Nanostructured Zinc Oxide for Water Treatment

Abstract

Environmental pollution and industrialization on a global scale have drawn attention to the vital need for developing new hygienically friendly purification technologies. Existing wastewater treatment technologies demand high capital investment and operation & maintenance cost, and large area. Cost-effective treatment of pollutants requires the transformation of hazardous substances into benign forms and the subsequent development of effective risk management strategies from harmful effects of pollutants that are highly toxic, persistent, and difficult to treat. Application of nanotechnology that results in improved water treatment options might include removal of the finest contaminants from water (< 300 nm) and "smart materials" or "reactive surface coatings" with engineered specificity to a certain pollutant that destroy, transform or immobilize toxic compounds. Nanomaterials have been gaining increasing interest in the area of environmental remediation mainly due to their enhanced surface and also other specific changes in their physical, chemical and biological properties that develop due to size effects. Heterogeneous photocatalytic systems via metal oxide semiconductors like TiO 2 and ZnO, are capable of operating effectively and efficiently for waste water treatment which has been discussed along with other nanotechnology routes that can be useful for water treatments. Multifunctional photocatalytic membranes using ZnO nanostructures are considered advantageous over freely suspended nanoparticles due to the ease of its removal from the purified water. A short discussion on the study of charge transfer mechanisms during photocatalytic reactions has also been included.

Panorama de la investigación y desarrollo de las nanotecnologías para el tratamiento de agua en México

“…Para la filtración, las nanotecnologías tienen el potencial de desarrollar dispositivos capaces de detectar y de controlar la contaminación del agua, acelerando el trán-sito para su remediación o purificación (Qu et al, 2016;El-Safty et al, 2016;Pendergast et al, 2016;Pronovost, 2016). Para la desalinización, los nanoprocesos prometen disminuir los costos, por ejemplo, mediante el uso de membranas con nanopartículas de plata y de zinc (Baruah et al, 2016;Seul-Yi y Park, 2016). descentralizados, politécnicos y escuelas normales.…”

Synthesis and optical properties of ZnO and ZnO/PEO nanonsructured powders

“…Ovim procesima se formiraju kvazi stabilna energetska stanja u okviru energetskog procepa koja olakšavaju formiranje parova elektron-šupljina pri interakciji sa fotonima čije su energije manje od energije energetskog procepa [13]. S obzirom da optička svojstva materijala zavise od faznog sastava, homogenosti materijala, veličine čestica, morfologije, kao i kristaliničnosti, metode procesiranja prahova kao što su precipitacija [14], sol-gel postupak [15], sprej piroliza [16], hidrotermalni/solvotermalni postupak [17], ili mehanohemijsko procesiranje [18] se uspešno koriste za sintezu prahova ZnO sa kontrolisanim osobinama.…”

Removal of metals using a ZnO/Au composite under visible-light illumination

“…Nanoscaled semiconductor photocatalysts, e.g. ZnO, have recently been suggested to improve photocatalytic efficiencies, since nanoparticles are characterized by enormous surface-to-volume ratio, thus allowing higher adsorption of the target molecules [1]. This means that interactions of the nanoparticles and surrounding media affect essentially the emission spectrum.…”