Yongliang Wang

Preparation and characterization of a novel hybrid chelating material for effective adsorption of Cu(II) and Pb(II)

The discharge of heavy metal ions such as Cu2+ and Pb2+ poses a severe threat to public health and the environment owing to their extreme toxicity and bioaccumulation through food chains. Herein, we report a novel organic-inorganic hybrid adsorbent, Al(OH)3-poly(acrylamide-dimethyldiallylammonium chloride)-graft-dithiocarbamate (APD), for rapid and effective removal of Cu2+ and Pb2+. In this adsorbent, the star-like structure of Al(OH)3-poly(acrylamide-dimethyldiallylammonium chloride) served as the support of dithiocarbamate (DTC) functional groups for easy access of heavy metal ions and assisted development of large and compact floccules. The synthesized adsorbent was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). APD was demonstrated to have rapid adsorption kinetics with an initial rate of 267.379 and 2569.373mg/(g·min) as well as superior adsorption capacities of 317.777 and 586.699mg/g for Cu2+ and Pb2+ respectively. The adsorption process was spontaneous and endothermic, involving intraparticle diffusion and chemical interaction between heavy metal ions and the functional groups of APD. To assess its versatility and wide applicability, APD was also used in turbid heavy metal wastewater, and performed well in removing suspended particles and heavy metal ions simultaneously through flocculation and chelation. The rapid, convenient and effective adsorption of Cu2+ and Pb2+ gives APD great potential for heavy metal decontamination in industrial applications.

Alkalic Leaching and Stabilization of Arsenic from Pyrite Cinders

Results & Discussion: The content of arsenic in pyrite cinders was reduced to 0.08% through the investigation of the factors, including particle size, alkaline concentration, temperature, solid-liquid ratio (S/L) and leaching time. Then, the ferric precipitation method was used to remove the arsenic in the leaching solution. More than 99% of the arsenic can be removed by controlling the pH and the ratio of ferric and arsenic (Fe/As) in ambient temperature, and the arsenic concentration in the solution was reduced to less than 0.5mg/L.

Arsenic removal from alkaline leaching solution using Fe (III) precipitation

ABSTRACT The alkaline leaching solution from arsenic-containing gold concentrate contains a large amount of arsenate ions, which should be removed because it is harmful to the production process and to the environment. In this study, conventional Fe (III) precipitation was used to remove arsenic from the leaching solution. The precipitation reaction was carried out at the normal temperature, and the effects of pH value and Fe/As ratio on the arsenic removal were investigated. The results show that the removal rate of arsenic is distinctive at different pH values, and the effect is best within the pH range of 5.25–5.96. The removal rate can be further increased by increasing the ratio of Fe/As. When the pHu2009=u20095.25–5.96 and Fe/Asu2009>u20091.8, the arsenic in the solution can be reduced to below 5u2005mg/L. However, the crystallinity of ferric arsenate is poor, and the particle size is small, most of which is about 1u2005μm. The leaching toxicity test shows the leaching toxicity of precipitates gradually decreased by the increase of Fe/As. The precipitates can be stored safely as the ratio of Fe/As exceeded 2.5.