Leaching Performance of Nanotechnology-Induced High-Arsenic-Bearing Tooeleite-like Mineral Nanowaste

Abstract

For arsenic decontamination from groundwater, arsenic crystallization is becoming adopted due to its sustainability and economic benefits. However, arsenic crystallization technology is a two-step process, which makes it complex and generates hazardous waste. Successful efforts toward making it a single-step process are presented here. The addition of nanorods and ball-milled zinc sulfide nanoparticles to arsenic-contaminated water result in highly monodispersed and high-arsenic-containing mineralized nanowaste with a crystalline structure similar to the mineral Tooeleite ((Fe3+6(As3+O3)4SO4(OH)4·4H2O)). This study reports the results of a short-term stability test based on a toxicity characteristic leaching procedure and a long-term stability test of the mineralized synthetic nanowaste produced from water treatment. The Tooeleite-like mineralized nanowaste passed short-term stability tests. Arsenic in the leachate were found to be 1.1 ± 0.2 mg L−1 and 4.8 ± 0.3 mg L−1 from waste generated by the nanorod and ball-milled nanoparticles, respectively. The crystallinity was well preserved, as observed from the post-stability-test diffraction patterns, consequently proving that the waste product can be non-hazardous and therefore would not require any secondary treatment before final disposal.