Aijiang Yang

Large volumes of coal mine drainage sludge (CMDS), a byproduct of acid mine drainage (AMD) treatment, impose both environmental and operational burdens. This review comprehensively evaluates the potential of CMDS as a sustainable resource and introduces a novel integrated framework covering its formation mechanisms, physicochemical properties, environmental risks, and application pathways. Rich in iron, aluminum, and manganese oxides, CMDS features a high specific surface area and porosity, making it suitable for use as an adsorbent. Pretreated CMDS can adsorb arsenic at capacities reaching 67 mg g ^− 1 , with strong desorption and reusability. When applied as an iron source in Fenton-like oxidation, it achieves up to 98% chemical oxygen demand and total organic carbon removal. In combination with calcium-based wastes, it significantly reduces As, Cu, and Pb leaching by more than 90% in soil. Nevertheless, concerns over secondary metal release persist. This study discusses these limitations and proposes a “dual-core” strategy integrating AMD treatment optimization with targeted CMDS modification, offering a new direction for ecological remediation and circular resource utilization in mining-impacted areas.

Rubber plantations are a key component of managed forest ecosystems. Quantifying the carbon budget is essential for assessing their carbon sequestration potential and informing sustainable management practices. However, previous studies have focused primarily on individual carbon pools or specific regions, lacking a comprehensive assessment of the carbon budget in rubber plantation ecosystems (RPEs). This study systematically synthesizes the carbon budget of RPEs based on 678 data points extracted from 58 publications. The results indicate that (1) The carbon stock of RPEs (including plant, soil (0–100 cm), and litter carbon stocks) shows an accumulation trend with stand age, increasing from an average of 113.41 ± 21.63 tC ha⁻¹ in young plantations to 252.64 ± 24.61 tC ha⁻¹ in over-mature plantations. (2) RPEs exhibit high photosynthetic capacity and significant carbon sequestration potential during rotation phase, with mean gross primary productivity (GPP) of 22.99 ± 2.14 tC ha⁻¹ yr⁻¹, mean ecosystem respiration (Reco) of 13.92 ± 2.87 tC ha⁻¹ yr⁻¹, and net ecosystem carbon exchange (NEE) of −9.07 ± 1.91 tC ha⁻¹ yr⁻¹. (3) The carbon sequestration capacity of RPEs is influenced by stand age, and carbon sink capacity varies across different planting regions. (4) RPEs act as carbon sinks during rotation phase (−9.07 ± 1.91 tC ha⁻¹ yr⁻¹), with mean carbon storage of 196.13 ± 23.58 tC ha⁻¹ (comprising plant biomass, litterfall, and soil carbon stocks of 70.25 ± 17.47, 2.50 ± 1.30, and 123.38 ± 14.47 tC ha⁻¹, respectively). This synthesis provides representative baseline values for RPEs carbon dynamics, offering a scientific foundation for assessments of carbon sequestration potential and management practices.

In this study, Pseudomonas aeruginosa PA-1, a manganese-oxidizing bacterium screened from the soil at a manganese mining area, was found to be tolerated to Sb(III) stress during the Mn(II) oxidation, and the generated biological manganese oxide (BMO) outperformed the identical type of Abiotic-MnO_X in terms of oxidation and adsorption of Sb(III). Adsorption kinetics and isotherm experiments indicated that Sb(III) was primarily adsorbed through chemisorption and multilayer adsorption on BMO; the maximum adsorption capacity of BMO was 143.15 mg·g⁻¹. Removal kinetic studies showed that the Sb(III) removal efficiency by BMO was 72.38–95.71% after 15 min, and it could be up to 96.32–98.31% after 480 min. The removal procedure could be divided into two stages, fast (within 15 min) and slow (15 ~ 480 min), both of which exhibited first-order kinetic behavior. Dynamic fitting in two steps revealed that the removal speed correlated to the level of dissolved Sb(III) with low Sb(III) concentrations, but with the initial concentration being high, the removal speed rate was independent of dissolved Sb(III). During the whole process, the Sb(III) removal speed by BMO was also higher than that by the Abiotic-MnO_X. Combining multiple spectroscopic techniques revealed that Sb(V) was generated through the Sb(III) oxidation by BMO and replacing surface metal hydroxyl groups to form the complex internal Mn–O(H)-Sb(V) or generating stable Mn(II)-antimonate precipitates on the surface. In addition, microbial metabolites, including tryptophan and humus, in BMO may be complex with Sb(III) and Sb(V) to achieve the treatment of Sb(III). This research investigates the factors and mechanisms influencing the adsorption and removal of Sb(III) by BMO, which could aid in its future engineering applications for the BMO.