It is noteworthy to highlight that ammonia nitrogen contamination in wastewater has been reported to pose a great threat to the environment. This conventional method of remediating ammonia nitrogen contamination in wastewater applies the packed bed tower technology. Nevertheless, this technology appears to pose several application issues. Over the years, researchers have tested various types of ammonia stripping process to overcome the shortcomings of the conventional ammonia stripping technology. Along this line, the present study highlights the recent development of ammonia stripping process for industrial wastewater treatment. In addition, this study reviews ammonia stripping application for varied types of industrial wastewater and several significant operating parameters. Furthermore, this paper discusses some issues related to the conventional ammonia stripper for industrial treatment application. Finally, this study explicates the future prospects of the ammonia stripping method. This review, hence, contributes by enhancing the ammonia stripping treatment efficiency and its application for industrial wastewater treatment.

An accumulating body of evidence reports the synthesis and biomedical applications of silver nanoparticles. However, the studies regarding the use of maleic acid and citric acid in the synthesis of nano-sized silver particles (AgNPs) and micro-sized silver particles (AgMPs) as well as their antibacterial, antifungal, and anticancer activities have not been reported. In the current study, we synthesized AgNPs and AgMPs using maleic acid and citric acid as capping agents and have characterized them by UV-Vis, energy-dispersive X-Ray spectroscopy (EDS), X-Ray diffraction (XRD), and scanning electron microscope (SEM) analysis. The capped silver particles were examined for their antimicrobial activity and cytotoxicity against bacteria, fungi, and brine shrimp. Additionally, the anticancer activity of these particles was tested against human breast and liver cancer cell lines. The free radical scavenging activity of capped silver particles was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. SEM analysis revealed a round plate-like morphology of maleic acid capped particles with an average size of 39 ± 4 nm, whereas citric acid capped particles display flower-shaped morphology with rough surfaces and an average size of 250 ± 5 nm. The uncapped AgMPs were hexagonal with 500 ± 4 nm size. EDS and XRD analysis confirmed the presence of Ag and face-centered cubic crystalline nature, respectively. Functionally, capped silver particles exhibited antibacterial activity against Gram-positive (Staphylococcus aureus, Bacillus subtilis, and Micrococcus luteus) and Gram-negative bacteria (Salmonella setubal, Enterobacter aerogenes, and Agrobacterium tumefaciens). The bactericidal activity was more active against Gram-negative bacteria with minimum inhibitory concentration (MIC) as low as 5 ppm as compared to 25 ppm for Gram-positive. Similarly, the silver particles demonstrated antifungal activity by inhibiting the growth of five fungal strains (Mucor species, Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, and Fusarium solani) up to 50% at the concentration of 500 ppm. Additionally, these particles showed substantial toxicity against brine shrimp and also significantly inhibited the proliferation of breast cancer (MCF7) and liver cancer (HePG2) cell lines (IC₅₀ 8.9–18.56 µM). Uncapped AgMPs were less effective, inhibiting only the proliferation of MCF7 cells with IC₅₀ 46.54 µM. Besides cytotoxicity, these particles acted as potential antioxidants, showing free radical scavenging up to 74.4% in a concentration-dependent manner. Taken together, our results showed that the modifiers affect the shape and size of silver particles and may, in part, contribute to the antimicrobial and antioxidant activity of silver particles. However, the contribution of maleic acid and citric acid in enhancing the antimicrobial, anticancer, and antioxidant potential independent of silver nano and microparticles needs to be studied further. In vivo experiments may determine the therapeutic effectiveness of silver particles capped with these modifiers.

Laser joining of dissimilar materials has been the subject of intensive studies in the past decade or thereabout. This is mainly due to the several benefits it offers when used to manufacture various electromechanical components for automotive, aerospace, electronics, and biomedical applications. There are many possible variations of joining dissimilar materials; this article, however, considers the main engineering materials in use today, namely, metal, polymer, ceramic, glass, and silicon. The strength of the joints determined by, inter alia, the material combinations, joining technique, and material treatment is crucial for the above mentioned applications if safety and reliability requirements are to be adhered to. Undoubtedly, the challenges posed by such complex selection of materials and process factors are unquantifiable and as such have been given a critical review in this article. The relationship between some important laser processing parameters and joint strength are also discussed. Furthermore, it has been observed that the joint strength can also be influenced by factors such as bubbles morphology, material preparation/treatment, depth of molten pool and formation of chemical bonds, and intermetallic phases and their effects are also reviewed and discussed. This article is concluded with an outlook providing the summary and key findings of the authors.