Many global mining activities release large amounts of acidic mine drainage with high levels of manganese (Mn) having potentially detrimental effects on the environment. This review provides a comprehensive assessment of the main implications and challenges of Mn(II) removal from mine drainage. We first present the sources of contamination from mineral processing, as well as the adverse effects of Mn on mining ecosystems. Then the comparison of several techniques to remove Mn(II) from wastewater, as well as an assessment of the challenges associated with precipitation, adsorption, and oxidation/filtration are provided. We also critically analyze remediation options with special emphasis on Mn-oxidizing bacteria (MnOB) and microalgae. Recent literature demonstrates that MnOB can efficiently oxidize dissolved Mn(II) to Mn(III, IV) through enzymatic catalysis. Microalgae can also accelerate Mn(II) oxidation through indirect oxidation by increasing solution pH and dissolved oxygen production during its growth. Microbial oxidation and the removal of Mn(II) have been effective in treating artificial wastewater and groundwater under neutral conditions with adequate oxygen. Compared to physicochemical techniques, the bioremediation of manganese mine drainage without the addition of chemical reagents is relatively inexpensive. However, wastewater from manganese mines is acidic and has low-levels of dissolved oxygen, which inhibit the oxidizing ability of MnOB. We propose an alternative treatment for manganese mine drainage that focuses on the synergistic interactions of Mn in wastewater with co-immobilized MnOB/microalgae.

The temperature-dependent optical properties of lanthanide-doped phosphors have been enthusiastically investigated in the fields of biomedicine, night-vision security, and optical information storage. In this work, the dynamically varying temperature-dependent photoluminescence and long persistent luminescence at low temperature (4–250 K) in the CaSrNb₂O₇:Pr³⁺ phosphor are explored. The photoluminescence of CaSrNb₂O₇:Pr³⁺ is white and the matrix emits cyan at 470 nm under 325 nm excitation at 84 K, whereas the CaSrNb₂O₇:Pr³⁺ phosphor exhibits bright red long persistent luminescence for more than 400 s at 250 K. Moreover, the CaSrNb₂O₇:Pr³⁺ exhibits a dramatic photoluminescence transition from white to red as the temperature rises by thermal quenching and the trap compensation luminescence. This optical property at low temperature shows great superiority not only in biomedicine and cryotherapy as a means of visualizing safe and non-toxic detection but also opens up new opportunities in the field of space remote sensing superconductivity.

NaBaScSi₂O₇ with Eu²⁺ doped phosphors are prepared by high temperature solid state reaction. It is found that there are two different sites for Eu²⁺ occupied, which is responsible for different emission color of NaBaScSi₂O₇: Eu²⁺ with increasing Eu²⁺concentration. Pr³⁺ ions are introduced to regulate the Eu²⁺ ions occupied sites. When Pr³⁺ ions content climbs, conversion of blue to green emitting light can be realized because of the location migration of Eu²⁺ ions. Meanwhile, the defect structure of NaBaScSi₂O₇: Eu²⁺ has been adjusted by introducing Pr³⁺ ions, the shallow and deep traps generated benefits the long persistent luminescence (LPL) and photo-stimulated luminescence (PSL) phenomenon. It is interesting to note that NaBaScSi₂O₇: Eu²⁺, Pr³⁺ demonstrates different LPL and PSL color compared to NaBaScSi₂O₇: Eu²⁺. The controllable optical properties are realized on the basis of Eu²⁺ site preferences assisted by doping Pr³⁺, which provides guidance for the development of electron trapping materials.

A low-temperature chemical vapor deposition method was developed to synthesize high-quality, single-crystalline Bi ₂ S ₃ microrods with superior visible photodetection properties.

A combined approach involving machine learning, DFT, and experiments was employed to identify 5-acetylsalicylamide as a multifunctional additive for synergistic defect passivation and crystallization regulation in inverted perovskite solar cells.