Recent Advancements in Fluorometric and Colorimetric Detection of Cd2+ Using Organic Chemosensors: A Review (2019-2024).

In recent decades, heavy metal ions have emerged as a significant global environmental concern, posing threats to the delicate balance of ecosystems worldwide. Their introduction into ecosystems occurs through various activities and poses a serious risk to human health. Among heavy metal ions, Cd2+ is recognized as a highly toxic pollutant. Its widespread use contributes to its accumulation in the environment. Chronic exposure to Cd2+ ions present serious risks to both the environment and human health. Therefore, the detection of these metal ions are very important. Organic fluorometric and colorimetric detection have emerged as promising tools for this purpose, offering advantages such as high sensitivity, selectivity, and sometimes reversibility. This review offers a comprehensive overview of the recent advancements in the fluorometric and colorimetric detection of Cd2+ using organic chemosensors from 2019 to 2024. We delve into key aspects of these studies, including the design strategies employed to design novel chemosensors and the underlying sensing mechanisms. Furthermore, we explore the diverse applications of these organic chemosensors, ranging from environmental monitoring to biomedical diagnostics. By analyzing the latest research findings, this review aims to offer insights into the current state-of-the-art in the field of Cd2+ detection using organic chemosensors. Additionally, it highlights the potential opportunities and challenges that lie ahead, paving the way for future advancements in this important area of research.

Nano round polycrystalline adsorbent of chicken bones origin for Congo red dye adsorption.

Nano round polycrystalline adsorbent (NRPA) of chicken bones origin was utilize as effective adsorbent in Congo red dye removal via aqueous media. The NRPA adsorbent was prepared via thermal decomposition and its structure was investigated with the aids of Transmission Electron Microscopy, Fourier Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy, Energy Dispersive X-ray Analysis (EDX), and X-ray Diffractometer (XRD). A monophasic apatite phase was confirmed from XRD investigation, while functional groups analysis showed that NRPA possessed CO32-, PO43- and OH- absorption bands. The maximum adsorption capacities derived from Langmuir isotherm is 98.216 mg g-1. From the combined values of n from Freundlich and separation factor (RL) of Langmuir models, the adsorption of CR by NRPA is favourable. Thermodynamic values of 5.280 kJ mol-1 and 16.403 kJ mol-1 K-1 were found for ΔH° and ΔS° respectively. The entire values of ΔG° which ranges from - 35.248 to - 459.68 kJ mol-1 were all negative at different temperatures. Thus, nano polycrystalline adsorbent of chicken bone origin can serve as excellent adsorbent in Congo red dye removal from waste water.

Medicinal and chemosensing applications of chitosan based material: A review.

Chitosan (CTS), has emerged as a highly intriguing biopolymer with widespread applications, drawing significant attention in various fields ranging from medicinal to chemosensing. Key characteristics of chitosan include solubility, biocompatibility, biodegradability and reactivity, making it versatile in numerous sectors. Several derivatives have been documented for their diverse therapeutic properties, such as antibacterial, antifungal, anti-diabetic, anti-inflammatory, anticancer and antioxidant activities. Furthermore, these compounds serve as highly sensitive and selective chemosensor for the detection of various analytes such as heavy metal ions, anions and various other species in agricultural, environmental and biological matrixes. CTS derivatives interacting with these species and give analytical signals. In this review, we embark on an exploration of the latest advancements in CTS-based materials, emphasizing their noteworthy contributions to medicinal chemistry spanning the years from 2021 to 2023. The intrinsic biological and physiological properties of CTS make it an ideal platform for designing materials that interact seamlessly with biological systems. The review also explores the utilization of chitosan-based materials for the development of colorimetric and fluorimetric chemosensors capable of detecting metal ions, anions and various other species, contributing to advancements in environmental monitoring, healthcare diagnostics, and industrial processes.

Development of Plumeria alba extract supplemented biodegradable films containing chitosan and cellulose derived from bagasse and corn cob waste for antimicrobial food packaging.

With the increase in global plastic pollution due to conventional plastic packaging (petroleum-derived), bioplastics have emerged as an alternative green source for practising a circular economy. This research aimed to extract cellulose from bagasse and corn cob waste and utilized in mixed form to prepare bioplastic film. The mixed cellulose was further reinforced with natural substances such as chitosan, bentonite, and P. alba extract. These newly developed bioplastics films were characterized by various physical tests like film thickness, moisture content, water solubility and spectroscopic techniques such as Fourier transform infrared (FTIR), scanning electron microscopy-energy dispersive spectroscopic (SEM-EDX), thermal gravimetric analysis (TGA), and ultraviolet-visible (UV-Vis) spectroscopy for opacity testing. The results revealed the enhanced bioplastic thermal and mechanical characteristics through robust interactions between cellulose and bentonite molecules. Moreover, incorporating chitosan solution as reinforcements in bio-composite films resulted in improved water barrier properties. The results indicated lower absorption in the UV range of 250-400 nm, attributed to the absence of UV-absorbing groups. Finally, their biodegradability was tested in soil, and 85.3 % weight loss of bioplastic films was observed after 50 days of the experiment which is the main task of this research. The antimicrobial properties of bioplastic films have been evaluated, and showed an inhibition zone of 16 mm against E. coli. After 12 days of incubation of sherbet berries, complete spoilage is identified in the control group compared to those covered with the bioplastic film. This outcome is attributed to the antioxidant and antimicrobial activities provided by chitosan and P. alba extract in the bioplastic film. The comprehensive outcomes of this study suggest the potential future adoption of these entirely bio-derived, environmentally sustainable and biodegradable bioplastic films as a viable substitute for the plastic packaging currently present in the market.

Nanocellulose/wood ash-reinforced starch-chitosan hydrogel composites for soil conditioning and their impact on pea plant growth.

Hydrogels are 3-dimensional polymer networks capable of absorbing a large amount of water. Natural polymeric hydrogels are biodegradable, non-toxic and biocompatible. They can effectively retain nutrients for the plant and can be used as soil conditioners. This study uses a chemical cross-linking technique to synthesize starch and chitosan-based hydrogel using citric acid as a cross-linker. Additionally, hydrogel composites were developed by incorporating wood ash, nano-cellulose, and NPK (nitrogen-phosphorus-potassium) fertilizer as fillers to enhance their properties. The formulated hydrogel/hydrogel composite samples were characterized by FTIR spectroscopy, SEM analysis, X-ray diffraction and thermo-gravimetric analysis. The experiment results showed the chemical cross-linking among the polymeric chain and the semi-crystalline nature of the hydrogel/hydrogel composite samples. The swelling capacity of the hydrogel/hydrogel composite samples was 200-420% (in distilled water) and 104-220% (in saline medium) and demonstrated biodegradability within 110 days. The NPK reinforced hydrogel composite showed an excellent effect on the growth of pea plants (leaves count = 37, stem height = 20.2 cm), and could be effectively used as soil conditioners for agricultural applications. Considering the ability of hydrogel composites to reduce irrigation needs, enhance nutrient retention, and improve crop production, these novel hydrogel composites present an economically viable solution for sustainable agricultural practices.