Arsenic (As) contamination is of serious concern to the human health due to its toxicity and carcinogenicity. Long-term exposure to As contaminated water causes cancers in skin and lung,; as well pigmentation changes, hyperkeratosis, and neurological disorders. It could also induce cardiovascular and cerebrovascular diseases. To minimize these risks, the World Health Organization suggested a low guideline limit of 0.01 mg/L standard in drinking water. Implementing this strict guideline limit requires to develop simple and cost effective approaches for As-removal. Adsorption is the most promising technology at low concentration due to its simplicity, cost-effectiveness, potential for regeneration, and sludge free operation. In the natural water, As occurs in two predominant species, arsenate (As(V)) and arsenite (As(III)). The As(III), existing as nonionic H3AsO3at various pH values is reported to have a lower affinity to various adsorbents compared to As(V). To enhance As removal, a pretreatment (oxidation and pH justifiction) is needed before the coprecipitation/adsorption. This requires a post-adjustment of pH, which causes operation cost increase and secondary pollution. Thus, to develop adsorbents with enhanced adsorption effect on both As (III) and As (V) without pre-treatment becomes desirable.The development of a series of highly efficient As adsorbents composed of nano-sized metal oxides will be presented in this talk. A single step adsorption treatment could be available to remove As from water without the pre-/post-treatment for industrialization. To address the issue of the difficult separation of nanoadsorbents from treated water bodies, superparamagnetic magnesium ferrite nanoadsorbents were developed to achieve high dispersion and high contact efficiency when there was no external magnetic field applied. It is feasible for magnetic separation from treated water bodies when the external magnetic field was applied after the water treatment. Additionally, highly porous, nanostructured zirconium oxide spheres and its adsportive performance will be presented.

Highly efficient nano-adsorbents for the removal of arsenic (III, V) from water

247th National Meeting (2014)

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