Assessment of Al-Madra clay as an adsorbent of copper ions from aqueous solutions

Al-Madra clay, a local, cheap and readily available material in Qatar, was tested for the removal of copper ions from aqueous solutions. Batch experiments of copper ion adsorption onto natural and treated clay in different conditions were undertaken. Different types of activated Al-Madra clay were used, such as Na-clay, Al-clay, thermal-clay and cyclohexane-clay. Thermally treated clay achieved the highest removal of Cu ions, followed by Al-clay, cyclohexane-clay, and finally Na-clay. A maximum of 50% adsorption of copper ions can be achieved using the natural clay while about 72% adsorption can be achieved when the clay is thermally treated. The amount of copper adsorbed by untreated Al-Madra clay was dependent on the process conditions; increasing with an increase in pH and initial metal concentration but decreasing with an increase in sorbent concentration. The increase in temperature from 5 to 50 °C resulted in only a very slight increase in copper uptake by untreated Al-Madra clay.