Adsorption of copper ions from water by different types of natural seed materials

Different plant seeds of okra, pumpkin, grape, and squash available locally were used as adsorbents for the removal of copper ions from their aqueous solutions. Batch sorption experiments were carried out to investigate the seeds' capability to remove copper ions. Grape seeds showed higher uptake compared with other adsorbents. Experimental results for grape seeds showed that an increase in the initial pH, temperature, or initial adsorbate concentration influenced copper uptake positively. However, copper ion uptake decreased with increasing adsorbent concentration. The optimum pH range for metals removal was 3-4. Addition of sodium or potassium salts to the metal solution resulted in greater metal removal. The copper equilibrium was attained after 3 h contact time. The uptake of Cu+2 were found to be reliable on both the Freundlich and Langmuir isotherms. The results of work will urge the public to use these tested seeds in their diet for possible removal of heavy metals that contaminate either food or drinking water.