Elemental boron, an eco-friendly and cost-effective metalloid reductant, was employed as a reductive co-catalyst to accelerate Fe3+/Fe2+ redox cycling in Fe2+-initiated periodate (PI) activation for sulfamethazine (SMT) degradation. The standalone Fe2+/PI system achieved only 24.1% SMT elimination within 30 min, whereas the constructed B/Fe2+/PI system delivered up to 97.7% removal under an extremely low iron dosage (10 μM Fe2+) and acidic condition (pH 3.0). Radical quenching assays combined with molecular probe identification revealed the co-existence of Fe(IV), •OH, 1O2, O2•−, and IO3•−, with •OH, among which •OH was identified as the dominant oxidant, and its generation was notably amplified by boron. X-ray photoelectron spectroscopy (XPS) characterization demonstrated that surface B-B bonds and low-valent boron moieties act as electron donors to reduce Fe3+ to Fe2+, sustaining continuous Fe3+/Fe2+ redox turnover. Eight transformation intermediates were identified by mass spectrometry, based on which plausible degradation pathways for SMT were proposed. The B/Fe2+/PI system exhibited robust tolerance against prevalent inorganic anions, maintained favorable catalytic capability in natural lake water, and preserved stable performance across five successive recycling runs. Accordingly, boron-augmented Fe2+-triggered periodate activation represents a promising low-iron technical paradigm for antibiotic remediation in water environments.
Efficient, durable, and low-cost electrocatalysts for the Oxygen Evolution Reaction (OER) are essential for the improvement of Alkaline Water Electrolysis and sustainable hydrogen production. In this work, a conductive CoMn2O4/polyaniline (CoMn2O4/PANI) nanohybrid was successfully synthesized via a simple hydrothermal method to overcome the drawbacks of low conductivity and nanoparticle aggregation of pristine CoMn2O4. The successful incorporation of the crystalline spinel CoMn2O4 nanoparticles into the conductive PANI matrix was confirmed by structural and physicochemical characterization using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX), resulting in a porous, interconnected architecture with uniformly distributed catalytic active sites. The synergistic coupling between CoMn2O4 and PANI greatly improved electrical conductivity, active-site accessibility, electrolyte penetration, and charge-transfer kinetics. It was found that the CoMn2O4/PANI nanohybrid had a low overpotential, 373 mV at 10 mA cm−2, a small Tafel slope, 57 mV dec−1, a remarkably low charge-transfer resistance, 0.12 Ω, and a sevenfold increase in electrochemically active surface area, 350 cm2, compared with pristine CoMn2O4. In addition, the nanohybrid also proved to be extremely durable for operation, retaining the same catalytic activity after 50 h of continuous operation in alkaline OER conditions. This superior electrocatalytic activity is explained by the synergistic role of the conductive PANI network and catalytically active CoMn2O4 nanoparticles that enable fast electron transport, efficient adsorption of hydroxide ions, fast creation of oxygen-containing intermediates, and structural stability. Most significantly, this work furnishes a complete structure–property–performance relationship that delivers a fundamental understanding of how conductive polymer/spinel oxide hybridization controls the OER activity. The present results show that the hydrothermally synthesized CoMn2O4/PANI nanohybrid is an efficient electrocatalyst for oxygen evolution and present design guidelines for designing the next-generation electrocatalysts for water splitting towards sustainable hydrogen energy.
Rational application of microbes in coal mines helps achieve coordinated progress in resource utilisation, economic growth, production safety and environmental protection. This paper reviews recent laboratory and field research to examine advances in microbial applications for safe coal mining, coal conversion, carbon sequestration, pollutant remediation and ecological restoration, alongside remaining critical knowledge gaps. Researchers have gained a thorough understanding of the metabolic pathways and biological properties of some of the microorganisms utilised. Methanotrophs are deployed to mitigate gas hazards in coal mines, while a range of other microorganisms suppress spontaneous combustion of low-rank coal by consuming reactive functional groups and blocking pore spaces. Low-rank coal can be effectively biodegraded via alkaline, enzymatic, chelating and surfactant-driven pathways, with degradation rates varying widely by strain and pretreatment. Biocatalytic CO2 mineralisation and hydrogenotrophic methanogenesis offer dual sequestration routes but face obstacles in biocatalyst longevity and cost. With regard to the remediation of acid mine drainage, recent research covers approaches including microbial synergism, the addition of adsorbents and the construction of microbial fuel cells. Microbial and biocatalysis techniques that suppress pollutant generation at the source have also begun to attract research attention. Addressing these gaps requires multi-omics (proteomics, metabolomics, transcriptomics, genomics) and improved subsurface monitoring. Overall, microbial solutions offer low-energy, selective adjuncts to conventional practices, but industrial-scale viability demands lifecycle modelling and robust in situ validation.
Developing cost-effective bifunctional electrocatalysts for alkaline water splitting is essential for sustainable hydrogen production. Herein, Ni(II)–aniline complex-modified TiO2 (Ni–TiO2) nanoparticles were synthesized via a simple surface-modification strategy and evaluated for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 M KOH. X-ray diffraction and Raman spectroscopy confirmed the retention of the anatase TiO2 structure without detectable crystalline nickel-containing secondary phases. Surface characterization of Ni–TiO2 nanoparticles before and after OER testing was performed using FE-SEM and EDX. X-ray photoelectron spectroscopy revealed predominantly Ti4+ and surface-associated Ni2+ species, while optical and photoluminescence analyses indicated modifications to the optical and interfacial properties of TiO2. Ni–TiO2 exhibited improved HER activity, requiring overpotentials of 267.2 and 373.1 mV at current densities of 10 and 50 mA cm−2, respectively, compared with 317.3 and 462.2 mV for pristine TiO2. Its lower Tafel slope (126.5 versus 163.79 mV dec−1) and higher electrochemically active surface area (142.25 versus 5.87 cm2) further indicated improved reaction kinetics and surface accessibility. Ni–TiO2 retained 92.55% of its initial HER activity after 12 h at 100 mA cm−2. For OER, it achieved 50 mA cm−2 at an overpotential of 381.3 mV, compared with 500.6 mV for pristine TiO2, and exhibited a lower Tafel slope (86.7 versus 143.4 mV dec−1). The catalyst maintained 88.2% of its initial OER current after 12 h at 50 mA cm−2. These findings demonstrate that Ni(II)–aniline modification improves the electrocatalytic activity and operational stability of TiO2 toward both HER and OER, highlighting its potential as a coordination-chemistry-assisted strategy for alkaline water splitting.
OPO structural lipids (1, 3-dioleoyl-2-palmitoylglycerol) are the most abundant type of triglycerides in breast milk. They are beneficial for providing energy and calcium absorption for infants and can prevent constipation caused by the formation of insoluble calcium soaps. Currently, enzymatic synthesis of OPO mainly involves three routes: acid hydrolysis, ester exchange, and alcoholysis–esterification combined catalysis. The acid hydrolysis process completes in one step, and the product separation is simple, but it is limited by the migration of acyl groups, resulting in generally low OPO yields. The ester exchange process uses both the substrate and product as triglycerides, and the subsequent separation is costly. In contrast, lipase, as an oil–water interface enzyme, has higher activity in oil–water systems, and the combined catalytic route of first alcoholysis to prepare 2-monoglyceride and then esterification to introduce oleic acid is more likely to achieve a higher OPO yield. However, in the process of enzymatic synthesis of OPO, free lipases have the disadvantages of poor thermal stability, easy inactivation, and difficulty in recovery, and immobilization is a key strategy to improve their industrial applicability in combined processes. This paper focuses on the research progress of immobilized lipases in the enzymatic synthesis of OPO structural lipids, systematically reviews the principles, advantages, and limitations of the main immobilization methods, and compares the performance of carrier systems in terms of enzyme loading, catalytic activity, operational stability, and reusability. Finally, this paper looks forward to future directions such as composite immobilization strategies, multi-enzyme combined catalytic systems, and rational design of carrier structures, with the aim of providing theoretical references for the efficient and green enzymatic synthesis of OPO structural lipids.
