Abstract:

In order to clarify the optimum conditions, removal effect and mechanism of low concentration phosphate from aqueous solution by particle anthracite activated carbon (AC). A pilot experiment was conducted to investigate the effects of adsorbent dose, temperature range, adsorption time, and pH on phosphate removal. Characterization and mechanism of phosphate adsorption on anthracite activated carbon by isothermal adsorption, fourier transform infrared spectroscopy (FTIR), X-ray energy spectrum (XRD) and Zeta potential,SEM were studied. The results show that different pH and temperature conditions in the adsorption system have different effects on the adsorption of phosphate on particle activated carbon, and the adsorption effect was the best when pH was 6.0, and it is advantageous to the adsorption of phosphate on activated carbon at high temperature. The optimum adsorption conditions for particle anthracite activated carbon to low concentration phosphate (2 mg·L^-1) were as follows:10 g·L^-1 of anthracite activated carbon, 6 h of adsorption time, 6.0 of the pH, and the removal rate of phosphate was 80%, at 25℃. The isothermal adsorption of phosphate on particle activated carbon followed Langmuir and Freundlich models, which showed that the activated carbon had both physical and chemical adsorption on phosphate. So that there was not only mutual adsorption between phosphate and surface functional groups of activated carbon, but also the removal of phosphate was related to the precipitation of metal ions on activated carbon. Therefore, this study provides a basis for the advanced treatment of low concentration phosphate wastewater with anthracite activated carbon.

Key words: phosphate, adsorption, particle anthracite activated carbon, low concentration, mechanism