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The existence of organic pollutants in our environment is a growing concern. Many processes (e.g., textiles, painting, and printing) release waste effluents with organic pollutants (e.g., synthetic dyes) that harm aquatic systems. However, detecting and removing them efficiently and effectively is challenging. This study addressed this by developing a dual-functional plasmonic membrane using biowaste-derived nanocellulose for both detection and removal. The plasmonic nanomaterial was integrated with surface-enhanced Raman spectroscopy (SERS) to identify and quantify three organic pollutants (basic red 9, BR9; malachite green, MG; and methylene blue, MB). The nanocellulose removed these pollutants through electrostatic attraction. The organic pollutants were detected down to 0.05 mg/L, 0.25 mg/L, and 0.05 mg/L for BR9, MG, and MB, respectively; these concentrations are well below those considered to be environmentally hazardous. SERS analysis was performed in spiked streamwater samples to demonstrate detection in an environmentally relevant matrix. The nanomaterial was also used to remove the pollutants from aqueous matrices; removal efficiencies were 99.54 ± 0.16% for BR9, 99.50 ± 0.25% for MG, and 99.84 ± 0.10% for MB. For pollutant-spiked stream samples, removal efficiencies were 98.76 ± 1.26% for BR9, 97.50 ± 2.29% for MG, and 98.33 ± 1.59% for MB. This study demonstrates the high potential of this nanomaterial for the simultaneous detection and removal of organic contaminants, which provides the first example of using biowaste-derived functional nanomaterial for water testing and remediation concurrently. 

The increased demand for agricultural productivity to support the growing population has resulted in the expanded use of pesticides. However, modern pesticide applications contaminate air, water, soil, and unintentional target species. It is necessary to develop effective and sustainable methods to detect different pesticides within our environment. Surface-enhanced Raman spectroscopy (SERS) has garnered significant attention for its ability to detect and quantify environmental contaminants, as it is a rapid and sensitive technique that requires minimal sample preparation. The present study demonstrates the development of a biowaste-derived nanocellulose-based thin-film that, when integrated with gold nanoparticles, produces a sustainable and reproducible SERS nanosubstrate. In this study, three pesticides (carbaryl, ferbam, and thiabendazole) were sensitively and selectively detected by the combined use of this novel nanocellulose-based SERS nanosubstrate and a portable Raman instrument. The limits of detection were determined to be 1.34, 1.01, and 1.41 mg/L for carbaryl, ferbam, and thiabendazole, respectively, all of which are well below the agricultural application concentrations recommended. SERS signals were collected for both prepared ferbam spray solution and collected sprayed droplets, and it was found that there is no major difference in the signals, indicating that this detection method is reliable to detect pesticide droplets. A commercial pesticide was detectable by the biowaste-derived SERS nanosubstrate. This study is among the first to utilize biowaste-derived nanocellulose to create SERS nanosubstrate for pesticide detection in spray droplets. We demonstrate the high potential of biowaste-derived nanocellulose in combination with the portable Raman technique for agricultural pesticide spray detection.