Adsorption and Its Mechanism of Arsenate in Aqueous Solutions by Red Soil

The removal, and its mechanism, of arsenate from aqueous solutions was investigated using Yunnan red soil. A series of adsorption experiments was designed to disclose the effect of key factors (soil types, soil/solution rates, initial arsenate concentrations, and shaking speeds) on the adsorption ca...

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Bibliographic Details
Published inWater (Basel) Vol. 14; no. 4; p. 579
Main Authors Guo, Min, Shi, Lili, Gu, Wen, Wu, Wenzhu
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.02.2022
Subjects
Adsorption
Aluminum
Aqueous solutions
Arsenates
Arsenic
Arsenic compounds
Arsenic removal
Arsenides
As(V)
China
Drinking water
Hydrochloric acid
Infrared spectroscopy
Lakes
mechanism
Orthogonal arrays
Pollution
Potassium
Precipitates
Reagents
Scanning electron microscopy
Shaking
soil
Soil investigations
Soil types
Surface chemistry
Surface water
Water pollution
Water treatment
China
United States > US
Yunnan China
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Summary:The removal, and its mechanism, of arsenate from aqueous solutions was investigated using Yunnan red soil. A series of adsorption experiments was designed to disclose the effect of key factors (soil types, soil/solution rates, initial arsenate concentrations, and shaking speeds) on the adsorption capacity of Yunnan red soil for arsenate. The soil/solution ratio was optimized as 0.05 g/100 mL to balance the adsorption capacity and removal efficiency. The optimal shaking speed (225 rpm) not only ensured enough contact frequency between the Yunnan red soil and the arsenate, but also reduced the mass transfer resistance. The results from applying an orthogonal array method showed that the most significant factor affecting arsenate removal efficiency was soil type, followed by the soil/solution ratio, contact time, and shaking speed. The IR spectra of the precipitates further confirmed that the metal arsenide was settled by the Yunnan red soil, indicating that the arsenate ion existed on the red soil surface in the form of protonated bidentate surface complexation of –FeO2As(O)(OH)− and FeO2As(O)2−. These results indicate that Yunnan red soil is promising for the removal of arsenate from aqueous solutions; it may thus be suitable as a new adsorbent for arsenate removal during water treatment.
ISSN:2073-4441
2073-4441
DOI:10.3390/w14040579