Influence of pH on arsenic(III) removal by fly ash

ABSTRACT

The objective of this study was to compare arsenic(III) removal at natural pH (pH 10.5) with that at high alkaline (pH 12.2). Experiments were carried out using fly ash from burning brown coal and biomass from the power plant (Zgierz, Poland). Experimental data were well described by the Langmuir and the pseudo-second-order chemisorption models. The maximum adsorption capacity was 19.04 and 42.73 mg/g at pH 10.5 and 12.2, respectively. It can be explained by the fact that a phase CaAsO₂OH is formed at highly alkaline pH. The value of thermodynamic parameters revealed that arsenic(III) adsorption is a spontaneous and endothermic process.

KEYWORDS:

• Adsorption isotherms
• arsenic
• fly ash
• kinetics models
• thermodynamic parameters

Funding

This work was financially supported by a statutory subsidy from the Polish Ministry of Science and Higher Education for the Faculty of Chemistry of Wroclaw University of Technology.

Additional information

Funding

This work was financially supported by a statutory subsidy from the Polish Ministry of Science and Higher Education for the Faculty of Chemistry of Wroclaw University of Technology.