This study developed a novel geopolymer (RM-SGP) using industrial solid wastes red mud and slag activated by sodium silicate, aiming to remediate composite heavy metal contaminated soil. The effects of aluminosilicate component dosage, alkali equivalent, and heavy metal concentration on the unconfined compressive strength (UCS), toxicity leaching characteristics, resistivity, pH, and electrical conductivity (EC) of RM-SGP solidified composite heavy metal contaminated soil were systematically investigated. Additionally, the chemical composition and microstructural characteristics of solidified soil were analyzed using XRD, FTIR, SEM, and NMR tests to elucidate the solidification mechanisms. The results demonstrated that RM-SGP exhibited excellent solidification efficacy for composite heavy metal contaminated soil. Optimal performance occurred at 15 % aluminosilicate component dosage and 16 % alkali equivalent, achieving UCS >350 kPa and compliant heavy metal leaching (excluding Cd in high-concentration groups). Acid/alkaline leaching tests revealed distinct metal behaviors: Cu/Cd decreased progressively, while Pb initially declined then rebounded. Microstructural analysis indicated that RM-SGP generated abundant hydration products (e.g., C-A-S-H, N-A-S-H gels), which acted as cementitious substances wrapping soil particles and filling and connecting pores, thereby increasing the soil's compactness and improving the solidification effect. Furthermore, heavy metal ions were solidified through adsorption, encapsulation, precipitation, ion exchange, and covalent bond et al., transforming their active states into less bioavailable forms, proving novel insights into the remediation of composite heavy metal contaminated soils and the resource utilization of industrial solid wastes.

The accumulation or landfill of lithium slag will contaminate the surrounding soil and water quality with residual sulfides and harmful elements, causing serious environmental hazards. This study aims to use Lithium slag (LS) as a sustainable alternative for silica flour (SF) in high-temperature cementing and examines the effects of this substitution on the microstructural and mechanical properties of cement pastes. The results show that an appropriate amount of LS can reduce the permeability of oil well cement and increase its high temperature compressive strength. Compared with pure paste (RS), the compressive strength of the sample replaced by 30 % LS increased by 87.8 % and the permeability decreased by 57.1 % after 28 days of high temperature curing. From the phase point of view, the samples supplemented with LS can form Xonotlite and Katoite with dense structure and high temperature stability. These hydration products can reduce the matrix porosity and permeability, increase the matrix density, and effectively improve the compressive strength of the cement pastes. In addition, the environmental effect analysis showed that the leaching toxicity and radioactivity of the sample did not exceed the standard requirements. This study provides a new direction for the sustainable utilization of LS resources, which not only combats the environmental pollution caused by LS accumulation, but also reduces the cost of cementing materials.

Phosphogypsum (PG), an industrial solid waste produced from the wet phosphoric acid process, has seriously damaged the ecological environment. Its comprehensive utilization rate needs to be improved urgently. In this paper, the chemical enhancement effect of solid waste PG on expansive soil, known as engineering cancer, was investigated through systematic macroscopic and microscopic experiments. The positive and negative environmental impacts of the PG modifier were also comprehensively analyzed. Laboratory soil test results show that PG mixed with expansive soil can change the consistency limit of expansive soil, effectively increase the soil strength by 2-3 times and reduce the expansion of expansive soil to 62%. Therefore, it can be considered to be applied to the improvement of expansive soil roadbed. However, when the dosage is too high, it may be affected by the dissolution of PG, and the improvement effect is relatively decreased. The optimal dosage of PG is 15%. XRD, XRF, SEM and MIP microcosmic tests show that the mineral composition, element content and porosity of the expansive soil have changed after the addition of PG. Its microstructure is much tighter. Through TCLP test, the environmental effects of heavy metals caused by resource utilization of PG modified expansive soil were evaluated. In this study, only Cr element exceeded 2.6% slightly when the content of PG was 25%. The analysis found that the engineering properties of expansive soil were effectively improved, resulting in the effective solidification of heavy metals in PG.

Straw return and plastic film mulching are two critical management measures that not only maintain high and stable crop yields, but also have a significant impact on the ecological environment. However, there is still a lack of research on the comprehensive effects of straw return and different film mulching treatments on the ecological environment. Thus, a 2-year field experiment was conducted and six treatments, which included two main treatments, namely straw return (SR) and non-straw return (NR), and three sub-treatments, namely no film mulching (CK), plastic film mulching (PM) and fully biodegradable film mulching (BM), were applied in a garlic cropping system. Based on the life cycle assessment method, six endpoint damage categories, resource consumption, global warming potential, environmental acidification, eutrophication, human health, and ecotoxicity, were assessed. Furthermore, we also evaluated the costs and economic benefits of the six treatments and optimized the treatment of used mulch and straw off-farm. The results indicated that the environmental impacts of the six endpoint damages in the garlic cropping system were ranked as ecotoxicity, eutrophication, environmental acidification, global warming potential, human health, and resource consumption. The SR-BM treatment had the lowest life cycle environmental impact composite index at 27.68 per unit area, followed by SR-PM at 27.75. All six endpoint damage categories for the PM and BM treatments were lower than the CK treatment per t of yield, with the SR-BM treatment being the most economically efficient, yielding at 3691.03 CNYt-1 and exceeding that of the SR-CK treatment by 7.26%. Fertilizer inputs were the primary contributor to resource consumption, global warming potential, environmental acidification, eutrophication, and ecotoxicity, accounting for about 72.80% of these five environmental impacts. Crop protection significantly affected human health, and garlic mulching helped minimize pesticide use, thereby reducing potential health impacts. Compared to straw incineration and waste mulch power generation, straw power generation and waste mulch recycling granulation offered positive environmental benefits and were more effective offset strategies. In conclusion, straw return with biodegradable mulch is a synergistic cultivation measure that offers both environmental and economic benefits. For straw return with plastic film mulch, environmental impacts can be reduced by waste mulch recycling granulation.

Permafrost regions of Qilian Mountains in China are rich in gas hydrate resources. Once greenhouse gases in deep frozen layer are released into the atmosphere during hydrate mining, a series of negative consequences occur. This study aims to evaluate the impact of hydrate thermal exploitation on regional permafrost and carbon budgets based on a multi-physical field coupling simulation. The results indicate that the permeability of the frozen soil is anisotropic, and the low permeability frozen layer can seal the methane gas in the natural state. Heat injection mining of hydrates causes the continuous melting of permafrost and the escape of methane gas, which transforms the regional permafrost from a carbon sink to a carbon source. A higher injection temperature concentrates the heat and causes uneven melting of the upper frozen layer, which provides a dominant channel for methane gas and results in increased methane emissions. However, dense heat injection wells cause more uniform melting of the lower permafrost layer, and the melting zone does not extend to the upper low permeability formation, which cannot provide advantageous channels for methane gas. Therefore, a reasonable and dense number of heat injection wells can reduce the risk of greenhouse gas emissions during hydrate exploitation.

As the use of biodegradable plastics becomes increasingly widespread, their environmental behaviors and impacts warrant attention. Unlike conventional plastics, their degradability predisposes them to fragment into microplastics (MPs) more readily. These MPs subsequently enter the terrestrial environment. The abundant functional groups of biodegradable MPs significantly affect their transport and interactions with other contaminants (e.g., organic contaminants and heavy metals). The intermediates and additives released from depolymerization of biodegradable MPs, as well as coexisting contaminants, induce alterations in soil ecosystems. These processes indicate that the impacts of biodegradable MPs on soil ecosystems might significantly diverge from conventional MPs. However, an exhaustive and timely comparison of the environmental behaviors and effects of biodegradable and conventional MPs within soil ecosystems remains scarce. To address this gap, the Web of Science database and bibliometric software were utilized to identify publications with keywords containing biodegradable MPs and soil. Moreover, this review comprehensively summarizes the transport behavior of biodegradable MPs, their role as contaminant carriers, and the potential risks they pose to soil physicochemical properties, nutrient cycling, biota, and CO2 emissions as compared with conventional MPs. Biodegradable MPs, due to their great transport and adsorption capacity, facilitate the mobility of coexisting contaminants, potentially inducing widespread soil and groundwater contamination. Additionally, these MPs and their depolymerization products can disrupt soil ecosystems by altering physicochemical properties, increasing microbial biomass, decreasing microbial diversity, inhibiting the development of plants and animals, and increasing CO2 emissions. Finally, some perspectives are proposed to outline future research directions. Overall, this study emphasizes the pronounced effects of biodegradable MPs on soil ecosystems relative to their conventional counterparts and contributes to the understanding and management of biodegradable plastic contamination within the terrestrial ecosystem.

The improper disposal of discarded electronic and electrical equipment raises environmental and health concerns, spanning air pollution to water and soil contamination, underscoring the imperative for responsible management practises. This review explores the complex composition of discarded printed circuit boards (DPCBs), crucial components in electronic devices. Comprising substrates, electronic elements and solder, DPCBs showcase a heterogeneous structure with metal (30.0-50.0%) and non-metal (50.0-70.0%) fractions. Notably abundant in precious metals such as Au, Ag, and Pd, DPCBs offer a compelling avenue for recycling initiatives. The inclusion of heavy metals and flame retardants adds complexity, necessitating environmentally sound disposal methods. Ongoing research on smart disassembly, utilising 3D image recognition technology, underscores the importance of accurate identification and positioning of electronic components (ECs). The targeted approach of smart disassembly, centred on valuable components, highlights its significance, albeit with challenges in equipment costs and capacity limitations. In mechanical disassembly, techniques such as grinding and heat application are employed to extract ECs, with innovations addressing gas emissions and damage induced by overheating. Chemical disassembly methods, encompassing epoxy resin delamination and tin removal, present promising recovery options, whilst the integration of chemical and electrochemical processes shows potential. Efficient sorting, encompassing both manual and automated methods, is imperative post-disassembly, with smart sorting technologies augmenting accuracy in the identification and categorisation of ECs. In addition, explorations into NH3/NH4+ solutions for selective metal recovery underscore challenges and stress the necessity for meticulous process optimisation in environmentally sustainable PCB recycling. Challenges and future perspectives have also been expounded.

Background: Heavy elements such as antimony greatly affect the environment and living organisms. Antimony is discharged into the environment by mining and industries that use it as pesticides and flame retardants. This activity can lead to environmental pollution, water and soil contamination. Antimony can also accumulate in living organisms and cause negative health effects, such as damage to the respiratory system and skin, and growth abnormalities of animals and plants. Methods : The primary objective of this investigation was to explore the teratogenic impact of the antimony heavy metal on histological structure of the liver in adult rabbits ( Oryctolagus cuniculus ). The study included adult white rabbits divided into several groups: the first one is the control group injected with physiological saline (0.09% NaCl), the other group injected with 20 mg/kg antimony, and the last injected with 30 mg/kg antimony over a 30 -day period. Following this, postmortem procedures were conducted to extract and fix the liver organ, and tissue sections were prepared. Result : The results revealed significant histological changes, including distortion and rupture in Glisson's Capsule, leading to the formation of a sub -capsular space due to its separation from hepatocytes. Additionally, alterations in the radial organization of hepatocytes and pyknosis in the nuclei were observed, characterized by a dark color and reduced size. Karyolysis, where nuclei completely disappeared, and hydropic degeneration in hepatocytes with swollen appearance and dark nuclei due to fluid accumulation were noted. Moreover, an increase in Kupffer cells and blood congestion in the central vein, resulting in dilation compared to the control group, were observed. Conclusion : Overall, the treatment with antimony at 20 and 30 mg/g doses for 30 days show profound teratogenic effects on the histological structure of the liver in adult rabbits. These effects are represented by the destruction of various parts of liver, in addition to changes in arrangement, and distortion and rupture of the cells. Furthermore, an increase in Kupffer cells and blood congestion were also recorded.

Gasification slag (GS) is rich in SiO2, Al2O3, and Fe2O3, and has excellent particle size gradation, which has the potential to be employed as an aggregate in the field of controlled low-strength material (CLSM). Nevertheless, the large-scale application of GS as the fine aggregate for the preparation of CLSM has been scarcely investigated. In the present work, the applicability of replacing part of coal gangue (CG) with gasification coarse slag (GCS) as fine aggregate for the preparation of CLSM was investigated. The results revealed that using GCS as a fine aggregate improved the flowability of CLSM, and increasing the GCS content from 0 to 50 wt% improved the flowability from 250.0 to 280.0 mm. The 28-day compressive strength of all CLSM conformed to the requirements of ACI Committee 229. Compared to the Blank group, the 7- and 28-day compressive strength of the CLSM increased by 23.07% and 26.80%, respectively, at a GCS content of 50 wt%. The increase in compressive strength was mainly due to the pore-filling and hydration-promoting effect of the GCS, which made the structure denser. The dense structure reduced the expansion rate, absorption, and porosity rate of CLSM and increased the wet density. The optimal process parameter was the addition of 10 wt% of GCS. The results of heavy metal ion leaching showed that the optimal sample GS10 leached all heavy metal ions in much less than the limit values of GB 8978-1996 and GB 5085.3-2007. The results will provide new ideas and technical approaches for the large-scale application of GCS as the fine aggregate in CLSM.

Tibetan Plateau (TP) is known as the water tower of Asia, and glaciers are solid reservoirs that can regulate the amount of water. Black carbon (BC), as one of the important factors accelerating glacier melting, is causing evident environmental effects in snow and ice. However, a systematical summary of the potential sources, analytical methods, distributions, and environmental effects of BC in snow and ice on the TP's glaciers is scarce. Therefore, this study drew upon existing research on snow and ice BC on glaciers of the TP to describe the detection methods and uncertainties associated with them to clarify the concentrations of BC in snow and ice and their climatic effects. The primary detection methods are the optical method, the thermal-optical method, the thermochemical method, and the single-particle soot photometer method. However, few studies have systematically compared the results of BC and this study found that concentrations of BC in different types of snow and ice varied by 1-3 orders of magnitude, which drastically affected the regional hydrologic process by potentially accelerating the ablation of glaciers by approximately 15% and reducing the duration of snow accumulation by 3-4 days. In general, results obtained from the various testing methods differ drastically, which limited the systematical discussion. Accordingly, a universal standard for the sampling and measurement should be considered in the future work, which will be beneficial to facilitate the comparison of the spatiotemporal features and to provide scientific data for the model-simulated climatic effects of BC.