Adsorption Isotherm of Removal of Heavy Metals in Waste Water by Orange Peels as Low-Cost Adsorbents

الملخص

The contamination of wastewater by heavy metals represents a critical threat to human health and ecological stability, prompting an urgent search for cost-effective and efficient purification methods. Despite previous advancements, there remains a significant need for research focused on the long-term durability and industrial scalability of various adsorption systems and low-cost sorbents. The objective of this research was to evaluate the efficacy of orange peels as a natural adsorbent for removing heavy metals from wastewater through a series of batch experiments. The adsorption capacity was found to be highly dependent on the contact time. All experimental trials were conducted under a controlled temperature of 30°C.To characterize the adsorption process, the experimental isotherms were modeled using the Langmuir and the Freundlich equations. Experimental data revealed that the highest removal rates were achieved by orange peels at a contact time of 24 hours. The data indicate that adsorption capacity is highly time-dependent, with optimal removal rates achieved at a 24-hour contact time. Under these conditions, orange peels exhibited the highest removal efficiencies of 99.11%–99.25% for iron, 94.17%–98.76% for copper, and 70.13%–92.30% for nickel. It is worth noting that extending the contact time to 48 hours resulted in increased performance variability and a general decrease in adsorption stability. During this extended period, the removal efficiency decreased to 77.89%–98.09% for iron, 12.98%–99.22% for copper, and 48.45%–95.83% for nickel