Xuefen Xia

Bio: Xuefen Xia is an academic researcher from Tongji University. The author has contributed to research in topics: Energy-dispersive X-ray spectroscopy & Aqueous solution. The author has an hindex of 3, co-authored 3 publications receiving 310 citations.

Genesis of Pure Se(0) Nano- and Micro- structures in Wastewater

Abstract: Advanced materials are essential to the quality of modern day life, but the synthesis of these compounds is often inefficient in terms of energy, time and resources; especially when considering the hydrothermal batch methods used to prepare many such compounds – often requiring week-long reaction times with variable yields and product quality. In contrast, Continuous flow synthesis (CFS) provides a more readily scalable means for the efficient, effective and reproducible synthesis of inorganic compounds. This publication demonstrates the novel CFS of several metal ammonium phosphates and compare the effect of synthesis route on particle size, size distribution, and crystallinity.

Genesis of pure Se(0) nano- and micro-structures in wastewater with nanoscale zero-valent iron (nZVI)

Abstract: Formation of pure elemental selenium has important implications in the separation, purification and recovery of selenium, a trace but vital and increasingly important industrial material. nZVI can quickly reduce both Se(VI) and Se(IV) to Se(0). Herein, we report highly efficient and rapid separation of selenium from wastewater and the discovery of distinctive nano- and micro-scale structures of pure selenium via the reduction of Se(IV) to Se(0) with nanoscale zero-valent iron (nZVI). Specifically, spherical and needle shaped Se(0) nanoparticles were observed under ambient conditions. Aqueous Se(IV) is first adsorbed to the nZVI surface, diffuses across the oxide layer and subsequently reduced to Se(0). The formed Se(0) particles were characterized using spherical aberration corrected scanning transmission electron microscopy (Cs-STEM) combined with energy dispersive spectroscopy (EDS), electron energy loss spectroscopy (EELS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). XRD revealed that the Se(0) nanoparticles were pure hexagonal phase selenium crystals. EELS analysis provided additional and independent evidence on the Se(IV) reduction to Se(0). Selenium has long been discharged to the environment due to low efficiency of conventional technologies, and the discovery of pure Se(0) solids by nZVI reduction offers an innovative route for recovery of this valuable resource from wastewater.

Wearable potentiometric ion sensors

Abstract: Wearable potentiometric ion sensors (WPISs) have become an exciting analytical platform that combines chemical, material and electronic efforts to supply physiological information during certain human activities. The real possibility of wearing an analytical device with diverse configurations—sweatband, patches, garments—without disturbing the welfare of the carrier has enabled potentiometric ion sensors both as health quality and sport performance controllers. Recent studies show a large involvement of WPISs in the following of critical biomarkers (timely or continuously), such as sodium, potassium, calcium, magnesium, ammonium and chloride, which are present at relatively high concentrations in sweat (∼mM levels). Certainly, the non-invasive nature of WPISs and other significant features, e.g., simplicity and cost-effectiveness, have broadened new horizons in relation to applied analytical chemistry. This has been pointed out in the literature over the last decade with the predominance of two analytical outcomes: (i) the improvement of sport performance as a result of continuous detection of ions in sweat (health status of the individual) while decreasing physiological complications (injuries, muscle cramps, fatigue and dehydration) during practice; and (ii) advancements in clinical diagnostics and preventive medicine as a consequence of the monitoring of the health status of patients suffering from any kind of disorder. Beyond the undeniable importance of the integration of WPISs to satisfy current societal needs, the following crucial questions about misleading and missing analytical features need to be answered: To what extent is WPIS technology a reliable analytical tool for the quantification of ions? Is cross-validation the current bottleneck toward further progress? Which are the fundamental steps involving the ion-selective electrode side that would benefit WPIS outcomes? Why is sweat the main (and almost the only) biological fluid to be monitored by WPISs? What is the best sampling strategy to be incorporated into WPIS devices for on-body monitoring of sweat? Which precision limits should be considered to assure a reliable decision-making process? Accordingly, this review focuses on the progression of WPISs from an analytical perspective—merely our vision of the field—within the period between 2010 and 2018. An updated search using specific keywords (wearable, ion, potentiometry, sensor) provided 43 contributions, which are herein highlighted, with a sustainable acceleration over the last three years. Thus, this review describes the current state of WPIS technology, the construction of wearable all-solid-state potentiometric sensors, critical requirements of potentiometric sensors to be fulfilled in a wearable configuration and key features regarding the ideal implementation of WPISs as reliable messengers of physiological information in real scenarios.