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Acid mine drainage (AMD) is a significant threat to the environment due to its high acidity and metal ion content. To effectively eliminate pollutants from AMD, various approaches are necessary. This review aims to provide a comprehensive understanding of recent advances in AMD mitigation. While treatment technologies have developed to eliminate AMD, they often produce sludge as a by-product and require expensive maintenance. As a cost-effective alternative, the recovery of AMD resources can reduce toxicity and promote reuse of heavy metals and rare earth elements. This review also analyzes the challenges and prospects of AMD mitigation implementation, including current mitigation conditions and knowledge gaps. Researchers can benefit from this review by gaining insight into research progress in this area, identifying strengths and weaknesses of current AMD mitigation applications, and exploring future research directions.

Evaluating Ageratum conyzoides L. (bandotan) weed potential, as a natural antibacterial agent that can be used in the biomedical fields, is the objective of this study. Bandotan leaves extract (BLE) loaded PVP/CA nanofibers were fabricated using an electrospinning technique. The resulting PVP/CA/BLE nanofibers exhibit a pure fibers morphology, with average fibers diameter range of 145–346 nm. Fourier transform infrared analysis demonstrates similarities in the spectra of PVP/CA/BLE nanofibers and pure BLE, confirming the effective loading of BLE into the nanofiber matrix. The nanofibers composed of PVP/CA/BLE exhibit significant antibacterial efficacy against both Staphylococcus aureus and Pseudomonas aeruginosa, ranging from 5 to 71 ( × 10−2 %mg−1), and a high swelling degree of 786%. PVP/CA/BLE nanofibers also exhibit two extract release profiles, burst and sustained release, with a cumulative release of 18–39%. These characteristics make PVP/CA/BLE nanofibers suitable for use as wound dressings, as they can inhibit bacterial growth, absorb wound exudate, and load drug molecules.

Coal-mining activities have well-documented adverse effects on both the environment and human health. Acid mine drainage, a pivotal concern, necessitates effective interventions. This study introduces a novel solution: a modified constructed wetlands crafted exclusively from waste materials, ensuring cost-effectiveness. The innovation yielded exceptional results, achieving a noteworthy reduction of up to 99% in heavy metal concentrations, alongside swift pH normalization. What sets this study apart is its potential beyond the laboratory setting; the utilization of waste materials and low-cost methodologies underscores its scalability and practicality. This solution addresses immediate challenges and showcases promise for real-world implementation. Moreover, the results of the study extend to its insights, which offer a comprehensive examination of the method’s reusability prospects, illuminating its sustained impacts; the recommendations for future action enhance its practical significance. This study marks a significant advancement in tackling acid mine drainage. The modified constructed wetlands, driven by cost-effective waste materials, embody scalable and sustainable potential. With its holistic outlook and strategic roadmap, this study holds the key to transforming acid mine drainage challenges, particularly in rural and developing regions.

The development of adsorbents capable of adsorbing both anionic and cationic dyes in wastewater treatment remains a challenge. This study presents the successful fabrication of Nb2O5-MgAl layered double hydroxide (LDH) nanocomposites for the effective removal of methylene blue (MB) and Congo red (CR) dyes via a one-step hydrothermal method. Incorporating a small amount of Nb into MgAl-LDH proved to be an effective strategy for creating nanocomposite materials with dual characteristics. The material’s morphological and crystalline structures were confirmed using FESEM-EDS and XRD. Incorporating Nb during the material preparation led to a remarkable enhancement in the material’s adsorption capacity - up to 3.4-fold and 9.0-fold increases for CR and MB, respectively. The kinetic and point zero charge analysis confirmed that the adsorption of the dyes onto the adsorbent surfaces occurred via an ionic interaction mechanism. These findings offer a promising alternative for fabricating dual-functional adsorbents, enhancing the effectiveness of dye removal in wastewater treatment technologies.

Indonesian red betel (Piper crocatum) has been used traditionally to cure wounds and to prevent diseases as well as an antiseptic, while the leaves were also reported to inhibit the growth of bacteria. On the other hand, polyvinyl alcohol (PVA) is a suitable biomaterial with a wide range of applications after being transformed into hydrogels. This paper reports on the encapsulation of P. crocatum extract in PVA hydrogel synthesized by the freeze-thaw method with varying compositions and its characterizations. The internal morphology of the composite hydrogels did show some phase separation between the liquid and solid phases, while the analysis of the Fourier-transform infrared spectra confirmed that the P. crocatum extract was successfully encapsulated in the hydrogels. The hydrogels were amorphous due to the scattering of the liquid trapped within the pores. The extract was stable within the range of the room to body temperature since no significant mass decomposition of the extract was observed. The compressive modulus and the fracture stress of the composite hydrogel decreased as the fraction of extract increased due to the unfrozen ethanol fraction during the freeze-thaw process. The composite hydrogels loaded by P. crocatum extract possessed antibacterial activity against Staphylococcus aureus (gram-positive) and Pseudomonas aeruginosa (gram-negative). The release of extract from the hydrogels was immediate release following the pseudo-fickian diffusion for most of the composite hydrogels. This report thus suggests that the composite hydrogels are potential antibacterial products and can be applied for a biomedical device that requires antibacterial activity.

Effects of electrolyte solution (i.e., KOH, NaOH, NaCl, and HCl) with various concentrations (from 0 to 0.71 M) on corrosion and mechanical properties of the copper alloys were investigated. Experimental results showed that the increases in the concentration of electrolytes allowed faster corrosion process. However, too high concentration of electrolytes has no further impacts on the corrosion profile due to the existence of the passivity phenomena on the surface of the material, preventing the material to get more corroded. Acidic (HCl) and salt (NaCl) electrolytes gave more impacts on the corrosion compared to the alkaline solution (i.e., NaOH and KOH) since the acidic and salt ions are able to destroy the formed passivation layer. The correlation of the corrosion rate and the mechanical properties was also presented, in which the increases in the corrosion rate were in line with the decreases in the mechanical properties (i.e., tensile and yield strength). During the corrosion, the atomic structure in the material received attacks from the electrolyte ions, making the structure inside the copper alloys to be less strong and easily fatigued. Understanding the corrosion process and mechanical properties is important for further applications of copper-related alloys in extreme and severe conditions.

Hydrogel is being broadly studied due to their tremendous properties, such as swelling behavior and biocompatibility. Numerous review articles have discussed hydrogel polymer types, hydrogel synthesis methods, hydrogel properties, and hydrogel applications. Hydrogel can be synthesized by physical and chemical cross-linking methods. One type of the physical cross-linking method is freeze-thaw (F–T), which works based on the crystallization process of the precursor solution to form a physical cross-link. To date, there has been no review paper which discusses the F–T technique specifically and comprehensively. Most of the previous review articles that exposed the hydrogel synthesis method usually mentioned the F–T process as a small part of the physical cross-linking method. This review attempts to discuss the F–T hydrogel specifically and comprehensively. In more detail, this review covers the basic principles of hydrogel formation in an F–T way, the parameters that influence hydrogel formation, the properties of the hydrogel, and its application in the biomedical field.

This research reports the investigation of the performance of a thin layer based on silver nanorods using the dip-coating method. The synthesis was conducted by polyol method at an oil bath temperature of 140 °C. In the synthesis of silver nanorods, materials used were silver nitrate (AgNO3) as the main raw material, ethylene glycol (EG) as the solvent, and a small amount of sodium chloride (NaCl) as a mediated-agent (precursor). Polyvinyl alcohol (PVA) used as a capping agent and stabilizer in this process. Diameter and length of silver nanorods were 800 nm and 15 µm, respectively. Furthermore, the silver nanorods suspension was deposition onto a glass substrate with a variety of dipping cycles. The result showed the thickness of the thin layer is linear with a number of dipping cycles. Electrical and optical properties of thin layer show that sheet resistance about of 30 Ω sq-1 by transmittance above of 80%. The silver nanorods thin film can be used as a conductive and transparent electrode for various optoelectronic applications.

Coal-mining activities have well-documented adverse effects on both the environment and human health. Acid mine drainage, a pivotal concern, necessitates effective interventions. This study introduces a novel solution: a modified constructed wetlands crafted exclusively from waste materials, ensuring cost-effectiveness. The innovation yielded exceptional results, achieving a noteworthy reduction of up to 99% in heavy metal concentrations, alongside swift pH normalization. What sets this study apart is its potential beyond the laboratory setting; the utilization of waste materials and low-cost methodologies underscores its scalability and practicality. This solution addresses immediate challenges and showcases promise for real-world implementation. Moreover, the results of the study extend to its insights, which offer a comprehensive examination of the method's reusability prospects, illuminating its sustained impacts; the recommendations for future action enhance its practical significance. This study marks a significant advancement in tackling acid mine drainage. The modified constructed wetlands, driven by cost-effective waste materials, embody scalable and sustainable potential. With its holistic outlook and strategic roadmap, this study holds the key to transforming acid mine drainage challenges, particularly in rural and developing regions. [ABSTRACT FROM AUTHOR]