Adsorption characteristics of Ariake clays to Chromium and the effect of pH-value

摘要

Adsorption characteristics of two Ariake clays (Clay-1 and Clay-2) to chromium were investigated by batch contact tests and advection-diffusion column tests. A strong non-linear adsorption isotherm was observed from batch contact test results. When the concentration of the solution is larger than a few ppm, the amount of adsorbed chromium almost became a constant. This non-linear adsorption characteristic has been confirmed by analyzing the advection-diffusion column test results. The analysis results also revealed that the adsorption process of Ariake clays to chromium is irreversible or only partially reversible. The pH-value of the solution has a strong effect on the adsorption capacity. Reducing pH-value increases the adsorption capacity significantly, especially for pH-value from 8 to 7. Soil-to-solution ratios of 1:4, 1:10 and 1:20 were adopted to investigate the effect of soil-to-solution ratio on the adsorption characteristics. It is tentatively concluded that for the range tested, soil-to-solution ratio does not have a significant effect on the adsorption capacity of Ariake clays.