Recent advances in instrumental techniques for heavy metal quantification.

Heavy metals (HMs) are ubiquitous; they are found in soil, water, air, and all biological matrices. The toxicity, bioaccumulation potential, and deleterious effects of most of these metals on humans and the environment have been widely documented. Consequently, the detection and quantification of HMs in various environmental samples have become a pressing issue. The analysis of the concentrations of HMs is a vital component of environmental monitoring; hence, the selection of the most suitable analytical technique for their determination has become a topic of great interest in food, environment, and human health safety. Analytical techniques for the quantification of these metals have evolved. Presently, a broad range of HM analytical techniques are available with each having its outstanding merits as well as limitations. Most analytical scientists, therefore, adopt complementation of more than one method, with the choice influenced by the specific metal of interest, desired limits of detection and quantification, nature of the interference, level of sensitivity, and precision among others. Sequel to the above, this work comprehensively reviews the most recent advances in instrumental techniques for the determination of HMs. It gives a general overview of the concept of HMs, their sources, and why their accurate quantification is pertinent. It highlights various conventional and more advanced techniques for HM determination, and as one of its kind, it also gives special attention to the specific merits and demerits of the analytical techniques. Finally, it presents the most recent studies in this regard.

Influence of size classifications on the crystallinity index of Albizia gummifera cellulose.

The isolation of cellulose has found considerable applications recently due to its attractive characteristics. Cellulose from Albizia gummifera of different size classifications (425 µm-599 µm and 600 µm-849 µm) was investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analyses. The crystal plane of the preferred orientation was at (020) for the most prominent peaks. The two size classifications have a strong broad peak around 3320 cm-1 (425 µm-599 µm), and 3330 cm-1 (600 µm-849 µm), which corresponds to a different stretching mode of O-H. High percentages of carbon (C) and oxygen (O) were noticed among the elements observed in the two size classifications. The crystallinity index (CrI) obtained for the two sizes were 61.1% for 425-599 µm, and 55.8% for 600 µm-849 µm. The 425 µm-599 µm size classification had a greater crystallinity index than the 600 µm-849 µm size classification, which indicates a stronger capacity for reinforcing. These particles were also effective as fillers in composite materials. The results revealed that Albizia gummifera cellulose possessed promising potential for device applications and capable of being used in the preparation of composite materials.

Recent advances in nanotechnology for remediation of heavy metals.

Heavy metal contamination of the environment has become an alarming environmental issue that has constituted serious threats to humans and the ecosystem. These metals have been identified as a priority class of pollutants due to their persistency in the environment and their potential to bioaccumulate in biological systems. Consequently, the remediation of heavy metals from various environmental matrices becomes a critical topic from the biological and environmental perspectives. To this end, various research interests have shifted to the need to put forward economically feasible and highly efficient approaches for mitigating these contaminants in the environment. Thus, numerous conventional approaches have reportedly been employed for the remediation of heavy metals, with each of the methods having its inherent limitations. More recently, studies have revealed that nanomaterials in their various forms show unique potential for the removal of various contaminants including heavy metals in comparison to their bulk counterparts making them a topic of importance to researchers in various fields. Also, various studies have documented specifically tailored nanomaterials that have been synthesized for the removal of heavy metals from various environmental matrices. This review provides up-to-date information on the application of nanotechnology for the remediation of heavy metals. It highlights various nanomaterials that have been employed for the remediation of heavy metals, current details on their methods of synthesis, factors affecting their adsorption processes, and the environmental and health impact of nanomaterials. Finally, it provides the challenges and future trends of nanomaterials for heavy metal removal.