Phosphorus is an essential yet non-renewable resource facing global scarcity, and its recovery from wastewater has become a critical research focus, driving the development of diverse recycling technologies. Among emerging approaches, vivianite-based phosphorus recovery has attracted increasing attention because of its compatibility with anaerobic wastewater treatment processes and its potential for efficient magnetic separation. This review systematically synthesizes current knowledge on the formation mechanisms of vivianite, with particular emphasis on microbially mediated reductive precipitation and its physicochemical pathways in wastewater systems. Building on this mechanistic understanding, the key factors governing vivianite crystallization are critically discussed together with their corresponding control strategies. In addition, the magnetic properties of vivianite are analyzed, and the performance of different magnetic separation technologies, including permanent magnet separation, high-gradient magnetic separation, and low-gradient magnetic separation, is comparatively evaluated. The review also highlights recent applications and proposes future development directions for this technology. By integrating mechanistic insights, influencing factors, and technological advancements, this analysis aims to offer new perspectives and recommendations for further research on vivianite-based phosphorus recovery from wastewater and the optimization of magnetic separation methods.

In order to verify the bearing performance of Mg-Li alloy thread connections, the tightening performance and axial pull-out performance of the Mg-Li alloy thread structure with wire thread insert were tested, and the failure load and mode were obtained. The finite element 2D axisymmetric model was used to numerically analyze the bearing properties of Mg-Li alloy threads. The reliability of the analysis model was verified by comparison with the experimental results and theoretical basis. The load distribution and stress distribution characteristics of the thread connection were studied, and the influence of boundary constraints on the axial pull-out performance was studied. The results show that the M5 Mg-Li alloy embeded wire threat insert with 8 rounds has sufficient connection strength under the action of tightening torque and axial pull-out load, and the failure mode is mainly bolts fracture. Boundary constraints will have an influence on the load distribution and performance of the Mg-Li alloy thread connection structure. The load-bearing ratio of each round thread changes obviously with the downward movement of the top of the boundary. As the top of the boundary moves downward, the location where the maximum load-bearing ratio will be transformed from the first thread to the last thread. The load-bearing ratio of the last thread gradually increases from 11.3% when the outer circumference fully restrained to 23.1% when the boundary area below 4 mm from the last thread. For the M5 Mg-Li alloy embeded wire threat insert with 8 rounds, the axial pull-out bearing capacity of M5 inserts is between 9.5 kN and 12 kN under different boundary conditions.

Using Pr (NO 3 ) 3 , butyl titanate, ethylene glycol and citric acid as main raw materials, praseodymium titanate (Pr 2 Ti 2 O 7 ) was prepared by the sol-gel process. The samples were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), thermal gravity-differential thermal analysis (TG-DTA), diffuse-reflection spectra (DRS) and Fourier transform infrared (FT-IR). The effect of different calcination temperature and illumination time on the photocatalytic properties of Pr 2 Ti 2 O 7 was investigated. It was found that the single phase Pr 2 Ti 2 O 7 could be obtained through sol-gel process and calcination at 1000 °C. The Pr 2 Ti 2 O 7 samples calcination at 1000 °C were uniform , and the resulting product had a particle size of 200 nm and an optical band gap of 3.26 eV. Under ultraviolet light, the degradation of methyl orange arrived to 80.11% after 180 min of photocatalytic reaction. The Pr 2 Ti 2 O 7 samples showed good photocatalytic activity for decomposition of methyl orange.

The aerobic granular sludge (AGS) was used to remove pollutants (COD, NH3-N, TN and TP) in wastewater under different salinity in a sequencing batch reactor (SBR). The results show that: the salinity has a significant impact on the removal of COD and TN, and the removal rate declines to 60% and 56% respectively when the water salinity rises from 5g/L to15g/L. The NH3-N removal is not much affected by the salinity, and the average removal rate is 75%. TP removal rate changes little at low-salted environment (the salinity less than 10g/L), however, the rate declines heavily when the salinity gets more than 10g/L, 70% in 10g/L and 57% in 15g/L.

Acid Red B dye wastewater was collaborative degradated by ozone and hydrogen peroxide. Various reaction conditions are studied which affect on decoloration rates of wastewater. The decoloration rate of Wastewater increases with O 3 gas flow rate increasing, and also increases with pH value increasing. O 3 /H 2 O 2 collaborative effects are better than O 3 alone, and the decoloration rate is higher with more H 2 O 2 addition. Ozone Oxidation have a good effect to degrade Acid Red B dye wastewater, the decoloration rate can reach 98% with inflating O 3 30min. H 2 O 2 synergy can greatly increase the reaction rate, shorten the reaction time, improve the utilization of ozone.

To explore new pathways of CO2 geological storage, the mechanism of CO2 stored in abandoned coal mine gob was analyzed through the investigation of the gobs exploitation current situation. Methods to calculate the capacity to store CO2 was proposed based on establishing mathematical model. This paper presented suggestions about how to carry out research in the future. Research suggests that after the coal mine is abandoned, there are large underground spaces consisting of rock cavities of gob caving zone, rock fissures of fractured zone, and permanent residual laneways, which CO2 can be stored, and there will be tremendous sequestration potential. Compared with deep aquifers storage, the space has the advantages of larger scale porosity, simpler storage mechanism, easier injection, more abundant geological data, etc. At the same time, the space also remains problems such as lower seal strength and failure of overburden strata easily causing CO2 leaks, etc. This paper suggests that six aspects should be further researched in the future.

A series of complex oxide Cu1-xKxFe2O4 fibers have been prepared via a sol-gel process related electron-spinning procedure, in which x is among 0, 0.05, 0.1 and 0.2 corresponding to the quantity of Cu2+ partial substitution by K+. The average diameter of the fiber was 500 nm. The catalytic activity of the catalysts in removal of NOx and carbon black from diesel exhaust gases were examined in detail using temperature-programmed reaction technique. The results show that after partial substitution of Cu2+ with K+, the catalytic activities have been improved. Cu0.95K0.05Fe2O4 as an optimal catalyst can significantly decrease the ignition temperature (Tig) of the PM, and has high catalytic activity on the removal of NOx.