Copper is perhaps the most widespread heavy metal used in the industries, from food to metal-mechanic factories. Conventional techniques eliminate copper at high costs and generate side-products that need to be taken care of. This work suggests the use of a raw material such as chai teabags (CT) and alginate beads (AB) as candidates for the removal of copper from solutions. Batch experiments were carried out to maximize the adsorption of copper (II) ions. Parameters such as acidity, salinity, adsorbent dose, metal concentration, presence of crowding agents, adsorption time, presence of organic molecules and other heavy metals, and desorption were explored. Experimental data shows that the maximum adsorption is reached at pH 5 for AB and 6 for CT. The maximum adsorption of copper is achieved with 150 mg of CT and decreases with the presence of salts, crowding agents, organic molecules and other heavy metals. On the other hand, AB presents a higher adsorption under the same conditions. Isotherm modeling according to the theories of Langmuir, Freundlich, Dubinin-Radushkevich and Temkin indicates that AB is able to adsorb up to 80 mg of copper ions per gram of adsorbent, whereas CT only adsorbs 16 mg of the metal per gram. Desorption experiments propose mild acidic conditions to recover the metal and reuse the adsorbent in consecutive cycles. Finally, instrumental and classical analyses were used to determine the specific surface area, thermogravimetric stability, and morphology by using scanning electron microscopy. These studies indicate that both adsorbents are promising cost-efficient materials for the selective recovery and treatment of metal ions from wastewaters.
Buy this Article