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The heavy metal lead (Pb) holds significant importance in the manufacturing industry due to its extensive range of applications. However, its high toxicity poses a serious risk to both environment and human health. Consequently, on-site portable analysis methods have been developed to detect Pb2+, which is advantageous for obtaining timely information regarding environmental pollution. In this study, a fungal-like porous CoS (FP CoS) was discovered to selectively recognize, adsorb, and detect Pb2+. FP CoS exhibited rapid kinetics (reducing from 8.56 mg∙L–1 to 69 µg∙L–1 within 30 min) as well as exceptional adsorption capacity of 88.14 mg∙g−1 for Pb2+. Benefiting from the selective enrichment of Pb2+, the peroxidase-like activity of FP CoS nanoenzyme was further enhanced, enabling colorimetric detection of Pb2+ with a detection limit of 14 ng∙L–1, surpassing numerous reported materials. When applied to environmental samples spiked with 0–100 μg∙L–1 Pb2+, the combination of FP CoS nanosensor and a portable RGB color sensor yielded an impressive recovery percentage of 112 %. Based on these results, the FP CoS nanosensor not only provides a rapid and visually discernible colorimetric approach for trace and ultra-trace Pb2+ but also serves as a sensitive sensor for detecting Pb2+ in various scenarios. [Display omitted] • A fungal-like porous CoS (FP CoS) for the adsorption, removal and monitoring of Pb2+ was generated. • After selective enrichment of Pb2+, the peroxidase-like activity of FP CoS nanoenzyme was further enhanced. • When coupling to an integrated enrichment-detection strategy utilizing the RGB sensor, a detection limit as low as 0.014 μg L−1. • FP CoS nanosensor detect Pb2+ in river water with impressive recoveries of 112–117 %. • The current results provide a new avenue to the on-site detection of Pb2+ ions. [ABSTRACT FROM AUTHOR]

A portable Hg 2 + nanosensor was developed based on the colorimetric reaction by using the unmodified Ag nanowires (Ag NWs). Ag NWs were synthesized by a solvothermal method, with the length longer than 20 μ m and the diameter of 1 3 0 ∼ 1 5 0 nm. The colorimetric assay can be affected by pH, temperature and the amount of Ag NWs, with the optimum parameters being 5, 4 ∘ C and 100 μ L, respectively. The developed nanosensor presents excellent selectivity for Hg 2 + . The dynamic detection range is 25 ∼ 5000 ppb, and the limit of detection (LOD) for Hg 2 + is 19.9 ppb. The developed Hg 2 + sensor shows great potentials in environmental monitoring and onsite analysis of Hg 2 + . [ABSTRACT FROM AUTHOR]

A class of nitrogenous porous carbon materials (OAMPCs) has been successfully fabricated for the enrichment of ultra-trace hexachlorocyclohexane (HCH) in real water samples. The obtained optimal nitrogenous porous carbon material (OAMPC-700) has a porous curled graphene-like carbon-nanosheets morphology, large surface area (506.4 m2 g−1) and large pore volume (2.49 cm3 g−1), as well as abundant oxygen- and nitrogen-containing functional groups. Based on such unique structural characteristics, OAMPC-700 exhibits rapid uptake kinetics (99.2% HCH within just 1 min) and a superior maximum capacity (751.6 mg g−1). After six cycles of tests, OAMPC-700 still maintains a 94.27% removal percentage towards HCH, which is only 5.53% lower than that of original OAMPC-700, demonstrating the outstanding reusability. OAMPC-700 was applied to pre-enrich ultra-trace HCH from water sample with a portable enrichment equipment, demonstrating fast speed, high efficiency, and low energy consumption. Corresponding standard curves were obtained between enrichment (C en) and initial (C in) concentrations of HCH with a correlation coefficient (R2 =0.9901), significantly pushing down the detection limit of common analytical instruments. The enrichment mechanism for OAMPC-700 towards HCH mainly includes the synergism of hydrophobicity and hydrogen-bonding. This work may open a new avenue to the fabrication of unique carbon materials for the adsorption, enrichment, separation, and ultimate detection of ultra-trace organic pollutants. [Display omitted] • Nitrogenous porous carbon material (OAMPC-700) was fabricated. • Enrichment of ultra-trace organochlorine pesticides (HCH). • 99.2% HCH removed by OAMPC-700 within 1 min • Organochlorine pesticides maximum capacity is 751.6 mg g−1. • Pushing down the detection limit of analytical instruments. [ABSTRACT FROM AUTHOR]