Modification of coconut shell-based activated carbon and purification of wastewater

The purification of wastewater, including heavy metals (Cu2+, Cd2+, Pb2+, and Zn2+), was investigated using the coconut shell-based activated carbon that the different agents modified of acid, alkali, potassium permanganate, and iron salt. Several effects using the modified coconut shell-based activated carbon were observed through the experimental characterization. First, the shortened time of adsorption equilibrium to heavy metal ions, reduced addition of carbon absorbents, and improved removal purification was observed. Second, the agents of acid and potassium-modified coconut shell-based activated carbon showed improved removal rate on heavy metal wastewater containing Zn2+ with up to 95% and 96.5%, respectively. Alkali modification showed the highest removal effect on wastewater containing Cd2+ with 98%, and the iron-salt modification improved the adsorption capacity most for Pb2+ with 92%. Third, the increase of the adsorption reaction time and the amount of adsorbent showed a direct relationship to the adsorption effect. Saturated adsorption to reach an equilibrium was observed as the reaction time exceeded. Among agents, acid, alkali, and potassium specifically had a better impact on the purification than iron salt. With a 1-g dosage of adsorbent, three agents successfully removed more than 90% of the wastewater pollutants. Also, weak acidic conditions with pH = 5 showed more effect on removing heavy metal ions.

Automated summary

The study investigated the purification of wastewater containing heavy metals using coconut shell-based activated carbon modified by different agents. The modification significantly reduced adsorption equilibrium time, decreased carbon adsorbent addition, and improved removal purification. The agents of acid, alkali, and potassium showed better impact on purification than iron salt, successfully removing over 90% of pollutants with a 1-g dosage of adsorbent. Additionally, increasing adsorption reaction time and the amount of adsorbent showed a direct relationship to the adsorption effect.