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This study aimed to use a simple, low-cost and eco-friendly microwave-assisted method for the synthesis of carbon dots-based fluorescent sensor that can detect more one target analyte in aqueous media. Herein, we report the synthesis of carbon dots (CDs) from peels of an indigenous and abundant wild fruit called wild medlar (Vangueria infausta). Functional groups such as hydroxyl (–OH) and carbonyl (C=O) were revealed on the surface of the as-prepared carbon dots using Fourier transform infrared spectroscopy (FTIR). The as-prepared CDs exhibited an amorphous structure and a broad distribution of particle size with an average size of 10 nm. In addition, the as-prepared CDs demonstrated excellent hydrophilicity and intense blue photoluminescence under UV light at 365 nm. The water-soluble CDs were employed for the detection of Al${}^{3+}$ using a ‘turn on’ mechanism and Hg${}^{2+}$ using a ‘turn off’ mechanism. Addition of increasing concentration of Al${}^{3+}$ resulted in an increase in the fluorescence intensity of the as-prepared CDs while addition of increasing concentration of Hg${}^{2+}$ resulted in quenching of the fluorescence intensity of CDs. The lowest limit of detection (LOD) for Al${}^{3+}$ and Hg${}^{2+}$ ions in aqueous media was determined at 817 nM and 612 nM, respectively. Furthermore, the as-prepared CDs have excellent selectivity towards Al${}^{3+}$ and Hg${}^{2+}$ among other potential metal ion interferences. Practical application of the as-prepared CDs towards detection of Al${}^{3+}$ and Hg${}^{2+}$ in tap water revealed good recovery rates of 86.0% to 87.4% and 96.4% to 106.5%, respectively. Therefore, this work has demonstrated a potent strategy for potential application of this nanoprobe towards dual detection of Al${}^{3+}$ and Hg${}^{2+}$ in aqueous samples.

Green chemistry has emerged as a powerful tool to rationally design environmentally sustainable chemical processes by choosing safe chemicals and minimizing the production of waste. This article focuses on the opportunity, yet underexplored, to evaluate the green syntheses of phthalocyanines by means of metrics such as the E-factor and EcoScale, in a view to better assess their sustainability and provide insights on their viability with respect to standard procedures.

The quest for the design and synthesis of carbon dots with anti-counterfeit properties that are derived via green, environmentally friendly and economical procedures is a continuous process. Carbon dots (C-dots) derived from biowaste are cheap to synthesize, possess good photo-stability and high synthetic yield, making them applicable in the anti-counterfeiting of currency. Herein, we report a novel eco-friendly, cheaper, and faster method for the synthesis of carbon dots with strong photoluminescence properties from monkey orange fruit (Strychnos spinosa) biowaste. The presence of the hydroxyl and carbonyl functional groups of the carbon dots were determined by the Fourier transform infrared spectroscopy (FTIR). The carbon dots showed strong blue emission fluorescence (emission wavelength of 452nm) when excited at 330nm. The morphology and size were determined by the atomic force microscopy (AFM) which indicated amorphous and spherical nanoparticles with an average size of less than 2nm. The no-crystallinity of the as-prepared carbon dots was confirmed using X-ray diffraction which showed the graphite-like structure. The carbon dots were produced and demonstrated good photo and chemical stability as well as high covert properties. The anti-counterfeiting of currency application by the synthesized carbon dots was demonstrated when the subsequent gel ink printed on the currency showed excellent chemical stability when exposed to washing with water, ethanol, and acetone. It also showed superior photostability when exposed to UV light at 365nm and daylight for an extended period of up to 6h. This work provides a facile, economical, and green approach for large scale production of carbon dots from the abundant biowaste.

Selenium nanoparticles have drawn interest recently, due to their distinctive physicochemical characteristics and potential usage in numerous applications, including medicine, electronics and catalysis. In this study, we employed Biancaea sappan (BS), often known as sappan wood or Brazilwood, which is a flowering tree that is endemic to Southeast Asia. Due to its antioxidant, anti-inflammatory and anticancer properties, this tree’s heartwood is frequently used in traditional medicine. Additionally, the wood is used to make natural dyes. In this study, we aim to develop an ecofriendly selenium nanoparticle using BS$,$ as a natural reducing agent and curcumin as a capping agent. The nanoparticles were synthesized using the green synthesis method and characterized using various techniques. Biocompatibility was evaluated using hemolytic assay and the bioactivity of the nanoparticles was assessed using anti-inflammatory and antioxidant assays. Selenium nanoparticles (BCSeN) were successfully synthesized using BS bark extract and functionalized with curcumin. The nanoparticles were characterized by UV-Vis Spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy and Energy-dispersive X-ray spectroscopy (EDX) analysis, confirming their morphology, crystallinity, functionalization, elemental composition, size and stability. In vitro, bioactivity studies revealed that the BCSeN exhibited significant anti-inflammatory activity. They also demonstrated notable antioxidant efficacy against DPPH (2,2-diphenyl-1-picrylhydrazyl) and were also found to have minimal hemolytic potential. Our findings highlight the potential of BCSeN as a promising candidate for anti-inflammatory and antioxidant applications. However, further in-depth analysis is required to fully understand their efficacy and toxicity.

The synthetic scalability of water harvesting metal–organic frameworks (MOFs) is crucial for making these promising materials accessible and widely available for use in household devices. Herein, we present a facile, sustainable, and high-yield synthesis method to produce a series of water-harvesting MOFs, including MOF-303, CAU-23, MIL-160, MOF-313, CAU-10, and Al-fumarate. Using readily available reactants and water as the only solvent, we were able to synthesize these materials at the kilogram scale in a 200 L batch reactor with yields of 84–96% and space-time yields of 238–305 kg/day/m³ under optimized reaction conditions. We also show that our procedure preserves framework crystallinity, porosity, and water-harvesting performance of the MOFs synthesized at scale.