively with this method. Environmentally friendly bioleaching of gold and silver from electronic waste using cyanogenic bacteria has emerged as a promising approach. In the process of cyanide bioleaching, cyanide ions produced by cyanogenic bacteria form complexes (such as AuCN and AgCN) with metals in the waste structure and lead to their dissolution. The recovery rate of these valuable elements during bioleaching is influenced by extracellular polymeric substances (EPS). For the first time, this study presents an investigation into the role of EPS from Pseudomonas atacamensis in the bioleaching of gold and silver from spent telecommunication printed circuit boards (STPCBs). The experimental results demonstrate that, after 6 days of bioleaching, gold and silver recoveries reached 22% and 36.2%, respectively. Complementary analyses employing FE-SEM and attachment tests shed light on the interactions between EPS, bacterial attachment to particle surfaces, and biofilm development stages during gold and silver bioleaching. Notably, the most significant bacterial attachment occurred on the fourth day of bioleaching. Zeta potential tests conducted on bacteria and EPS provided insights into the potential absorption of soluble cations such as Au+ and Ag+ by EPS. Furthermore, 250 mg/L polyvinylpyrrolidone (PVP) effectively removed EPS from the particle surfaces, improving gold and silver recovery rates, reaching 26% and 43.2%, respectively. These findings highlight the importance of understanding the role of EPS in bioleaching processes and offer insights into enhancing gold and silver recovery from electronic waste. [ABSTRACT FROM AUTHOR]

The C02 emission of iron and steel industry is large, and the urination of metallurgical solid waste such as steel slag is difficult. Steel sag carbonation material has good stability and durability, but its low tenia strength and easy cracking limit the application in the construction field. In this paper, still lag is used as carbonization raw material, polypropyiene fiber is used as reinforcement material, and carbonization curing is used to develop and prepare fiber reinforced steel lag carbonization material. Based on the compressive strength, flexural strength and carbonation degree of steel lag carbonation materials, the influence of polypropylene fiber content on the mechanical properties and carbonation consolidation properties of still lag carbonation materials were studied by means of micro-analysis methods including thermogravimetric and mercury intron method. [ABSTRACT FROM AUTHOR]

The necessity for urban mining of metals has arisen due to the growing demand for metals brought about by technological innovation, the depletion of natural resources, and the exponential growth in e-waste generation. However, to be industrially adaptable, any recycling process must be economically profitable. Therefore, in this article, an economic feasibility study was conducted to determine the profitability of the proposed recycling process for recovering valuable metals from waste tantalum capacitors. Firstly, an integrated process was developed for the recovery of almost all economically and strategically significant metals. A detailed elemental and metallurgical balance followed this to determine the mass flow of metals during various stages of treatment. Lastly, the economic feasibility analysis has been done by estimating various cost components from capital and operating costs (utilizing Indian cost as foundation for calculation) to evaluate the profit that might be made by operating the suggested recycling facility for a month. Sensitivity and scenario analysis further investigated the impact of the most significant cost component on the percentage profit. The findings of this study support the notion that the suggested recycling method has a great deal of potential value and is commercially feasible with an ample profit margin. [ABSTRACT FROM AUTHOR]

The paper presents a specific model used to assess and select the method of heavy metal leaching from waste materials. A recommendation for the rational selection of the leaching method was made, taking into account the crucial parameters affecting the leaching process derived from the authors' research experience. The assessment models were supplemented with characteristics relating to the cost and time required to perform the tests. An approach was developed that links the weights of the assessment criteria with the degree of environmental risk from a particular heavy metal and waste type. Using multiple-criteria decision analysis, four models were developed for the assessment and selection of a test method for the leaching of heavy metals from waste. The difference is in the way the weights of the assessment criteria depend on the potential threat of the waste to the environment. A key element of the proposed approach is assigning the weights of the criterion to the toxicity of the heavy metal, the type of waste, and their management method. The results obtained prove that the current practice of only employing the batch leaching test is inappropriate. The choice of method should be justified in terms of environmental safety as well as time- and cost-effectiveness. The results of the paper show that the proposed model can be used in practice and be a recommendation for choosing the method of leaching heavy metals from waste and their further treatment, following the principles of sustainable waste management. [ABSTRACT FROM AUTHOR]