Ecological restoration has notably impacted microbe and soil characteristics in abandoned open pit mines, especially in alpine regions. Yet, the adaptive responses of microbial communities in the initial years of mine site restoration remain largely unexplored. This study endeavors to offer a thorough comprehension of soil properties and microbial dynamics during the initial phases of alpine mining land reclamation. It places emphasis on physicochemical properties and microbial community composition and evaluates the feasibility of phytoremediation, along with proposing subsequent measures. Our study employs spatial sequence instead of time-sequenceal sequence to investigate early-stage changes in soil microbes and physicochemical properties in alpine mining land reclamation. We used high-throughput sequencing for the 16S rRNA amplicon study. Over time, soil physicochemical properties improved noticeably. Soil pH shifted from neutral to alkaline (7.04–8.0), while soil electrical conductivity (EC) decreased to 77 μS·cm⁻¹ in R_6a. Cation exchange capacity (CEC) initially decreased from R_2a (12.30–27.98 cmol·kg⁻¹) and then increased. Soil organic matter increased from 17.7 to 43.2 g·kg⁻¹ over time during mine reclamation and restoration. The dominant bacterial community consisted of Proteobacteria (33.94% to 52.09%), Acidobacteriota (4.94% to 15.88%), Bacteroidota (6.52% to 11.15%), Actinobacteriota (7.18% to 9.61%), and Firmicutes (4.52% to 16.80%) with varying relative abundances. Gene annotation of sequences from various reclamation years revealed general function prediction, translation, ribosome structure, cell wall/membrane/envelope biogenesis, nucleotide translocation, and metabolism, along with other related functions. Mine reclamation improved soil fertility and properties, with the R_6a treatment being the most effective. Starting in the 2nd year of reclamation, the effective phosphorus content and the dominance of microbial bacteria, notably the Bacillus content, decreased. Firmicute fertilization promoted phosphorus and bacterial growth. In conclusion, employing a blend of sequencing and experimental approaches, our study unveils early-stage enhancements in soil microbial and physicochemical properties during the reclamation of alpine mining areas. The results underscore the beneficial impacts of vegetation restoration on key properties, including soil fertility, pore structure, and bacterial community composition. Special attention is given to assessing the effectiveness of the R_6a treatment and identifying deficiencies in the R_2a treatment. It serves as a reference for addressing the challenges associated with soil fertility and microbial community structure restoration in high-altitude mining areas in Qinghai–Tibet. This holds great significance for soil and water conservation as well as vegetation restoration in alpine mining regions. Furthermore, it supports the sustainable restoration of local ecosystems.

The adsorption mechanism of superabsorbent polymer (SAP) can provide theoretical guidance for their practical applications in different environments. However, there has been limited research on the mechanism of attapulgite–sodium polyacrylate. This research aimed to compare the Cd(II) adsorption characteristics and water retention properties of organic–inorganic composite SAP (attapulgite–sodium polyacrylate, OSAP) and organic SAP (polyacrylamide, JSAP). Batch experiments were used to investigate the kinetics of Cd(II) adsorption, as well as the thermodynamic properties and factors influencing these properties. The results show that the Cd(II) adsorption capacity was directly proportional to the pH value. The maximum adsorption capacities of OSAP and JSAP were of 770 and 345 mg·g−1. The Cd(II) adsorption for OSAP and JSAP conformed to the Langmuir and the quasi-second-order kinetic model. This indicates that chemical adsorption is the primary mechanism. The adsorption process was endothermic (ΔH0 > 0) and spontaneous (ΔG0 < 0). The water adsorption ratios of OSAP and SAP were 474.8 and 152.6 in pure water. The ratio decreases with the increase in Cd(II) concentration. OSAP and JSAP retained 67.23% and 38.37% of the initial water adsorption after six iterations of water adsorption. Hence, OSAP is more suitable than JSAP for agricultural and environmental ecological restoration in arid and semi-arid regions.

Perfluorooctanesulfonate (PFOS) is a persistent pollutant in soils due to its exceptional chemical and biological stability. Pyrolysis has been recognized as an effective technology for the remediation of PFOS-contaminated soil. However, its large-scale application faces challenges such as the requirement of high temperatures, long residence time, and corrosive off-gas treatment. The application of additives during pyrolysis is a promising strategy to overcome these challenges. In this study, six additives (Fe₂O₃, Fe₃O₄, CaO, Ca(OH)₂, kaolinite, and MgO) were employed to improve PFOS removal from soil by pyrolysis. The effects of temperature, residence time, and removal efficiency with additives on the PFOS decomposition mechanism and economic benefits were systematically investigated. The results showed that all additives could allow for effective PFOS removal at a relatively low temperature (350 °C) and with a short residence time (30 min). Fe₂O₃ and CaO at a 5% dosage exhibited PFOS removal efficiency reaching 95.19% and 95.49%, respectively, which were 21.00% higher than that of the no-additive system. The thermodynamic analysis showed that the additives could reduce the activation energy (Ea) of PFOS pyrolysis, among which Fe₂O₃ showed the most significant effect (54.24 kJ/mol). Although additives exerted no significant effect on the type of PFOS decomposition products in soil, they effectively reduced the emission of acidic off-gases. Among them, CaO and Ca(OH)₂ showed the most significant reduction by forming inorganic fluorides, followed by Fe₂O₃ and Fe₃O₄, through providing active sites. Economic analysis indicated that CaO had the lowest cost for PFOS removal (2.86 CNY/mg), followed by Fe₂O₃ (2.88 CNY/mg). Comprehensively considering PFOS removal efficiency, decomposition mechanism, economic cost, and pH of treated soil, Fe₂O₃ was identified as the optimal additive. This study provides new insights into the PFOS pyrolysis in soils, and proposes an energy-efficient remediation approach by reducing temperature, residence time, Ea, and off-gas emissions, which offers support for the large-scale application of this technology.