The development of antimicrobial agents with excellent antimicrobial activity, high thermal stability, and non-toxic properties is an essential demand in food packaging, pharmaceutical, and biomedical applications. In the present study, MgO nanoflakes were synthesized via the co-precipitation method by varying calcination temperatures at 400, 500, and 600 °C. The effect of calcination temperature on the morphology, thermal stability, antimicrobial activity, and cytotoxicity of the MgO nanoflakes was analyzed. All synthesized MgO samples showed a Face-Centered Cubic (FCC) structure. As the calcination temperature increased, the MgO crystallite and particle sizes increased, whereas the surface area decreased. In addition, the MgO synthesized from higher calcination temperatures showed higher thermal stability and crystallinity. The MgO synthesized from the lower calcination temperatures (400 and 500 °C) showed superior antimicrobial activity against Escherichia coli (100% R) and Staphylococcus aureus (100% R) than that from the higher calcination temperature (600 °C). The cytotoxicity test demonstrates slight cytotoxicity in MgO-400 °C at concentrations ranging from 100 to 200 µg/mL. Interestingly, MgO-500 °C and MgO-600 °C demonstrate biocompatibility and exhibit non-cytotoxic effects, respectively, highlighting their potential for practical applications in active food packaging and biomedical fields.

Thermophilic aeration and electrochemical reactions are well-established methods for wastewater treatment to reduce metallic content, organic and inorganic matter, turbidity, coloration, and nutrient levels. In this study, thermophilic aerobic oxidation (TAO) and electrocoagulation (EC) were implemented together to improve the quality of liquid fertilizer by reducing the nutrient load and toxicity of swine manure. The influent in this study was prepared by mixing anaerobic digestate and liquid swine manure at a 1:9 ratio and treating it for 3 days at 50–60 °C in a field-scale TAO system. The TAO effluent was then processed in an EC reactor for 180 min with a 30 V electric supply through two sets of iron and aluminum hybrid electrodes. The combined TAO and EC processes led to a germination index of 133% using the final efflux. The high retention of important nutrients such as total nitrogen and potassium, combined with the 100% reduction in heavy metals, over 60% reduction in trace minerals, and 89% reduction in pollutants in the final product, helped to achieve a higher germination index. Overall, the combination of TAO and EC was demonstrated to be an effective technique for enhancing the quality of liquid fertilizer derived from swine manure.

Bio-curtain (i.e., curtain) is a permeable cover equipped with a spraying system for ammonia (NH₃) control in a swine facility. Previous studies investigated the NH₃ reduction effects primarily based on concentration units. It is challenging to determine the actual efficiency because of the large amount of air discharged through the large surface of the curtain, and external wind rapidly dilutes and disperses the exhausted air. Therefore, this study investigates a technique to evaluate the NH₃ reduction effect of the curtain in terms of emission rate. We constructed a metallic cover with a single hole around the curtain to gather the air discharged through it. The NH₃ reduction effect was calculated by comparing the NH₃ emission rate that was monitored in the barn exhaust fan and at the single hole of metallic cover during the non-spray and spray treatments inside the curtain at the maximum and minimum operating rate of the barn’s exhaust fan. NH₃ emission rates declined both non-spray and spray at the minimum operation rate of the barn exhaust fan, but the reduction effect was higher in spray conditions than non-spray. Accumulating NH₃-absorbed water inside the curtain under the low ventilation of the exhaust fan caused these circumstances.