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Photoreduction of chromium hexavalent ions (Cr6+) from the aquatic environment is urgently needed due to its impairing effect on human health. Adsorption, photoreduction, and desorption of reduced trivalent chromium (Cr3+) at the photocatalyst surface are all significant factors for determining photocatalytic reduction efficiency. Herein, we report a facile, template-free hydrothermal approach to fabricate green and homogeneous mixed-phase (1 T/2H) molybdenum disulfide (MoS2) nanosheets for highly efficient removal of Cr6+ ions and pharmaceuticals from wastewater. The nanostructure and morphology of the obtained (1 T/2H) MoS2 are investigated; the calculated crystallite size of the (2H/1 T) MoS2 nanosheets is found to be 1.7 nm. The presence of surface functional groups adsorption, and photoreduction processes is confirmed by spectroscopic studies using Fourier transform infrared (FTIR) spectra. Additionally, Raman spectra confirmed the formation of 1 T/2H mixed-phase MoS2 which illustrates its crystal phases, structure, and chemical composition. Moreover, the point-of-zero charge analysis revealed the positively charged surface in the acid system. The obtained results revealed the non-toxicity of MoS2 nanosheets at doses lower than 1000 ppm. The results reveal that the (1 T/2H) MoS2 exhibited impressive reduction performance for Cr6+; the reduction efficiency of chromium Cr6+ is 100% under simulated sunlight, 90 min at pH (3). Further spectroscopic study results confirm the importance of the adsorption step in Cr6+ ions photoreduction. Different pharmaceuticals are also completely degraded over (1 T/2H) MoS2 nanosheets. Interestingly, complete removals of E. coli O157:H7, Listeria monocytogenes, and Candida albicans were observed at a dose of MoS2 nanosheets of 250 ppm after a contact time of 30, 30, and 45 min, respectively. The results of the current work could lead to a rational design of high-performance nanosheets for the efficient decontamination of heavy metals, pharmaceuticals, and pathogens from aquatic environments. [ABSTRACT FROM AUTHOR]

The development of robust bioanalytical devices and biosensors for infectious pathogens is progressing well with the advent of new materials, concepts, and technology. The progress is also stepping towards developing high throughput screening technologies that can quickly identify, differentiate, and determine the concentration of harmful pathogens, facilitating the decision-making process for their elimination and therapeutic interventions in large-scale operations. Recently, much effort has been focused on upgrading these analytical devices to an intelligent technological platform by integrating them with modern communication systems, such as the internet of things (IoT) and machine learning (ML), to expand their application horizon. This review outlines the recent development and applications of bioanalytical devices and biosensors to detect pathogenic microbes in environmental samples. First, the nature of the recent outbreaks of pathogenic microbes such as foodborne, waterborne, and airborne pathogens and microbial toxins are discussed to understand the severity of the problems. Next, the discussion focuses on the detection systems chronologically, starting with the conventional methods, advanced techniques, and emerging technologies, such as biosensors and other portable devices and detection platforms for pathogens. Finally, the progress on multiplex assays, wearable devices, and integration of smartphone technologies to facilitate pathogen detection systems for wider applications are highlighted. [ABSTRACT FROM AUTHOR]